@article{DenglerWagnerDembiczetal.2018, author = {Dengler, J{\"u}rgen and Wagner, Viktoria and Dembicz, Iwona and Garcia-Mijangos, Itziar and Naqinezhad, Alireza and Boch, Steffen and Chiarucci, Alessandro and Conradi, Timo and Filibeck, Goffredo and Guarino, Riccardo and Janisova, Monika and Steinbauer, Manuel J. and Acic, Svetlana and Acosta, Alicia T. R. and Akasaka, Munemitsu and Allers, Marc-Andre and Apostolova, Iva and Axmanova, Irena and Bakan, Branko and Baranova, Alina and Bardy-Durchhalter, Manfred and Bartha, Sandor and Baumann, Esther and Becker, Thomas and Becker, Ute and Belonovskaya, Elena and Bengtsson, Karin and Benito Alonso, Jose Luis and Berastegi, Asun and Bergamini, Ariel and Bonini, Ilaria and Bruun, Hans Henrik and Budzhak, Vasyl and Bueno, Alvaro and Antonio Campos, Juan and Cancellieri, Laura and Carboni, Marta and Chocarro, Cristina and Conti, Luisa and Czarniecka-Wiera, Marta and De Frenne, Pieter and Deak, Balazs and Didukh, Yakiv P. and Diekmann, Martin and Dolnik, Christian and Dupre, Cecilia and Ecker, Klaus and Ermakov, Nikolai and Erschbamer, Brigitta and Escudero, Adrian and Etayo, Javier and Fajmonova, Zuzana and Felde, Vivian A. and Fernandez Calzado, Maria Rosa and Finckh, Manfred and Fotiadis, Georgios and Fracchiolla, Mariano and Ganeva, Anna and Garcia-Magro, Daniel and Gavilan, Rosario G. and Germany, Markus and Giladi, Itamar and Gillet, Francois and Giusso del Galdo, Gian Pietro and Gonzalez, Jose M. and Grytnes, John-Arvid and Hajek, Michal and Hajkova, Petra and Helm, Aveliina and Herrera, Mercedes and Hettenbergerova, Eva and Hobohm, Carsten and Huellbusch, Elisabeth M. and Ingerpuu, Nele and Jandt, Ute and Jeltsch, Florian and Jensen, Kai and Jentsch, Anke and Jeschke, Michael and Jimenez-Alfaro, Borja and Kacki, Zygmunt and Kakinuma, Kaoru and Kapfer, Jutta and Kavgaci, Ali and Kelemen, Andras and Kiehl, Kathrin and Koyama, Asuka and Koyanagi, Tomoyo F. and Kozub, Lukasz and Kuzemko, Anna and Kyrkjeeide, Magni Olsen and Landi, Sara and Langer, Nancy and Lastrucci, Lorenzo and Lazzaro, Lorenzo and Lelli, Chiara and Leps, Jan and Loebel, Swantje and Luzuriaga, Arantzazu L. and Maccherini, Simona and Magnes, Martin and Malicki, Marek and Marceno, Corrado and Mardari, Constantin and Mauchamp, Leslie and May, Felix and Michelsen, Ottar and Mesa, Joaquin Molero and Molnar, Zsolt and Moysiyenko, Ivan Y. and Nakaga, Yuko K. and Natcheva, Rayna and Noroozi, Jalil and Pakeman, Robin J. and Palpurina, Salza and Partel, Meelis and Paetsch, Ricarda and Pauli, Harald and Pedashenko, Hristo and Peet, Robert K. and Pielech, Remigiusz and Pipenbaher, Natasa and Pirini, Chrisoula and Pleskova, Zuzana and Polyakova, Mariya A. and Prentice, Honor C. and Reinecke, Jennifer and Reitalu, Triin and Pilar Rodriguez-Rojo, Maria and Rolecek, Jan and Ronkin, Vladimir and Rosati, Leonardo and Rosen, Ejvind and Ruprecht, Eszter and Rusina, Solvita and Sabovljevic, Marko and Maria Sanchez, Ana and Savchenko, Galina and Schuhmacher, Oliver and Skornik, Sonja and Sperandii, Marta Gaia and Staniaszek-Kik, Monika and Stevanovic-Dajic, Zora and Stock, Marin and Suchrow, Sigrid and Sutcliffe, Laura M. E. and Swacha, Grzegorz and Sykes, Martin and Szabo, Anna and Talebi, Amir and Tanase, Catalin and Terzi, Massimo and Tolgyesi, Csaba and Torca, Marta and Torok, Peter and Tothmeresz, Bela and Tsarevskaya, Nadezda and Tsiripidis, Ioannis and Tzonev, Rossen and Ushimaru, Atushi and Valko, Orsolya and van der Maarel, Eddy and Vanneste, Thomas and Vashenyak, Iuliia and Vassilev, Kiril and Viciani, Daniele and Villar, Luis and Virtanen, Risto and Kosic, Ivana Vitasovic and Wang, Yun and Weiser, Frank and Went, Julia and Wesche, Karsten and White, Hannah and Winkler, Manuela and Zaniewski, Piotr T. and Zhang, Hui and Ziv, Yaron and Znamenskiy, Sergey and Biurrun, Idoia}, title = {GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands}, series = {Phytocoenologia}, volume = {48}, journal = {Phytocoenologia}, number = {3}, publisher = {Cramer}, address = {Stuttgart}, issn = {0340-269X}, doi = {10.1127/phyto/2018/0267}, pages = {331 -- 347}, year = {2018}, abstract = {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.}, language = {en} } @article{CrawfordJeltschMayetal.2018, author = {Crawford, Michael and Jeltsch, Florian and May, Felix and Grimm, Volker and Schl{\"a}gel, Ulrike E.}, title = {Intraspecific trait variation increases species diversity in a trait-based grassland model}, series = {Oikos}, volume = {128}, journal = {Oikos}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {0030-1299}, doi = {10.1111/oik.05567}, pages = {441 -- 455}, year = {2018}, abstract = {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.}, language = {en} } @article{BergholzMayRistowetal.2017, author = {Bergholz, Kolja and May, Felix and Ristow, Michael and Giladi, Itamar and Ziv, Yaron and Jeltsch, Florian}, title = {Two Mediterranean annuals feature high within-population trait variability and respond differently to a precipitation gradient}, series = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie}, volume = {25}, journal = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie}, publisher = {Elsevier}, address = {Jena}, issn = {1439-1791}, doi = {10.1016/j.baae.2017.11.001}, pages = {48 -- 58}, year = {2017}, abstract = {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.}, language = {en} } @article{BergholzMayGiladietal.2017, author = {Bergholz, Kolja and May, Felix and Giladi, Itamar and Ristow, Michael and Ziv, Yaron and Jeltsch, Florian}, title = {Environmental heterogeneity drives fine-scale species assembly and functional diversity of annual plants in a semi-arid environment}, series = {Perspectives in plant ecology, evolution and systematics}, volume = {24}, journal = {Perspectives in plant ecology, evolution and systematics}, publisher = {Elsevier}, address = {Jena}, issn = {1433-8319}, doi = {10.1016/j.ppees.2017.01.001}, pages = {138 -- 146}, year = {2017}, abstract = {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.}, language = {en} } @article{KoernerPfestorfMayetal.2014, author = {Koerner, Katrin and Pfestorf, Hans and May, Felix and Jeltsch, Florian}, title = {Modelling the effect of belowground herbivory on grassland diversity}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {273}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2013.10.025}, pages = {79 -- 85}, year = {2014}, abstract = {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.}, language = {en} } @misc{GiladiMayRistowetal.2014, author = {Giladi, Itamar and May, Felix and Ristow, Michael and Jeltsch, Florian and Ziv, Yaron}, title = {Scale-dependent species-area and species-isolation relationships: a review and a test study from a fragmented semi-arid agro-ecosystem}, series = {Journal of biogeography}, volume = {41}, journal = {Journal of biogeography}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0305-0270}, doi = {10.1111/jbi.12299}, pages = {1055 -- 1069}, year = {2014}, abstract = {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.}, language = {en} } @article{WeissPfestorfMayetal.2014, author = {Weiss, Lina and Pfestorf, Hans and May, Felix and K{\"o}rner, Katrin and Boch, Steffen and Fischer, Markus and M{\"u}ller, J{\"o}rg and Prati, Daniel and Socher, Stephanie A. and Jeltsch, Florian}, title = {Grazing response patterns indicate isolation of semi-natural European grasslands}, series = {Oikos}, volume = {123}, journal = {Oikos}, number = {5}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0030-1299}, doi = {10.1111/j.1600-0706.2013.00957.x}, pages = {599 -- 612}, year = {2014}, abstract = {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.}, language = {en} } @phdthesis{May2013, author = {May, Felix}, title = {Spatial models of plant diversity and plant functional traits : towards a better understanding of plant community dynamics in fragmented landscapes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68444}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {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.}, language = {en} } @article{MayGiladiRistowetal.2013, author = {May, Felix and Giladi, Itamar and Ristow, Michael and Ziv, Yaron and Jeltsch, Florian}, title = {Metacommunity, mainland-island system or island communities? : assessing the regional dynamics of plant communities in a fragmented landscape}, series = {Ecography : pattern and diversity in ecology ; research papers forum}, volume = {36}, journal = {Ecography : pattern and diversity in ecology ; research papers forum}, number = {7}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0906-7590}, doi = {10.1111/j.1600-0587.2012.07793.x}, pages = {842 -- 853}, year = {2013}, abstract = {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.}, language = {en} } @article{MayGiladiRistowetal.2013, author = {May, Felix and Giladi, Itamar and Ristow, Michael and Ziv, Yaron and Jeltsch, Florian}, title = {Plant functional traits and community assembly along interacting gradients of productivity and fragmentation}, series = {Perspectives in plant ecology, evolution and systematics}, volume = {15}, journal = {Perspectives in plant ecology, evolution and systematics}, number = {6}, publisher = {Elsevier}, address = {Jena}, issn = {1433-8319}, doi = {10.1016/j.ppees.2013.08.002}, pages = {304 -- 318}, year = {2013}, abstract = {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.}, language = {en} }