Author
Erik Welk
Other affiliations: Wittenberg University
Bio: Erik Welk is an academic researcher from Martin Luther University of Halle-Wittenberg. The author has contributed to research in topics: Range (biology) & Population. The author has an hindex of 27, co-authored 67 publications receiving 2916 citations. Previous affiliations of Erik Welk include Wittenberg University.
Papers published on a yearly basis
Papers
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University of Zurich1, Alexander von Humboldt Biological Resources Research Institute2, Lüneburg University3, Dresden University of Technology4, Martin Luther University of Halle-Wittenberg5, Chinese Academy of Sciences6, Leipzig University7, University of Freiburg8, University of Tübingen9, Helmholtz Centre for Environmental Research - UFZ10, East China Normal University11, Wenzhou University12, University of Kiel13, Peking University14, University of Bern15, University of Minnesota16, University of Oxford17, Central South University Forestry and Technology18, Zhejiang University19, Zhejiang Normal University20
TL;DR: The first results from a large biodiversity experiment in a subtropical forest in China suggest strong positive effects of tree diversity on forest productivity and carbon accumulation, and encourage multispecies afforestation strategies to restore biodiversity and mitigate climate change.
Abstract: Biodiversity experiments have shown that species loss reduces ecosystem functioning in grassland. To test whether this result can be extrapolated to forests, the main contributors to terrestrial primary productivity, requires large-scale experiments. We manipulated tree species richness by planting more than 150,000 trees in plots with 1 to 16 species. Simulating multiple extinction scenarios, we found that richness strongly increased stand-level productivity. After 8 years, 16-species mixtures had accumulated over twice the amount of carbon found in average monocultures and similar amounts as those of two commercial monocultures. Species richness effects were strongly associated with functional and phylogenetic diversity. A shrub addition treatment reduced tree productivity, but this reduction was smaller at high shrub species richness. Our results encourage multispecies afforestation strategies to restore biodiversity and mitigate climate change.
359 citations
Martin Luther University of Halle-Wittenberg1, Zürcher Fachhochschule2, University of Bayreuth3, University of Picardie Jules Verne4, University of Oviedo5, Wageningen University and Research Centre6, Masaryk University7, University of Nottingham8, University of Rostock9, Max Planck Society10, Universidade Federal do Rio Grande do Sul11, University of North Carolina at Chapel Hill12, Santa Clara University13, Leiden University14, Academy of Sciences of the Czech Republic15, Shahjalal University of Science and Technology16, Sapienza University of Rome17, Natural Resources Canada18, Florida International University19, Universidade Federal do Acre20, Ghent University21, University of Göttingen22, University of the Basque Country23, Aarhus University24, Environmental Change Institute25, Rocky Mountain Biological Laboratory26, Slovenian Academy of Sciences and Arts27, University of Nova Gorica28, King Juan Carlos University29, Czech University of Life Sciences Prague30, VU University Amsterdam31, University of Würzburg32, National University of Cordoba33, Wake Forest University34, National University of Saint Anthony the Abbot in Cuzco35, University of Exeter36, Université du Québec en Abitibi-Témiscamingue37, University of Montpellier38, University of Adelaide39, University of Chile40, IFREMER41, University of British Columbia42, Universidade do Estado de Santa Catarina43, University of Münster44, University of Hamburg45, University of Wrocław46, Swiss Federal Institute for Forest, Snow and Landscape Research47, University of Zurich48, University of Oldenburg49, University of Waikato50, University of Wyoming51, Institut national de la recherche agronomique52, Sofia University53, Royal Botanic Gardens54, University of Edinburgh55, Landcare Research56, Radboud University Nijmegen57, Spanish National Research Council58, University of Barcelona59, University of Leeds60, University of Tartu61, University of Sydney62, University of Minnesota63, University of Jena64, University of La Serena65, Peking University66, Iwokrama International Centre for Rain Forest Conservation and Development67, Aristotle University of Thessaloniki68, Bulgarian Academy of Sciences69, University of Oulu70, University of Wisconsin–Eau Claire71, American Museum of Natural History72, International Institute of Minnesota73, Leipzig University74
TL;DR: It is shown that global trait composition is captured by two main dimensions that are only weakly related to macro-environmental drivers, which reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale.
Abstract: Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs because different strategies can facilitate co-existence within communities. A key question is to what extent community-level trait composition is globally filtered and how well it is related to global versus local environmental drivers. Here, we perform a global, plot-level analysis of trait-environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support communities differing greatly in mean trait values. The two main community trait axes that capture half of the global trait variation (plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale. Similarly, within-plot trait variation does not vary systematically with macro-environment. Our results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be predominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning and biotic interactions.
349 citations
Martin Luther University of Halle-Wittenberg1, Leipzig University2, Lüneburg University3, University of Freiburg4, Helmholtz Centre for Environmental Research - UFZ5, East China Normal University6, Wenzhou University7, Peking University8, University of Tübingen9, University of Zurich10, Kunming Institute of Botany11, Zhejiang University12, University of Bern13
TL;DR: It is concluded that forest BEF experiments provide exciting and timely research options and especially require careful thinking to allow multiple disciplines to measure and analyse data jointly and effectively.
Abstract: Summary 1. Biodiversity–ecosystem functioning (BEF) experiments address ecosystem-level consequences of species loss by comparing communities of high species richness with communities from which species have been gradually eliminated. BEF experiments originally started with microcosms in the laboratory and with grassland ecosystems. A new frontier in experimental BEF research is manipulating tree diversity in forest ecosystems, compelling researchers to think big and comprehensively. 2. We present and discuss some of the major issues to be considered in the design of BEF experiments with trees and illustrate these with a new forest biodiversity experiment established in subtropical China (Xingangshan, Jiangxi Province) in 2009/2010. Using a pool of 40 tree species, extinction scenarios were simulated with tree richness levels of 1, 2, 4, 8 and 16 species on a total of 566 plots of 25� 8 9 25� 8m each. 3. The goal of this experiment is to estimate effects of tree and shrub species richness on carbon storage and soil erosion; therefore, the experiment was established on sloped terrain. The following important design choices were made: (i) establishing many small rather than fewer larger plots, (ii) using high planting density and random mixing of species rather than lower planting density and patchwise mixing of species, (iii) establishing a map of the initial ‘ecoscape’ to characterize site heterogeneity before the onset of biodiversity effects and (iv) manipulating tree species richness not only in random but also in trait-oriented extinction scenarios. 4. Data management and analysis are particularly challenging in BEF experiments with their hierarchical designs nesting individuals within-species populations within plots within-species compositions. Statistical analysis best proceeds by partitioning these random terms into fixed-term contrasts, for example, species composition into contrasts for species richness and the presence of particular functional groups, which can then be tested against the remaining random variation among compositions. 5. We conclude that forest BEF experiments provide exciting and timely research options. They especially require careful thinking to allow multiple disciplines to measure and analyse data jointly and effectively. Achiev
219 citations
Martin Luther University of Halle-Wittenberg1, University of Zurich2, University of Freiburg3, Helmholtz Centre for Environmental Research - UFZ4, East China Normal University5, Wenzhou University6, University of Bern7, University of Tübingen8, Peking University9, Chinese Academy of Sciences10, Max Planck Society11, Leipzig University12, ETH Zurich13
TL;DR: Subtropical broad-leaved forests in southeastern China support a high diversity of woody plants, and a number of environmen...
Abstract: Subtropical broad-leaved forests in southeastern China support a high diversity of woody plants. Using a comparative study design with 30 × 30 m plots (n = 27) from five successional stages ( 1 m in height in each plot and counted all woody recruits (bank of all seedlings ≤1 m in height) in each central 10 × 10 m quadrant of each plot. In addition, we measured a number of environmen...
205 citations
TL;DR: A novel chorological data compilation for the main European tree and shrub species is presented, intended to provide a synthetic continental-scale overview of the species ranges.
202 citations
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TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201
14,171 citations
TL;DR: In this paper, the use of the maximum entropy method (Maxent) for modeling species geographic distributions with presence-only data was introduced, which is a general-purpose machine learning method with a simple and precise mathematical formulation.
13,120 citations
Journal Article•
TL;DR: For the next few weeks the course is going to be exploring a field that’s actually older than classical population genetics, although the approach it’ll be taking to it involves the use of population genetic machinery.
Abstract: So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to
9,847 citations
3,213 citations
TL;DR: Although the entire invasion process is indeed complex, the geographic course that invasions are able to take can be anticipated with considerable confidence, and this predictivity depends on the premise that ecological niches constitute long‐term stable constraints on the potential geographic distributions of species.
Abstract: Species’ invasions have long been regarded as enormously complex processes, so complex as to defy predictivity Phases of this process, however, are emerging as highly predictable: the potential geographic course of an invasion can be anticipated with high precision based on the ecological niche characteristics of a species in its native geographic distributional area This predictivity depends on the premise that ecological niches constitute long‐term stable constraints on the potential geographic distributions of species, for which a sizeable body of evidence is accumulating Hence, although the entire invasion process is indeed complex, the geographic course that invasions are able to take can be anticipated with considerable confidence
1,079 citations