TY  - JOUR
A1  - May, Felix
A1  - Giladi, Itamar
A1  - Ziv, Yaron
A1  - Jeltsch, Florian
T1  - Dispersal and diversity - unifying scale-dependent relationships within the neutral theory
JF  - Oikos
N2  - The response of species diversity to dispersal capability is inherently scale-dependent: increasing dispersal capability is expected to increase diversity at the local scale, while decreasing diversity at the metacommunity scale. However, these expectations are based on model formulations that neglect dispersal limitation and species segregation at the local scale. We developed a unifying framework of dispersaldiversity relationships and tested the generality of these expectations. For this purpose we used a spatially-explicit neutral model with various combinations of survey area (local scale) and landscape size (metacommunity scale). Simulations were conducted using landscapes of finite and of conceptually infinite size. We analyzed the scale-dependence of dispersal-diversity relationships for exponentially-bounded versus fat-tailed dispersal kernels, several levels of speciation rate and contrasting assumptions on recruitment at short dispersal distances. We found that the ratio of survey area to landscape size is a major determinant of dispersaldiversity relationships. With increasing survey-to-landscape area ratio the dispersaldiversity relationship switches from monotonically increasing through a U-shaped pattern (with a local minimum) to a monotonically decreasing pattern. Therefore, we provide a continuous set of dispersaldiversity relationships, which contains the response shapes reported previously as extreme cases. We suggest the mean dispersal distance with the minimum of species diversity (minimizing dispersal distance) for a certain scenario as a key characteristic of dispersaldiversity relationships. We show that not only increasing mean dispersal distances, but also increasing variances of dispersal can enhance diversity at the local scale, given a diverse species pool at the metacommunity scale. In conclusion, the response of diversity to variations of dispersal capability at spatial scales of interest, e.g. conservation areas, can differ more widely than expected previously. Therefore, land use and conservation activities, which manipulate dispersal capability, need to consider the landscape context and potential species pools carefully.
Y1  - 2012
U6  - https://doi.org/10.1111/j.1600-0706.2011.20078.x
SN  - 0030-1299
VL  - 121
IS  - 6
SP  - 942
EP  - 951
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bergholz, Kolja
A1  - May, Felix
A1  - Giladi, Itamar
A1  - Ristow, Michael
A1  - Ziv, Yaron
A1  - Jeltsch, Florian
T1  - Environmental heterogeneity drives fine-scale species assembly and functional diversity of annual plants in a semi-arid environment
JF  - Perspectives in plant ecology, evolution and systematics
N2  - Spatial environmental heterogeneity is considered a fundamental factor for the maintenance of plant species richness. However, it still remains unclear whether heterogeneity may also facilitate coexistence at fine grain sizes or whether other processes, like mass effects and source sink dynamics due to dispersal, control species composition and diversity at these scales. In this study, we used two complimentary analyses to identify the role of heterogeneity within 15 m x 15 m plots for the coexistence of species-rich annual communities in a semi-arid environment along a steep precipitation gradient. Specifically, we: (a) analyzed the effect of environmental heterogeneity on species, functional and phylogenetic diversity within microsites (alpha diversity, 0.06 m(2) and 1 m(2)), across microsites (beta diversity), and diversity at the entire plot (gamma diversity); (b) further we used two null models to detect non-random trait and phylogenetic patterns in order to infer assembly processes, i.e. whether co-occurring species tend to share similar traits (trait convergence) or dissimilar traits (trait divergence). In general, our results showed that heterogeneity had a positive effect on community diversity. Specifically, for alpha diversity, the effect was significant for functional diversity, and not significant for either species or phylogenetic diversities. For beta diversity, all three measures of community diversity (species, functional, and phylogenetic) increased significantly, as they also did for gamma diversity, where functional measures were again stronger than for species or phylogenetic measures. In addition, the null model approach consistently detected trait convergence, indicating that species with similar traits tended to co-occur and had high abundances in a given microsite. While null model analysis across the phylogeny partly supported these trait findings, showing phylogenetic underdispersion at the 1m(2) grain size, surprisingly when species abundances in microsites were analyzed they were more evenly distributed across the phylogenetic tress than expected (phylogenetic overdispersion). In conclusion, our results provide compelling support that environmental heterogeneity at a relatively fine scale is an important factor for species co-existence as it positively affects diversity as well as influences species assembly. Our study underlines the need for trait-based approaches conducted at fine grain sizes in order to better understand species coexistence and community assembly. (C) 2017 Elsevier GmbH. All rights reserved.
KW  - Community assembly
KW  - Plant functional trait
KW  - Habitat heterogeneity
KW  - Limiting similarity
KW  - Environmental filtering
KW  - Heterogeneity species diversity relationship
Y1  - 2017
U6  - https://doi.org/10.1016/j.ppees.2017.01.001
SN  - 1433-8319
VL  - 24
SP  - 138
EP  - 146
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Dengler, Jürgen
A1  - Wagner, Viktoria
A1  - Dembicz, Iwona
A1  - Garcia-Mijangos, Itziar
A1  - Naqinezhad, Alireza
A1  - Boch, Steffen
A1  - Chiarucci, Alessandro
A1  - Conradi, Timo
A1  - Filibeck, Goffredo
A1  - Guarino, Riccardo
A1  - Janisova, Monika
A1  - Steinbauer, Manuel J.
A1  - Acic, Svetlana
A1  - Acosta, Alicia T. R.
A1  - Akasaka, Munemitsu
A1  - Allers, Marc-Andre
A1  - Apostolova, Iva
A1  - Axmanova, Irena
A1  - Bakan, Branko
A1  - Baranova, Alina
A1  - Bardy-Durchhalter, Manfred
A1  - Bartha, Sandor
A1  - Baumann, Esther
A1  - Becker, Thomas
A1  - Becker, Ute
A1  - Belonovskaya, Elena
A1  - Bengtsson, Karin
A1  - Benito Alonso, Jose Luis
A1  - Berastegi, Asun
A1  - Bergamini, Ariel
A1  - Bonini, Ilaria
A1  - Bruun, Hans Henrik
A1  - Budzhak, Vasyl
A1  - Bueno, Alvaro
A1  - Antonio Campos, Juan
A1  - Cancellieri, Laura
A1  - Carboni, Marta
A1  - Chocarro, Cristina
A1  - Conti, Luisa
A1  - Czarniecka-Wiera, Marta
A1  - De Frenne, Pieter
A1  - Deak, Balazs
A1  - Didukh, Yakiv P.
A1  - Diekmann, Martin
A1  - Dolnik, Christian
A1  - Dupre, Cecilia
A1  - Ecker, Klaus
A1  - Ermakov, Nikolai
A1  - Erschbamer, Brigitta
A1  - Escudero, Adrian
A1  - Etayo, Javier
A1  - Fajmonova, Zuzana
A1  - Felde, Vivian A.
A1  - Fernandez Calzado, Maria Rosa
A1  - Finckh, Manfred
A1  - Fotiadis, Georgios
A1  - Fracchiolla, Mariano
A1  - Ganeva, Anna
A1  - Garcia-Magro, Daniel
A1  - Gavilan, Rosario G.
A1  - Germany, Markus
A1  - Giladi, Itamar
A1  - Gillet, Francois
A1  - Giusso del Galdo, Gian Pietro
A1  - Gonzalez, Jose M.
A1  - Grytnes, John-Arvid
A1  - Hajek, Michal
A1  - Hajkova, Petra
A1  - Helm, Aveliina
A1  - Herrera, Mercedes
A1  - Hettenbergerova, Eva
A1  - Hobohm, Carsten
A1  - Huellbusch, Elisabeth M.
A1  - Ingerpuu, Nele
A1  - Jandt, Ute
A1  - Jeltsch, Florian
A1  - Jensen, Kai
A1  - Jentsch, Anke
A1  - Jeschke, Michael
A1  - Jimenez-Alfaro, Borja
A1  - Kacki, Zygmunt
A1  - Kakinuma, Kaoru
A1  - Kapfer, Jutta
A1  - Kavgaci, Ali
A1  - Kelemen, Andras
A1  - Kiehl, Kathrin
A1  - Koyama, Asuka
A1  - Koyanagi, Tomoyo F.
A1  - Kozub, Lukasz
A1  - Kuzemko, Anna
A1  - Kyrkjeeide, Magni Olsen
A1  - Landi, Sara
A1  - Langer, Nancy
A1  - Lastrucci, Lorenzo
A1  - Lazzaro, Lorenzo
A1  - Lelli, Chiara
A1  - Leps, Jan
A1  - Loebel, Swantje
A1  - Luzuriaga, Arantzazu L.
A1  - Maccherini, Simona
A1  - Magnes, Martin
A1  - Malicki, Marek
A1  - Marceno, Corrado
A1  - Mardari, Constantin
A1  - Mauchamp, Leslie
A1  - May, Felix
A1  - Michelsen, Ottar
A1  - Mesa, Joaquin Molero
A1  - Molnar, Zsolt
A1  - Moysiyenko, Ivan Y.
A1  - Nakaga, Yuko K.
A1  - Natcheva, Rayna
A1  - Noroozi, Jalil
A1  - Pakeman, Robin J.
A1  - Palpurina, Salza
A1  - Partel, Meelis
A1  - Paetsch, Ricarda
A1  - Pauli, Harald
A1  - Pedashenko, Hristo
A1  - Peet, Robert K.
A1  - Pielech, Remigiusz
A1  - Pipenbaher, Natasa
A1  - Pirini, Chrisoula
A1  - Pleskova, Zuzana
A1  - Polyakova, Mariya A.
A1  - Prentice, Honor C.
A1  - Reinecke, Jennifer
A1  - Reitalu, Triin
A1  - Pilar Rodriguez-Rojo, Maria
A1  - Rolecek, Jan
A1  - Ronkin, Vladimir
A1  - Rosati, Leonardo
A1  - Rosen, Ejvind
A1  - Ruprecht, Eszter
A1  - Rusina, Solvita
A1  - Sabovljevic, Marko
A1  - Maria Sanchez, Ana
A1  - Savchenko, Galina
A1  - Schuhmacher, Oliver
A1  - Skornik, Sonja
A1  - Sperandii, Marta Gaia
A1  - Staniaszek-Kik, Monika
A1  - Stevanovic-Dajic, Zora
A1  - Stock, Marin
A1  - Suchrow, Sigrid
A1  - Sutcliffe, Laura M. E.
A1  - Swacha, Grzegorz
A1  - Sykes, Martin
A1  - Szabo, Anna
A1  - Talebi, Amir
A1  - Tanase, Catalin
A1  - Terzi, Massimo
A1  - Tolgyesi, Csaba
A1  - Torca, Marta
A1  - Torok, Peter
A1  - Tothmeresz, Bela
A1  - Tsarevskaya, Nadezda
A1  - Tsiripidis, Ioannis
A1  - Tzonev, Rossen
A1  - Ushimaru, Atushi
A1  - Valko, Orsolya
A1  - van der Maarel, Eddy
A1  - Vanneste, Thomas
A1  - Vashenyak, Iuliia
A1  - Vassilev, Kiril
A1  - Viciani, Daniele
A1  - Villar, Luis
A1  - Virtanen, Risto
A1  - Kosic, Ivana Vitasovic
A1  - Wang, Yun
A1  - Weiser, Frank
A1  - Went, Julia
A1  - Wesche, Karsten
A1  - White, Hannah
A1  - Winkler, Manuela
A1  - Zaniewski, Piotr T.
A1  - Zhang, Hui
A1  - Ziv, Yaron
A1  - Znamenskiy, Sergey
A1  - Biurrun, Idoia
T1  - GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands
JF  - Phytocoenologia
N2  - GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board.
KW  - biodiversity
KW  - European Vegetation Archive (EVA)
KW  - Eurasian Dry Grassland Group (EDGG)
KW  - grassland vegetation
KW  - GrassPlot
KW  - macroecology
KW  - multi-taxon
KW  - nested plot
KW  - scale-dependence
KW  - species-area relationship (SAR)
KW  - sPlot
KW  - vegetation-plot database
Y1  - 2018
U6  - https://doi.org/10.1127/phyto/2018/0267
SN  - 0340-269X
VL  - 48
IS  - 3
SP  - 331
EP  - 347
PB  - Cramer
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Weiss, Lina
A1  - Pfestorf, Hans
A1  - May, Felix
A1  - Körner, Katrin
A1  - Boch, Steffen
A1  - Fischer, Markus
A1  - Müller, Jörg
A1  - Prati, Daniel
A1  - Socher, Stephanie A.
A1  - Jeltsch, Florian
T1  - Grazing response patterns indicate isolation of semi-natural European grasslands
JF  - Oikos
N2  - Identifying drivers of species diversity is a major challenge in understanding and predicting the dynamics of species-rich semi-natural grasslands. In particular in temperate grasslands changes in land use and its consequences, i.e. increasing fragmentation, the on-going loss of habitat and the declining importance of regional processes such as seed dispersal by livestock, are considered key drivers of the diversity loss witnessed within the last decades.
Y1  - 2014
U6  - https://doi.org/10.1111/j.1600-0706.2013.00957.x
SN  - 0030-1299
SN  - 1600-0706
VL  - 123
IS  - 5
SP  - 599
EP  - 612
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Jeltsch, Florian
A1  - Blaum, Niels
A1  - Brose, Ulrich
A1  - Chipperfield, Joseph D.
A1  - Clough, Yann
A1  - Farwig, Nina
A1  - Geissler, Katja
A1  - Graham, Catherine H.
A1  - Grimm, Volker
A1  - Hickler, Thomas
A1  - Huth, Andreas
A1  - May, Felix
A1  - Meyer, Katrin M.
A1  - Pagel, Jörn
A1  - Reineking, Björn
A1  - Rillig, Matthias C.
A1  - Shea, Katriona
A1  - Schurr, Frank Martin
A1  - Schroeder, Boris
A1  - Tielbörger, Katja
A1  - Weiss, Lina
A1  - Wiegand, Kerstin
A1  - Wiegand, Thorsten
A1  - Wirth, Christian
A1  - Zurell, Damaris
T1  - How can we bring together empiricists and modellers in functional biodiversity research?
JF  - Basic and applied ecology : Journal of the Gesellschaft für Ökologie
N2  - Improving our understanding of biodiversity and ecosystem functioning and our capacity to inform ecosystem management requires an integrated framework for functional biodiversity research (FBR). However, adequate integration among empirical approaches (monitoring and experimental) and modelling has rarely been achieved in FBR. We offer an appraisal of the issues involved and chart a course towards enhanced integration. A major element of this path is the joint orientation towards the continuous refinement of a theoretical framework for FBR that links theory testing and generalization with applied research oriented towards the conservation of biodiversity and ecosystem functioning. We further emphasize existing decision-making frameworks as suitable instruments to practically merge these different aims of FBR and bring them into application. This integrated framework requires joint research planning, and should improve communication and stimulate collaboration between modellers and empiricists, thereby overcoming existing reservations and prejudices. The implementation of this integrative research agenda for FBR requires an adaptation in most national and international funding schemes in order to accommodate such joint teams and their more complex structures and data needs.
KW  - Biodiversity theory
KW  - Biodiversity experiments
KW  - Conservation management
KW  - Decision-making
KW  - Ecosystem functions and services
KW  - Forecasting
KW  - Functional traits
KW  - Global change
KW  - Monitoring programmes
KW  - Interdisciplinarity
Y1  - 2013
U6  - https://doi.org/10.1016/j.baae.2013.01.001
SN  - 1439-1791
VL  - 14
IS  - 2
SP  - 93
EP  - 101
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Crawford, Michael
A1  - Jeltsch, Florian
A1  - May, Felix
A1  - Grimm, Volker
A1  - Schlägel, Ulrike E.
T1  - Intraspecific trait variation increases species diversity in a trait-based grassland model
JF  - Oikos
N2  - Intraspecific trait variation (ITV) is thought to play a significant role in community assembly, but the magnitude and direction of its influence are not well understood. Although it may be critical to better explain population persistence, species interactions, and therefore biodiversity patterns, manipulating ITV in experiments is challenging. We therefore incorporated ITV into a trait‐ and individual‐based model of grassland community assembly by adding variation to the plants’ functional traits, which then drive life‐history tradeoffs. Varying the amount of ITV in the simulation, we examine its influence on pairwise‐coexistence and then on the species diversity in communities of different initial sizes. We find that ITV increases the ability of the weakest species to invade most, but that this effect does not scale to the community level, where the primary effect of ITV is to increase the persistence and abundance of the competitively‐average species. Diversity of the initial community is also of critical importance in determining ITV's efficacy; above a threshold of interspecific diversity, ITV does not increase diversity further. For communities below this threshold, ITV mainly helps to increase diversity in those communities that would otherwise be low‐diversity. These findings suggest that ITV actively maintains diversity by helping the species on the margins of persistence, but mostly in habitats of relatively low alpha and beta diversity.
KW  - community assembly
KW  - individual-based model
KW  - intraspecific trait variation
Y1  - 2018
U6  - https://doi.org/10.1111/oik.05567
SN  - 0030-1299
SN  - 1600-0706
VL  - 128
IS  - 3
SP  - 441
EP  - 455
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - May, Felix
A1  - Giladi, Itamar
A1  - Ristow, Michael
A1  - Ziv, Yaron
A1  - Jeltsch, Florian
T1  - Metacommunity, mainland-island system or island communities? : assessing the regional dynamics of plant communities in a fragmented landscape
JF  - Ecography : pattern and diversity in ecology ; research papers forum
N2  - Understanding the regional dynamics of plant communities is crucial for predicting the response of plant diversity to habitat fragmentation. However, for fragmented landscapes the importance of regional processes, such as seed dispersal among isolated habitat patches, has been controversially debated. Due to the stochasticity and rarity of among-patch dispersal and colonization events, we still lack a quantitative understanding of the consequences of these processes at the landscape-scale. In this study, we used extensive field data from a fragmented, semi-arid landscape in Israel to parameterize a multi-species incidence-function model. This model simulates species occupancy pattern based on patch areas and habitat configuration and explicitly considers the locations and the shapes of habitat patches for the derivation of patch connectivity. We implemented an approximate Bayesian computation approach for parameter inference and uncertainty assessment. We tested which of the three types of regional dynamics - the metacommunity, the mainland-island, or the island communities type - best represents the community dynamics in the study area and applied the simulation model to estimate the extinction debt in the investigated landscape. We found that the regional dynamics in the patch-matrix study landscape is best represented as a system of highly isolated island' communities with low rates of propagule exchange among habitat patches and consequently low colonization rates in local communities. Accordingly, the extinction rates in the local communities are the main drivers of community dynamics. Our findings indicate that the landscape carries a significant extinction debt and in model projections 33-60% of all species went extinct within 1000 yr. Our study demonstrates that the combination of dynamic simulation models with field data provides a promising approach for understanding regional community dynamics and for projecting community responses to habitat fragmentation. The approach bears the potential for efficient tests of conservation activities aimed at mitigating future losses of biodiversity.
Y1  - 2013
U6  - https://doi.org/10.1111/j.1600-0587.2012.07793.x
SN  - 0906-7590
VL  - 36
IS  - 7
SP  - 842
EP  - 853
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Koerner, Katrin
A1  - Pfestorf, Hans
A1  - May, Felix
A1  - Jeltsch, Florian
T1  - Modelling the effect of belowground herbivory on grassland diversity
JF  - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog
N2  - One challenging question in ecology is to explain species coexistence in highly diverse temperate grassland plant communities. Within this context, a clear understanding of the consequences of belowground herbivory for the composition and the diversity of plant communities continue to elude ecologists. The existing body of empirical evidence reveals partly contradictory responses ranging from negative to neutral or positive effects of belowground herbivory on grassland diversity.
 To reveal possible mechanistic grounds for these discrepancies, we extended an existing simulation model of grassland communities based on plant functional types to include root herbivory. This enabled us to test the effects of different feeding modes that represent different herbivore guilds. For each belowground feeding mode, we systematically varied the intensity and frequency of herbivory events for three different levels of soil fertility both in the presence and absence of additional aboveground grazing.
 Our modelling approach successfully reproduced various empirically reported diversity responses, merely on the basis of the different feeding modes. Different levels of plant resource availability affected the strength, but not the direction of the belowground herbivory effects. The only exception was the scenario with low resource levels, which promoted neutral (neither positive nor negative) diversity responses for some of the feeding modes. Interestingly, aboveground biomass production was largely unaffected by diversity changes induced by belowground herbivory except in the case of selective feeding modes that were related to specific functional traits.
 Our findings provide possible explanations for the broad spectrum of belowground herbivory effects on plant community diversity. Furthermore, the presented theoretical modelling approach provides a suitable conceptual framework to better understand the complex linkage between plant community and belowground herbivory dynamics.
KW  - Belowground herbivory
KW  - Individual based simulation model
KW  - Plant functional types
KW  - Species coexistence
KW  - IBC-grass model
KW  - ODD protocol
Y1  - 2014
U6  - https://doi.org/10.1016/j.ecolmodel.2013.10.025
SN  - 0304-3800
SN  - 1872-7026
VL  - 273
SP  - 79
EP  - 85
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - May, Felix
A1  - Giladi, Itamar
A1  - Ristow, Michael
A1  - Ziv, Yaron
A1  - Jeltsch, Florian
T1  - Plant functional traits and community assembly along interacting gradients of productivity and fragmentation
JF  - Perspectives in plant ecology, evolution and systematics
N2  - Quantifying the association of plant functional traits to environmental gradients is a promising approach for understanding and projecting community responses to land use and climatic changes. Although habitat fragmentation and climate are expected to affect plant communities interactively, there is a lack of empirical studies addressing trait associations to fragmentation in different climatic regimes.
 In this study, we analyse data on the key functional traits: specific leaf area (SLA), plant height, seed mass and seed number. First, we assess the evidence for the community assembly mechanisms habitat filtering and competition at different spatial scales, using several null-models and a comprehensive set of community-level trait convergence and divergence indices. Second, we analyse the association of community-mean traits with patch area and connectivity along a south-north productivity gradient.
 We found clear evidence for trait convergence due to habitat filtering. In contrast, the evidence for trait divergence due to competition fundamentally depended on the null-model used. When the null-model controlled for habitat filtering, there was only evidence for trait divergence at the smallest sampling scale (0.25 m x 0.25 m). All traits varied significantly along the S-N productivity gradient. While plant height and SLA were consistently associated with fragmentation, the association of seed mass and seed number with fragmentation changed along the S-N gradient.
 Our findings indicate trait convergence due to drought stress in the arid sites and due to higher productivity in the mesic sites. The association of plant traits to fragmentation is likely driven by increased colonization ability in small and/or isolated patches (plant height, seed number) or increased persistence ability in isolated patches (seed mass).
 Our study provides the first empirical test of trait associations with fragmentation along a productivity gradient. We conclude that it is crucial to study the interactive effects of different ecological drivers on plant functional traits.
KW  - Connectivity
KW  - Drought-stress
KW  - Habitat filtering
KW  - Limiting similarity
KW  - Null models
KW  - Plant height
KW  - Seed mass
KW  - Seed number
KW  - Specific leaf area (SLA)
Y1  - 2013
U6  - https://doi.org/10.1016/j.ppees.2013.08.002
SN  - 1433-8319
VL  - 15
IS  - 6
SP  - 304
EP  - 318
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - May, Felix
A1  - Grimm, Volker
A1  - Jeltsch, Florian
T1  - Reversed effects of grazing on plant diversity : the role of below-ground competition and size symmetry
N2  - Grazing is known as one of the key factors for diversity and community composition in grassland ecosystems, but the response of plant communities towards grazing varies remarkably between sites with different environmental conditions. It is generally accepted that grazing increases plant diversity in productive environments, while it tends to reduce diversity in unproductive habitats (grazing reversal hypothesis). Despite empirical evidence for this pattern the mechanistic link between modes of plant-plant competition and grazing response at the community level still remains poorly understood. Root-competition in particular has rarely been included in theoretical studies, although it has been hypothesized that variations in productivity and grazing regime can alter the relative importance of shoot- and root-competition. We therefore developed an individual-based model based on plant functional traits to investigate the response of a grassland community towards grazing. Models of different complexity, either incorporating only shoot competition or with distinct shoot- and root-competition, were used to study the interactive effects of grazing, resource availability, and the mode of competition (size-symmetric or asymmetric). The pattern predicted by the grazing reversal hypothesis (GRH) can only be explained by our model if shoot- and root-competition are explicitly considered and if size asymmetry of above- and symmetry of below-ground competition is assumed. For this scenario, the model additionally reproduced empirically observed plant trait responses: erect and large plant functional types (PFTs) dominated without grazing, while frequent grazing favoured small PFTs with a rosette growth form. We conclude that interactions between shoot- and root-competition and size symmetry/asymmetry of plant-plant interactions are crucial in order to understand grazing response under different habitat productivities. Our results suggest that future empirical trait surveys in grassland communities should include root traits, which have been largely ignored in previous studies, in order to improve predictions of plants" responses to grazing.
Y1  - 2009
UR  - http://www3.interscience.wiley.com/journal/118531693/home
U6  - https://doi.org/10.1111/j.1600-0706.2009.17724.x
SN  - 0030-1299
ER  -