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  - Bergholz, Kolja
A1  - May, Felix
A1  - Ristow, Michael
A1  - Giladi, Itamar
A1  - Ziv, Yaron
A1  - Jeltsch, Florian
T1  - Two Mediterranean annuals feature high within-population trait variability and respond differently to a precipitation gradient
JF  - Basic and applied ecology : Journal of the Gesellschaft für Ökologie
N2  - Intraspecific trait variability plays an important role in species adaptation to climate change. However, it still remains unclear how plants in semi-arid environments respond to increasing aridity. We investigated the intraspecific trait variability of two common Mediterranean annuals (Geropogon hybridus and Crupina crupinastrum) with similar habitat preferences. They were studied along a steep precipitation gradient in Israel similar to the maximum predicted precipitation changes in the eastern Mediterranean basin (i.e. -30% until 2100). We expected a shift from competitive ability to stress tolerance with decreasing precipitation and tested this expectation by measuring key functional traits (canopy and seed release height, specific leaf area, N-and P-leaf content, seed mass). Further, we evaluated generative bet-hedging strategies by different seed traits. Both species showed different responses along the precipitation gradient. C. crupinastrum exhibited only decreased plant height toward saridity, while G. hybridus showed strong trends of generative adaptation to aridity. Different seed trait indices suggest increased bet-hedging of G. hybridus in arid environments. However, no clear trends along the precipitation gradient were observed in leaf traits (specific leaf area and leaf N-/P-content) in both species. Moreover, variance decomposition revealed that most of the observed trait variation (>> 50%) is found within populations. The findings of our study suggest that responses to increased aridity are highly species-specific and local environmental factors may have a stronger effect on intraspecific trait variation than shifts in annual precipitation. We therefore argue that trait-based analyses should focus on precipitation gradients that are comparable to predicted precipitation changes and compare precipitation effects to effects of local environmental factors. (C) 2017 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.
KW  - Climate change
KW  - Functional ecology
KW  - Plant height
KW  - Drought stress
KW  - Rainfall gradient
KW  - Trait-environment relationship
KW  - Local adaptation
KW  - Phenotypic plasticity
Y1  - 2017
U6  - https://doi.org/10.1016/j.baae.2017.11.001
SN  - 1439-1791
SN  - 1618-0089
VL  - 25
SP  - 48
EP  - 58
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  - 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  - Giladi, Itamar
A1  - May, Felix
A1  - Ristow, Michael
A1  - Jeltsch, Florian
A1  - Ziv, Yaron
T1  - Scale-dependent species-area and species-isolation relationships: a review and a test study from a fragmented semi-arid agro-ecosystem
JF  - Journal of biogeography
N2  - Aim Patterns that relate species richness with fragment area (the species-area relationship, SAR) and with isolation (the species-isolation relationship, SIR) are well documented. However, those that relate species density - the number of species within a standardized area - with fragment area (D-SAR) or isolation (D-SIR) have not been sufficiently explored, despite the potential for such an analysis to disentangle the underlying mechanisms of SARs and SIRs. Previous spatial theory predicts that a significant D-SAR or D-SIR is unlikely to emerge in taxa with high dispersal limitation, such as plants. Furthermore, a recent model predicts that the detection and the significance of D-SARs or D-SIRs may decrease with grain size. We combined a literature review with grain size-dependent sampling in a fragmented landscape to evaluate the prevalence and grain size-dependent nature of D-SARs and D-SIRs in plants. Location Worldwide (review) and a semi-arid agro-ecosystem in Israel (case study). Methods We combined an extensive literature review of 31 D-SAR studies of plants in fragmented landscapes with an empirical study in which we analysed grain size-dependent D-SARs and D-SIRs using a grain size-dependent hierarchical sampling of species density and species richness in a fragmented, semi-arid agro-ecosystem. Results We found that significantly increasing D-SARs are rare in plant studies. Furthermore, we found that the detection of a significant D-SAR is often possible only after the data have been stratified by species, habitat or landscape characteristics. The results from our case study indicated that the significance and the slopes of both D-SARs and D-SIRs increase as grain size decreases. Main conclusions These results call for a careful consideration of scale while analysing and interpreting the responses of species richness and species density to fragmentation. Our results suggest that grain size-dependent analyses of D-SARs and D-SIRs may help to disentangle the mechanisms that generate SARs and SIRs and may enable early detection of the effects of fragmentation on plant biodiversity.
KW  - species density
KW  - isolation
KW  - scale-dependence
KW  - habitat fragmentation
KW  - extinction debt
KW  - Conservation biogeography
KW  - species-area relationship
KW  - island ecology
KW  - habitat islands
KW  - island biogeography theory
Y1  - 2014
U6  - https://doi.org/10.1111/jbi.12299
SN  - 0305-0270
SN  - 1365-2699
VL  - 41
IS  - 6
SP  - 1055
EP  - 1069
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Giladi, Itamar
A1  - Ziv, Yaron
A1  - May, Felix
A1  - Jeltsch, Florian
T1  - Scale-dependent determinants of plant species richness in a semi-arid fragmented agro-ecosystem
JF  - Journal of vegetation science
N2  - Aims: (1) Understanding how the relationship between species richness and its determinants depends on the interaction between scales at which the response and explanatory variables are measured. (2) Quantifying the relative contributions of local, intermediate and large-scale determinants of species richness in a fragmented agro-ecosystem. (3) Testing the hypothesis that the relative contribution of these determinants varies with the grain size at which species richness is measured.
 Location: A fragmented agro-ecosystem in the Southern Judea Lowland, Israel, within a desert-Mediterranean transition zone.
 Methods: Plant species richness was estimated using hierarchical nested sampling in 81 plots, positioned in 38 natural vegetation patches within an agricultural matrix (mainly wheat fields) among three land units along a sharp precipitation gradient. Explanatory variables included position along that gradient, patch area, patch isolation, habitat heterogeneity and overall plant density. We used general linear models and hierarchical partitioning of variance to test and quantify the effect of each explanatory variable on species richness at four grain sizes (0.0625, 1, 25 and 225m(2)).
 Results: Species richness was mainly affected by position along a precipitation gradient and overall plant density, and to a lesser extent by habitat heterogeneity. It was also significantly affected by patch area and patch isolation, but only for small grain sizes. The contribution of each explanatory variable to explained variance in species richness varied with grain size, i.e. scale-dependent. The influence of geographic position and habitat heterogeneity on species richness increased with grain size, while the influence of plant density decreased with grain size.
 Main conclusions: Species richness is determined by the combined effect of several scale-dependent determinants. Ability to detect an effect and effect size of each determinant varies with the scale (grain size) at which it is measured. The combination of a multi-factorial approach and multi-scale sampling reveals that conclusions drawn from studies that ignore these dimensions are restricted and potentially misleading.
KW  - Habitat fragmentation
KW  - Hierarchical partitioning of variance
KW  - Multi-grain sampling
KW  - Scale-dependence
KW  - Species density
KW  - Uniform sampling
Y1  - 2011
U6  - https://doi.org/10.1111/j.1654-1103.2011.01309.x
SN  - 1100-9233
VL  - 22
IS  - 6
SP  - 983
EP  - 996
PB  - Wiley-Blackwell
CY  - Malden
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  - 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  - THES
A1  - May, Felix
T1  - Spatial models of plant diversity and plant functional traits : towards a better understanding of plant community dynamics in fragmented landscapes
T1  - Räumliche Modelle der Diversität und der funktionellen Eigenschaften von Pflanzen : für ein besseres Verständnis der Dynamik von Pflanzengemeinschaften in fragmentierten Landschaften
N2  - The fragmentation of natural habitat caused by anthropogenic land use changes is one of the main drivers of the current rapid loss of biodiversity. In face of this threat, ecological research needs to provide predictions of communities' responses to fragmentation as a prerequisite for the effective mitigation of further biodiversity loss. However, predictions of communities' responses to fragmentation require a thorough understanding of ecological processes, such as species dispersal and persistence. Therefore, this thesis seeks an improved understanding of community dynamics in fragmented landscapes. In order to approach this overall aim, I identified key questions on the response of plant diversity and plant functional traits to variations in species' dispersal capability, habitat fragmentation and local environmental conditions. All questions were addressed using spatially explicit simulations or statistical models. In chapter 2, I addressed scale-dependent relationships between dispersal capability and species diversity using a grid-based neutral model. I found that the ratio of survey area to landscape size is an important determinant of scale-dependent dispersal-diversity relationships. With small ratios, the model predicted increasing dispersal-diversity relationships, while decreasing dispersal-diversity relationships emerged, when the ratio approached one, i.e. when the survey area approached the landscape size. For intermediate ratios, I found a U-shaped pattern that has not been reported before. With this study, I unified and extended previous work on dispersal-diversity relationships. In chapter 3, I assessed the type of regional plant community dynamics for the study area in the Southern Judean Lowlands (SJL). For this purpose, I parameterised a multi-species incidence-function model (IFM) with vegetation data using approximate Bayesian computation (ABC). I found that the type of regional plant community dynamics in the SJL is best characterized as a set of isolated “island communities” with very low connectivity between local communities. Model predictions indicated a significant extinction debt with 33% - 60% of all species going extinct within 1000 years. In general, this study introduces a novel approach for combining a spatially explicit simulation model with field data from species-rich communities. In chapter 4, I first analysed, if plant functional traits in the SJL indicate trait convergence by habitat filtering and trait divergence by interspecific competition, as predicted by community assembly theory. Second, I assessed the interactive effects of fragmentation and the south-north precipitation gradient in the SJL on community-mean plant traits. I found clear evidence for trait convergence, but the evidence for trait divergence fundamentally depended on the chosen null-model. All community-mean traits were significantly associated with the precipitation gradient in the SJL. The trait associations with fragmentation indices (patch size and connectivity) were generally weaker, but statistically significant for all traits. Specific leaf area (SLA) and plant height were consistently associated with fragmentation indices along the precipitation gradient. In contrast, seed mass and seed number were interactively influenced by fragmentation and precipitation. In general, this study provides the first analysis of the interactive effects of climate and fragmentation on plant functional traits. Overall, I conclude that the spatially explicit perspective adopted in this thesis is crucial for a thorough understanding of plant community dynamics in fragmented landscapes. The finding of contrasting responses of local diversity to variations in dispersal capability stresses the importance of considering the diversity and composition of the metacommunity, prior to implementing conservation measures that aim at increased habitat connectivity. The model predictions derived with the IFM highlight the importance of additional natural habitat for the mitigation of future species extinctions. In general, the approach of combining a spatially explicit IFM with extensive species occupancy data provides a novel and promising tool to assess the consequences of different management scenarios. The analysis of plant functional traits in the SJL points to important knowledge gaps in community assembly theory with respect to the simultaneous consequences of habitat filtering and competition. In particular, it demonstrates the importance of investigating the synergistic consequences of fragmentation, climate change and land use change on plant communities. I suggest that the integration of plant functional traits and of species interactions into spatially explicit, dynamic simulation models offers a promising approach, which will further improve our understanding of plant communities and our ability to predict their dynamics in fragmented and changing landscapes.
N2  - Die Fragmentierung von Landschaften umfasst die Zerschneidung und den Verlust von Flächen mit natürlicher Vegetationsentwicklung und ist eine der Hauptursachen für den gegenwärtigen drastischen Verlust an Biodiversität. Diese Dissertation soll zu einem besseren Verständnis der Vegetationsdynamik in fragmentierten Landschaften beitragen. Damit verbunden ist das Ziel, Vorhersagen über die Reaktion von Pflanzengemeinschaften auf Fragmentierung zu verbessern. Diese Vorhersagen sind notwendig, um gezielte Naturschutzmaßnahmen zur Verminderung eines weiteren Verlustes an Biodiversität umsetzen zu können. In Kapitel 2 der Dissertation wird mit einem Simulationsmodell untersucht, wie sich die Ausbreitungsdistanz von Samen auf die lokale Artenzahl von Pflanzengemeinschaften auswirkt. Dabei zeigte sich, dass längere Ausbreitungsdistanzen die lokale Artenvielfalt sowohl erhöhen, als auch verringern können. Der wichtigste Einflussfaktor war dabei die Artenvielfalt der über-geordneten Pflanzengemeinschaft, in der die betrachtete lokale Gemeinschaft eingebettet war. Im dritten Kapitel wird die Konnektivität zwischen Pflanzengemeinschaften in Habitat-fragmenten, d.h. der Austausch von Arten und Individuen durch Samenausbreitung, im Unter-suchungsgebiet in Israel analysiert. Dafür wurde ein zweites räumliches Simulationsmodell mit statistischen Verfahren an Felddaten angepasst. Der Vergleich des Modells mit den Daten wies auf eine sehr geringe Konnektivität zwischen den Habitatfragmenten hin. Das Modell sagte vorher, dass innerhalb von 1000 Jahren 33% - 60% der Arten aussterben könnten. In Kapitel 4 wird zuerst analysiert, welche Prozesse die Verteilung von funktionellen Eigenschaften in Pflanzengemeinschaften bestimmen. In einem zweiten Schritt wird dann unter-sucht, wie sich funktionelle Eigenschaften von Pflanzengemeinschaften mit dem Niederschlag und der Fragmentierung im Untersuchungsgebiet in Israel verändern. Der Zusammenhang zwischen den Eigenschaften Pflanzenhöhe, sowie spezifischer Blattfläche und der Fragmentierung änderte sich nicht entlang des Niederschlagsgradienten. Im Gegensatz dazu, änderte sich der Zusammenhang zwischen der Samenmasse bzw. der Samenzahl und der Fragmentierung mit dem Niederschlag. Aus den Ergebnissen der ersten Teilstudie wird deutlich, dass Naturschutzmaßnahmen, die natürliche Habitate stärker vernetzen sollen, die Diversität, sowie die Zusammensetzung der übergeordneten Artengemeinschaft berücksichtigen müssen, um Verluste an Biodiversität zu vermeiden. Die Verknüpfung eines räumlichen Simulationsmodells mit Felddaten in der zweiten Teilstudie stellt einen neuen und vielversprechenden Ansatz für die Untersuchung der Auswirkungen verschiedener Management-Szenarien dar. Die dritte Teilstudie ist die erste Analyse der gemeinsamen Auswirkungen von Klima und Fragmentierung auf funktionelle Pflanzen-eigenschaften und zeigt die hohe Bedeutung der Untersuchung von Synergie-Effekten verschiedener Umweltfaktoren. Für zukünftige Forschung legt diese Dissertation nahe, funktionelle Eigenschaften und Konkurrenz zwischen Arten in räumlichen Simulationsmodellen zu berücksichtigen, um das Verständnis von Artengemeinschaften in fragmentierten Landschaften noch weiter zu verbessern.
KW  - Diversität
KW  - Ausbreitung
KW  - Pflanzengemeinschaften
KW  - Fragmentierung
KW  - ökologische Modellierung
KW  - diversity
KW  - dispersal
KW  - plant communities
KW  - fragmentation
KW  - ecological modelling
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-68444
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  -