Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Bibliometric Analysis of the Structure and Evolution of Research on Assisted Migration

Bibliometric Analysis of the Structure and Evolution of Research on Assisted Migration Purpose of Review Assisted migration is increasingly proposed as a proactive management strategy to mitigate the con- sequences of maladaptation predicted under climate change. Exploring the social and academic structure of the field, its research gaps, and future research directions can help further the understanding and facilitate the implementation of assisted migration strategies. Here we used bibliometric analysis to examine the intellectual, social, and conceptual structures of assisted migration research to identify gaps and opportunities for future research. Bibliometric data based on publications on assisted migration were collected from Scopus and Web of Science databases using assisted migration and climate change or their synonyms as queries. Metadata were merged, processed and several networks were constructed. Recent Findings Co-citation and keyword co-occurrence networks identified three major clusters focused on (i) theory and risk of assisted migration of threatened and endangered species, (ii) impact of climate change on realized and fundamental climate and geographic niches, and (iii) assisted population migration. Collaboration network analysis identified three social core hubs: North America, Europe, and Australia, with the USA and Canada being the most productive and the most col- laborative countries. Summary We conclude that future research is expected to concern mainly the assessment of physiological response of spe- cies and populations to extreme climate events such as drought and frost, and the contribution of non-climatic factors and biotic interactions in local adaptation and population performance under climate change. Social core hubs distinguished in this work can be used to identify potential international research and training collaborators necessary to address gaps and challenges underlying assisted migration implementation. Keywords Bibliometrics · Network analysis · Assisted migration · Climate change · Conservation biology · Ecological restoration This article is part of the Topical Collection on Climate Change and Carbon Sequestration Introduction * Lahcen Benomar Anthropogenic climate change is having substantial impact lahcen.benomar2@uqat.ca on the composition and structure of native biodiversity lead- ing to shift associated with species distributions [1–3], and Forest Research Institute, University of Québec in Abitibi- Témiscamingue, Rouyn-Noranda, QC J9X 5E4, Canada • • ecosystem functioning [4, 5, 6 , 7 , 8]. Some species have shifted their distribution as they track their changing cli- Trois-Rivières, QC, Canada matic niche. These range shifts depend on species’ ability Department of Ecosystem Science and Management, to track changing abiotic cues and biotic interactions, and Pennsylvania State University, University Park, PA 16801, USA may lead to range contraction, fragmentation, or expansion •• [1, 9 , 10–14]. However, while some species maintain the Kalamalka Forestry Centre, Forest Improvement and Research Management Branch, BC, Ministry of Forests, capacity to track a shifting ecological niche [2, 15, 16], the Lands, Natural Resource Operations and Rural Development, vast majority may not be able to keep pace under rapid cli- 3401 Reservoir Road, Vernon, BC V1B 2C7, Canada mate change [17, 18]. Management Department, University of Quebec at Rimouski, Campus Lévis, Lévis, QC G6V 0A6, Canada Vol.:(0123456789) 1 3 200 Current Forestry Reports (2022) 8:199–213 Among the various strategies that have been proposed to various metrics (collaboration index, productivity index, manage species under climate change, assisted migration impact metrics, and hybrid metrics) (see Aria and Mas- (AM) is a proactive conservation and restoration strategy simo [33 ] for additional details). Relational studies that aims to limit species’ maladaptation by facilitating gene examine the relationships between units of analysis flow and transfer of genetic material that may be adapted (article, author, institution, journal, reference, and key- •• to the climate of the recipient environment [9 , 19–21]. word) within a research field and can be divided into AM, also called “assisted colonization,” “managed reloca- four types of analyses: co-citation analysis, bibliographic tion,” and “assisted gene flow” is defined as the intentional coupling, co-authorship analysis, and co-word analysis. movement of species or populations to regions predicted to Collectively, these four approaches allow assessment •• be suitable under future climate conditions [9 , 21, 22]. of the intellectual, social, and conceptual structure of According to the literature above, there are three categories a research area [34–37]. In this way, relational studies of assisted migration: can identify changing trajectories of research themes within a scientific field and the collaborative networks (i) Assisted population migration, also called assisted associated with those research themes [32, 36]. These gene flow, is the intentional movement of seed analyses can be used to visually illustrate the intellec- sources or populations to locations within a species’ tual structure of a field of research by identifying and current natural distribution. quantifying the inf luence of authors, sources (journals), (ii) Assisted range expansion is the intentional move- and articles in this field [34, 35]. The social structure ment of seed sources or populations to locations examines the relationships (the levels of scientific col- slightly beyond a species’ current natural distribu- laboration) between individual actors at different scales tion. (authors, institutions, and countries) based on jointly (iii) Exotic translocation is the intentional movement published documents [27]. The conceptual structure of species to locations that are predicted to be more examines the relation among keywords in a field, with suitable under future climate but distant from their aims to (i) structure knowledge into the research domain natural geographic range. or topic and (ii) identify potential knowledge gaps and future research themes. The latter are identified through Assisted migration could significantly reduce the evaluation of implicit gaps (identified in the literature) expected negative impacts of climate change [23, 24]. that have low co-occurrence [32]. However, devising and implementing a system of assisted For example, by investigating the evolution of ecological migration that will be safe, effective, and readily adopted restoration using a bibliometric analysis, Guan et al. [38 ] by practitioners requires multidisciplinary understanding highlighted the need to develop more international aca- of diverse fields including biology, climatology, geog- demic collaborations, together with techniques of manage- raphy, computer programming, and social science [25]. ment and monitoring of restored ecosystems, and the social Bibliometric analysis can assist in identifying research issues associated with this field. In a bibliometric analysis gaps and individuals active in collaborative networks of remote sensing applied in forest management, Abad- required for this work. Segura et al. [39] found that ecological sensitivity assess- Bibliometric analysis involves a set of quantitative ment, satellite fire mapping, topological acoustic sensing, explorations that aims to provide insight into the evo- unsupervised treetop detector, and air pollution mitigation lution of a given discipline, detect research gaps, and would be the predicted hotspots of future research in this describe the collaborative structure between academic research domain. A recent bibliometric analysis of tem- institutions or countries [26–28]. It also allows identifi- poral trends in frequencies of title words revealed a shift cation of authors actively contributing to a research field in research away from sustained-yield-based forestry and and those that have established a collaborative founda- towards a more interdisciplinary view of forests as ecologi- tion to build upon. Bibliometric analyses have become cally important and dynamic systems [40]. widely used in social and economic sciences and even The objectives of the study were to (i) examine the in basic sciences [28–32], but few bibliometric analyses intellectual, social, and conceptual structures of AM have been conducted within the field of forest science. research using bibliometric relational methods; (ii) Bibliometric studies are categorized into three types: examine the pattern and evolution of AM research; (iii) reviews, evaluative, and relational studies [28, 30, identify knowledge gaps and future research directions. 33 ]. Review studies often include literature reviews Together, these results will provide a roadmap for ongo- or meta-analyses, called “review methods” [28]. Evalu- ing research and implementation of AM, and identify ative studies measure the academic impact of articles gaps in the field that will benefit from new collaborative or authors associated with a given research field using research programs. 1 3 Current Forestry Reports (2022) 8:199–213 201 to identify the duplicates due to special characters and Materials and Methods those were inspected and deleted (n = 17) using a VBA custom script following [31], leaving 622 publications 1. Data Collection and Processing (194 and 64 exclusively from WOS and Scopus, respec- Bibliometric data were collected from the Web of tively and 364 shared between WOS and Scopus). A Science (WOS) and Scopus databases, the two larg- final step to accept or remove published material (eli - est multidisciplinary scientific databases. Previous gibility) was performed using the following criteria: studies have indicated substantial complementarity (i) non-English language publications were accepted if between these databases, arguing the importance of keywords, title, and abstract were provided in English using both to conduct a single integrated bibliomet- (n = 22); (ii) documents without ISSN (International ric investigation [31, 41]. We retrieved bibliometric Standard Serial Number) were removed (n = 1); and (iii) metadata related to assisted migration from these document types such as errata notes, conference papers, two databases between 1900 to 2020 using the fol- and short surveys were excluded (n = 8) [32, 44]. Con- lowing strings to query across titles, abstracts, and ference papers are often the initial product of ongoing keywords: (“assisted migration” or “assisted popula- research or synthesis of published material. As such, tion migration” or “assisted gene flow” or “assisted their impact is generally lower than original research colonization” or “assisted colonization” or “man- papers. Although editorial material is usually excluded aged relocation”) and (“climate change” or “global from bibliometric studies, we included this type of docu- change” or “climate-change” or “climatic change” or ment (n = 13) since they are relevant for the dissemina- “global warming”) and (Language = all) and (docu- tion of scientific knowledge [ 45] (Table 1). The final ment type = All document types). This query syntax dataset contained 614 articles (Fig. 1). was used to identify articles where assisted migration 2. Thesaurus Construction is proposed as a climate change adaptation strategy, Text data mining and the construction of a thesaurus while avoiding documents on assisted migration from are crucial to keyword co-occurrence-based analysis. other fields such as chemistry, physics, and social sci- ences. The search yielded 561 and 425 publications in WOS and Scopus, respectively, and the data were Table 1 Descriptive statistics of the database downloaded as BIBTEX and CSV files, respectively. Bibliometric data were processed and analyzed in Description Results R version (4.0.0) [42]. First, metadata files associated Main information with each database (WOS or Scopus) were loaded,   Sources (journals, books, etc.) 220 transformed into a data frame, and merged in one step   Documents 614 using the function bib2df of the Bibliometrix R package   Average number of citations per document 28.52 [43]. Second, variables within the two datasets (WOS   Average number of citations per year per document 3.35 and Scopus) were shortened to 18 common and relevant   References 29,406 variables (“Authors,” “Author Keywords (ISI),” “Index Document type Keywords (Scopus),” “Affiliations,” “Document Type,”   Article 493 “Source title,” “Cited by,” “Bibliographic Database,”   Book chapter 21 “References,” “Abstract,” “Correspondence Address,”   Editorial material 13 “Title,” “Year,” “Country of affiliation for the first   Letter 10 author,” “Country of affiliation for co-authors,” “Uni -   Proceedings paper 10 versity of affiliation for each co-author and the corre -   Review 67 sponding author,” “Language”, “ISSN”), and the two Document content data frames were merged. Duplicated documents were   Keywords Plus (ID) 2002 removed from the merged data frame using duplicated-   Author’s Keywords (DE) 1814 Matching function of the Bibliometrix R package [33 ]. Authors The abstract was used as the tag variable to identify   Authors 1952 duplicated records, and the minimum relative similar-   Author appearances 2759 ity (MRS) was set to 0.85. Three hundred forty-seven   Authors of single-authored documents 47 duplicate records were identified and removed, leaving   Authors of multi-authored documents 1905 639 unique publications based on our search criteria. For Author’s collaboration documents with title and abstract published in bilingual   Average co-authors per document 4.49 format, the duplicatedMatching function was unable   Collaboration index 3.39 1 3 202 Current Forestry Reports (2022) 8:199–213 Fig. 1 Flowchart diagram illustrating the data processing steps The use of plural or singular (e.g., range shifts/range The co-authors per document index was calculated as shift; ecosystem/ecosystems; provenance test/prove- The number of co-authors per document/The number of nance tests) or different synonyms for the same keyword documents, and the collaboration index (CI) was calcu- (e.g., climate change, global change, global warming, lated as Total authors of multi-authored articles/Total climatic change/climate-change) is a common issue that multi-authored articles [33 ]. directly affects both the frequency and co-occurrence of For each network illustration, clusters are distin- keywords. guished by color, while the size of each node ref lects We constructed a thesaurus file manually by group- its occurrence. The shorter the distance between two ing all synonyms and plural or singular forms of key- nodes, the more closely connected they are. Finally, words under the same word, except synonyms for the thickness of the connection between two nodes assisted migration to show their co-occurrence. We indicates the strength of their relationships [33 ]. also merged keywords containing two or three words Clustering was performed using the LinLog algo- that were wrongly separated by removing semicolons rithm and the modularity clustering technique, where to create uniformity among multi-word keywords. the weighted sum of the squared Euclidean distances For example, we replaced “range; shift” by “range with all pairs of nodes is minimized [47]. Nodes were shift,” “local; adaptation,” by “local adaptation,” and then assigned to clusters based on their similarities “assisted migration,” by “assisted migration”. (related to co-occurrences). 3. Analysis Using Bibliometrix and VOSviewer The intellectual structure of a discipline can be Descriptive statistics (average number of publica- assessed by examining the inf luence of authors or tions per year, most productive author, most productive articles and their connectivity, which is quantified by institutions, most productive countries, and most cited examining the relationship between pairs of authors author) were calculated using Bibliometrix R package (or articles) based on the frequency of their co-cita- [33 ], and network analyses were conducted to assess tion in other articles. We constructed distance-based the social, intellectual, and conceptual structure of our co-citation networks [37] in VOSviewer to identify final dataset (Fig.  1) using VOSviewer software [37, 46]. the most active authors in the research field, based on 1 3 Current Forestry Reports (2022) 8:199–213 203 the number of papers published, the number of local citations (citation of a given author within the field of AM) as well as their influence in structuring the knowledge on AM. The minimum number of citations for authors or articles was set to 10 during network construction. The social structure of AM research was assessed using the co-authorship network to identify connec- tions between authors, institutions, or countries based on jointly authored publications [37]. The conceptual structure examines the relations among words in the bibliometric database. This analysis aims to (i) structure the knowledge into the research domains or topics and (ii) highlight the most frequently covered topics and identify trends Fig. 2 Annual number of assisted migration-related articles from that may allow prediction of possible future lines of 2007 to 2020 obtained from Web of Science and Scopus research. We assessed keyword co-occurrence net- work using author keywords in VOSviewer [37, 46]. The minimum occurrence of a keyword was set to 1. Intellectual Structure four. Web of Science provides another category of keywords named “KeyWords Plus” which are gener- Based on the number of published articles, our results showed that the most productive author in the field of ated using algorithms based on the title of references cited in an article. The overlap between KeyWords assisted migration is Cuauhtémoc Saenz-Romero from Instituto de Investigaciones Sobre los Recursos Naturales Plus and titles of papers may reach 50% [47]. Simi- larly, Scopus provides '”Indexed keywords'” which (Mexico), followed by Andreas Hamann from the University of Alberta, Canada (Fig. 3). The 15 most productive authors are chosen by content suppliers. The use of Key- Words Plus or Indexed keywords to complement the were from the forest ecology and management domain with research emphasizing commercial forest tree species author keywords may consolidate author keyword- based analysis [48, 49]. However, the similarity (Fig. 3). The two most cited authors were Gerald Rehfeldt from US Forest Service (USA) and Jason McLachlan from between Index keywords and KeyWords Plus has not yet been documented, making their use in merged the University of Notre Dame (USA) based on local cita- tions. Lack of correspondence between author productivity databases not recommended. (publication number) and influence (local citation) may be due, in part, to the novelty of an author’s research topics Results and Discussion (particularly if more recently introduced topics or ideas have not had the time to garner citations), or gender, or race or Since the first publications on assisted migration as a country bias [51–53]. Regarding institutions, the University of British Columbia (Canada), North Arizona University climate change adaptation strategy in 2007, the num- ber of publications per year increased rapidly from 4 to (USA) and University of Alberta (Canada) were the three most productive institutions in terms of published papers 75 between 2007 to 2015 thereafter f luctuated moder- ately (Fig. 2), the average publication per year was 43.8. (Fig. 3). These results regarding the intellectual structure of the field of assisted migration may help guide researchers Research articles and reviews account for 91% of the total publications (Table 1). Multi-authored documents when planning research and future collaboration. The co-citation network consisted of 81 nodes forming contained an average of 4.5 authors, with only 6% of the documents being single-authored. The collaboration three clusters (Fig. 4), with each node representing one co- cited document (Fig. 4a) or one co-cited author (Fig. 4b). index (CI) averaged 3.4 (Table 1) and was highest dur- ing the 2017–2020 period (CI = 4.49) compared with Node size is proportional to its number of citations. The green cluster (Fig. 4b) consisted primarily of plant and ani- the 2007–2011 (CI = 3.66) and 2012–2016 (CI = 3.48) periods. The same temporal pattern in collaboration was mal conservation ecologists who have focused on theory, foundation, and risk of AM. This group was comprised of observed in the field of biodiversity research [50]. These results point towards the growing emphasis on collabora- at least five authors: Ove Hoegh-Guldberg (University of Queensland, Australia), Jason S. McLachlan (University of tion for assisted migration research. Notre Dame, USA), Anthony Ricciardi (McGill University, 1 3 204 Current Forestry Reports (2022) 8:199–213 cluster (red) focused on assisted population migration for forest tree species with an emphasis on modeling growth and ecophysiology. Together, the foundational theory underlying the shift of the ecological niche and its evolutionary conse- quences for species under climate change are represented by authors in the blue cluster (Fig. 4b) with empirical testing, monitoring, and application of assisted migration research to conservation and restoration by authors in the green and red clusters (Fig. 4b). To examine the evolution of intellectual influence in structuring knowledge of assisted migration research for each cluster, the data collected between 2007 and 2020 were divided into three time periods. During the first period (2007–2011), the green and blue clusters (Fig. 5a) were the most prominent communities producing publications on the theoretical foundation of species range shifts due to climate change. This research provided a framework for assessing ecological benefits and risks associated with AM as a con- servation option [3, 19, 21, 22]. During the second period (2012–2016), based on the size and position of the node, some prominent authors (e.g., Schwartz M; Thomas CD; Hunter ML) within the first period (Fig.  5a) became less influential relative to other authors (e.g., Ricciardi A; Hewitt N; Pedar JH) (Fig.  5b). The blue cluster narrowed while the red cluster expanded and became more structured with reduced distance between members. The red cluster, an intel- lectual community dominated by forest geneticists [20, 55, 57], became more numerous with strong linkages among its members. During the third period (2017–2020), the pat- tern observed in the second period was accentuated for all groups (Fig. 5c). Shifts in authorship suggest that research on assisted migration is expanding into new research areas Fig. 3 The most productive authors (a), the most cited authors (b), with an influx of new authors (e.g., Isaac-Renton MG, Val- and the most productive institutions (c) in assisted migration-related. ladares F; Hamann A; Gray LK; Jump AS) from differ - U, university ent disciplines, such as ecophysiology, growth modeling, and seedling production, to complement existing theory Canada), David M. Richardson (Stellenbosch University, (Fig. 5c). Over time, the three clusters had distinct trajecto- South Africa), and Mark W. Schwartz (University of Cali- ries and dynamics, and highlight the following aspects: (i) fornia at Davis, USA) who initiated the debate of using AM the green cluster (working mainly on long-distance AM) as a conservation strategy to mitigate the consequence of cli- had a slower evolution with limited empirical data needed mate change on the distribution of species [19, 21, 22, 54]. to shift to a new structure; (ii) the blue cluster might disap- Authors within the blue cluster (Fig. 4b) were mostly ecolo- pear in the next few years as the theoretical foundations of gists who have assessed the impact of climate change on AM (e.g., the shift in species ecological niche under climate species’ geographical distributions and range shifts (Fig. 4a). change) now appear to have sufficient empirical support; The authors Camille Parmesan (University of Plymouth, (iii) inversely, the dynamic evolution observed within the USA) and Chris D. Thomas (University of York, UK) were red cluster is more likely to quickly achieve a new structure the prominent members of this cluster [3]. The red clus- and might dominate the AM research for the coming years. ter (Fig. 4b) was comprised of forest geneticists who have The rapid evolution of the red cluster may originate from (i) conducted population genetics studies, often using prov- the economic impact of climate change on forest productiv- enance trials and molecular data for commercial forest trees ity and (ii) the long history of growing trees in provenance (Fig. 4a). The most prominent authors within this cluster trials established many decades ago (starting from the 40 s were Sally N. Aitken (UBC, Canada) and Gerald E. Rehfeldt for some species) which provides a laboratory to test the (US Forest Service, USA). Ten additional authors in this impact of climate change and assisted population migration 1 3 Current Forestry Reports (2022) 8:199–213 205 Fig. 4 Co-citation network of assisted migration research based on a The shorter the distance between two nodes, the more closely con- articles and b authors. Each cluster is represented by a color. The size nected they are (based on their co-citation) of a node (author or article) reflects the number of received citations. •• on species’ success [9 , 55, 56]. The data from these tri- and funders are not informed or sufficiently convinced als has been essential in the development of seed transfer of the potential benefit of AM research, or that natural models and the implementation of assisted migration [23, sciences funding cycles are unable to support long-term 25, 57, 58]. research needed on assisted migration [59]. Moreover, the intellectual structure of AM research might yet change since research on AM is still relatively 2. Social Structure new (15 years) with limited publications when compared with other similar research fields. Furthermore, securing Collaborations between countries were explored by funds to support extensive research on AM is still chal- examining co-authorship networks (Fig.  6). Our results lenging. This may reflect the fact that both stakeholders identified clusters representing four collaborative groups: 1 3 206 Current Forestry Reports (2022) 8:199–213 1 3 Current Forestry Reports (2022) 8:199–213 207 ◂Fig. 5 The network map of authors’ co-citation for a the period from North America and Europe, with greater collaboration 2007 to 2011, b the period from 2012 to 2016, and c the period from between Canada and Germany, and groups in the USA col- 2017 to 2020. Each cluster is represented by a color laborating primarily with the UK. Collaborations between North America and Europe were more frequent than collabo- the blue cluster was composed of North American coun- rations within Europe. The same pattern was observed with tries (USA, Canada, and Mexico) and China, and within the green cluster where collaborations between USA and this group, the most prolific teams were from Canadian Australia were more frequent than collaboration within the and US institutions. The green cluster included Australia, group led by Australia. In Europe, most frequent collabora- South Africa, and New Zealand, and was led by Australia tions were observed between the UK and Germany (Fig. 6). according to the size of the nodes. The red and yellow Greater productivity of Canadian and US authors and institu- clusters included European countries identifying German tions might be due in part to the awareness of rapid climate and British research groups as the most active (Fig. 6). change of northern countries relative to tropical or southern Substantial collaboration was observed between the USA countries, their substantial economic dependence on for- and Canada relative to all other countries (Fig. 6). Interest- estry, and the greater amount of research resources available ingly, the network also identified collaborations between in the global North than in the global South. Fig. 6 The network map of country collaborations based on corresponding author affiliations of assisted migration research. Each cluster is represented by a color. The size of the node represents the productivity of the country (the number of pub- lications in collaboration with other countries). The shorter the distance between two nodes, the more closely connected they are (based on co-authored articles) 1 3 208 Current Forestry Reports (2022) 8:199–213 Fig. 7 The network map of author keywords co-occurrence of of a keyword. The distance between nodes is proportional to the fre- assisted migration research. Each cluster is represented by a color. quency of keywords co-occurrence The size of the node is proportional to the number of occurrences 3. Conceptual Structure species (Fig. 7). The red cluster (37 keywords) was domi- nated by the terms: assisted migration, climate change, Seventy-one keywords that occurred at least 4 times populations, adaptation strategies, plasticity, gene- were identified. They were grouped into three distinct cology, and local adaptation. These terms referred to clusters (Fig. 7) based on their co-occurrence. The blue assisted population migration used for forest tree species. cluster (11 keywords) was mainly represented by the fol- We noted that ecologists have been mostly working on lowing terms: species distribution, distribution model, the second and third categories of AM (green cluster), and range shifts. This cluster was mainly focused on the usually using the terms assisted colonization or managed shift in species distribution as a response or a conse- relocation rather than assisted migration.) quence of climate change and on different approaches to model the ecological niche. The green cluster (23 4. Research Gaps and Future Directions keywords) was dominated by the terms: climate change adaptation, conservation, biodiversity, assisted coloniza- The temporal scaling of the keyword co-occurrence tion, managed relocation, translocation, and ecological network (Fig.  7) showed different patterns of research restoration. This cluster corresponded to research on AM evolving within each cluster (Fig. 8). The terms in blue of species as a proactive conservation and management are linked to early research done before 2014 (average strategy under climate change. This cluster focused on publication year) (Fig. 8). They are generally from the the theoretical conceptualization, debate, and arguments green and blue clusters in Fig.  7 and correspond to the on the impact of action or inaction regarding the deploy- second and third categories of AM. The emerging terms ment of such a strategy for endangered and vulnerable from these clusters were vulnerability (assessment), 1 3 Current Forestry Reports (2022) 8:199–213 209 Fig. 8 The network map of author keywords co-occurrence indexed per publication year. The keywords were colored based on the average pub- lication year ecological restoration, range shift, and species distribu- restoration. In addition, research assessing biotic inter- tion models (Fig. 8), and each exhibited linear to expo- actions of the introduced species in their new ecosystem nential growth as keywords over time (Fig.  9). Within is needed for effective species translocation. For exam- these clusters, terms such as conservation, biodiversity, ple, assisted migration of forest trees should consider and species distribution showed a quadratic pattern with above- and below-ground interactions, including existing a decrease in their occurrence from 2015. As a conser- f lora, predominant pests, pollinators, and grazing fauna vation strategy, assisted migration for threatened and alongside below-ground communities. endangered species has been controversial [19, 21, 22, Research related to assisted population migration was 54, 60]. Traditional conservation failed for several spe- more recent compared to the second and third catego- cies reintroductions [61] because species establishment ries of assisted migration (Fig. 8). Within the red cluster was likely limited by the ontogenetic niche rather than (assisted population migration), research was focused the climatic niche [62]. Species establishment is a com- initially on the genetic structure of species popula- plex ecological process which depends on different biotic tions (2015 on average), followed by the investigation and abiotic factors and their interactions, such as pres- of growth-climate relationships, which was facilitated ence of pollinators, mycorrhizas, herbivory pressure, by the availability of growth data from old provenance pathogens or competitors, and habitat physico-chemical tests (2016). More recently (2017 to 2020), research on parameters required for seeds germination and seed- assisted population migration focused on forest man- ling establishment. Conservation-oriented restoration agement, local adaptation, plasticity, and drought and appeared to be the optimal strategy because it integrates frost-related traits (bud burst, bud set and cold hardiness) both climate and ontogenetic niches in the process of where research on local adaptation and mortality has species translocation [62]. The linear increase of research grown linearly, and exponentially for drought (Fig. 9). on ecological restoration (Fig. 9) suggests an increased The growing interest of research in local adaptation interest in both biodiversity conservation and habitat and plasticity of functional traits were related to their 1 3 210 Current Forestry Reports (2022) 8:199–213 Fig. 9 The number of occurrences of author keywords that have increasing or decreasing patterns in assisted migration-related articles crucial role in species adaptation to climate change and change which represents an additional challenge for the •• therefore to resilience capacity [9 , 20, 63]. The fifth implementation of assisted migration [64, 65]. This may report of Intergovernmental Panel on Climate Change [5] have contributed to stimulate research on adaptation highlighted an increase in the frequency and severity of to frost and drought events. Then, we expect intensive extreme climate events (frost and drought) under climate research on the assessment of the specific responses of 1 3 Current Forestry Reports (2022) 8:199–213 211 species populations to both drought and frost events in translocation, which may largely be contingent on eco- the future. An important additional issue in the response nomic interest. The network analysis demonstrated that of tree populations to climate change is the noticeable the knowledge was structured in three intellectual and increase of mortality of forest trees (Fig.  8) which is conceptual groups working on species distribution, exotic attributable mostly to the effect of more frequent extreme translocation, and assisted population migration. drought events [66, 67]. Finally, more research on the Our work provides new insights into the development role of microbiome and epigenetics in the adaptation to of research on assisted migration of forest trees under climate change and the development of a new generation climate change. For example, to minimize the mortality of seed transfer models is needed. This research should and vulnerability of forest trees, our bibliometric analysis consider growth-climate relationships, drought and frost indicates that the research on the consequences of extreme tolerance, and interactions between the translocated spe- climatic events like drought and frost anomalies is a prom- cies and their biotic environment. ising avenue. Therefore, the development of research on the physiological basis of drought and frost tolerance in trees and the interaction with increased atmospheric C O Study Limitations is crucial. In addition, assessing the potential role of epi- genetic memory to traits variation may help improve the We acknowledge two limitations to our analysis which prediction of drought and frost impacts to plant fitness. likely resulted in our failing to locate all articles dealing In addition, new research themes linked to the observed with AM. First, our search could not detect articles that growing interest in ecological conservation may include focused on AM but did not explicitly use “assisted migra- the contribution of soil properties (physics, chemistry, and tion: or its synonyms. For example, Mátyás and Yeatman microbiome) and the impact of biotic interactions on local (1992) [68], who developed a seed transfer model for jack adaptation patterns for different tree species. Overall, this pine and discussed its use to define safe ecological trans- bibliometric analysis points towards the need to establish fer distance, and Ledig and Kitzmiller (1992) [69], who new, long-term experiments that expand international col- recommended establishing plantations with populations laborations and foster development of interdisciplinary from climates that are warmer than the plantation site cli- toolkits to fill existing and evolving knowledge gaps that mate, are not included in our study because they did not are important to assisted migration and its application to use the term “assisted migration” or any of its synonyms. conservation and restoration. Despite not being recorded in our database, the authors Mátyás and Ledig figured in the intellectual structure Funding This research was supported by the University of Québec in (Fig. 5). The second limitation is related to the standard Abitibi-Témiscamingue (UQAT) through startup funds to ML. search engines used, which looked at the term “assisted migration” or its synonyms in titles, article keywords, Data Availability The datasets generated for this study are available and abstracts, but not in the text. This limitation likely upon request to the corresponding author. excluded some articles, such as Andalo et al. (2005) [70], Code Availability R codes are available upon request to the correspond- who developed a seed transfer model for white spruce. ing author. The article did not use the term “assisted migration” in the title, keywords, or abstract but evoked its potential Declarations use in the discussion section. More accurate search tools using novel approaches like machine learning would be Conflict of Interest The authors declare no competing of interests. more efficient in detecting articles in the “blind spots” of conventional search engines. Human and Animal Rights and Informed Consent This article does not contain any studies with human or animal subjects performed by any of the authors. Conclusion and Perspectives Open Access This article is licensed under a Creative Commons Attri- bution 4.0 International License, which permits use, sharing, adapta- This study showed that much of the research on assisted tion, distribution and reproduction in any medium or format, as long migration has been carried out in North America, as you give appropriate credit to the original author(s) and the source, where Canada and the USA have established strong col- provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are laborative networks. Canada–USA collaborations have included in the article's Creative Commons licence, unless indicated emphasized research related to assisted migration of otherwise in a credit line to the material. If material is not included in populations for forest trees, compared to other research the article's Creative Commons licence and your intended use is not categories, including assisted range expansion and exotic 1 3 212 Current Forestry Reports (2022) 8:199–213 permitted by statutory regulation or exceeds the permitted use, you will 13. Muffler L, Beier kuhnlein C, Aas G, Jentsch A, Schweiger AH, need to obtain permission directly from the copyright holder. To view a Zohner C, Kreyling J. Distribution ranges and spring phenol- copy of this licence, visit http://cr eativ ecommons. or g/licen ses/ b y/4.0/ . ogy explain late frost sensitivity in 170 woody plants from the Northern Hemisphere. Glob Ecol Biogeogr. 2016;25:1061–71. 14. Bai Y, Wei X, Li X: Distributional dynamics of a vulnerable species in response to past and future climate change: a window for conservation prospects. PeerJ 2018; 2018. References 15. Hill JK, Griffiths HM, Thomas CD. Climate change and evolu- tionary adaptations at species’ range margins. Annu Rev Ento- Papers of particular interest, published recently, have mol. 2011;56:143–59. been highlighted as: 16. Aguilée R, Raoul G, Rousset F, Ronce O. Pollen dispersal slows geographical range shift and accelerates ecological niche shift • Of importance under climate change. Proc Natl Acad Sci. 2016;113:E5741–8. •• Of major importance 17. McLachlan JS, Clark JS, Manos PS. Molecular indicators of tree migration capacity under rapid climate change. Ecology. 1. Davis MB, Shaw RG. Range shifts and adaptive responses to 2005;86:2088–98. Quaternary climate change. Science. 2001;292:673–9. 18. Ash JD, Givnish TJ, Waller DM. Tracking lags in historical 2. Chen I-C, Hill JK, Ohlemüller R, Roy DB, Thomas CD. Rapid plant species’ shifts in relation to regional climate change. Glob range shifts of species associated with high levels of climate Change Biol. 2017;23:1305–15. warming. Science. 2011;333:1024–6. 19. McLachlan JS, Hellmann JJ, Schwartz MW. A framework for 3. Parmesan C, Ryrholm N, Stefanescu C, Hill J, Thomas C, Desci- debate of assisted migration in an era of climate change. Conserv mon H, Huntley B, Kaila L, Kullberg J, Tammaru T, et al. Pole- Biol. 2007;21:297–302. ward shifts of species’ ranges associated with regional warming. 20. Aitken SN, Whitlock MC: Assisted gene flow to facilitate local Nature. 1999;399:579–83. adaptation to climate change. In Annual Review of Ecology, 4. Williams JW, Jackson ST, Kutzbach JE. Projected distributions Evolution, and Systematics. Edited by: Annual Reviews Inc.; of novel and disappearing climates by 2100 AD. Proc Natl Acad 2013:367–388. vol 44. Sci USA. 2007;104:5738–42. 21. Hoegh-Guldberg O, Hughes L, McIntyre S, Lindenmayer 5. IPCC: Climate change 2014: Impacts, adaptation, and vulner- DB, Parmesan C, Possingham HP, Thomas CD. Ecology: ability. Part a: Global and sectoral aspects. Contribution of work- Assisted colonization and rapid climate change. Science. ing group ii to the fifth assessment report of the intergovern - 2008;321:345–6. mental panel on climate change. Edited by. Cambridge, United 22. Richardson DM, Hellmann JJ, McLachlan JS, Sax DF, Schwartz Kingdom and New York, NY, USA: Cambridge University MW, Gonzalez P, Brennan EJ, Camacho A, Root TL, Sala OE, Press; 2014:1132. et al. Multidimensional evaluation of managed relocation. Proc 6.• Blowes SA, Supp SR, Antao LH, Bates A, Bruelheide H, Chase Natl Acad Sci USA. 2009;106:9721–4. JM, Moyes F, Magurran A, McGill B, Myers-Smith IH, et al.: 23. Wang T, O’Neill GA, Aitken SN. Integrating environmental The geography of biodiversity change in marine and terrestrial and genetic effects to predict responses of tree populations to assemblages. Science 2019; 366:339. This paper is useful to climate. Ecol Appl. 2010;20:153–63. understand spatial variation in species richness and composi- 24. Nigh G. Mitigating the effects of climate change on lodgepole tion change and provides an important criterion for target- pine site height in British Columbia, Canada, with a transfer ing conservation. function. Forestry. 2014;87:377–87. 7.• Butt N, Chauvenet ALM, Adams VM, Beger M, Gallagher RV, 25. O'Neill G, Wang T, Ukrainetz N, Charleson L, McAuley L, Yan- Shanahan DF, Ward M, Watson JEM, Possingham HP: importance chuk A, Zedel S: A proposed climate-based seed transfer system of species translocations under rapid climate change. Conservation for British Columbia. Edited by Ministry of Forests LaNRO. Biology 2020. This paper presents practical recommendations British Columbia. Ministry of Forests, Lands and Natural to advance assisted migration as a conservation tool. Resource Operations; 2017. 8. Clark JS, Andrus R, Aubry-Kientz M, Bergeron Y, Bogdziewicz 26. McBurney M, Novak P: What is bibliometrics and why should M, Bragg DC, Brockway D, Cleavitt NL, Cohen S, Courbaud B, you care?; 2002. IEEE International Professional Communica- et al. Continent-wide tree fecundity driven by indirect climate tion Conference. 108 - 114. https://doi. or g/10. 1109/ IPCC. 2002. effects. Nat Commun. 2021;12:1242. 10490 94. 9.•• Aitken SN, Yeaman S, Holliday JA, Wang TL, Curtis-McLane S: 27. Glänzel W: Bibliometrics as a research field: a course on theory Adaptation, migration or extirpation: climate change outcomes and application of bibliometric indicators. Course Handouts for tree populations. Evolutionary Applications 2008; 1:95–111. In this review, the authors highlighted the question of the 28. Zupic I, Cater T. Bibliometric methods in management and fate of forest tree populations and identified three potential organization. Organ Res Methods. 2015;18:429–72. responses to a rapidly changing environment: migration, 29. Boyack K, Borner K, Klavans R. Mapping the structure and adaptation, or extinction. evolution of chemistry research. Scientometrics. 2009;79:45–60. 10. Moir ML, Vesk PA, Brennan KEC, Poulin R, Hughes L, 30. Johnson A-G, Samakovlis I: A bibliometric analysis of knowl- Keith DA, McCarthy MA, Coates DJ. Considering extinction edge development in smart tourism research. Journal of Hospi- of dependent species during translocation, ex situ conserva- tality and Tourism Technology 2019; 10. tion, and assisted migration of threatened hosts. Conserv Biol. 31. Echchakoui S. Why and how to merge Scopus and Web of Sci- 2012;26:199–207. ence during bibliometric analysis: the case of sales force litera- 11. Thomas LF, Rehfeldt GE, Sáenz-Romero C, Flores-López C. ture from 1912 to 2019. J Mark Anal. 2020;8:165–84. Projections of suitable habitat for rare species under global 32. Oliveira O, da Silva F, Juliani F, Ferreira L, Barbosa L, Nunhes warming scenarios. Am J Bot. 2010;97:970–87. T: Bibliometric method for mapping the state-of-the-art and 12. Parmesan C, Hanley ME. Plants and climate change: complexi- identifying research gaps and trends in literature: an essential ties and surprises. Ann Bot. 2015;116:849–64. instrument to support the development of scientific projects. In 1 3 Current Forestry Reports (2022) 8:199–213 213 Scientometrics Recent Advances; IntechOpen: Rijeka, Croatia, 51. Singh D: Publication bias - a reason for the decreased research 2019; p. 13. ISBN 978–1–78984–713–0. output in developing countries. Afr J Psychiatry 2006; 9. 33.• Aria, Massimo: bibliometrix: An R-tool for comprehensive sci- 52. Mulimani P. Publication bias towards Western populations harms ence mapping analysis. Journal of Informetrics 2017; 11:959– humanity. Nat Hum Behav. 2019;3:1026–7. 975. This paper propose an R-package that help to perform 53. Huang J, Gates AJ, Sinatra R, Barabási A-L. Historical compari- a comprehensive science mapping analysis of scientific son of gender inequality in scientic fi careers across countries and literature. disciplines. Proc Natl Acad Sci. 2020;117:4609. 34. Boyack K, Klavans R. Co-citation analysis, bibliographic cou- 54. Ricciardi A, Simberloff D. Assisted colonization is not a viable pling, and direct citation: which citation approach represents the conservation strategy. Trends Ecol Evol. 2009;24:248–53. research front most accurately? J Am Soc Inform Sci Technol. 55. Mátyás C. Modeling climate change effects with provenance test 2010;61:2389–404. data. Tree Physiol. 1994;14:797–804. 35. Cobo M, López-Herrera AG, Herrera-Viedma E, Herrera F. 56. Mátyás C. Climatic adaptation of trees: rediscovering prove- Science mapping software tools: review, analysis, and coop- nance tests. Euphytica. 1996;92:45–54. erative study among tools. J Am Soc Inform Sci Technol. 57. O’Neill GA, Hamann A, Wang T. Accounting for population 2011;62:1382–402. variation improves estimates of the impact of climate change on 36. Benckendorff P, Zehrer A. A network analysis of tourism species’ growth and distribution. J Appl Ecol. 2008;45:1040–9. research. Ann Tour Res. 2014;43:121–49. 58. Pedlar JH, McKenney DW, Aubin I, Beardmore T, Beaul- 37. van Eck NJ, Waltman L. Visualizing bibliometric networks. In: ieu J, Iverson L, O’Neill GA, Winder RS, Ste-Marie C. Plac- Ding Y, Rousseau R, editors. Measuring scholarly impact: meth- ing forestry in the assisted migration debate. Bioscience. ods and practice. Wolfram D: Springer International Publishing; 2012;62:835–42. 2014. p. 285–320. 59. Hughes B, Beas-Luna R, Barner AK, Brewitt K, Brumbaugh 38.• Guan Y, Kang R, Liu J: Evolution of the field of ecological DR, Cerny-Chipman EB, Close SL, Coblentz KE, de Nesnera restoration over the last three decades: a bibliometric analysis. KL, Drobnitch ST, et al. Long-term studies contribute dispro- Restoration Ecology 2019; 27:647–660. This paper uses bib- portionately to ecology and policy. Bioscience. 2017;67:271–81. liometric approach as a systematic and quantitative analysis 60. Sandler R. The value of species and the ethical foundations of of the evolution of the field of ecological restoration. assisted colonization. Conserv Biol. 2010;24:424–31. 39. Abad-Segura E, González-Zamar M-D, Vázquez-Cano E, López- 61. Maschinski J, Haskins KE: Plant reintroduction in a changing Meneses E. Remote sensing applied in forest management to climate: promises and perils; 2012. optimize ecosystem services: advances in research. Forests. 62. Volis S: Conservation-oriented restoration – a two for one 2020;11:969. method to restore both threatened species and their habitats. 40. Polinko A, Coupland K: Paradigm shifts in forestry and forest 2019. research: a bibliometric analysis. Canadian Journal of Forest 63. Benomar L, Lamhamedi MS, Rainville A, Beaulieu J, Bousquet Research 2020; 51. J, Margolis HA: Genetic adaptation vs. ecophysiological plastic- 41. Mongeon P, Paul-Hus A: The journal coverage of web of science ity of photosynthetic-related traits in young Picea glauca trees and scopus: a comparative analysis. Scientometrics 2015; 106. along a regional climatic gradient. Front Plant Sci 2016; 7. 42. R Core Team R: A language and environment for statistical 64. Aitken SN, Bemmels JB. Time to get moving: assisted gene flow computing. R Foundation for Statistical Computing, Vienna, of forest trees. Evol Appl. 2016;9:271–90. Austria. 2020. https:// www.R- proje ct. org/. 65. Wadgymar S, Cumming M, Weis A: The success of assisted 43. Ottolinger P: bib2df: Parse a BibTeX File to a Data Frame. R colonization and assisted gene flow depends on phenology. Glob package version 1.1.1. 2019. https://CRAN .R-pr oject. or g/pac ka Change Biol 2015; 21. ge= bib2df. 66. Menezes-Silva PE, Loram-Lourenço L, Alves RDFB, Sousa LF. 44. Garza-Reyes JA. Lean and green – a systematic review of the Almeida SEdS, Farnese FS: Different ways to die in a changing state of the art literature. J Clean Prod. 2015;102:18–29. world: consequences of climate change for tree species perfor- 45. van Leeuwen T, Costas R, Calero-Medina C, Visser M. The mance and survival through an ecophysiological perspective. role of editorial material in bibliometric research performance Ecol Evol. 2019;9:11979–99. assessments. Scientometrics. 2013;95:817–28. 67. Allen C, Macalady A, Bachelet D, McDowell N, Vennetier M, 46. van Eck NJ, Waltman LR: VOSviewer: A computer program Kitzberger T, Rigling A, Breshears D, Hogg EH, Gonzalez P, for bibliometric mapping. Erasmus Research Institute of Man- et al. A global overview of drought and heat-induced tree mortal- agement (ERIM), ERIM is the joint research institute of the ity reveals emerging climate change risks for forests. For Ecol Rotterdam School of Management, Erasmus University and the Manage. 2010;259:660–84. Erasmus School of Economics (ESE) at Erasmus Uni, Research 68. Mátyás C, Yeatman CW. Effect of geographical transfer on Paper 2009. growth and survival of jack pine (Pinus banksiana Lamb.) popu- 47. Newman MEJ. Modularity and community structure in networks. lations. Silvae Genetica. 1992;41:370–6. Proc Natl Acad Sci. 2006;103:8577–82. 69. Ledig TF, Kitzmiller JH. Genetic strategies for reforesta- 48. Small H, Garfield E. The g eography of science: disciplinary and tion in the face of global climate change. For Ecol Manage. national mappings. J Inf Sci. 1985;11:147–59. 1992;50:153–69. 49. Zhang J, Yu Q, Zheng F, Long C, Lu Z, Duan Z: Comparing key- 70. Andalo C, Beaulieu J, Bousquet J. The impact of climate change words plus of WOS and author keywords: a case study of patient on growth of local white spruce populations in Québec Canada. adherence research. Journal of the Association for Information For Ecol Manag. 2005;205:169–82. Science and Technology 2015; 67. 50. Liu X, Zhang L, Hong S. Global biodiversity research dur- Publisher's Note Springer Nature remains neutral with regard to ing 1900–2009: a bibliometric analysis. Biodivers Conserv. jurisdictional claims in published maps and institutional affiliations. 2011;20:807–26. 1 3 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Current Forestry Reports Springer Journals

Bibliometric Analysis of the Structure and Evolution of Research on Assisted Migration

Download PDF
15 pages

Loading next page...
 
/lp/springer-journals/bibliometric-analysis-of-the-structure-and-evolution-of-research-on-xAynfiLNah

References (89)

Publisher
Springer Journals
Copyright
Copyright © The Author(s) 2022
eISSN
2198-6436
DOI
10.1007/s40725-022-00165-y
Publisher site
See Article on Publisher Site

Abstract

Purpose of Review Assisted migration is increasingly proposed as a proactive management strategy to mitigate the con- sequences of maladaptation predicted under climate change. Exploring the social and academic structure of the field, its research gaps, and future research directions can help further the understanding and facilitate the implementation of assisted migration strategies. Here we used bibliometric analysis to examine the intellectual, social, and conceptual structures of assisted migration research to identify gaps and opportunities for future research. Bibliometric data based on publications on assisted migration were collected from Scopus and Web of Science databases using assisted migration and climate change or their synonyms as queries. Metadata were merged, processed and several networks were constructed. Recent Findings Co-citation and keyword co-occurrence networks identified three major clusters focused on (i) theory and risk of assisted migration of threatened and endangered species, (ii) impact of climate change on realized and fundamental climate and geographic niches, and (iii) assisted population migration. Collaboration network analysis identified three social core hubs: North America, Europe, and Australia, with the USA and Canada being the most productive and the most col- laborative countries. Summary We conclude that future research is expected to concern mainly the assessment of physiological response of spe- cies and populations to extreme climate events such as drought and frost, and the contribution of non-climatic factors and biotic interactions in local adaptation and population performance under climate change. Social core hubs distinguished in this work can be used to identify potential international research and training collaborators necessary to address gaps and challenges underlying assisted migration implementation. Keywords Bibliometrics · Network analysis · Assisted migration · Climate change · Conservation biology · Ecological restoration This article is part of the Topical Collection on Climate Change and Carbon Sequestration Introduction * Lahcen Benomar Anthropogenic climate change is having substantial impact lahcen.benomar2@uqat.ca on the composition and structure of native biodiversity lead- ing to shift associated with species distributions [1–3], and Forest Research Institute, University of Québec in Abitibi- Témiscamingue, Rouyn-Noranda, QC J9X 5E4, Canada • • ecosystem functioning [4, 5, 6 , 7 , 8]. Some species have shifted their distribution as they track their changing cli- Trois-Rivières, QC, Canada matic niche. These range shifts depend on species’ ability Department of Ecosystem Science and Management, to track changing abiotic cues and biotic interactions, and Pennsylvania State University, University Park, PA 16801, USA may lead to range contraction, fragmentation, or expansion •• [1, 9 , 10–14]. However, while some species maintain the Kalamalka Forestry Centre, Forest Improvement and Research Management Branch, BC, Ministry of Forests, capacity to track a shifting ecological niche [2, 15, 16], the Lands, Natural Resource Operations and Rural Development, vast majority may not be able to keep pace under rapid cli- 3401 Reservoir Road, Vernon, BC V1B 2C7, Canada mate change [17, 18]. Management Department, University of Quebec at Rimouski, Campus Lévis, Lévis, QC G6V 0A6, Canada Vol.:(0123456789) 1 3 200 Current Forestry Reports (2022) 8:199–213 Among the various strategies that have been proposed to various metrics (collaboration index, productivity index, manage species under climate change, assisted migration impact metrics, and hybrid metrics) (see Aria and Mas- (AM) is a proactive conservation and restoration strategy simo [33 ] for additional details). Relational studies that aims to limit species’ maladaptation by facilitating gene examine the relationships between units of analysis flow and transfer of genetic material that may be adapted (article, author, institution, journal, reference, and key- •• to the climate of the recipient environment [9 , 19–21]. word) within a research field and can be divided into AM, also called “assisted colonization,” “managed reloca- four types of analyses: co-citation analysis, bibliographic tion,” and “assisted gene flow” is defined as the intentional coupling, co-authorship analysis, and co-word analysis. movement of species or populations to regions predicted to Collectively, these four approaches allow assessment •• be suitable under future climate conditions [9 , 21, 22]. of the intellectual, social, and conceptual structure of According to the literature above, there are three categories a research area [34–37]. In this way, relational studies of assisted migration: can identify changing trajectories of research themes within a scientific field and the collaborative networks (i) Assisted population migration, also called assisted associated with those research themes [32, 36]. These gene flow, is the intentional movement of seed analyses can be used to visually illustrate the intellec- sources or populations to locations within a species’ tual structure of a field of research by identifying and current natural distribution. quantifying the inf luence of authors, sources (journals), (ii) Assisted range expansion is the intentional move- and articles in this field [34, 35]. The social structure ment of seed sources or populations to locations examines the relationships (the levels of scientific col- slightly beyond a species’ current natural distribu- laboration) between individual actors at different scales tion. (authors, institutions, and countries) based on jointly (iii) Exotic translocation is the intentional movement published documents [27]. The conceptual structure of species to locations that are predicted to be more examines the relation among keywords in a field, with suitable under future climate but distant from their aims to (i) structure knowledge into the research domain natural geographic range. or topic and (ii) identify potential knowledge gaps and future research themes. The latter are identified through Assisted migration could significantly reduce the evaluation of implicit gaps (identified in the literature) expected negative impacts of climate change [23, 24]. that have low co-occurrence [32]. However, devising and implementing a system of assisted For example, by investigating the evolution of ecological migration that will be safe, effective, and readily adopted restoration using a bibliometric analysis, Guan et al. [38 ] by practitioners requires multidisciplinary understanding highlighted the need to develop more international aca- of diverse fields including biology, climatology, geog- demic collaborations, together with techniques of manage- raphy, computer programming, and social science [25]. ment and monitoring of restored ecosystems, and the social Bibliometric analysis can assist in identifying research issues associated with this field. In a bibliometric analysis gaps and individuals active in collaborative networks of remote sensing applied in forest management, Abad- required for this work. Segura et al. [39] found that ecological sensitivity assess- Bibliometric analysis involves a set of quantitative ment, satellite fire mapping, topological acoustic sensing, explorations that aims to provide insight into the evo- unsupervised treetop detector, and air pollution mitigation lution of a given discipline, detect research gaps, and would be the predicted hotspots of future research in this describe the collaborative structure between academic research domain. A recent bibliometric analysis of tem- institutions or countries [26–28]. It also allows identifi- poral trends in frequencies of title words revealed a shift cation of authors actively contributing to a research field in research away from sustained-yield-based forestry and and those that have established a collaborative founda- towards a more interdisciplinary view of forests as ecologi- tion to build upon. Bibliometric analyses have become cally important and dynamic systems [40]. widely used in social and economic sciences and even The objectives of the study were to (i) examine the in basic sciences [28–32], but few bibliometric analyses intellectual, social, and conceptual structures of AM have been conducted within the field of forest science. research using bibliometric relational methods; (ii) Bibliometric studies are categorized into three types: examine the pattern and evolution of AM research; (iii) reviews, evaluative, and relational studies [28, 30, identify knowledge gaps and future research directions. 33 ]. Review studies often include literature reviews Together, these results will provide a roadmap for ongo- or meta-analyses, called “review methods” [28]. Evalu- ing research and implementation of AM, and identify ative studies measure the academic impact of articles gaps in the field that will benefit from new collaborative or authors associated with a given research field using research programs. 1 3 Current Forestry Reports (2022) 8:199–213 201 to identify the duplicates due to special characters and Materials and Methods those were inspected and deleted (n = 17) using a VBA custom script following [31], leaving 622 publications 1. Data Collection and Processing (194 and 64 exclusively from WOS and Scopus, respec- Bibliometric data were collected from the Web of tively and 364 shared between WOS and Scopus). A Science (WOS) and Scopus databases, the two larg- final step to accept or remove published material (eli - est multidisciplinary scientific databases. Previous gibility) was performed using the following criteria: studies have indicated substantial complementarity (i) non-English language publications were accepted if between these databases, arguing the importance of keywords, title, and abstract were provided in English using both to conduct a single integrated bibliomet- (n = 22); (ii) documents without ISSN (International ric investigation [31, 41]. We retrieved bibliometric Standard Serial Number) were removed (n = 1); and (iii) metadata related to assisted migration from these document types such as errata notes, conference papers, two databases between 1900 to 2020 using the fol- and short surveys were excluded (n = 8) [32, 44]. Con- lowing strings to query across titles, abstracts, and ference papers are often the initial product of ongoing keywords: (“assisted migration” or “assisted popula- research or synthesis of published material. As such, tion migration” or “assisted gene flow” or “assisted their impact is generally lower than original research colonization” or “assisted colonization” or “man- papers. Although editorial material is usually excluded aged relocation”) and (“climate change” or “global from bibliometric studies, we included this type of docu- change” or “climate-change” or “climatic change” or ment (n = 13) since they are relevant for the dissemina- “global warming”) and (Language = all) and (docu- tion of scientific knowledge [ 45] (Table 1). The final ment type = All document types). This query syntax dataset contained 614 articles (Fig. 1). was used to identify articles where assisted migration 2. Thesaurus Construction is proposed as a climate change adaptation strategy, Text data mining and the construction of a thesaurus while avoiding documents on assisted migration from are crucial to keyword co-occurrence-based analysis. other fields such as chemistry, physics, and social sci- ences. The search yielded 561 and 425 publications in WOS and Scopus, respectively, and the data were Table 1 Descriptive statistics of the database downloaded as BIBTEX and CSV files, respectively. Bibliometric data were processed and analyzed in Description Results R version (4.0.0) [42]. First, metadata files associated Main information with each database (WOS or Scopus) were loaded,   Sources (journals, books, etc.) 220 transformed into a data frame, and merged in one step   Documents 614 using the function bib2df of the Bibliometrix R package   Average number of citations per document 28.52 [43]. Second, variables within the two datasets (WOS   Average number of citations per year per document 3.35 and Scopus) were shortened to 18 common and relevant   References 29,406 variables (“Authors,” “Author Keywords (ISI),” “Index Document type Keywords (Scopus),” “Affiliations,” “Document Type,”   Article 493 “Source title,” “Cited by,” “Bibliographic Database,”   Book chapter 21 “References,” “Abstract,” “Correspondence Address,”   Editorial material 13 “Title,” “Year,” “Country of affiliation for the first   Letter 10 author,” “Country of affiliation for co-authors,” “Uni -   Proceedings paper 10 versity of affiliation for each co-author and the corre -   Review 67 sponding author,” “Language”, “ISSN”), and the two Document content data frames were merged. Duplicated documents were   Keywords Plus (ID) 2002 removed from the merged data frame using duplicated-   Author’s Keywords (DE) 1814 Matching function of the Bibliometrix R package [33 ]. Authors The abstract was used as the tag variable to identify   Authors 1952 duplicated records, and the minimum relative similar-   Author appearances 2759 ity (MRS) was set to 0.85. Three hundred forty-seven   Authors of single-authored documents 47 duplicate records were identified and removed, leaving   Authors of multi-authored documents 1905 639 unique publications based on our search criteria. For Author’s collaboration documents with title and abstract published in bilingual   Average co-authors per document 4.49 format, the duplicatedMatching function was unable   Collaboration index 3.39 1 3 202 Current Forestry Reports (2022) 8:199–213 Fig. 1 Flowchart diagram illustrating the data processing steps The use of plural or singular (e.g., range shifts/range The co-authors per document index was calculated as shift; ecosystem/ecosystems; provenance test/prove- The number of co-authors per document/The number of nance tests) or different synonyms for the same keyword documents, and the collaboration index (CI) was calcu- (e.g., climate change, global change, global warming, lated as Total authors of multi-authored articles/Total climatic change/climate-change) is a common issue that multi-authored articles [33 ]. directly affects both the frequency and co-occurrence of For each network illustration, clusters are distin- keywords. guished by color, while the size of each node ref lects We constructed a thesaurus file manually by group- its occurrence. The shorter the distance between two ing all synonyms and plural or singular forms of key- nodes, the more closely connected they are. Finally, words under the same word, except synonyms for the thickness of the connection between two nodes assisted migration to show their co-occurrence. We indicates the strength of their relationships [33 ]. also merged keywords containing two or three words Clustering was performed using the LinLog algo- that were wrongly separated by removing semicolons rithm and the modularity clustering technique, where to create uniformity among multi-word keywords. the weighted sum of the squared Euclidean distances For example, we replaced “range; shift” by “range with all pairs of nodes is minimized [47]. Nodes were shift,” “local; adaptation,” by “local adaptation,” and then assigned to clusters based on their similarities “assisted migration,” by “assisted migration”. (related to co-occurrences). 3. Analysis Using Bibliometrix and VOSviewer The intellectual structure of a discipline can be Descriptive statistics (average number of publica- assessed by examining the inf luence of authors or tions per year, most productive author, most productive articles and their connectivity, which is quantified by institutions, most productive countries, and most cited examining the relationship between pairs of authors author) were calculated using Bibliometrix R package (or articles) based on the frequency of their co-cita- [33 ], and network analyses were conducted to assess tion in other articles. We constructed distance-based the social, intellectual, and conceptual structure of our co-citation networks [37] in VOSviewer to identify final dataset (Fig.  1) using VOSviewer software [37, 46]. the most active authors in the research field, based on 1 3 Current Forestry Reports (2022) 8:199–213 203 the number of papers published, the number of local citations (citation of a given author within the field of AM) as well as their influence in structuring the knowledge on AM. The minimum number of citations for authors or articles was set to 10 during network construction. The social structure of AM research was assessed using the co-authorship network to identify connec- tions between authors, institutions, or countries based on jointly authored publications [37]. The conceptual structure examines the relations among words in the bibliometric database. This analysis aims to (i) structure the knowledge into the research domains or topics and (ii) highlight the most frequently covered topics and identify trends Fig. 2 Annual number of assisted migration-related articles from that may allow prediction of possible future lines of 2007 to 2020 obtained from Web of Science and Scopus research. We assessed keyword co-occurrence net- work using author keywords in VOSviewer [37, 46]. The minimum occurrence of a keyword was set to 1. Intellectual Structure four. Web of Science provides another category of keywords named “KeyWords Plus” which are gener- Based on the number of published articles, our results showed that the most productive author in the field of ated using algorithms based on the title of references cited in an article. The overlap between KeyWords assisted migration is Cuauhtémoc Saenz-Romero from Instituto de Investigaciones Sobre los Recursos Naturales Plus and titles of papers may reach 50% [47]. Simi- larly, Scopus provides '”Indexed keywords'” which (Mexico), followed by Andreas Hamann from the University of Alberta, Canada (Fig. 3). The 15 most productive authors are chosen by content suppliers. The use of Key- Words Plus or Indexed keywords to complement the were from the forest ecology and management domain with research emphasizing commercial forest tree species author keywords may consolidate author keyword- based analysis [48, 49]. However, the similarity (Fig. 3). The two most cited authors were Gerald Rehfeldt from US Forest Service (USA) and Jason McLachlan from between Index keywords and KeyWords Plus has not yet been documented, making their use in merged the University of Notre Dame (USA) based on local cita- tions. Lack of correspondence between author productivity databases not recommended. (publication number) and influence (local citation) may be due, in part, to the novelty of an author’s research topics Results and Discussion (particularly if more recently introduced topics or ideas have not had the time to garner citations), or gender, or race or Since the first publications on assisted migration as a country bias [51–53]. Regarding institutions, the University of British Columbia (Canada), North Arizona University climate change adaptation strategy in 2007, the num- ber of publications per year increased rapidly from 4 to (USA) and University of Alberta (Canada) were the three most productive institutions in terms of published papers 75 between 2007 to 2015 thereafter f luctuated moder- ately (Fig. 2), the average publication per year was 43.8. (Fig. 3). These results regarding the intellectual structure of the field of assisted migration may help guide researchers Research articles and reviews account for 91% of the total publications (Table 1). Multi-authored documents when planning research and future collaboration. The co-citation network consisted of 81 nodes forming contained an average of 4.5 authors, with only 6% of the documents being single-authored. The collaboration three clusters (Fig. 4), with each node representing one co- cited document (Fig. 4a) or one co-cited author (Fig. 4b). index (CI) averaged 3.4 (Table 1) and was highest dur- ing the 2017–2020 period (CI = 4.49) compared with Node size is proportional to its number of citations. The green cluster (Fig. 4b) consisted primarily of plant and ani- the 2007–2011 (CI = 3.66) and 2012–2016 (CI = 3.48) periods. The same temporal pattern in collaboration was mal conservation ecologists who have focused on theory, foundation, and risk of AM. This group was comprised of observed in the field of biodiversity research [50]. These results point towards the growing emphasis on collabora- at least five authors: Ove Hoegh-Guldberg (University of Queensland, Australia), Jason S. McLachlan (University of tion for assisted migration research. Notre Dame, USA), Anthony Ricciardi (McGill University, 1 3 204 Current Forestry Reports (2022) 8:199–213 cluster (red) focused on assisted population migration for forest tree species with an emphasis on modeling growth and ecophysiology. Together, the foundational theory underlying the shift of the ecological niche and its evolutionary conse- quences for species under climate change are represented by authors in the blue cluster (Fig. 4b) with empirical testing, monitoring, and application of assisted migration research to conservation and restoration by authors in the green and red clusters (Fig. 4b). To examine the evolution of intellectual influence in structuring knowledge of assisted migration research for each cluster, the data collected between 2007 and 2020 were divided into three time periods. During the first period (2007–2011), the green and blue clusters (Fig. 5a) were the most prominent communities producing publications on the theoretical foundation of species range shifts due to climate change. This research provided a framework for assessing ecological benefits and risks associated with AM as a con- servation option [3, 19, 21, 22]. During the second period (2012–2016), based on the size and position of the node, some prominent authors (e.g., Schwartz M; Thomas CD; Hunter ML) within the first period (Fig.  5a) became less influential relative to other authors (e.g., Ricciardi A; Hewitt N; Pedar JH) (Fig.  5b). The blue cluster narrowed while the red cluster expanded and became more structured with reduced distance between members. The red cluster, an intel- lectual community dominated by forest geneticists [20, 55, 57], became more numerous with strong linkages among its members. During the third period (2017–2020), the pat- tern observed in the second period was accentuated for all groups (Fig. 5c). Shifts in authorship suggest that research on assisted migration is expanding into new research areas Fig. 3 The most productive authors (a), the most cited authors (b), with an influx of new authors (e.g., Isaac-Renton MG, Val- and the most productive institutions (c) in assisted migration-related. ladares F; Hamann A; Gray LK; Jump AS) from differ - U, university ent disciplines, such as ecophysiology, growth modeling, and seedling production, to complement existing theory Canada), David M. Richardson (Stellenbosch University, (Fig. 5c). Over time, the three clusters had distinct trajecto- South Africa), and Mark W. Schwartz (University of Cali- ries and dynamics, and highlight the following aspects: (i) fornia at Davis, USA) who initiated the debate of using AM the green cluster (working mainly on long-distance AM) as a conservation strategy to mitigate the consequence of cli- had a slower evolution with limited empirical data needed mate change on the distribution of species [19, 21, 22, 54]. to shift to a new structure; (ii) the blue cluster might disap- Authors within the blue cluster (Fig. 4b) were mostly ecolo- pear in the next few years as the theoretical foundations of gists who have assessed the impact of climate change on AM (e.g., the shift in species ecological niche under climate species’ geographical distributions and range shifts (Fig. 4a). change) now appear to have sufficient empirical support; The authors Camille Parmesan (University of Plymouth, (iii) inversely, the dynamic evolution observed within the USA) and Chris D. Thomas (University of York, UK) were red cluster is more likely to quickly achieve a new structure the prominent members of this cluster [3]. The red clus- and might dominate the AM research for the coming years. ter (Fig. 4b) was comprised of forest geneticists who have The rapid evolution of the red cluster may originate from (i) conducted population genetics studies, often using prov- the economic impact of climate change on forest productiv- enance trials and molecular data for commercial forest trees ity and (ii) the long history of growing trees in provenance (Fig. 4a). The most prominent authors within this cluster trials established many decades ago (starting from the 40 s were Sally N. Aitken (UBC, Canada) and Gerald E. Rehfeldt for some species) which provides a laboratory to test the (US Forest Service, USA). Ten additional authors in this impact of climate change and assisted population migration 1 3 Current Forestry Reports (2022) 8:199–213 205 Fig. 4 Co-citation network of assisted migration research based on a The shorter the distance between two nodes, the more closely con- articles and b authors. Each cluster is represented by a color. The size nected they are (based on their co-citation) of a node (author or article) reflects the number of received citations. •• on species’ success [9 , 55, 56]. The data from these tri- and funders are not informed or sufficiently convinced als has been essential in the development of seed transfer of the potential benefit of AM research, or that natural models and the implementation of assisted migration [23, sciences funding cycles are unable to support long-term 25, 57, 58]. research needed on assisted migration [59]. Moreover, the intellectual structure of AM research might yet change since research on AM is still relatively 2. Social Structure new (15 years) with limited publications when compared with other similar research fields. Furthermore, securing Collaborations between countries were explored by funds to support extensive research on AM is still chal- examining co-authorship networks (Fig.  6). Our results lenging. This may reflect the fact that both stakeholders identified clusters representing four collaborative groups: 1 3 206 Current Forestry Reports (2022) 8:199–213 1 3 Current Forestry Reports (2022) 8:199–213 207 ◂Fig. 5 The network map of authors’ co-citation for a the period from North America and Europe, with greater collaboration 2007 to 2011, b the period from 2012 to 2016, and c the period from between Canada and Germany, and groups in the USA col- 2017 to 2020. Each cluster is represented by a color laborating primarily with the UK. Collaborations between North America and Europe were more frequent than collabo- the blue cluster was composed of North American coun- rations within Europe. The same pattern was observed with tries (USA, Canada, and Mexico) and China, and within the green cluster where collaborations between USA and this group, the most prolific teams were from Canadian Australia were more frequent than collaboration within the and US institutions. The green cluster included Australia, group led by Australia. In Europe, most frequent collabora- South Africa, and New Zealand, and was led by Australia tions were observed between the UK and Germany (Fig. 6). according to the size of the nodes. The red and yellow Greater productivity of Canadian and US authors and institu- clusters included European countries identifying German tions might be due in part to the awareness of rapid climate and British research groups as the most active (Fig. 6). change of northern countries relative to tropical or southern Substantial collaboration was observed between the USA countries, their substantial economic dependence on for- and Canada relative to all other countries (Fig. 6). Interest- estry, and the greater amount of research resources available ingly, the network also identified collaborations between in the global North than in the global South. Fig. 6 The network map of country collaborations based on corresponding author affiliations of assisted migration research. Each cluster is represented by a color. The size of the node represents the productivity of the country (the number of pub- lications in collaboration with other countries). The shorter the distance between two nodes, the more closely connected they are (based on co-authored articles) 1 3 208 Current Forestry Reports (2022) 8:199–213 Fig. 7 The network map of author keywords co-occurrence of of a keyword. The distance between nodes is proportional to the fre- assisted migration research. Each cluster is represented by a color. quency of keywords co-occurrence The size of the node is proportional to the number of occurrences 3. Conceptual Structure species (Fig. 7). The red cluster (37 keywords) was domi- nated by the terms: assisted migration, climate change, Seventy-one keywords that occurred at least 4 times populations, adaptation strategies, plasticity, gene- were identified. They were grouped into three distinct cology, and local adaptation. These terms referred to clusters (Fig. 7) based on their co-occurrence. The blue assisted population migration used for forest tree species. cluster (11 keywords) was mainly represented by the fol- We noted that ecologists have been mostly working on lowing terms: species distribution, distribution model, the second and third categories of AM (green cluster), and range shifts. This cluster was mainly focused on the usually using the terms assisted colonization or managed shift in species distribution as a response or a conse- relocation rather than assisted migration.) quence of climate change and on different approaches to model the ecological niche. The green cluster (23 4. Research Gaps and Future Directions keywords) was dominated by the terms: climate change adaptation, conservation, biodiversity, assisted coloniza- The temporal scaling of the keyword co-occurrence tion, managed relocation, translocation, and ecological network (Fig.  7) showed different patterns of research restoration. This cluster corresponded to research on AM evolving within each cluster (Fig. 8). The terms in blue of species as a proactive conservation and management are linked to early research done before 2014 (average strategy under climate change. This cluster focused on publication year) (Fig. 8). They are generally from the the theoretical conceptualization, debate, and arguments green and blue clusters in Fig.  7 and correspond to the on the impact of action or inaction regarding the deploy- second and third categories of AM. The emerging terms ment of such a strategy for endangered and vulnerable from these clusters were vulnerability (assessment), 1 3 Current Forestry Reports (2022) 8:199–213 209 Fig. 8 The network map of author keywords co-occurrence indexed per publication year. The keywords were colored based on the average pub- lication year ecological restoration, range shift, and species distribu- restoration. In addition, research assessing biotic inter- tion models (Fig. 8), and each exhibited linear to expo- actions of the introduced species in their new ecosystem nential growth as keywords over time (Fig.  9). Within is needed for effective species translocation. For exam- these clusters, terms such as conservation, biodiversity, ple, assisted migration of forest trees should consider and species distribution showed a quadratic pattern with above- and below-ground interactions, including existing a decrease in their occurrence from 2015. As a conser- f lora, predominant pests, pollinators, and grazing fauna vation strategy, assisted migration for threatened and alongside below-ground communities. endangered species has been controversial [19, 21, 22, Research related to assisted population migration was 54, 60]. Traditional conservation failed for several spe- more recent compared to the second and third catego- cies reintroductions [61] because species establishment ries of assisted migration (Fig. 8). Within the red cluster was likely limited by the ontogenetic niche rather than (assisted population migration), research was focused the climatic niche [62]. Species establishment is a com- initially on the genetic structure of species popula- plex ecological process which depends on different biotic tions (2015 on average), followed by the investigation and abiotic factors and their interactions, such as pres- of growth-climate relationships, which was facilitated ence of pollinators, mycorrhizas, herbivory pressure, by the availability of growth data from old provenance pathogens or competitors, and habitat physico-chemical tests (2016). More recently (2017 to 2020), research on parameters required for seeds germination and seed- assisted population migration focused on forest man- ling establishment. Conservation-oriented restoration agement, local adaptation, plasticity, and drought and appeared to be the optimal strategy because it integrates frost-related traits (bud burst, bud set and cold hardiness) both climate and ontogenetic niches in the process of where research on local adaptation and mortality has species translocation [62]. The linear increase of research grown linearly, and exponentially for drought (Fig. 9). on ecological restoration (Fig. 9) suggests an increased The growing interest of research in local adaptation interest in both biodiversity conservation and habitat and plasticity of functional traits were related to their 1 3 210 Current Forestry Reports (2022) 8:199–213 Fig. 9 The number of occurrences of author keywords that have increasing or decreasing patterns in assisted migration-related articles crucial role in species adaptation to climate change and change which represents an additional challenge for the •• therefore to resilience capacity [9 , 20, 63]. The fifth implementation of assisted migration [64, 65]. This may report of Intergovernmental Panel on Climate Change [5] have contributed to stimulate research on adaptation highlighted an increase in the frequency and severity of to frost and drought events. Then, we expect intensive extreme climate events (frost and drought) under climate research on the assessment of the specific responses of 1 3 Current Forestry Reports (2022) 8:199–213 211 species populations to both drought and frost events in translocation, which may largely be contingent on eco- the future. An important additional issue in the response nomic interest. The network analysis demonstrated that of tree populations to climate change is the noticeable the knowledge was structured in three intellectual and increase of mortality of forest trees (Fig.  8) which is conceptual groups working on species distribution, exotic attributable mostly to the effect of more frequent extreme translocation, and assisted population migration. drought events [66, 67]. Finally, more research on the Our work provides new insights into the development role of microbiome and epigenetics in the adaptation to of research on assisted migration of forest trees under climate change and the development of a new generation climate change. For example, to minimize the mortality of seed transfer models is needed. This research should and vulnerability of forest trees, our bibliometric analysis consider growth-climate relationships, drought and frost indicates that the research on the consequences of extreme tolerance, and interactions between the translocated spe- climatic events like drought and frost anomalies is a prom- cies and their biotic environment. ising avenue. Therefore, the development of research on the physiological basis of drought and frost tolerance in trees and the interaction with increased atmospheric C O Study Limitations is crucial. In addition, assessing the potential role of epi- genetic memory to traits variation may help improve the We acknowledge two limitations to our analysis which prediction of drought and frost impacts to plant fitness. likely resulted in our failing to locate all articles dealing In addition, new research themes linked to the observed with AM. First, our search could not detect articles that growing interest in ecological conservation may include focused on AM but did not explicitly use “assisted migra- the contribution of soil properties (physics, chemistry, and tion: or its synonyms. For example, Mátyás and Yeatman microbiome) and the impact of biotic interactions on local (1992) [68], who developed a seed transfer model for jack adaptation patterns for different tree species. Overall, this pine and discussed its use to define safe ecological trans- bibliometric analysis points towards the need to establish fer distance, and Ledig and Kitzmiller (1992) [69], who new, long-term experiments that expand international col- recommended establishing plantations with populations laborations and foster development of interdisciplinary from climates that are warmer than the plantation site cli- toolkits to fill existing and evolving knowledge gaps that mate, are not included in our study because they did not are important to assisted migration and its application to use the term “assisted migration” or any of its synonyms. conservation and restoration. Despite not being recorded in our database, the authors Mátyás and Ledig figured in the intellectual structure Funding This research was supported by the University of Québec in (Fig. 5). The second limitation is related to the standard Abitibi-Témiscamingue (UQAT) through startup funds to ML. search engines used, which looked at the term “assisted migration” or its synonyms in titles, article keywords, Data Availability The datasets generated for this study are available and abstracts, but not in the text. This limitation likely upon request to the corresponding author. excluded some articles, such as Andalo et al. (2005) [70], Code Availability R codes are available upon request to the correspond- who developed a seed transfer model for white spruce. ing author. The article did not use the term “assisted migration” in the title, keywords, or abstract but evoked its potential Declarations use in the discussion section. More accurate search tools using novel approaches like machine learning would be Conflict of Interest The authors declare no competing of interests. more efficient in detecting articles in the “blind spots” of conventional search engines. Human and Animal Rights and Informed Consent This article does not contain any studies with human or animal subjects performed by any of the authors. Conclusion and Perspectives Open Access This article is licensed under a Creative Commons Attri- bution 4.0 International License, which permits use, sharing, adapta- This study showed that much of the research on assisted tion, distribution and reproduction in any medium or format, as long migration has been carried out in North America, as you give appropriate credit to the original author(s) and the source, where Canada and the USA have established strong col- provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are laborative networks. Canada–USA collaborations have included in the article's Creative Commons licence, unless indicated emphasized research related to assisted migration of otherwise in a credit line to the material. If material is not included in populations for forest trees, compared to other research the article's Creative Commons licence and your intended use is not categories, including assisted range expansion and exotic 1 3 212 Current Forestry Reports (2022) 8:199–213 permitted by statutory regulation or exceeds the permitted use, you will 13. Muffler L, Beier kuhnlein C, Aas G, Jentsch A, Schweiger AH, need to obtain permission directly from the copyright holder. To view a Zohner C, Kreyling J. Distribution ranges and spring phenol- copy of this licence, visit http://cr eativ ecommons. or g/licen ses/ b y/4.0/ . ogy explain late frost sensitivity in 170 woody plants from the Northern Hemisphere. Glob Ecol Biogeogr. 2016;25:1061–71. 14. Bai Y, Wei X, Li X: Distributional dynamics of a vulnerable species in response to past and future climate change: a window for conservation prospects. PeerJ 2018; 2018. References 15. Hill JK, Griffiths HM, Thomas CD. Climate change and evolu- tionary adaptations at species’ range margins. Annu Rev Ento- Papers of particular interest, published recently, have mol. 2011;56:143–59. been highlighted as: 16. Aguilée R, Raoul G, Rousset F, Ronce O. Pollen dispersal slows geographical range shift and accelerates ecological niche shift • Of importance under climate change. Proc Natl Acad Sci. 2016;113:E5741–8. •• Of major importance 17. McLachlan JS, Clark JS, Manos PS. Molecular indicators of tree migration capacity under rapid climate change. Ecology. 1. Davis MB, Shaw RG. Range shifts and adaptive responses to 2005;86:2088–98. Quaternary climate change. Science. 2001;292:673–9. 18. Ash JD, Givnish TJ, Waller DM. Tracking lags in historical 2. Chen I-C, Hill JK, Ohlemüller R, Roy DB, Thomas CD. Rapid plant species’ shifts in relation to regional climate change. Glob range shifts of species associated with high levels of climate Change Biol. 2017;23:1305–15. warming. Science. 2011;333:1024–6. 19. McLachlan JS, Hellmann JJ, Schwartz MW. A framework for 3. Parmesan C, Ryrholm N, Stefanescu C, Hill J, Thomas C, Desci- debate of assisted migration in an era of climate change. Conserv mon H, Huntley B, Kaila L, Kullberg J, Tammaru T, et al. Pole- Biol. 2007;21:297–302. ward shifts of species’ ranges associated with regional warming. 20. Aitken SN, Whitlock MC: Assisted gene flow to facilitate local Nature. 1999;399:579–83. adaptation to climate change. In Annual Review of Ecology, 4. Williams JW, Jackson ST, Kutzbach JE. Projected distributions Evolution, and Systematics. Edited by: Annual Reviews Inc.; of novel and disappearing climates by 2100 AD. Proc Natl Acad 2013:367–388. vol 44. Sci USA. 2007;104:5738–42. 21. Hoegh-Guldberg O, Hughes L, McIntyre S, Lindenmayer 5. IPCC: Climate change 2014: Impacts, adaptation, and vulner- DB, Parmesan C, Possingham HP, Thomas CD. Ecology: ability. Part a: Global and sectoral aspects. Contribution of work- Assisted colonization and rapid climate change. Science. ing group ii to the fifth assessment report of the intergovern - 2008;321:345–6. mental panel on climate change. Edited by. Cambridge, United 22. Richardson DM, Hellmann JJ, McLachlan JS, Sax DF, Schwartz Kingdom and New York, NY, USA: Cambridge University MW, Gonzalez P, Brennan EJ, Camacho A, Root TL, Sala OE, Press; 2014:1132. et al. Multidimensional evaluation of managed relocation. Proc 6.• Blowes SA, Supp SR, Antao LH, Bates A, Bruelheide H, Chase Natl Acad Sci USA. 2009;106:9721–4. JM, Moyes F, Magurran A, McGill B, Myers-Smith IH, et al.: 23. Wang T, O’Neill GA, Aitken SN. Integrating environmental The geography of biodiversity change in marine and terrestrial and genetic effects to predict responses of tree populations to assemblages. Science 2019; 366:339. This paper is useful to climate. Ecol Appl. 2010;20:153–63. understand spatial variation in species richness and composi- 24. Nigh G. Mitigating the effects of climate change on lodgepole tion change and provides an important criterion for target- pine site height in British Columbia, Canada, with a transfer ing conservation. function. Forestry. 2014;87:377–87. 7.• Butt N, Chauvenet ALM, Adams VM, Beger M, Gallagher RV, 25. O'Neill G, Wang T, Ukrainetz N, Charleson L, McAuley L, Yan- Shanahan DF, Ward M, Watson JEM, Possingham HP: importance chuk A, Zedel S: A proposed climate-based seed transfer system of species translocations under rapid climate change. Conservation for British Columbia. Edited by Ministry of Forests LaNRO. Biology 2020. This paper presents practical recommendations British Columbia. Ministry of Forests, Lands and Natural to advance assisted migration as a conservation tool. Resource Operations; 2017. 8. Clark JS, Andrus R, Aubry-Kientz M, Bergeron Y, Bogdziewicz 26. McBurney M, Novak P: What is bibliometrics and why should M, Bragg DC, Brockway D, Cleavitt NL, Cohen S, Courbaud B, you care?; 2002. IEEE International Professional Communica- et al. Continent-wide tree fecundity driven by indirect climate tion Conference. 108 - 114. https://doi. or g/10. 1109/ IPCC. 2002. effects. Nat Commun. 2021;12:1242. 10490 94. 9.•• Aitken SN, Yeaman S, Holliday JA, Wang TL, Curtis-McLane S: 27. Glänzel W: Bibliometrics as a research field: a course on theory Adaptation, migration or extirpation: climate change outcomes and application of bibliometric indicators. Course Handouts for tree populations. Evolutionary Applications 2008; 1:95–111. In this review, the authors highlighted the question of the 28. Zupic I, Cater T. Bibliometric methods in management and fate of forest tree populations and identified three potential organization. Organ Res Methods. 2015;18:429–72. responses to a rapidly changing environment: migration, 29. Boyack K, Borner K, Klavans R. Mapping the structure and adaptation, or extinction. evolution of chemistry research. Scientometrics. 2009;79:45–60. 10. Moir ML, Vesk PA, Brennan KEC, Poulin R, Hughes L, 30. Johnson A-G, Samakovlis I: A bibliometric analysis of knowl- Keith DA, McCarthy MA, Coates DJ. Considering extinction edge development in smart tourism research. Journal of Hospi- of dependent species during translocation, ex situ conserva- tality and Tourism Technology 2019; 10. tion, and assisted migration of threatened hosts. Conserv Biol. 31. Echchakoui S. Why and how to merge Scopus and Web of Sci- 2012;26:199–207. ence during bibliometric analysis: the case of sales force litera- 11. Thomas LF, Rehfeldt GE, Sáenz-Romero C, Flores-López C. ture from 1912 to 2019. J Mark Anal. 2020;8:165–84. Projections of suitable habitat for rare species under global 32. Oliveira O, da Silva F, Juliani F, Ferreira L, Barbosa L, Nunhes warming scenarios. Am J Bot. 2010;97:970–87. T: Bibliometric method for mapping the state-of-the-art and 12. Parmesan C, Hanley ME. Plants and climate change: complexi- identifying research gaps and trends in literature: an essential ties and surprises. Ann Bot. 2015;116:849–64. instrument to support the development of scientific projects. In 1 3 Current Forestry Reports (2022) 8:199–213 213 Scientometrics Recent Advances; IntechOpen: Rijeka, Croatia, 51. Singh D: Publication bias - a reason for the decreased research 2019; p. 13. ISBN 978–1–78984–713–0. output in developing countries. Afr J Psychiatry 2006; 9. 33.• Aria, Massimo: bibliometrix: An R-tool for comprehensive sci- 52. Mulimani P. Publication bias towards Western populations harms ence mapping analysis. Journal of Informetrics 2017; 11:959– humanity. Nat Hum Behav. 2019;3:1026–7. 975. This paper propose an R-package that help to perform 53. Huang J, Gates AJ, Sinatra R, Barabási A-L. Historical compari- a comprehensive science mapping analysis of scientific son of gender inequality in scientic fi careers across countries and literature. disciplines. Proc Natl Acad Sci. 2020;117:4609. 34. Boyack K, Klavans R. Co-citation analysis, bibliographic cou- 54. Ricciardi A, Simberloff D. Assisted colonization is not a viable pling, and direct citation: which citation approach represents the conservation strategy. Trends Ecol Evol. 2009;24:248–53. research front most accurately? J Am Soc Inform Sci Technol. 55. Mátyás C. Modeling climate change effects with provenance test 2010;61:2389–404. data. Tree Physiol. 1994;14:797–804. 35. Cobo M, López-Herrera AG, Herrera-Viedma E, Herrera F. 56. Mátyás C. Climatic adaptation of trees: rediscovering prove- Science mapping software tools: review, analysis, and coop- nance tests. Euphytica. 1996;92:45–54. erative study among tools. J Am Soc Inform Sci Technol. 57. O’Neill GA, Hamann A, Wang T. Accounting for population 2011;62:1382–402. variation improves estimates of the impact of climate change on 36. Benckendorff P, Zehrer A. A network analysis of tourism species’ growth and distribution. J Appl Ecol. 2008;45:1040–9. research. Ann Tour Res. 2014;43:121–49. 58. Pedlar JH, McKenney DW, Aubin I, Beardmore T, Beaul- 37. van Eck NJ, Waltman L. Visualizing bibliometric networks. In: ieu J, Iverson L, O’Neill GA, Winder RS, Ste-Marie C. Plac- Ding Y, Rousseau R, editors. Measuring scholarly impact: meth- ing forestry in the assisted migration debate. Bioscience. ods and practice. Wolfram D: Springer International Publishing; 2012;62:835–42. 2014. p. 285–320. 59. Hughes B, Beas-Luna R, Barner AK, Brewitt K, Brumbaugh 38.• Guan Y, Kang R, Liu J: Evolution of the field of ecological DR, Cerny-Chipman EB, Close SL, Coblentz KE, de Nesnera restoration over the last three decades: a bibliometric analysis. KL, Drobnitch ST, et al. Long-term studies contribute dispro- Restoration Ecology 2019; 27:647–660. This paper uses bib- portionately to ecology and policy. Bioscience. 2017;67:271–81. liometric approach as a systematic and quantitative analysis 60. Sandler R. The value of species and the ethical foundations of of the evolution of the field of ecological restoration. assisted colonization. Conserv Biol. 2010;24:424–31. 39. Abad-Segura E, González-Zamar M-D, Vázquez-Cano E, López- 61. Maschinski J, Haskins KE: Plant reintroduction in a changing Meneses E. Remote sensing applied in forest management to climate: promises and perils; 2012. optimize ecosystem services: advances in research. Forests. 62. Volis S: Conservation-oriented restoration – a two for one 2020;11:969. method to restore both threatened species and their habitats. 40. Polinko A, Coupland K: Paradigm shifts in forestry and forest 2019. research: a bibliometric analysis. Canadian Journal of Forest 63. Benomar L, Lamhamedi MS, Rainville A, Beaulieu J, Bousquet Research 2020; 51. J, Margolis HA: Genetic adaptation vs. ecophysiological plastic- 41. Mongeon P, Paul-Hus A: The journal coverage of web of science ity of photosynthetic-related traits in young Picea glauca trees and scopus: a comparative analysis. Scientometrics 2015; 106. along a regional climatic gradient. Front Plant Sci 2016; 7. 42. R Core Team R: A language and environment for statistical 64. Aitken SN, Bemmels JB. Time to get moving: assisted gene flow computing. R Foundation for Statistical Computing, Vienna, of forest trees. Evol Appl. 2016;9:271–90. Austria. 2020. https:// www.R- proje ct. org/. 65. Wadgymar S, Cumming M, Weis A: The success of assisted 43. Ottolinger P: bib2df: Parse a BibTeX File to a Data Frame. R colonization and assisted gene flow depends on phenology. Glob package version 1.1.1. 2019. https://CRAN .R-pr oject. or g/pac ka Change Biol 2015; 21. ge= bib2df. 66. Menezes-Silva PE, Loram-Lourenço L, Alves RDFB, Sousa LF. 44. Garza-Reyes JA. Lean and green – a systematic review of the Almeida SEdS, Farnese FS: Different ways to die in a changing state of the art literature. J Clean Prod. 2015;102:18–29. world: consequences of climate change for tree species perfor- 45. van Leeuwen T, Costas R, Calero-Medina C, Visser M. The mance and survival through an ecophysiological perspective. role of editorial material in bibliometric research performance Ecol Evol. 2019;9:11979–99. assessments. Scientometrics. 2013;95:817–28. 67. Allen C, Macalady A, Bachelet D, McDowell N, Vennetier M, 46. van Eck NJ, Waltman LR: VOSviewer: A computer program Kitzberger T, Rigling A, Breshears D, Hogg EH, Gonzalez P, for bibliometric mapping. Erasmus Research Institute of Man- et al. A global overview of drought and heat-induced tree mortal- agement (ERIM), ERIM is the joint research institute of the ity reveals emerging climate change risks for forests. For Ecol Rotterdam School of Management, Erasmus University and the Manage. 2010;259:660–84. Erasmus School of Economics (ESE) at Erasmus Uni, Research 68. Mátyás C, Yeatman CW. Effect of geographical transfer on Paper 2009. growth and survival of jack pine (Pinus banksiana Lamb.) popu- 47. Newman MEJ. Modularity and community structure in networks. lations. Silvae Genetica. 1992;41:370–6. Proc Natl Acad Sci. 2006;103:8577–82. 69. Ledig TF, Kitzmiller JH. Genetic strategies for reforesta- 48. Small H, Garfield E. The g eography of science: disciplinary and tion in the face of global climate change. For Ecol Manage. national mappings. J Inf Sci. 1985;11:147–59. 1992;50:153–69. 49. Zhang J, Yu Q, Zheng F, Long C, Lu Z, Duan Z: Comparing key- 70. Andalo C, Beaulieu J, Bousquet J. The impact of climate change words plus of WOS and author keywords: a case study of patient on growth of local white spruce populations in Québec Canada. adherence research. Journal of the Association for Information For Ecol Manag. 2005;205:169–82. Science and Technology 2015; 67. 50. Liu X, Zhang L, Hong S. Global biodiversity research dur- Publisher's Note Springer Nature remains neutral with regard to ing 1900–2009: a bibliometric analysis. Biodivers Conserv. jurisdictional claims in published maps and institutional affiliations. 2011;20:807–26. 1 3

Journal

Current Forestry Reports – Springer Journals

Published: Jun 1, 2022

Keywords: Bibliometrics; Network analysis; Assisted migration; Climate change; Conservation biology; Ecological restoration

There are no references for this article.