Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Eric Allan is active.

Publication


Featured researches published by Eric Allan.


Nature | 2010

Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment

Christoph Scherber; Nico Eisenhauer; Wolfgang W. Weisser; Bernhard Schmid; Winfried Voigt; Markus Fischer; Ernst-Detlef Schulze; Christiane Roscher; Alexandra Weigelt; Eric Allan; Holger Beßler; Michael Bonkowski; N. C. Buchmann; François Buscot; Lars W. Clement; Anne Ebeling; Christof Engels; Stefan Halle; Ilona Kertscher; Alexandra-Maria Klein; Robert Koller; Stephan König; Esther Kowalski; Volker Kummer; Annely Kuu; Markus Lange; Dirk Lauterbach; Cornelius Middelhoff; Varvara D. Migunova; Alexandru Milcu

Biodiversity is rapidly declining, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades.


Nature | 2016

Biodiversity at multiple trophic levels is needed for ecosystem multifunctionality

Santiago Soliveres; Fons van der Plas; Peter Manning; Daniel Prati; Martin M. Gossner; Swen C. Renner; Fabian Alt; Hartmut Arndt; Vanessa Baumgartner; Julia Binkenstein; Klaus Birkhofer; Stefan Blaser; Nico Blüthgen; Steffen Boch; Stefan Böhm; Carmen Börschig; François Buscot; Tim Diekötter; Johannes Heinze; Norbert Hölzel; Kirsten Jung; Valentin H. Klaus; Till Kleinebecker; Sandra Klemmer; Jochen Krauss; Markus Lange; E. Kathryn Morris; Jörg Müller; Yvonne Oelmann; Jörg Overmann

Many experiments have shown that loss of biodiversity reduces the capacity of ecosystems to provide the multiple services on which humans depend. However, experiments necessarily simplify the complexity of natural ecosystems and will normally control for other important drivers of ecosystem functioning, such as the environment or land use. In addition, existing studies typically focus on the diversity of single trophic groups, neglecting the fact that biodiversity loss occurs across many taxa and that the functional effects of any trophic group may depend on the abundance and diversity of others. Here we report analysis of the relationships between the species richness and abundance of nine trophic groups, including 4,600 above- and below-ground taxa, and 14 ecosystem services and functions and with their simultaneous provision (or multifunctionality) in 150 grasslands. We show that high species richness in multiple trophic groups (multitrophic richness) had stronger positive effects on ecosystem services than richness in any individual trophic group; this includes plant species richness, the most widely used measure of biodiversity. On average, three trophic groups influenced each ecosystem service, with each trophic group influencing at least one service. Multitrophic richness was particularly beneficial for ‘regulating’ and ‘cultural’ services, and for multifunctionality, whereas a change in the total abundance of species or biomass in multiple trophic groups (the multitrophic abundance) positively affected supporting services. Multitrophic richness and abundance drove ecosystem functioning as strongly as abiotic conditions and land-use intensity, extending previous experimental results to real-world ecosystems. Primary producers, herbivorous insects and microbial decomposers seem to be particularly important drivers of ecosystem functioning, as shown by the strong and frequent positive associations of their richness or abundance with multiple ecosystem services. Our results show that multitrophic richness and abundance support ecosystem functioning, and demonstrate that a focus on single groups has led to researchers to greatly underestimate the functional importance of biodiversity.


Proceedings of the National Academy of Sciences of the United States of America | 2011

More diverse plant communities have higher functioning over time due to turnover in complementary dominant species

Eric Allan; Wolfgang W. Weisser; Alexandra Weigelt; Christiane Roscher; Markus Fischer; Helmut Hillebrand

More diverse communities have been shown to have higher and more temporally stable ecosystem functioning than less diverse ones, suggesting they should also have a consistently higher level of functioning over time. Diverse communities could maintain consistently high function because the species driving function change over time (functional turnover) or because they are more likely to contain key species with temporally stable functioning. Across 7 y in a large biodiversity experiment, we show that more diverse plant communities had consistently higher productivity, that is, a higher level of functioning over time. We identify the mechanism for this as turnover in the species driving biomass production; this was substantial, and species that were rare in some years became dominant and drove function in other years. Such high turnover allowed functionally more diverse communities to maintain high biomass over time and was associated with higher levels of complementarity effects in these communities. In contrast, turnover in communities composed of functionally similar species did not promote high biomass production over time. Thus, turnover in species promotes consistently high ecosystem function when it sustains functionally complementary interactions between species. Our results strongly reinforce the argument for conservation of high biodiversity.


Ecology Letters | 2015

Land use intensification alters ecosystem multifunctionality via loss of biodiversity and changes to functional composition

Eric Allan; Peter Manning; Fabian Alt; Julia Binkenstein; Stefan Blaser; Nico Blüthgen; Stefan Böhm; Fabrice Grassein; Norbert Hölzel; Valentin H. Klaus; Till Kleinebecker; E. Kathryn Morris; Yvonne Oelmann; Daniel Prati; Swen C. Renner; Matthias C. Rillig; Martin Schaefer; Michael Schloter; Barbara Schmitt; Ingo Schöning; Marion Schrumpf; Emily F. Solly; Elisabeth Sorkau; Juliane Steckel; Ingolf Steffen-Dewenter; Barbara Stempfhuber; Marco Tschapka; Christiane N. Weiner; Wolfgang W. Weisser; Michael Werner

Abstract Global change, especially land‐use intensification, affects human well‐being by impacting the delivery of multiple ecosystem services (multifunctionality). However, whether biodiversity loss is a major component of global change effects on multifunctionality in real‐world ecosystems, as in experimental ones, remains unclear. Therefore, we assessed biodiversity, functional composition and 14 ecosystem services on 150 agricultural grasslands differing in land‐use intensity. We also introduce five multifunctionality measures in which ecosystem services were weighted according to realistic land‐use objectives. We found that indirect land‐use effects, i.e. those mediated by biodiversity loss and by changes to functional composition, were as strong as direct effects on average. Their strength varied with land‐use objectives and regional context. Biodiversity loss explained indirect effects in a region of intermediate productivity and was most damaging when land‐use objectives favoured supporting and cultural services. In contrast, functional composition shifts, towards fast‐growing plant species, strongly increased provisioning services in more inherently unproductive grasslands.


Proceedings of the National Academy of Sciences of the United States of America | 2014

Interannual variation in land-use intensity enhances grassland multidiversity

Eric Allan; Oliver Bossdorf; Carsten F. Dormann; Daniel Prati; Martin M. Gossner; Teja Tscharntke; Nico Blüthgen; Michaela Bellach; Klaus Birkhofer; Steffen Boch; Stefan Böhm; Carmen Börschig; Antonis Chatzinotas; Sabina Christ; Rolf Daniel; Tim Diekötter; Christiane Fischer; Thomas Friedl; Karin Glaser; Christine Hallmann; Ladislav Hodač; Norbert Hölzel; Kirsten Jung; Alexandra-Maria Klein; Valentin H. Klaus; Till Kleinebecker; Jochen Krauss; Markus Lange; E. Kathryn Morris; Jörg Müller

Significance Land-use intensification is a major threat to biodiversity. So far, however, studies on biodiversity impacts of land-use intensity (LUI) have been limited to a single or few groups of organisms and have not considered temporal variation in LUI. Therefore, we examined total ecosystem biodiversity in grasslands varying in LUI with a newly developed index called multidiversity, which integrates the species richness of 49 different organism groups ranging from bacteria to birds. Multidiversity declined strongly with increasing LUI, but changing LUI across years increased multidiversity, particularly of rarer species. We conclude that encouraging farmers to change the intensity of their land use over time could be an important strategy to maintain high biodiversity in grasslands. Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation.


Ecology Letters | 2011

Contrasting effects of insect and molluscan herbivores on plant diversity in a long-term field experiment

Eric Allan; Michael J. Crawley

The importance of invertebrate herbivores in regulating plant communities remains unclear, due to the absence of long-term exclusion experiments. An experiment in an English grassland involving long-term exclusions of insect and mollusc herbivores, along with rabbit fencing, showed strong, but opposing, effects of the invertebrate herbivores. Plant species richness declined and biomass increased following insect exclusion, due to increased dominance by a grass species, whereas mollusc exclusion led to increased herbs abundance. The two herbivores had a compensatory interaction: molluscs had no effects in the absence of insects and large insect effects depended on the absence of molluscs. The effects of invertebrate exclusion became apparent only after 8 years, and would have been seriously underestimated in shorter studies. Our results suggest that theorists and conservation managers need to shift from their historic focus on vertebrate herbivory, to a recognition that invertebrates can be equally important drivers of plant community structure.


Nature Communications | 2013

Epigenetic diversity increases the productivity and stability of plant populations

Vít Latzel; Eric Allan; Amanda Bortolini Silveira; Vincent Colot; Markus Fischer; Oliver Bossdorf

Biological diversity within species can be an important driver of population and ecosystem functioning. Until now, such within-species diversity effects have been attributed to underlying variation in DNA sequence. However, within-species differences, and thus potentially functional biodiversity, can also be created by epigenetic variation. Here, we show that epigenetic diversity increases the productivity and stability of plant populations. Epigenetically diverse populations of Arabidopsis thaliana produce up to 40% more biomass than epigenetically uniform populations. The positive epigenetic diversity effects are strongest when populations are grown together with competitors and infected with pathogens, and they seem to be partly driven by complementarity among epigenotypes. Our study has two implications: first, we may need to re-evaluate previous within-species diversity studies where some effects could reflect epigenetic diversity; second, we need to incorporate epigenetics into basic ecological research, by quantifying natural epigenetic diversity and testing for its ecological consequences across many different species.


Nature | 2016

Land-use intensification causes multitrophic homogenization of grassland communities.

Martin M. Gossner; Thomas M. Lewinsohn; Tiemo Kahl; Fabrice Grassein; Steffen Boch; Daniel Prati; Klaus Birkhofer; Swen C. Renner; Johannes Sikorski; Tesfaye Wubet; Hartmut Arndt; Vanessa Baumgartner; Stefan Blaser; Nico Blüthgen; Carmen Börschig; François Buscot; Tim Diekötter; Leonardo R. Jorge; Kirsten Jung; Alexander C. Keyel; Alexandra-Maria Klein; Sandra Klemmer; Jochen Krauss; Markus Lange; Jörg Müller; Jörg Overmann; Esther Pašalić; Caterina Penone; David J. Perović; Oliver Purschke

Land-use intensification is a major driver of biodiversity loss. Alongside reductions in local species diversity, biotic homogenization at larger spatial scales is of great concern for conservation. Biotic homogenization means a decrease in β-diversity (the compositional dissimilarity between sites). Most studies have investigated losses in local (α)-diversity and neglected biodiversity loss at larger spatial scales. Studies addressing β-diversity have focused on single or a few organism groups (for example, ref. 4), and it is thus unknown whether land-use intensification homogenizes communities at different trophic levels, above- and belowground. Here we show that even moderate increases in local land-use intensity (LUI) cause biotic homogenization across microbial, plant and animal groups, both above- and belowground, and that this is largely independent of changes in α-diversity. We analysed a unique grassland biodiversity dataset, with abundances of more than 4,000 species belonging to 12 trophic groups. LUI, and, in particular, high mowing intensity, had consistent effects on β-diversity across groups, causing a homogenization of soil microbial, fungal pathogen, plant and arthropod communities. These effects were nonlinear and the strongest declines in β-diversity occurred in the transition from extensively managed to intermediate intensity grassland. LUI tended to reduce local α-diversity in aboveground groups, whereas the α-diversity increased in belowground groups. Correlations between the β-diversity of different groups, particularly between plants and their consumers, became weaker at high LUI. This suggests a loss of specialist species and is further evidence for biotic homogenization. The consistently negative effects of LUI on landscape-scale biodiversity underscore the high value of extensively managed grasslands for conserving multitrophic biodiversity and ecosystem service provision. Indeed, biotic homogenization rather than local diversity loss could prove to be the most substantial consequence of land-use intensification.


Functional Ecology | 2015

Species richness, but not phylogenetic diversity, influences community biomass production and temporal stability in a re-examination of 16 grassland biodiversity studies

Patrick Venail; Kevin Gross; Todd H. Oakley; Anita Narwani; Eric Allan; Pedro Flombaum; Forest Isbell; Jasmin Joshi; Peter B. Reich; David Tilman; Jasper van Ruijven; Bradley J. Cardinale

Summary 1. Hundreds of experiments have now manipulated species richness (SR) of various groups of organisms and examined how this aspect of biological diversity influences ecosystem functioning. Ecologists have recently expanded this field to look at whether phylogenetic diversity (PD) among species, often quantified as the sum of branch lengths on a molecular phylogeny leading to all species in a community, also predicts ecological function. Some have hypothesized that phylogenetic divergence should be a superior predictor of ecological function than SR because evolutionary relatedness represents the degree of ecological and functional differentiation among species. But studies to date have provided mixed support for this hypothesis. 2. Here, we reanalyse data from 16 experiments that have manipulated plant SR in grassland ecosystems and examined the impact on above-ground biomass production over multiple time points. Using a new molecular phylogeny of the plant species used in these experiments, we quantified how the PD of plants impacts average community biomass production as well as the stability of community biomass production through time. 3. Using four complementary analyses, we show that, after statistically controlling for variation in SR, PD (the sum of branches in a molecular phylogenetic tree connecting all species in a community) is neither related to mean community biomass nor to the temporal stability of biomass. These results run counter to past claims. However, after controlling for SR, PD was


Ecology | 2013

Functionally and phylogenetically diverse plant communities key to soil biota

Alexandru Milcu; Eric Allan; Christiane Roscher; Tania Jenkins; Sebastian T. Meyer; Dan F. B. Flynn; Holger Bessler; François Buscot; Christof Engels; Marlén Gubsch; Stephan König; Annett Lipowsky; Jessy Loranger; Carsten Renker; Christoph Scherber; Bernhard Schmid; Elisa Thébault; Tesfaye Wubet; Wolfgang W. Weisser; Stefan Scheu; Nico Eisenhauer

Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity--ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset of a grassland biodiversity experiment. Plant functional and phylogenetic diversity were generally better predictors of soil biota than the traditionally used species or functional group richness. Functional diversity was a reliable predictor for most biota, with the exception of soil microorganisms, which were better predicted by phylogenetic diversity. These results provide empirical support for the idea that the diversity of plant functional traits and the diversity of evolutionary lineages in a community are important for maintaining higher abundances and diversity of soil communities.

Collaboration


Dive into the Eric Allan's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Christiane Roscher

Helmholtz Centre for Environmental Research - UFZ

View shared research outputs
Top Co-Authors

Avatar

François Buscot

Helmholtz Centre for Environmental Research - UFZ

View shared research outputs
Top Co-Authors

Avatar

Jörg Müller

Bavarian Forest National Park

View shared research outputs
Researchain Logo
Decentralizing Knowledge