Eric Allan

Eric Allan
Universität Bern | UniBe · Institute of Plant Sciences

PhD

About

118
Publications
65,450
Reads
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5,837
Citations
Additional affiliations
September 2013 - present
Universität Bern
Position
  • Professor (Assistant)
November 2010 - August 2013
Universität Bern
Position
  • PostDoc Position
Description
  • Postdoc
May 2008 - May 2010
Friedrich Schiller University Jena
Position
  • PostDoc Position
Description
  • Postdoc
Education
January 2004 - December 2007
Imperial College London
Field of study
  • Herbivore interactions and grassland biodiversity
October 2000 - May 2003
University of Oxford
Field of study
  • Biology

Publications

Publications (118)
Article
Full-text available
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 effect...
Article
Full-text available
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 addit...
Article
The importance of competition between similar species in driving community assembly is much debated. Recently, phylogenetic patterns in species composition have been investigated to help resolve this question: phylogenetic clustering is taken to imply environmental filtering, and phylogenetic overdispersion to indicate limiting similarity between s...
Article
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...
Article
Full-text available
Alnus viridis is a pioneer species that has expanded in Central Europe in the last decades, causing a series of negative agro-environmental impacts. Robust livestock grazing could be used as a targeted tool to reduce its encroachment, but more information is needed to find the best approach to achieve this goal. In this study, we assessed the poten...
Preprint
Full-text available
In the long-term absence of disturbance, ecosystems often enter a decline or retrogressive phase which leads to reductions in primary productivity, plant biomass, nutrient cycling and foliar quality. However, the consequences of ecosystem retrogression for higher trophic levels such as herbivores and predators, are less clear. Using a post-fire for...
Article
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International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm gene...
Article
Full-text available
International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm gene...
Article
Full-text available
Biodiversity effects on ecosystem functioning can be partitioned into complementarity effects, driven by many species, and selection effects, driven by few. Selection effects occur through interspecific abundance shifts (dominance) and intraspecific shifts in functioning. Complementarity and selection effects are often calculated for biomass, but v...
Article
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Our results add to a growing body of literature showing large intraspecific trait variation and emphasise the importance of using field collected data to determine community functional composition. However, they also show that intraspecific variation does not necessarily affect ecosystem functioning and therefore response–effect trait relationships...
Article
Land-use intensification has contrasting effects on different ecosystem services, often leading to land-use conflicts. While multiple studies have demonstrated how landscape-scale strategies can minimise the trade-off between agricultural production and biodiversity conservation, little is known about which land-use strategies maximise the landscap...
Article
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Many experiments have shown that biodiversity promotes ecosystem functioning and stability and that this relationship varies with resource availability. However, we still have a poor understanding of the underlying physiological and ecological mechanisms driving diversity effects and how they may interact with soil nutrient availability. We collect...
Article
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Land-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local-and l...
Article
Full-text available
Die Intensivierung der Landnutzung bedroht die Biodiversität unserer Grasländer und dies nicht nur im Tiefland, sondern auch in Bergregionen. Ein Versuch in Bergwiesen im Kanton Wallis zeigte bereits nach 5 Jahren, dass besonders die Düngung negative Auswirkungen auf die Pflanzenvielfalt hat und die Artenzusammensetzung verändert. Die Studie deckte...
Article
Plant–soil feedback (PSF) and diversity–productivity relationships are important research fields to study drivers and consequences of changes in plant biodiversity. While studies suggest that positive plant diversity–productivity relationships can be explained by variation in PSF in diverse plant communities, key questions on their temporal relatio...
Article
Questions Woody‐shrub encroachment affects community structure and composition. However, most studies focus on their effects on understorey plant communities, and the relative importance of shrubs in affecting plants vs soil biota communities is poorly known. Location Inner Mongolian Steppe, China. Methods We examined the effect of shrubs on mult...
Article
Full-text available
1. While the ecological impact of environmental change drivers, such as alien plant invasions, is relatively well described, quantitative social-ecological studies detailing how these changes impact multiple ecosystem services, and subsequently stakeholders, are lacking. 2. We used a social-ecological approach to assess how Prosopis juliflora (Pros...
Article
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Using 642 forest plots from three regions in Germany, we analyzed the direct and indirect effects of forest management intensity and of environmental variables on lichen functional diversity (FDis). Environmental stand variables were affected by management intensity and acted as an environmental filter: summing direct and indirect effects resulted...
Article
Full-text available
Green alder (Alnus viridis) is a shrub species that has expanded over former pastures in Central Europe due to land abandonment, leading to negative agri-environmental impacts, such as a reduction in forage yield and quality and an increase in nitrate leaching. Robust livestock breeds such as Highland cattle could be used to control A. viridis encr...
Preprint
Full-text available
Plant functional traits can provide a more mechanistic understanding of community responses to global change and effects on ecosystem functions. In particular, nitrogen enrichment shifts trait composition by promoting dominance of fast growing, acquisitive plants (with high specific leaf area [SLA] and low leaf dry matter content [LDMC]), and such...
Article
Full-text available
Land-use intensification is a major threat to biodiversity in agricultural grasslands and fertilization is one of the main drivers. The effects of fertilization on biodiversity and plant functional composition (community-weighted mean traits and mean ecological indicator values) are well studied in lowland regions, but have received less attention...
Article
Full-text available
Land-use intensification can increase provisioning ecosystem services, such as food and timber production, but it also drives changes in ecosystem functioning and biodiversity loss, which may ultimately compromise human wellbeing. To understand how changes in land-use intensity affect the relationships between biodiversity, ecosystem functions, and...
Article
Full-text available
Aboveground fungal pathogens can substantially reduce biomass production in grasslands. However, we lack a mechanistic understanding of the drivers of fungal pathogen infection and impact. Using a grassland global change and biodiversity experiment we show that the trade‐off between plant growth and defense is the main determinant of infection inci...
Article
Full-text available
Recent studies revealed a high diversity of fungal endophytes in traded tree seeds, including potential plant pathogens. The factors determining richness and composition of seed mycobiomes are poorly understood, but might be an important determinant for tree health. We assessed the relative impact of host identity, site, several site-specific envir...
Article
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Ecologists have long argued that higher functioning in diverse communities arises from the niche differences stabilizing species coexistence and from the fitness differences driving competitive dominance. However, rigorous tests are lacking. We couple field-parameterized models of competition between 10 annual plant species with a biodiversity-func...
Preprint
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The ability of an ecosystem to deliver multiple functions at high levels (multifunctionality) typically increases with biodiversity but there is substantial variation in the strength and direction of biodiversity effects, suggesting context-dependency. However, the drivers of this context dependency have not been identified and understood in compar...
Preprint
Full-text available
Land-use intensification has contrasting effects on different ecosystem services, often leading to land-use conflicts. Multiple studies, especially within the ‘land-sharing versus land-sparing’ debate, have demonstrated how landscape-scale strategies can minimise the trade-off between agricultural production and biodiversity conservation. However,...
Article
Nitrogen (N) enrichment has direct effects on ecosystem functioning by altering soil abiotic conditions and indirect effects by reducing plant diversity and shifting plant functional composition from dominance by slow to fast growing species. Litter decomposition is a key ecosystem function and is affected by N enrichment either by a change in litt...
Article
Full-text available
Understanding the sustainability of social-ecological systems requires quantifying the relationships between ecosystem service supply and use. However, these relationships, and the influence of environmental change on supply and use, are poorly known. Here we apply a nested sampling design to analyse supply-use relationships in ten administrative u...
Preprint
Global environmental change is strongly altering biodiversity and ecosystem functioning. Antagonistic biotic interactions affect the diversity and functioning of plant communities but are notoriously context dependent and are therefore likely to be altered by global change drivers. Global change can directly affect biotic interactions and can also...
Article
Full-text available
Models of natural processes necessarily sacrifice some realism for the sake of tractability. Detailed, parameter‐rich models often provide accurate estimates of system behaviour but can be data‐hungry and difficult to operationalise. Moreover, complexity increases the danger of “over‐fitting”, which leads to poor performance when models are applied...
Article
Full-text available
1. The inference of pairwise competitive outcomes (PCO) and multispecies competitive ranks and intransitivity from empirical data is essential to evaluate how competition shapes plant communities. Three categories of methods, differing in theoretical background and data requirements, have been used: (a) theoretically sound coexistence theory-based...
Preprint
Full-text available
Aboveground fungal pathogens can substantially reduce biomass production in grasslands. However, we lack a mechanistic understanding of the drivers of fungal infection and impact. Using a global change biodiversity experiment we show that the trade-off between plant growth and defense is the main determinant of fungal infection in grasslands. Nitro...
Preprint
Full-text available
With ongoing biodiversity loss, it is important to understand how the mechanisms that promote coexistence relate to those that increase functioning in diverse communities. Both coexistence and biodiversity functioning research have unified their mechanisms into two classes. However, despite seeming similarities, theory suggests that coexistence and...
Article
Full-text available
Plant diversity is an important driver of diversity at other trophic levels, suggesting that cascading extinctions could reduce overall biodiversity. Most evidence for positive effects of plant diversity comes from grasslands. Despite the fact that forests are hotspots of biodiversity, the importance of tree diversity, in particular its relative im...
Article
Full-text available
For decades, ecologists have investigated the effects of tree species diversity on tree productivity at different scales and with different approaches ranging from observational to experimental study designs. Using data from five European national forest inventories (16,773 plots), six tree species diversity experiments (584 plots), and six network...
Article
Full-text available
1.Global change, such as exotic invasions, dramatically affects ecosystem functioning. However, the mechanisms behind the impacts are often unclear and despite extensive experimental work, we know little about the importance of biodiversity loss as a component of global change effects in real‐world ecosystems. 2.We disentangled several mechanisms b...
Article
Full-text available
The international seed trade is considered relatively safe from a phytosanitary point of view and is therefore less regulated than trade in other plants for planting. However, the pests carried by traded seeds are not well known. We assessed insects and fungi in 58 traded seed lots of eleven gymnosperm and angiosperm tree species from North America...
Article
1.Despite the importance of local adaptation and the extended literature that has addressed it, there are few methods available to explore local adaptation across large temporal scales. However, long‐term patterns are likely to be essential to understanding adaptation in long‐lived species, such as trees. 2. Here, we propose a methodology named ‘vi...
Preprint
Full-text available
Nitrogen (N) enrichment has direct effects on ecosystem functioning by altering soil abiotic conditions and indirect effects by reducing plant diversity and shifting plant functional composition from dominance by slow to fast growing species. Litter decomposition is a key ecosystem function and is affected by N enrichment either by a change in litt...
Article
Bats and birds are key providers of ecosystem services in forests. How climate and habitat jointly shape their communities is well studied, but whether biotic predictors from other trophic levels may improve bird and bat diversity models is less known, especially across large bioclimatic gradients. Here, we achieved multi-taxa surveys in 209 mature...
Article
Full-text available
While forest management strongly influences biodiversity, it remains unclear how the structural and compositional changes caused by management affect different community dimensions (e.g. richness, specialisation, abundance or completeness) and how this differs between taxa. We assessed the effects of nine forest features (representing stand structu...
Article
1.Forest ecosystem functioning generally benefits from higher tree species richness, but variation within richness levels is typically large. This is mostly due to the contrasting performances of communities with different compositions. Evidence‐based understanding of composition effects on forest productivity, as well as on multiple other function...
Article
Full-text available
Trade-offs and synergies in the supply of forest ecosystem services are common but the drivers of these relationships are poorly understood. To guide management that seeks to promote multiple services, we investigated the relationships between 12 stand-level forest attributes, including structure, composition, heterogeneity and plant diversity, plu...
Article
Full-text available
Background Understanding and predicting the response of tree populations to climate change requires understanding the pattern and scale of their adaptation. Climate is often considered the major driver of local adaptation but, although biotic factors such as soil pathogens or mutualists could be as important, their role has typically been neglected...
Article
Full-text available
In the version of this Perspective originally published, in the figure in Box 3 the middle panel of the top row was incorrectly labelled '50% threshold-plus'; it should have read '50% threshold'. This has now been corrected.
Article
Full-text available
1.Rapid growth of the world's human population has increased pressure on landscapes to deliver high levels of multiple ecosystem services, including food and fibre production, carbon storage, biodiversity conservation and recreation. However, we currently lack general principles describing how to achieve this landscape multifunctionality. 2.We comb...
Article
Land-use intensification is the major threat for biodiversity in agricultural grasslands, and fertilization has been suggested as the most important driver. A common explanation for the decline of bryophyte diversity with higher land-use intensity is an indirect negative effect via the increase in vascular plant productivity, which reduces light le...
Conference Paper
The Biodiversity Exploratories (www.biodiversity-exploratories.de) are a broad-scale research project with 300 people involved addressing interactions between land-use intensity, biodiversity and ecosystem functioning in agricultural grasslands (and managed forests). The project started in 2006 and aims at gathering data for functional biodiversity...
Article
Full-text available
Increasing CO2 concentration ([CO2]) is likely to affect future species distributions, in interaction with other climate change drivers. However, current modeling approaches still seldom consider interactions between climatic factors and the importance of these interactions therefore remains mostly unexplored. Here, we combined dendrochronological...
Article
Over 40 years after the introduction of the concept into ecology, intransitive (i.e. non‐hierarchical) competition remains overlooked by ecological theory, despite theoretical work showing it could be a major driver of species coexistence. This special feature presents six studies, including models, reviews, experimental studies and large‐scale obs...
Article
1. Competition can be fully hierarchical or intransitive, and this degree of hierarchy is driven by multiple factors, including environmental conditions, the functional traits of the species involved or the topology of competition networks. Studies simultaneously analysing these drivers of competition hierarchy are rare. Additionally, organisms com...
Article
Full-text available
Functional traits are increasingly being used to understand the response of species to environmental change and their effects on ecosystem functioning. However, some ecologically important traits, such as plant height, influence the probability of species detection during field surveys. Imperfect detection of species could therefore bias measures o...