Aims: Red Lists of threatened species are a well-established conservation tool throughout the wor... more Aims: Red Lists of threatened species are a well-established conservation tool throughout the world. In contrast, Red Lists of ecosystems, habitats or plant community types have only recently found interest at the global level, although they have a longer tradition in Central Europe. We contribute to the debate by presenting and discussing a comprehensive conservation assessment methodology for plant communities that was developed within the framework of the project 'The plant communities of Mecklenburg-Vorpommern and their vulnerability'.
Within the last 30 years the role of nitrogen in Central European forests has changed fundamental... more Within the last 30 years the role of nitrogen in Central European forests has changed fundamentally from limiting resource to environmental problem. As the retrospective tracking of nutrient availability by soil chemical and biogeochemical measurements faces serious problems, bioindication based on understorey species composition is indispensable for monitoring broad-scale eutrophication.
Trees at Alaskan treelines are assumed to be limited by temperature and to expand upslope and/or ... more Trees at Alaskan treelines are assumed to be limited by temperature and to expand upslope and/or to higher latitudes with global warming. However, recent studies describe negative temperature responses and drought stress of Alaskan treeline trees in recent decades. In this study, we have analyzed the responses of treeline white spruce to temperature and precipitation according to different climatic regimes in Alaska, described as negative (cool) and positive (warm) phases of the Pacific Decadal Oscillation (PDO). We found that in three consecutive phases (positive from 1925-46, negative from 1947-76, and positive again from 1977-98), the growth responses to temperature and precipitation differed markedly. Before 1947, in a phase of warm winters and with summer temperatures being close to the century mean, the trees at most sites responded positively to summer temperature, as one would expect from treeline trees at northern high latitudes. Between 1947 and 1976, a phase of cold winters and average summers, the trees showed similar responses, but a new pattern of negative responses to the summer temperature of the year prior to growth coupled with positive responses to the precipitation in the same year emerged at some sites. As the precipitation was relatively low at those sites, we assume that drought stress might have played a role. However, the climate responses were not uniform but were modified by regional gradients (trees at northern sites responded more often to temperature than trees at southern sites) and local site conditions (forest trees responded more often to precipitation than treeline trees), possibly reflecting differences in energy and water balance across regions and sites, respectively. However, since the shift in the PDO in 1976 from a negative to a positive phase, the trees' climate-growth responses are much less pronounced and climate seems to have lost its importance as a limiting factor for the growth of treeline white spruce. If predictions of continued warming and precipitation increase at northern high latitudes hold true, the growth of Alaskan treeline trees will likely depend on the ratio of temperature and precipitation increase more than on their absolute values, as well as on the interaction of periodic regime shifts with the global warming trend. Once a climatic limitation is lifted, other factors, such as insect outbreaks or interspecific competition, might become limiting to tree growth.
This article explains the fields that are used to provide an overview of the metadata for each da... more This article explains the fields that are used to provide an overview of the metadata for each database in the Global Index of Vegetation-Plot Databases (GIVD). The Fact Sheets published in the Long and Short Database Reports of this volume try to answer the readers' questions on availability, scope, format, status, completeness, amount of data, applied methods, and several more in a condensed compilation.
This editorial introduces the Special Volume "Vegetation databases for the 21st century", which i... more This editorial introduces the Special Volume "Vegetation databases for the 21st century", which is an outcome of the 9th Meeting on Vegetation Databases, held 24-26 February 2010 in Hamburg. We briefly report on the meeting with its presentations and workshops. Then we highlight the launch of the Global Index of Vegetation-Plot Databases (GIVD), an online metadatabase initiated during the conference and which currently lists 183 databases worldwide. Further, we report on plans for an electronic reference list of all European plant taxa (EuroSL) and the emerging European Vegetation Archive (EVA), which will join existing national and regional databases. Besides five regular articles, this Special Volume contains a series of Database Reports that present standardised Fact Sheets for the majority of GIVD-registered databases. The publication of the Database Reports will make these databases more visible, allowing their regular citation, and thus presenting an incentive for collaborative data use.
Biodiversity informatics has experienced tremendous developments in the last 15 years. There are ... more Biodiversity informatics has experienced tremendous developments in the last 15 years. There are now comprehensive online checklists for plant taxa as well as many large plant-taxon related databases, including the vegetation-plot databases registered in the Global Index of Vegetation-Plot Databases (GIVD; http://www.givd.info). However, efficient maintenance, analysis, and integration of these databases are still much impeded by the failure of presently available electronic taxonomic reference lists of plants to fully meet the requirements of such applications. Here we outline the principal specifications of an electronic taxonomic reference list for Europe ("EuroSL" = European standard list of plant taxa) and identify features not met in current practice. EuroSL should cover all macroscopic taxa of vascular plants, bryophytes, lichens, and algae that occur in European vegetation in a uniform database, irrespective of their floristic status (e.g. native, archaeophyte, neophyte, casual). The adoption of informal aggregates is essential to cover deviating species concepts and to capture legacy data. EuroSL should not only assign names but also match taxonomic concepts. This task cannot be fully automated, as the same correctly applied taxon name can have different meanings depending on the taxonomic concept applied. In order to be a useful tool, EuroSL would need to be better documented than most existing electronic checklists and be released in fixed versions. Every subsequent version should contain an unambiguous connection linking each taxon to the corresponding unit in the previous version. We identify possible components of EuroSL, of which Euro+Med PlantBase, the recent European checklists of bryophytes, and the taxonomic crosswalks between various national Turboveg checklists collected for SynBioSys Europe, are the major ones. Concepts developed for GermanSL might be adopted for EuroSL, but implemented in a software framework that is yet to be developed from existing tools. Such a framework would allow documented editing of the content by specialists distributed across Europe. To become successful, EuroSL would require intensive collaboration between taxonomists, ecologists and biodiversity informaticians, as well as appropriate funding. Establishing EuroSL would dramatically enhance the usability and reliability of plant-taxon related databases in Europe for the purposes of pure and applied research and conservation legislation. Its development should therefore be of highest priority.
Die GermanSL ist eine universelle elektronische Referenzliste für die Flora Deutschlands, welche ... more Die GermanSL ist eine universelle elektronische Referenzliste für die Flora Deutschlands, welche von der Sektion "Taxonomische Referenzlisten" innerhalb des Netzwerkes Phytodiversität Deutschland (NetPhyD) entwickelt und Anfang 2008 in der Version 1.0 der Öffentlichkeit zugänglich gemacht wurde. Neben der Nutzung für einzelne Vegetationsdatenbanken soll sie die leichte Verknüpfung verschiedener solcher Datenbanken untereinander und mit anderen artbezogenen Datenbanken (z. B. floristische Kartierung, plant functional traits) fördern. Die GermanSL basiert auf den publizierten Referenzlisten der botanischen Großgruppen in Deutschland, die erforderlichenfalls in genau dokumentierter Weise korrigiert oder ergänzt wurden. Sie stellt damit keine neue taxonomische Sicht dar, sondern kompiliert die vorhandenen und macht sie nutzbar. Die GermanSL enthält aktuell rund 30.000 angenommene Namen und Synonyme von Gefäßpflanzen, Moosen, Flechten und Algen, taxonomische Informationen wie die Zugehörigkeit zu übergeordneten Taxa sowie eine Auswahl an Artattributen (Zeigerwerte, Rote-Liste-Status). Die Liste steht als Excel-Datei und in einer Version für das vegetationskundliche Datenbankprogramm TURBOVEG zum kostenlosen Download bereit. Wir rufen alle interessierten Kollegen zur aktiven Mitarbeit bei der Pflege und Ergänzung der GermanSL auf.
Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names ... more Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names might occur through the course of vegetation analysis, from relevés upward through databases, and then to the final analyses. We discuss how these problems might ...
Using a microsatellite assay, we investigated sex ratios at three levels (apparent, intrinsic, ge... more Using a microsatellite assay, we investigated sex ratios at three levels (apparent, intrinsic, genet) for Populus euphratica stands in Xinjiang, China and possible consequences of sex-specific costs of reproduction in terms of clonal growth and individual growth or mortality. Sex ratios at all levels tended to be male biased (60 % of 3,295 flowering trees were male), although male excess was least pronounced at the genet level (52 % of 850 genets were male). Male clones comprised significantly more (708 vs. 572) trees than female clones. Reproductive investment was measured in terms of carbon (C) and nitrogen (N) contents of male and female reproductive organs: single flowers or fruit capsules, whole inflorescences or infructescences, and whole branches of ca. 2 cm diameter. Male flowers and catkins require less N than female fruits and catkins, but on average only 16 % of female catkins develop into fruits. This changes the measured investment for reproduction at branch level: now male branches spent 3.3 times more N than their female counterparts. This coincides with the annual increment of branches, measured as a possible trade-off for costs of reproduction: female branches needed 2 years less to reach a diameter of 2 cm. We conclude that full fruit set of females would give males a heavy comparative advantage, but frequent abortion of whole infructescences by females seems to be a powerful mechanism to compensate a higher reproductive effort, thus avoiding a pronounced runaway effect by more vigorous clonal growth of male trees over a long time.
Problem: The increasing availability of large vegetation databases holds great potential in ecolo... more Problem: The increasing availability of large vegetation databases holds great potential in ecological research and biodiversity informatics, However, inconsistent application of plant names compromises the usefulness of these databases. This problem has been acknowledged in recent years, and solutions have been proposed, such as the concept of ''potential taxa'' or ''taxon views''. Unfortunately, awareness of the problem remains low among vegetation scientists. Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names might occur through the course of vegetation analysis, from releve´s upward through databases, and then to the final analyses. We discuss how these problems might be minimized. Results: We highlight the importance of taxonomic reference lists for standardizing plant names and outline standards they should fulfill to be useful for vegetation databases. Additionally, we present the R package vegdata, which is designed to solve namerelated problems that arise when analysing vegetation databases. Conclusions: We conclude that by giving more consideration to the appropriate application of plant names, vegetation scientists might enhance the reliability of analyses obtained from large vegetation databases.
Question: How many vegetation plot observations (relevés) are available in electronic databases, ... more Question: How many vegetation plot observations (relevés) are available in electronic databases, how are they geographically distributed, what are their properties and how might they be discovered and located for research and application?
Questions: How are plant species distributed along grazing gradients? What is the shape of specie... more Questions: How are plant species distributed along grazing gradients? What is the shape of species richness patterns? How can we test for the existence of potential discontinuities in species turnover pattern?
In species response modelling, can a hierarchical logistic regression framework compete 16 agains... more In species response modelling, can a hierarchical logistic regression framework compete 16 against Generalised Additive Models in terms of statistical inference? Are bimodal shapes 17 useful to model species responses along ecological gradients? 18
ABSTRACT Aims Studies integrating phylogenetic history and large-scale community assembly are few... more ABSTRACT Aims Studies integrating phylogenetic history and large-scale community assembly are few, and many questions remain unanswered. Here, we use a global coastal dune plant data set to uncover the important factors in community assembly across scales from the local filtering processes to the global long-term diversification and dispersal dynamics. Coastal dune plant communities occur worldwide under a wide range of climatic and geologic conditions as well as in all biogeographic regions. However, global patterns in the phylogenetic composition of coastal dune plant communities have not previously been studied. Methods The data set comprised vegetation data from 18 463 plots in New Zealand, South Africa, South America, North America and Europe. The phylogenetic tree comprised 2241 plant species from 149 families. We calculated phylogenetic clustering (Net Relatedness Index, NRI, and Nearest Taxon Index, NTI) of regional dune floras to estimate the amount of in situ diversification relative to the global dune species pool and evaluated the relative importance of land and climate barriers for these diversification patterns by geographic analyses of phylogenetic similarity. We then tested whether dune plant communities exhibit similar patterns of phylogenetic structure within regions. Finally, we calculated NRI for local communities relative to the regional species pool and tested for an association with functional traits (plant height and seed mass) thought to vary along sea–inland gradients. Important Findings Regional species pools were phylogenetically clustered relative to the global pool, indicating regional diversification. NTI showed stronger clustering than NRI pointing to the importance of especially recent diversifications within regions. The species pools grouped phylogenetically into two clusters on either side of the tropics suggesting greater dispersal rates within hemispheres than between hemispheres. Local NRI plot values confirmed that most communities were also phylogenetically clustered within regions. NRI values decreased with increasing plant height and seed mass, indicating greater phylogenetic clustering in communities with short maximum height and good dispersers prone to wind and tidal disturbance as well as salt spray, consistent with environmental filtering along sea–inland gradients. Height and seed mass both showed significant phylogenetic signal, and NRI tended to correlate negatively with both at the plot level. Low NRI plots tended to represent coastal scrub and forest, whereas high NRI plots tended to represent herb-dominated vegetation. We conclude that regional diversification processes play a role in dune plant community assembly, with convergence in local phylogenetic community structure and local variation in community structure probably reflecting consistent coastal-inland gradients. Our study contributes to a better understanding of the globally distributed dynamic coastal ecosystems and the structuring factors working on dune plant communities across spatial scales and regions.
Aims: Red Lists of threatened species are a well-established conservation tool throughout the wor... more Aims: Red Lists of threatened species are a well-established conservation tool throughout the world. In contrast, Red Lists of ecosystems, habitats or plant community types have only recently found interest at the global level, although they have a longer tradition in Central Europe. We contribute to the debate by presenting and discussing a comprehensive conservation assessment methodology for plant communities that was developed within the framework of the project 'The plant communities of Mecklenburg-Vorpommern and their vulnerability'.
Within the last 30 years the role of nitrogen in Central European forests has changed fundamental... more Within the last 30 years the role of nitrogen in Central European forests has changed fundamentally from limiting resource to environmental problem. As the retrospective tracking of nutrient availability by soil chemical and biogeochemical measurements faces serious problems, bioindication based on understorey species composition is indispensable for monitoring broad-scale eutrophication.
Trees at Alaskan treelines are assumed to be limited by temperature and to expand upslope and/or ... more Trees at Alaskan treelines are assumed to be limited by temperature and to expand upslope and/or to higher latitudes with global warming. However, recent studies describe negative temperature responses and drought stress of Alaskan treeline trees in recent decades. In this study, we have analyzed the responses of treeline white spruce to temperature and precipitation according to different climatic regimes in Alaska, described as negative (cool) and positive (warm) phases of the Pacific Decadal Oscillation (PDO). We found that in three consecutive phases (positive from 1925-46, negative from 1947-76, and positive again from 1977-98), the growth responses to temperature and precipitation differed markedly. Before 1947, in a phase of warm winters and with summer temperatures being close to the century mean, the trees at most sites responded positively to summer temperature, as one would expect from treeline trees at northern high latitudes. Between 1947 and 1976, a phase of cold winters and average summers, the trees showed similar responses, but a new pattern of negative responses to the summer temperature of the year prior to growth coupled with positive responses to the precipitation in the same year emerged at some sites. As the precipitation was relatively low at those sites, we assume that drought stress might have played a role. However, the climate responses were not uniform but were modified by regional gradients (trees at northern sites responded more often to temperature than trees at southern sites) and local site conditions (forest trees responded more often to precipitation than treeline trees), possibly reflecting differences in energy and water balance across regions and sites, respectively. However, since the shift in the PDO in 1976 from a negative to a positive phase, the trees' climate-growth responses are much less pronounced and climate seems to have lost its importance as a limiting factor for the growth of treeline white spruce. If predictions of continued warming and precipitation increase at northern high latitudes hold true, the growth of Alaskan treeline trees will likely depend on the ratio of temperature and precipitation increase more than on their absolute values, as well as on the interaction of periodic regime shifts with the global warming trend. Once a climatic limitation is lifted, other factors, such as insect outbreaks or interspecific competition, might become limiting to tree growth.
This article explains the fields that are used to provide an overview of the metadata for each da... more This article explains the fields that are used to provide an overview of the metadata for each database in the Global Index of Vegetation-Plot Databases (GIVD). The Fact Sheets published in the Long and Short Database Reports of this volume try to answer the readers' questions on availability, scope, format, status, completeness, amount of data, applied methods, and several more in a condensed compilation.
This editorial introduces the Special Volume "Vegetation databases for the 21st century", which i... more This editorial introduces the Special Volume "Vegetation databases for the 21st century", which is an outcome of the 9th Meeting on Vegetation Databases, held 24-26 February 2010 in Hamburg. We briefly report on the meeting with its presentations and workshops. Then we highlight the launch of the Global Index of Vegetation-Plot Databases (GIVD), an online metadatabase initiated during the conference and which currently lists 183 databases worldwide. Further, we report on plans for an electronic reference list of all European plant taxa (EuroSL) and the emerging European Vegetation Archive (EVA), which will join existing national and regional databases. Besides five regular articles, this Special Volume contains a series of Database Reports that present standardised Fact Sheets for the majority of GIVD-registered databases. The publication of the Database Reports will make these databases more visible, allowing their regular citation, and thus presenting an incentive for collaborative data use.
Biodiversity informatics has experienced tremendous developments in the last 15 years. There are ... more Biodiversity informatics has experienced tremendous developments in the last 15 years. There are now comprehensive online checklists for plant taxa as well as many large plant-taxon related databases, including the vegetation-plot databases registered in the Global Index of Vegetation-Plot Databases (GIVD; http://www.givd.info). However, efficient maintenance, analysis, and integration of these databases are still much impeded by the failure of presently available electronic taxonomic reference lists of plants to fully meet the requirements of such applications. Here we outline the principal specifications of an electronic taxonomic reference list for Europe ("EuroSL" = European standard list of plant taxa) and identify features not met in current practice. EuroSL should cover all macroscopic taxa of vascular plants, bryophytes, lichens, and algae that occur in European vegetation in a uniform database, irrespective of their floristic status (e.g. native, archaeophyte, neophyte, casual). The adoption of informal aggregates is essential to cover deviating species concepts and to capture legacy data. EuroSL should not only assign names but also match taxonomic concepts. This task cannot be fully automated, as the same correctly applied taxon name can have different meanings depending on the taxonomic concept applied. In order to be a useful tool, EuroSL would need to be better documented than most existing electronic checklists and be released in fixed versions. Every subsequent version should contain an unambiguous connection linking each taxon to the corresponding unit in the previous version. We identify possible components of EuroSL, of which Euro+Med PlantBase, the recent European checklists of bryophytes, and the taxonomic crosswalks between various national Turboveg checklists collected for SynBioSys Europe, are the major ones. Concepts developed for GermanSL might be adopted for EuroSL, but implemented in a software framework that is yet to be developed from existing tools. Such a framework would allow documented editing of the content by specialists distributed across Europe. To become successful, EuroSL would require intensive collaboration between taxonomists, ecologists and biodiversity informaticians, as well as appropriate funding. Establishing EuroSL would dramatically enhance the usability and reliability of plant-taxon related databases in Europe for the purposes of pure and applied research and conservation legislation. Its development should therefore be of highest priority.
Die GermanSL ist eine universelle elektronische Referenzliste für die Flora Deutschlands, welche ... more Die GermanSL ist eine universelle elektronische Referenzliste für die Flora Deutschlands, welche von der Sektion "Taxonomische Referenzlisten" innerhalb des Netzwerkes Phytodiversität Deutschland (NetPhyD) entwickelt und Anfang 2008 in der Version 1.0 der Öffentlichkeit zugänglich gemacht wurde. Neben der Nutzung für einzelne Vegetationsdatenbanken soll sie die leichte Verknüpfung verschiedener solcher Datenbanken untereinander und mit anderen artbezogenen Datenbanken (z. B. floristische Kartierung, plant functional traits) fördern. Die GermanSL basiert auf den publizierten Referenzlisten der botanischen Großgruppen in Deutschland, die erforderlichenfalls in genau dokumentierter Weise korrigiert oder ergänzt wurden. Sie stellt damit keine neue taxonomische Sicht dar, sondern kompiliert die vorhandenen und macht sie nutzbar. Die GermanSL enthält aktuell rund 30.000 angenommene Namen und Synonyme von Gefäßpflanzen, Moosen, Flechten und Algen, taxonomische Informationen wie die Zugehörigkeit zu übergeordneten Taxa sowie eine Auswahl an Artattributen (Zeigerwerte, Rote-Liste-Status). Die Liste steht als Excel-Datei und in einer Version für das vegetationskundliche Datenbankprogramm TURBOVEG zum kostenlosen Download bereit. Wir rufen alle interessierten Kollegen zur aktiven Mitarbeit bei der Pflege und Ergänzung der GermanSL auf.
Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names ... more Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names might occur through the course of vegetation analysis, from relevés upward through databases, and then to the final analyses. We discuss how these problems might ...
Using a microsatellite assay, we investigated sex ratios at three levels (apparent, intrinsic, ge... more Using a microsatellite assay, we investigated sex ratios at three levels (apparent, intrinsic, genet) for Populus euphratica stands in Xinjiang, China and possible consequences of sex-specific costs of reproduction in terms of clonal growth and individual growth or mortality. Sex ratios at all levels tended to be male biased (60 % of 3,295 flowering trees were male), although male excess was least pronounced at the genet level (52 % of 850 genets were male). Male clones comprised significantly more (708 vs. 572) trees than female clones. Reproductive investment was measured in terms of carbon (C) and nitrogen (N) contents of male and female reproductive organs: single flowers or fruit capsules, whole inflorescences or infructescences, and whole branches of ca. 2 cm diameter. Male flowers and catkins require less N than female fruits and catkins, but on average only 16 % of female catkins develop into fruits. This changes the measured investment for reproduction at branch level: now male branches spent 3.3 times more N than their female counterparts. This coincides with the annual increment of branches, measured as a possible trade-off for costs of reproduction: female branches needed 2 years less to reach a diameter of 2 cm. We conclude that full fruit set of females would give males a heavy comparative advantage, but frequent abortion of whole infructescences by females seems to be a powerful mechanism to compensate a higher reproductive effort, thus avoiding a pronounced runaway effect by more vigorous clonal growth of male trees over a long time.
Problem: The increasing availability of large vegetation databases holds great potential in ecolo... more Problem: The increasing availability of large vegetation databases holds great potential in ecological research and biodiversity informatics, However, inconsistent application of plant names compromises the usefulness of these databases. This problem has been acknowledged in recent years, and solutions have been proposed, such as the concept of ''potential taxa'' or ''taxon views''. Unfortunately, awareness of the problem remains low among vegetation scientists. Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names might occur through the course of vegetation analysis, from releve´s upward through databases, and then to the final analyses. We discuss how these problems might be minimized. Results: We highlight the importance of taxonomic reference lists for standardizing plant names and outline standards they should fulfill to be useful for vegetation databases. Additionally, we present the R package vegdata, which is designed to solve namerelated problems that arise when analysing vegetation databases. Conclusions: We conclude that by giving more consideration to the appropriate application of plant names, vegetation scientists might enhance the reliability of analyses obtained from large vegetation databases.
Question: How many vegetation plot observations (relevés) are available in electronic databases, ... more Question: How many vegetation plot observations (relevés) are available in electronic databases, how are they geographically distributed, what are their properties and how might they be discovered and located for research and application?
Questions: How are plant species distributed along grazing gradients? What is the shape of specie... more Questions: How are plant species distributed along grazing gradients? What is the shape of species richness patterns? How can we test for the existence of potential discontinuities in species turnover pattern?
In species response modelling, can a hierarchical logistic regression framework compete 16 agains... more In species response modelling, can a hierarchical logistic regression framework compete 16 against Generalised Additive Models in terms of statistical inference? Are bimodal shapes 17 useful to model species responses along ecological gradients? 18
ABSTRACT Aims Studies integrating phylogenetic history and large-scale community assembly are few... more ABSTRACT Aims Studies integrating phylogenetic history and large-scale community assembly are few, and many questions remain unanswered. Here, we use a global coastal dune plant data set to uncover the important factors in community assembly across scales from the local filtering processes to the global long-term diversification and dispersal dynamics. Coastal dune plant communities occur worldwide under a wide range of climatic and geologic conditions as well as in all biogeographic regions. However, global patterns in the phylogenetic composition of coastal dune plant communities have not previously been studied. Methods The data set comprised vegetation data from 18 463 plots in New Zealand, South Africa, South America, North America and Europe. The phylogenetic tree comprised 2241 plant species from 149 families. We calculated phylogenetic clustering (Net Relatedness Index, NRI, and Nearest Taxon Index, NTI) of regional dune floras to estimate the amount of in situ diversification relative to the global dune species pool and evaluated the relative importance of land and climate barriers for these diversification patterns by geographic analyses of phylogenetic similarity. We then tested whether dune plant communities exhibit similar patterns of phylogenetic structure within regions. Finally, we calculated NRI for local communities relative to the regional species pool and tested for an association with functional traits (plant height and seed mass) thought to vary along sea–inland gradients. Important Findings Regional species pools were phylogenetically clustered relative to the global pool, indicating regional diversification. NTI showed stronger clustering than NRI pointing to the importance of especially recent diversifications within regions. The species pools grouped phylogenetically into two clusters on either side of the tropics suggesting greater dispersal rates within hemispheres than between hemispheres. Local NRI plot values confirmed that most communities were also phylogenetically clustered within regions. NRI values decreased with increasing plant height and seed mass, indicating greater phylogenetic clustering in communities with short maximum height and good dispersers prone to wind and tidal disturbance as well as salt spray, consistent with environmental filtering along sea–inland gradients. Height and seed mass both showed significant phylogenetic signal, and NRI tended to correlate negatively with both at the plot level. Low NRI plots tended to represent coastal scrub and forest, whereas high NRI plots tended to represent herb-dominated vegetation. We conclude that regional diversification processes play a role in dune plant community assembly, with convergence in local phylogenetic community structure and local variation in community structure probably reflecting consistent coastal-inland gradients. Our study contributes to a better understanding of the globally distributed dynamic coastal ecosystems and the structuring factors working on dune plant communities across spatial scales and regions.
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