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 - 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 - 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 - 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 -