@article{Jeltsch2003, author = {Jeltsch, Florian}, title = {{\"O}kologische Forschungen an der Unteren Havel}, series = {Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakult{\"a}t der Universit{\"a}t Potsdam}, volume = {13}, journal = {Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakult{\"a}t der Universit{\"a}t Potsdam}, issn = {1434-2375}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-4100}, pages = {138 -- 139}, year = {2003}, language = {de} } @article{Jeltsch2002, author = {Jeltsch, Florian}, title = {Wechselbeziehungen zwischen Artendiversit{\"a}t und struktureller Diversit{\"a}t : modellgest{\"u}tzte Untersuchungen am Beispiel einer semiariden Savanne}, year = {2002}, language = {de} } @article{WichmannJeltschDeanetal.2002, author = {Wichmann, Matthias and Jeltsch, Florian and Dean, Richard and Moloney, Kirk A. and Wissel, Christian}, title = {Weather does matter : simulating population dynamics of tawny eagle (Aquila rapax) under various rainfall scenarios}, year = {2002}, language = {en} } @article{JeltschWiegandHanskietal.2003, author = {Jeltsch, Florian and Wiegand, T. and Hanski, I. and Grimm, Volker}, title = {Using pattern-oriented modeling for revealing hidden information : a key for reconciling ecological theory and application}, year = {2003}, language = {en} } @article{EccardDeanWichmannetal.2006, author = {Eccard, Jana and Dean, W. Richard J. and Wichmann, Matthias and Huttunen, S. M and Eskelinen, Eeva-Liisa and Moloney, Kirk A. and Jeltsch, Florian}, title = {Use of large Acacia trees by the cavity dwelling Black-tailed Tree Rat in the southern Kalahari}, issn = {0140-1963}, doi = {10.1016/j.jaridenv.2005.06.019}, year = {2006}, abstract = {Recent extensive harvesting of large, often dead Acacia trees in and savanna of southern Africa is cause for concern about the conservation status of the arid savanna and its animal community. We mapped vegetation and nests of the Black-tailed Tree Rat Thallomy's nigricauda to assess the extent to which the rats depend on particular tree species and on the existence of dead, standing trees. The study was conducted in continuous Acacia woodland on the southern and eastern edge of the Kalahari, South Africa. Trees in which there were tree rat nests were compared with trees of similar size and vigour to identify the characteristics of nest sites. Spatial analysis of tree rat distribution was conducted using Ripley's-L function. We found that T nigricauda was able to utilize all available tree species, as long as trees were large and old enough so that cavities were existing inside the stem. The spatial distribution of nest trees did not show clumping at the investigated scale, and we therefore reject the notion of the rats forming colonies when inhabiting continuous woodlands. The selection of a particular tree as a nest site was furthermore depending on the close proximity of the major food plant, Acacia mellifera. This may limit the choice of suitable nest sites. since A. mellifera was less likely to grow within a vegetation patch containing a large trees than in patches without large trees.}, language = {en} } @incollection{LueckBalderjahnKammetal.2000, author = {L{\"u}ck, Erika and Balderjahn, Ingo and Kamm, Birgit and Greil, Holle and Wallschl{\"a}ger, Hans-Dieter and Jessel, Beate and B{\"o}ckmann, Christine and Oberh{\"a}nsli, Roland and Soyez, Konrad and Schmeer, Ernst and Blumenstein, Oswald and Berndt, Klaus-Peter and Edeling, Thomas and Friedrich, Sabine and Kaden, Klaus and Scheller, Frieder W. and Petersen, Hans-Georg and Asche, Hartmut and Bronstert, Axel and Giest, Hartmut and Gaedke, Ursula and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Jeltsch, Florian and J{\"a}nkel, Ralph and Gzik, Axel and Bork, Hans-Rudolf and Bork, Hans-Rudolf}, title = {Umweltforschung f{\"u}r das Land Brandenburg : Arbeitsgruppen und Professuren}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-3797}, publisher = {Universit{\"a}t Potsdam}, year = {2000}, language = {de} } @article{TittelBorkRoepkeetal.2000, author = {Tittel, J{\"o}rg and Bork, Rudolf and R{\"o}pke, Bj{\"o}rn and Geldmacher, Karl and Schnur, Tilo and Faust, Berno and Schaphoff, Sibyll and Dalchow, Claus and Woithe, Franka and Bronstert, Axel and Jeltsch, Florian and Jessel, Beate and Zschalich, Andrea and R{\"o}ßling, Holger and Spindler, Joris and Gaedke, Ursula and Tielb{\"o}rger, Katja and Kadmon, R. and M{\"u}ller, J. and Bissinger, Vera and Weithoff, Guntram and Wallschl{\"a}ger, Hans-Dieter and Wiegleb, Gerhard}, title = {Umweltforschung f{\"u}r das Land Brandenburg}, series = {Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakult{\"a}t der Universit{\"a}t Potsdam}, volume = {8}, journal = {Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakult{\"a}t der Universit{\"a}t Potsdam}, issn = {1434-2375}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-3828}, pages = {80 -- 134}, year = {2000}, abstract = {BISSINGER, V.; TITTEL, J.: Process rates and growth limiting factors of planktonic algae (Chlamydomonas sp.) from extremely acidic (pH 2,5 - 3) mining lakes in Germany ; BORK, H.-R. et al.: Erodierte Autos und Brunnen in Oregon, USA ; BRONSTERT, A. et al.: Bewirtschaftunsm{\"o}glichkeiten im Einzugsgebiet der Havel ; JELTSCH, F. et al.: Beweidung als Degradationsfaktor in ariden und semiariden Weidesystemen ; JELTSCH, F. et al.: Entstehung und Bedeutung r{\"a}umlicher Vegetationsstrukturen in Trockensavannen: Baum-Graskoexistenz und Artenvielfalt ; JESSEL, B. et al.: Bodenbewertung f{\"u}r Planungs- und Zulassungsverfahren in Brandenburg ; JESSEL, B.; ZSCHALICH, A.: Erarbeitung von Ausgleichs- und Ersatzmaßnahmen f{\"u}r die Wert- und Funktionselemente des Landschaftsbildes ; R{\"O}ßLING, H. et al.: Umsetzung von Ausgleichs- und Ersatzmaßnahmen beim Ausbau der Bundesautobahn A 9 ; SPINDLER, J.; GAEDKE, U.: Estimating production in plankton food webs from biomass size spectra and allometric relationships ; TIELB{\"O}RGER, K. et al.: Sukzessionsprozesse in einem Sandd{\"u}nengebiet nach Ausschluß von Beweidung ; TIELB{\"O}RGER, K. et al.: Populationsdynamische Funktionen von Ausbreitung und Dormanz ; TIELB{\"O}RGER, K. et al.: Raum-zeitliche Populationsdynamik von einj{\"a}hrigen W{\"u}stenpflanzen ; TITTEL, J. et al.: Ressourcennutzung und -weitergabe im planktischen Nahrungsnetz eines extrem sauren (pH 2,7) Tagebausees ; WALLSCHL{\"A}GER, D.; WIEGLEB, G.: Offenland-Management auf ehemaligen und in Nutzung befindlichen Truppen{\"u}bungspl{\"a}tzen im pleistoz{\"a}nen Flachland Nordostdeutschlands: Naturschutzfachliche Grundlagen und praktische Anwendungen ; WEITHOFF, G.; GAEDKE, U.: Planktische R{\"a}uber-Beute-Systeme: Experimentelle Untersuchung von {\"o}kologischen Synchronisationen}, language = {de} } @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{KruseWieczorekJeltschetal.2016, author = {Kruse, Stefan and Wieczorek, Mareike and Jeltsch, Florian and Herzschuh, Ulrike}, title = {Treeline dynamics in Siberia under changing climates as inferred from an individual-based model for Larix}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {338}, 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.2016.08.003}, pages = {101 -- 121}, year = {2016}, language = {en} } @article{TreydteGrantJeltsch2009, author = {Treydte, Anna C. and Grant, Rina C. C. and Jeltsch, Florian}, title = {Tree size and herbivory determine below-canopy grass quality and species composition in savannahs}, issn = {0960-3115}, doi = {10.1007/s10531-009-9694-3}, year = {2009}, abstract = {Large single-standing trees are rapidly declining in savannahs, ecosystems supporting a high diversity of large herbivorous mammals. Savannah trees are important as they support both a unique flora and fauna. The herbaceous layer in particular responds to the structural and functional properties of a tree. As shrubland expands stem thickening occurs and large trees are replaced by smaller trees. Here we examine whether small trees are as effective in providing advantages for grasses growing beneath their crowns as large trees are. The role of herbivory in this positive tree- grass interaction is also investigated. We assessed soil and grass nutrient content, structural properties, and herbaceous species composition beneath trees of three size classes and under two grazing regimes in a South African savannah. We found that grass leaf content (N and P) beneath the crowns of particularly large (ca. 3.5 m) and very large trees (ca. 9 m) was as much as 40\% greater than the same grass species not growing under a tree canopy, whereas nutrient contents of grasses did not differ beneath small trees (< 2.3 m). Moderate herbivory enhanced these effects slightly. Grass species composition differed beneath and beyond the tree canopy but not between tree size classes. As large trees significantly improve the grass nutrient quality for grazers in contrast to smaller trees, the decline of the former should be halted. The presence of trees further increases grass species diversity and patchiness by favouring shade- tolerant species. Both grazing wildlife and livestock will benefit from the presence of large trees because of their structural and functional importance for savannahs.}, language = {en} } @misc{BergholzKoberJeltschetal.2021, author = {Bergholz, Kolja and Kober, Klarissa and Jeltsch, Florian and Schmidt, Kristina and Weiß, Lina}, title = {Trait means or variance}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, issn = {1866-8372}, doi = {10.25932/publishup-51990}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-519905}, pages = {3357 -- 3365}, year = {2021}, abstract = {One of the few laws in ecology is that communities consist of few common and many rare taxa. Functional traits may help to identify the underlying mechanisms of this community pattern, since they correlate with different niche dimensions. However, comprehensive studies are missing that investigate the effects of species mean traits (niche position) and intraspecific trait variability (ITV, niche width) on species abundance. In this study, we investigated fragmented dry grasslands to reveal trait-occurrence relationships in plants at local and regional scales. We predicted that (a) at the local scale, species occurrence is highest for species with intermediate traits, (b) at the regional scale, habitat specialists have a lower species occurrence than generalists, and thus, traits associated with stress-tolerance have a negative effect on species occurrence, and (c) ITV increases species occurrence irrespective of the scale. We measured three plant functional traits (SLA = specific leaf area, LDMC = leaf dry matter content, plant height) at 21 local dry grassland communities (10 m × 10 m) and analyzed the effect of these traits and their variation on species occurrence. At the local scale, mean LDMC had a positive effect on species occurrence, indicating that stress-tolerant species are the most abundant rather than species with intermediate traits (hypothesis 1). We found limited support for lower specialist occurrence at the regional scale (hypothesis 2). Further, ITV of LDMC and plant height had a positive effect on local occurrence supporting hypothesis 3. In contrast, at the regional scale, plants with a higher ITV of plant height were less frequent. We found no evidence that the consideration of phylogenetic relationships in our analyses influenced our findings. In conclusion, both species mean traits (in particular LDMC) and ITV were differently related to species occurrence with respect to spatial scale. Therefore, our study underlines the strong scale-dependency of trait-abundance relationships.}, language = {en} } @article{BergholzKoberJeltschetal.2021, author = {Bergholz, Kolja and Kober, Klarissa and Jeltsch, Florian and Schmidt, Kristina and Weiß, Lina}, title = {Trait means or variance}, series = {Ecology and evolution}, volume = {11}, journal = {Ecology and evolution}, number = {7}, publisher = {John Wiley \& Sons, Inc.}, issn = {2045-7758}, doi = {10.1002/ece3.7287}, pages = {3357 -- 3365}, year = {2021}, abstract = {One of the few laws in ecology is that communities consist of few common and many rare taxa. Functional traits may help to identify the underlying mechanisms of this community pattern, since they correlate with different niche dimensions. However, comprehensive studies are missing that investigate the effects of species mean traits (niche position) and intraspecific trait variability (ITV, niche width) on species abundance. In this study, we investigated fragmented dry grasslands to reveal trait-occurrence relationships in plants at local and regional scales. We predicted that (a) at the local scale, species occurrence is highest for species with intermediate traits, (b) at the regional scale, habitat specialists have a lower species occurrence than generalists, and thus, traits associated with stress-tolerance have a negative effect on species occurrence, and (c) ITV increases species occurrence irrespective of the scale. We measured three plant functional traits (SLA = specific leaf area, LDMC = leaf dry matter content, plant height) at 21 local dry grassland communities (10 m × 10 m) and analyzed the effect of these traits and their variation on species occurrence. At the local scale, mean LDMC had a positive effect on species occurrence, indicating that stress-tolerant species are the most abundant rather than species with intermediate traits (hypothesis 1). We found limited support for lower specialist occurrence at the regional scale (hypothesis 2). Further, ITV of LDMC and plant height had a positive effect on local occurrence supporting hypothesis 3. In contrast, at the regional scale, plants with a higher ITV of plant height were less frequent. We found no evidence that the consideration of phylogenetic relationships in our analyses influenced our findings. In conclusion, both species mean traits (in particular LDMC) and ITV were differently related to species occurrence with respect to spatial scale. Therefore, our study underlines the strong scale-dependency of trait-abundance relationships.}, language = {en} } @article{ZurellBergerCabraletal.2010, author = {Zurell, Damaris and Berger, Uta and Cabral, Juliano Sarmento and Jeltsch, Florian and Meynard, Christine N. and Muenkemueller, Tamara and Nehrbass, Nana and Pagel, J{\"o}rn and Reineking, Bjoern and Schroeder, Boris and Grimm, Volker}, title = {The virtual ecologist approach : simulating data and observers}, issn = {0030-1299}, doi = {10.1111/j.1600-0706.2009.18284.x}, year = {2010}, abstract = {Ecologists carry a well-stocked toolbox with a great variety of sampling methods, statistical analyses and modelling tools, and new methods are constantly appearing. Evaluation and optimisation of these methods is crucial to guide methodological choices. Simulating error-free data or taking high-quality data to qualify methods is common practice. Here, we emphasise the methodology of the 'virtual ecologist' (VE) approach where simulated data and observer models are used to mimic real species and how they are 'virtually' observed. This virtual data is then subjected to statistical analyses and modelling, and the results are evaluated against the 'true' simulated data. The VE approach is an intuitive and powerful evaluation framework that allows a quality assessment of sampling protocols, analyses and modelling tools. It works under controlled conditions as well as under consideration of confounding factors such as animal movement and biased observer behaviour. In this review, we promote the approach as a rigorous research tool, and demonstrate its capabilities and practical relevance. We explore past uses of VE in different ecological research fields, where it mainly has been used to test and improve sampling regimes as well as for testing and comparing models, for example species distribution models. We discuss its benefits as well as potential limitations, and provide some practical considerations for designing VE studies. Finally, research fields are identified for which the approach could be useful in the future. We conclude that VE could foster the integration of theoretical and empirical work and stimulate work that goes far beyond sampling methods, leading to new questions, theories, and better mechanistic understanding of ecological systems.}, language = {en} } @article{JeltschMoloneySchurretal.2008, author = {Jeltsch, Florian and Moloney, Kirk A. and Schurr, Frank Martin and K{\"o}chy, Martin and Schwager, Monika}, title = {The state of plant population modelling in light of environmental change}, issn = {1433-8319}, doi = {10.1016/j.ppees.2007.11.004}, year = {2008}, abstract = {Plant population modelling has been around since the 1970s, providing a valuable approach to understanding plant ecology from a mechanistic standpoint. It is surprising then that this area of research has not grown in prominence with respect to other approaches employed in modelling plant systems. In this review, we provide an analysis of the development and role of modelling in the field of plant population biology through an exploration of where it has been, where it is now and, in our opinion, where it should be headed. We focus, in particular, on the role plant population modelling could play in ecological forecasting, an urgent need given current rates of regional and global environmental change. We suggest that a critical element limiting the current application of plant population modelling in environmental research is the trade-off between the necessary resolution and detail required to accurately characterize ecological dynamics pitted against the goal of generality, particularly at broad spatial scales. In addition to suggestions how to overcome the current shortcoming of data on the process-level we discuss two emerging strategies that may offer a way to overcome the described limitation: (1) application of a modern approach to spatial scaling from local processes to broader levels of interaction and (2) plant functional-type modelling. Finally we outline what we believe to be needed in developing these approaches towards a 'science of forecasting'.}, language = {en} } @article{ThulkeTischendorfStaubachetal.2000, author = {Thulke, Hans-Hermann and Tischendorf, L. and Staubach, C. and Selhorst, T. and Jeltsch, Florian and M{\"u}ller, T. and Schl{\"u}ter, H. and Wissel, Christian}, title = {The spatio-temporal dynamics of a post-vaccination recovery of rabies in foxes and emergency vaccination planning}, year = {2000}, language = {en} } @article{BielcikAguilarTriguerosLakovicetal.2019, author = {Bielcik, Milos and Aguilar-Trigueros, Carlos A. and Lakovic, Milica and Jeltsch, Florian and Rillig, Matthias C.}, title = {The role of active movement in fungal ecology and community assembly}, series = {Movement Ecology}, volume = {7}, journal = {Movement Ecology}, number = {1}, publisher = {BMC}, address = {London}, issn = {2051-3933}, doi = {10.1186/s40462-019-0180-6}, pages = {12}, year = {2019}, abstract = {Movement ecology aims to provide common terminology and an integrative framework of movement research across all groups of organisms. Yet such work has focused on unitary organisms so far, and thus the important group of filamentous fungi has not been considered in this context. With the exception of spore dispersal, movement in filamentous fungi has not been integrated into the movement ecology field. At the same time, the field of fungal ecology has been advancing research on topics like informed growth, mycelial translocations, or fungal highways using its own terminology and frameworks, overlooking the theoretical developments within movement ecology. We provide a conceptual and terminological framework for interdisciplinary collaboration between these two disciplines, and show how both can benefit from closer links: We show how placing the knowledge from fungal biology and ecology into the framework of movement ecology can inspire both theoretical and empirical developments, eventually leading towards a better understanding of fungal ecology and community assembly. Conversely, by a greater focus on movement specificities of filamentous fungi, movement ecology stands to benefit from the challenge to evolve its concepts and terminology towards even greater universality. We show how our concept can be applied for other modular organisms (such as clonal plants and slime molds), and how this can lead towards comparative studies with the relationship between organismal movement and ecosystems in the focus.}, language = {en} } @article{TeckentrupKramerSchadtJeltsch2019, author = {Teckentrup, Lisa and Kramer-Schadt, Stephanie and Jeltsch, Florian}, title = {The risk of ignoring fear: underestimating the effects of habitat loss and fragmentation on biodiversity}, series = {Landscape ecology}, volume = {34}, journal = {Landscape ecology}, number = {12}, publisher = {Springer}, address = {Dordrecht}, issn = {0921-2973}, doi = {10.1007/s10980-019-00922-8}, pages = {2851 -- 2868}, year = {2019}, language = {en} } @article{WeissJeltsch2015, author = {Weiß, Lina and Jeltsch, Florian}, title = {The response of simulated grassland communities to the cessation of grazing}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {303}, 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.2015.02.002}, pages = {1 -- 11}, year = {2015}, abstract = {Changes in land-use are supposed to be among the severest prospective threats to plant diversity worldwide. In semi-natural temperate grasslands, the cessation of traditional land use like livestock grazing is considered to be one of the most important drivers of the diversity loss witnessed within the last decades. Despite of the enormous number of studies on successional pathways following grazing abandonment there is no general pattern of how grassland communities are affected in terms of diversity, trait composition and pace of succession. To gain a comprehensive picture is difficult given the heterogeneity of environments and the time and effort needed for long-term investigations. We here use a proven individual- and trait-based grassland community model to analyze short- and long-term consequences of grazing abandonment under different assumptions of resource availability, pre-abandonment grazing intensity and regional isolation of communities. Grazing abandonment led to a decrease of plant functional type (PFT) diversity in all but two scenarios in the long-term. In short-term we also found an increase or no change in Shannon diversity for several scenarios. With grazing abandonment we overall found an increase in maximum plant mass, clonal integration and longer lateral spread, a decrease in rosette plant types and in stress tolerant plants, as well as an increase in grazing tolerant and a decrease in grazing avoiding plant types. Observed changes were highly dependent on the regional configuration of communities, prevalent resource conditions and land use intensity before abandonment. While long-term changes took around 10-20 years in resource rich conditions, new equilibria established in resource poor conditions only after 30-40 years. Our results confirm the potential threats caused by recent land-use changes and the assumption that oligotrophic communities are more resistant than mesotrophic communities also for long-term abandonment. Moreover, results revealed that species-rich systems are not per se more resistant than species-poor grasslands. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{FerTietjenJeltschetal.2017, author = {Fer, Istem and Tietjen, Britta and Jeltsch, Florian and Wolff, Christian Michael}, title = {The influence of El Nino-Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario}, series = {Biogeosciences}, volume = {14}, journal = {Biogeosciences}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-14-4355-2017}, pages = {4355 -- 4374}, year = {2017}, abstract = {The El Nino-Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature-eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.}, language = {en} } @article{FerTietjenJeltschetal.2017, author = {Fer, Istem and Tietjen, Britta and Jeltsch, Florian and Wolff, Christian Michael}, title = {The influence of El Nino-Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario}, series = {Biogeosciences}, volume = {14}, journal = {Biogeosciences}, number = {18}, publisher = {Copernicus}, address = {Katlenburg-Lindau}, issn = {1726-4170}, doi = {10.5194/bg-14-4355-2017}, pages = {4355 -- 4374}, year = {2017}, abstract = {The El Nino-Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature-eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.}, language = {en} } @misc{FerTietjenJeltschetal.2017, author = {Fer, Istem and Tietjen, Britta and Jeltsch, Florian and Wolff, Christian Michael}, title = {The influence of El Nino-Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403853}, pages = {20}, year = {2017}, abstract = {The El Nino-Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature-eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.}, language = {en} } @article{SynodinosTietjenLohmannetal.2018, author = {Synodinos, Alexis D. and Tietjen, Britta and Lohmann, Dirk and Jeltsch, Florian}, title = {The impact of inter-annual rainfall variability on African savannas changes with mean rainfall}, series = {Journal of theoretical biology}, volume = {437}, journal = {Journal of theoretical biology}, publisher = {Elsevier Ltd.}, address = {London}, issn = {0022-5193}, doi = {10.1016/j.jtbi.2017.10.019}, pages = {92 -- 100}, year = {2018}, abstract = {Savannas are mixed tree-grass ecosystems whose dynamics are predominantly regulated by resource competition and the temporal variability in climatic and environmental factors such as rainfall and fire. Hence, increasing inter-annual rainfall variability due to climate change could have a significant impact on savannas. To investigate this, we used an ecohydrological model of stochastic differential equations and simulated African savanna dynamics along a gradient of mean annual rainfall (520-780 mm/year) for a range of inter-annual rainfall variabilities. Our simulations produced alternative states of grassland and savanna across the mean rainfall gradient. Increasing inter-annual variability had a negative effect on the savanna state under dry conditions (520 mm/year), and a positive effect under moister conditions (580-780 mm/year). The former resulted from the net negative effect of dry and wet extremes on trees. In semi-arid conditions (520 mm/year), dry extremes caused a loss of tree cover, which could not be recovered during wet extremes because of strong resource competition and the increased frequency of fires. At high mean rainfall (780 mm/year), increased variability enhanced savanna resilience. Here, resources were no longer limiting and the slow tree dynamics buffered against variability by maintaining a stable population during 'dry' extremes, providing the basis for growth during wet extremes. Simultaneously, high rainfall years had a weak marginal benefit on grass cover due to density-regulation and grazing. Our results suggest that the effects of the slow tree and fast grass dynamics on tree-grass interactions will become a major determinant of the savanna vegetation composition with increasing rainfall variability.}, language = {en} } @article{RoticsKaatzResheffetal.2016, author = {Rotics, Shay and Kaatz, Michael and Resheff, Yehezkel S. and Turjeman, Sondra Feldman and Zurell, Damaris and Sapir, Nir and Eggers, Ute and Flack, Andrea and Fiedler, Wolfgang and Jeltsch, Florian and Wikelski, Martin and Nathan, Ran}, title = {The challenges of the first migration: movement and behaviour of juvenile vs. adult white storks with insights regarding juvenile mortality}, series = {Journal of animal ecology : a journal of the British Ecological Society}, volume = {85}, journal = {Journal of animal ecology : a journal of the British Ecological Society}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0021-8790}, doi = {10.1111/1365-2656.12525}, pages = {938 -- 947}, year = {2016}, abstract = {1. Migration conveys an immense challenge, especially for juvenile birds coping with enduring and risky journeys shortly after fledging. Accordingly, juveniles exhibit considerably lower survival rates compared to adults, particularly during migration. Juvenile white storks (Ciconia ciconia), which are known to rely on adults during their first fall migration presumably for navigational purposes, also display much lower annual survival than adults. 2. Using detailed GPS and body acceleration data, we examined the patterns and potential causes of age-related differences in fall migration properties of white storks by comparing first-year juveniles and adults. We compared juvenile and adult parameters of movement, behaviour and energy expenditure (estimated from overall dynamic body acceleration) and placed this in the context of the juveniles' lower survival rate. 3. Juveniles used flapping flight vs. soaring flight 23\% more than adults and were estimated to expend 14\% more energy during flight. Juveniles did not compensate for their higher flight costs by increased refuelling or resting during migration. When juveniles and adults migrated together in the same flock, the juvenile flew mostly behind the adult and was left behind when they separated. Juveniles showed greater improvement in flight efficiency throughout migration compared to adults which appears crucial because juveniles exhibiting higher flight costs suffered increased mortality. 4. Our findings demonstrate the conflict between the juveniles' inferior flight skills and their urge to keep up with mixed adult-juvenile flocks. We suggest that increased flight costs are an important proximate cause of juvenile mortality in white storks and likely in other soaring migrants and that natural selection is operating on juvenile variation in flight efficiency.}, language = {en} } @article{TewsBlaumJeltsch2004, author = {Tews, J{\"o}rg and Blaum, Niels and Jeltsch, Florian}, title = {Structural and animal species diversity in arid and semi-arid savannas of the southern Kalahari}, year = {2004}, language = {en} } @article{ZurellJeltschDormannetal.2009, author = {Zurell, Damaris and Jeltsch, Florian and Dormann, Carsten F. and Schr{\"o}der-Esselbach, Boris}, title = {Static species distribution models in dynamically changing systems : how good can predictions really be?}, issn = {0906-7590}, doi = {10.1111/j.1600-0587.2009.05810.x}, year = {2009}, abstract = {SDM performance varied for different range dynamics. Prediction accuracies decreased when abrupt range shifts occurred as species were outpaced by the rate of climate change, and increased again when a new equilibrium situation was realised. When ranges contracted, prediction accuracies increased as the absences were predicted well. Far- dispersing species were faster in tracking climate change, and were predicted more accurately by SDMs than short- dispersing species. BRTs mostly outperformed GLMs. The presence of a predator, and the inclusion of its incidence as an environmental predictor, made BRTs and GLMs perform similarly. Results are discussed in light of other studies dealing with effects of ecological traits and processes on SDM performance. Perspectives are given on further advancements of SDMs and for possible interfaces with more mechanistic approaches in order to improve predictions under environmental change.}, language = {en} } @article{MetzFreundtJeltsch2018, author = {Metz, Johannes and Freundt, Hanna and Jeltsch, Florian}, title = {Stable germination behavior but partly changing seed-seed interactions along a steep rainfall gradient}, series = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie}, volume = {28}, 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.2018.01.004}, pages = {5 -- 16}, year = {2018}, abstract = {Germination marks a critical transition in plant life that is prone to high mortality. Strong selection pressure is therefore expected to finely tune it to environmental conditions. Our study on the common Mediterranean grass Brachypodium hybridum assessed whether germination behavior changes systematically along a steep natural rainfall gradient ranging from harsh desert to rather mild mesic-Mediterranean conditions, We specifically tested hypotheses that germination behavior confers greater risk-spreading in populations from drier, unpredictable environments, and that seeds from wetter populations are better competitors. In 14 populations (spanning 114-954 mm annual rainfall) we assessed three alternative key parameters of germination in a greenhouse experiment: between-year dormancy, days to emergence within a season, and temporal spread. Addition of neighbor seeds accounted for competition as another crucial environmental factor. In six of the 14 populations, we also compared seeds originating from corresponding north (more mesic) and south (more arid) exposed hill slopes to test whether germination patterns along the large-scale rainfall gradient are paralleled at this smaller scale. B. hybridum exhibited generally high germination fractions and rapid emergence with very little temporal spread, indicating overall little risk-spreading germination. Surprisingly, none of the three parameters changed systematically with increasing aridity, neither at large scale along the rainfall gradient nor at small scale between north and south exposures. Neighbor seeds, however, mildly suppressed germination. Germination of neighbor seeds, in turn, was more strongly suppressed by B. hybridum seeds from drier populations, and this effect was stronger for forb than for grass neighbor species. Our results provide strong evidence that increased risk-spreading germination is not a universal, essential strategy to persist in increasingly dry, unpredictable environments. They also highlight that competition with neighbors occurs even at the earliest plant life stage. Since neighbor effects were species-specific, competition among seeds can affect community composition at later plant stages.}, language = {en} } @article{JeltschMoloney2001, author = {Jeltsch, Florian and Moloney, Kirk A.}, title = {Spatially-explicit vegetation models : what have we learned ?}, year = {2001}, language = {en} } @article{WasiolkaJeltschHenscheletal.2010, author = {Wasiolka, Bernd and Jeltsch, Florian and Henschel, Joh and Blaum, Niels}, title = {Space use of the spotted sand lizard (Pedioplanis l. lineoocellata) under different degradation states}, issn = {0141-6707}, doi = {10.1111/j.1365-2028.2009.01085.x}, year = {2010}, abstract = {Although the effects of grazing-induced savannah degradation on animal diversity are well documented, knowledge of how they affect space use or responding behaviour remains poor. In this study, we analysed space use of the spotted sand lizard (Pedioplanis l. lineoocellata) in degraded versus nondegraded habitats of southern Kalahari savannah habitats. Lizards were radio tracked, daily movement distances recorded and home range sizes calculated. In degraded Kalahari savannah habitats where plant diversity and perennial grass cover are low but shrub cover high, P. lineoocellata moves larger distances (40.88 +/- 6.42 m versus 27.43 +/- 5.08 m) and occupies larger home ranges (646.64 +/- 244.84 m(2) versus 209.15 +/- 109.84 m(2)) than in nondegraded habitats (high plant diversity, high perennial grass cover and low shrub cover). We assume that this increase in daily movement distances and home range sizes is a behavioural plasticity to limited food resources in degraded savannah habitats. Although P. lineoocellata is able to adjust to resource-poor savannah habitats, the increase in the lizard's movement activities is likely to result in a higher predation risk. This is supported by the lower availability of protective vegetation i.e. perennial grass cover. Hence, we conclude that despite behavioural plasticity of P. lineoocellata, overgrazing has a severe negative impact on the space use of P. lineoocellata.}, language = {en} } @article{MoloneyJeltsch2008, author = {Moloney, Kirk A. and Jeltsch, Florian}, title = {Space matters : novel developments in plant ecology through spatial modelling}, issn = {1433-8319}, doi = {10.1016/j.ppees.2007.12.002}, year = {2008}, language = {en} } @article{SchaeferMenzJeltschetal.2017, author = {Sch{\"a}fer, Merlin and Menz, Stephan and Jeltsch, Florian and Zurell, Damaris}, title = {sOAR: a tool for modelling optimal animal life-history strategies in cyclic environments}, series = {Ecography : pattern and diversity in ecology ; research papers forum}, volume = {41}, journal = {Ecography : pattern and diversity in ecology ; research papers forum}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {0906-7590}, doi = {10.1111/ecog.03328}, pages = {551 -- 557}, year = {2017}, abstract = {Periodic environments determine the life cycle of many animals across the globe and the timing of important life history events, such as reproduction and migration. These adaptive behavioural strategies are complex and can only be fully understood (and predicted) within the framework of natural selection in which species adopt evolutionary stable strategies. We present sOAR, a powerful and user-friendly implementation of the well-established framework of optimal annual routine modelling. It allows determining optimal animal life history strategies under cyclic environmental conditions using stochastic dynamic programming. It further includes the simulation of population dynamics under the optimal strategy. sOAR provides an important tool for theoretical studies on the behavioural and evolutionary ecology of animals. It is especially suited for studying bird migration. In particular, we integrated options to differentiate between costs of active and passive flight into the optimal annual routine modelling framework, as well as options to consider periodic wind conditions affecting flight energetics. We provide an illustrative example of sOAR where food supply in the wintering habitat of migratory birds significantly alters the optimal timing of migration. sOAR helps improving our understanding of how complex behaviours evolve and how behavioural decisions are constrained by internal and external factors experienced by the animal. Such knowledge is crucial for anticipating potential species' response to global environmental change.}, language = {en} } @article{JeltschHansenThulke2003, author = {Jeltsch, Florian and Hansen, Frank and Thulke, Hans-Hermann}, title = {Simulationsmodelle zur Planung von Strategien in der Bek{\"a}mpfung von Wildtiererkrankungen}, year = {2003}, language = {de} } @misc{ReegHeineMihanetal.2019, author = {Reeg, Jette and Heine, Simon and Mihan, Christine and McGee, Sean and Preuss, Thomas G. and Jeltsch, Florian}, title = {Simulation of herbicide impacts on a plant community}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {528}, issn = {1866-8372}, doi = {10.25932/publishup-42303}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-423039}, pages = {16}, year = {2019}, abstract = {Background Semi-natural plant communities such as field boundaries play an important ecological role in agricultural landscapes, e.g., provision of refuge for plant and other species, food web support or habitat connectivity. To prevent undesired effects of herbicide applications on these communities and their structure, the registration and application are regulated by risk assessment schemes in many industrialized countries. Standardized individual-level greenhouse experiments are conducted on a selection of crop and wild plant species to characterize the effects of herbicide loads potentially reaching off-field areas on non-target plants. Uncertainties regarding the protectiveness of such approaches to risk assessment might be addressed by assessment factors that are often under discussion. As an alternative approach, plant community models can be used to predict potential effects on plant communities of interest based on extrapolation of the individual-level effects measured in the standardized greenhouse experiments. In this study, we analyzed the reliability and adequacy of the plant community model IBC-grass (individual-based plant community model for grasslands) by comparing model predictions with empirically measured effects at the plant community level. Results We showed that the effects predicted by the model IBC-grass were in accordance with the empirical data. Based on the species-specific dose responses (calculated from empirical effects in monocultures measured 4 weeks after application), the model was able to realistically predict short-term herbicide impacts on communities when compared to empirical data. Conclusion The results presented in this study demonstrate an approach how the current standard greenhouse experiments—measuring herbicide impacts on individual-level—can be coupled with the model IBC-grass to estimate effects on plant community level. In this way, it can be used as a tool in ecological risk assessment.}, language = {en} } @article{ReegHeineMihanetal.2018, author = {Reeg, Jette and Heine, Simon and Mihan, Christine and McGee, Sean and Preuss, Thomas G. and Jeltsch, Florian}, title = {Simulation of herbicide impacts on a plant community}, series = {Environmental Sciences Europe}, volume = {30}, journal = {Environmental Sciences Europe}, number = {44}, publisher = {Springer}, address = {Berlin und Heidelberg}, issn = {2190-4715}, doi = {10.1186/s12302-018-0174-9}, pages = {16}, year = {2018}, abstract = {Background Semi-natural plant communities such as field boundaries play an important ecological role in agricultural landscapes, e.g., provision of refuge for plant and other species, food web support or habitat connectivity. To prevent undesired effects of herbicide applications on these communities and their structure, the registration and application are regulated by risk assessment schemes in many industrialized countries. Standardized individual-level greenhouse experiments are conducted on a selection of crop and wild plant species to characterize the effects of herbicide loads potentially reaching off-field areas on non-target plants. Uncertainties regarding the protectiveness of such approaches to risk assessment might be addressed by assessment factors that are often under discussion. As an alternative approach, plant community models can be used to predict potential effects on plant communities of interest based on extrapolation of the individual-level effects measured in the standardized greenhouse experiments. In this study, we analyzed the reliability and adequacy of the plant community model IBC-grass (individual-based plant community model for grasslands) by comparing model predictions with empirically measured effects at the plant community level. Results We showed that the effects predicted by the model IBC-grass were in accordance with the empirical data. Based on the species-specific dose responses (calculated from empirical effects in monocultures measured 4 weeks after application), the model was able to realistically predict short-term herbicide impacts on communities when compared to empirical data. Conclusion The results presented in this study demonstrate an approach how the current standard greenhouse experiments—measuring herbicide impacts on individual-level—can be coupled with the model IBC-grass to estimate effects on plant community level. In this way, it can be used as a tool in ecological risk assessment.}, language = {en} } @article{TietjenZeheJeltsch2009, author = {Tietjen, Britta and Zehe, Erwin and Jeltsch, Florian}, title = {Simulating plant water availability in dry lands under climate change : a generic model of two soil layers}, issn = {0043-1397}, doi = {10.1029/2007WR006589}, year = {2009}, abstract = {Dry lands are exposed to a highly variable environment and face a high risk of degradation. The effects of climate change are likely to increase this risk; thus a profound knowledge of the system dynamics is crucial for evaluating management options. This applies particularly for the interactions between water and vegetation, which exhibit strong feedbacks. To evaluate these feedbacks and the effects of climate change on soil moisture dynamics, we developed a generic, process-based, spatially explicit soil moisture model of two soil layers, which can be coupled with vegetation models. A time scale relevant for ecological processes can be simulated without difficulty, and the model avoids complex parameterization with data that are unavailable for most regions of the world. We applied the model to four sites in Israel along a precipitation and soil type gradient and assessed the effects of climate change by comparing possible climatic changes with present climate conditions. The results show that in addition to temperature, the total amount of precipitation and its intra-annual variability are an important driver of soil moisture patterns. This indicates that particularly with regard to climate change, the approach of many ecological models that simulate water dynamics on an annual base is far too simple to make reliable predictions. Thus, the introduced model can serve as a valuable tool to improve present ecological models of dry lands because of its focus on the applicability and transferability.}, language = {en} } @article{JeltschWeberMoloney2000, author = {Jeltsch, Florian and Weber, G. E. and Moloney, Kirk A.}, title = {Simulated long-term vegetation response to alternative stocking strategies in savanna rangelands}, year = {2000}, language = {en} } @article{LohmannTietjenBlaumetal.2012, author = {Lohmann, Dirk and Tietjen, Britta and Blaum, Niels and Joubert, David F. and Jeltsch, Florian}, title = {Shifting thresholds and changing degradation patterns: climate change effects on the simulated long-term response of a semi-arid savanna to grazing}, series = {Journal of applied ecology : an official journal of the British Ecological Society}, volume = {49}, journal = {Journal of applied ecology : an official journal of the British Ecological Society}, number = {4}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0021-8901}, doi = {10.1111/j.1365-2664.2012.02157.x}, pages = {814 -- 823}, year = {2012}, abstract = {1. The complex, nonlinear response of dryland systems to grazing and climatic variations is a challenge to management of these lands. Predicted climatic changes will impact the desertification of drylands under domestic livestock production. Consequently, there is an urgent need to understand the response of drylands to grazing under climate change. 2. We enhanced and parameterized an ecohydrological savanna model to assess the impacts of a range of climate change scenarios on the response of a semi-arid African savanna to grazing. We focused on the effects of temperature and CO2 level increase in combination with changes in inter- and intra-annual precipitation patterns on the long-term dynamics of three major plant functional types. 3. We found that the capacity of the savanna to sustain livestock grazing was strongly influenced by climate change. Increased mean annual precipitation and changes in intra-annual precipitation pattern have the potential to slightly increase carrying capacities of the system. In contrast, decreased precipitation, higher interannual variation and temperature increase are leading to a severe decline of carrying capacities owing to losses of the perennial grass biomass. 4. Semi-arid rangelands will be at lower risk of shrub encroachment and encroachment will be less intense under future climatic conditions. This finding holds in spite of elevated levels of atmospheric CO2 and irrespective of changes in precipitation pattern, because of the drought sensitivity of germination and establishment of encroaching species. 5. Synthesis and applications. Changes in livestock carrying capacities, both positive and negative, mainly depend on the highly uncertain future rainfall conditions. However, independent of the specific changes, shrub encroachment becomes less likely and in many cases less severe. Thus, managers of semi-arid rangelands should shift their focus from woody vegetation towards perennial grass species as indicators for rangeland degradation. Furthermore, the resulting reduced competition from woody vegetation has the potential to facilitate ecosystem restoration measures such as re-introduction of desirable plant species that are only little promising or infeasible under current climatic conditions. On a global scale, the reductions in standing biomass resulting from altered degradation dynamics of semi-arid rangelands can have negative impacts on carbon sequestration.}, language = {en} } @article{RossmanithBlaumHoentschetal.2009, author = {Rossmanith, Eva and Blaum, Niels and H{\"o}ntsch, Kerstin and Jeltsch, Florian}, title = {Sex-related parental care strategies in the lesser spotted woodpecker "Picoides minor" : of flexible mothers and dependable fathers}, issn = {0908-8857}, doi = {10.1111/j.1600-048X.2008.04353.x}, year = {2009}, abstract = {We investigated sex-specific parental care behaviour of lesser spotted woodpeckers Picoides minor in the low mountain range Taunus, Germany. Observed parental care included incubation, nest sanitation as well as brooding and feeding of nestlings. Contributions of the two sexes to parental care changed in progress of the breeding period. During incubation and the first half of the nestling period, parental care was divided equally between partners. However, in the late nestling stage, we found males to feed their nestlings irrespective of brood size while females considerably decreased feeding rate with the number of nestlings. This behaviour culminated in desertion of small broods by females shortly before fledging. The fact that even deserted nests were successful indicates that males were able to compensate for the females' absence. Interestingly, the mating of one female with two males with separate nests could be found in the population, which confirms earlier findings of polyandry in the lesser spotted woodpecker. We conclude that biparental care is not essential in the later stage and one partner can reduce effort and thus costs of parental care, at least in small broods where the mate is able to compensate for that behaviour. Reduced care and desertion appears only in females, which might be caused by a combination of two traits: First, females might suffer higher costs of investment in terms of mortality and secondly, male-biased sex ratio in the population generally leads to higher mating probabilities for females in the following breeding season. The occurrence of polyandry seems to be a result of these conditions.}, language = {en} } @article{EstherGroeneveldEnrightetal.2010, author = {Esther, Alexandra and Groeneveld, Juergen and Enright, Neal J. and Miller, Ben P. and Lamont, Byron B. and Perry, George L. W. and Blank, F. Benjamin and Jeltsch, Florian}, title = {Sensitivity of plant functional types to climate change : classification tree analysis of a simulation model}, issn = {1100-9233}, doi = {10.1111/j.1654-1103.2009.01155.x}, year = {2010}, abstract = {Question: The majority of studies investigating the impact of climate change on local plant communities ignores changes in regional processes, such as immigration from the regional seed pool. Here we explore: (i) the potential impact of climate change on composition of the regional seed pool, (ii) the influence of changes in climate and in the regional seed pool on local community structure, and (iii) the combinations of life history traits, i.e. plant functional types (PFTs), that are most affected by environmental changes. Location: Fire-prone, Mediterranean-type shrublands in southwestern Australia. Methods: Spatially explicit simulation experiments were conducted at the population level under different rainfall and fire regime scenarios to determine the effect of environmental change on the regional seed pool for 38 PFTs. The effects of environmental and seed immigration changes on local community dynamics were then derived from community-level experiments. Classification tree analyses were used to investigate PFT- specific vulnerabilities to climate change. Results: The classification tree analyses revealed that responses of PFTs to climate change are determined by specific trait characteristics. PFT-specific seed production and community patterns responded in a complex manner to climate change. For example, an increase in annual rainfall caused an increase in numbers of dispersed seeds for some PFTs, but decreased PFT diversity in the community. Conversely, a simulated decrease in rainfall reduced the number of dispersed seeds and diversity of PFTs. Conclusions: PFT interactions and regional processes must be considered when assessing how local community structure will be affected by environmental change.}, language = {en} } @article{JeltschGroeneveldWisseletal.2005, author = {Jeltsch, Florian and Groeneveld, J{\"u}rgen and Wissel, Christian and Wucherer, W. and Dimeyeva, L.}, title = {Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands}, isbn = {3-86537-386-0}, year = {2005}, language = {en} } @article{JeltschWiegandWard2004, author = {Jeltsch, Florian and Wiegand, K. and Ward, D.}, title = {Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands}, year = {2004}, language = {en} } @article{JeltschTewsSchurr2004, author = {Jeltsch, Florian and Tews, J{\"o}rg and Schurr, Frank Martin}, title = {Seed dispersal by cattle may cause shrub encroachment of Grewia flava on southern Kalahari rangelands}, year = {2004}, abstract = {Shrub encroachment, i.e. the increase in woody plant cover, is a major concern for livestock farming in southern Kalahari savannas. We developed a grid-based computer model simulating the population dynamics of Grewia flava, a common, fleshy-fruited encroaching shrub. In the absence of large herbivores, seeds of Grewia are largely deposited in the sub-canopy of Acacia erioloba. Cattle negate this dispersal limitation by browsing on the foliage of Grewia and dispersing seeds into the grassland matrix. In this study we first show that model predictions of Grewia cover dynamics are realistic by comparing model output with shrub cover estimates obtained from a time series of aerial photographs. Subsequently, we apply a realistic range of intensity of cattle-induced seed dispersal combined with potential precipitation and fire scenarios. Based on the simulation results we suggest that cattle may facilitate shrub encroachment of Grewia. The results show that the severity of shrub encroachment is governed by the intensity of seed dispersal. For a high seed dispersal intensity without fire (equivalent to a high stocking rate) the model predicts 56\% shrub cover and 85\% cell cover after 100 yr. With fire both recruitment and shrub cover are reduced, which may, under moderate intensities, prevent shrub encroachment. Climate change scenarios with two-fold higher frequencies of drought and wet years intensified shrub encroachment rates, although long-term mean of precipitation remained constant. As a management recommendation we suggest that shrub encroachment on rangelands may be counteracted by frequent fires and controlling cattle movements to areas with a high proportion of fruiting Grewia shrubs}, language = {en} } @inproceedings{RossmanithBlaumKeiletal.2006, author = {Rossmanith, Eva and Blaum, Niels and Keil, Manfred and Langerwisch, F. and Meyer, Jork and Popp, Alexander and Schmidt, Michael and Schultz, Christoph and Schwager, Monika and Vogel, Melanie and Wasiolka, Bernd and Jeltsch, Florian}, title = {Scaling up local population dynamics to regional scales}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7320}, year = {2006}, abstract = {In semi-arid savannas, unsustainable land use can lead to degradation of entire landscapes, e.g. in the form of shrub encroachment. This leads to habitat loss and is assumed to reduce species diversity. In BIOTA phase 1, we investigated the effects of land use on population dynamics on farm scale. In phase 2 we scale up to consider the whole regional landscape consisting of a diverse mosaic of farms with different historic and present land use intensities. This mosaic creates a heterogeneous, dynamic pattern of structural diversity at a large spatial scale. Understanding how the region-wide dynamic land use pattern affects the abundance of animal and plant species requires the integration of processes on large as well as on small spatial scales. In our multidisciplinary approach, we integrate information from remote sensing, genetic and ecological field studies as well as small scale process models in a dynamic region-wide simulation tool.
Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.}, language = {en} } @article{PoppVogelBlaumetal.2009, author = {Popp, Alexander and Vogel, Melanie and Blaum, Niels and Jeltsch, Florian}, title = {Scaling up ecohydrological processes : role of surface water flow in water-limited landscapes}, issn = {0148-0227}, doi = {10.1029/2008jg000910}, year = {2009}, abstract = {In this study, we present a stochastic landscape modeling approach that has the power to transfer and integrate existing information on vegetation dynamics and hydrological processes from the small scale to the landscape scale. To include microscale processes like ecohydrological feedback mechanisms and spatial exchange like surface water flow, we derive transition probabilities from a fine-scale simulation model. We applied two versions of the landscape model, one that includes and one that disregards spatial exchange of water to the situation of a sustainably used research farm and communally used and degraded rangeland in semiarid Namibia. Our simulation experiments show that including spatial exchange of overland flow among vegetation patches into our model is a precondition to reproduce vegetation dynamics, composition, and productivity, as well as hydrological processes at the landscape scale. In the model version that includes spatial exchange of water, biomass production at light grazing intensities increases 2.24-fold compared to the model without overland flow. In contrast, overgrazing destabilizes positive feedbacks through vegetation and hydrology and decreases the number of hydrological sinks in the model with overland flow. The buffer capacity of these hydrological sinks disappears and runoff increases. Here, both models predicted runoff losses from the system and artificial droughts occurring even in years with good precipitation. Overall, our study reveals that a thorough understanding of overland flow is an important precondition for improving the management of semiarid and arid rangelands with distinct topography.}, 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{GiladiZivMayetal.2011, author = {Giladi, Itamar and Ziv, Yaron and May, Felix and Jeltsch, Florian}, title = {Scale-dependent determinants of plant species richness in a semi-arid fragmented agro-ecosystem}, series = {Journal of vegetation science}, volume = {22}, journal = {Journal of vegetation science}, number = {6}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1100-9233}, doi = {10.1111/j.1654-1103.2011.01309.x}, pages = {983 -- 996}, year = {2011}, abstract = {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.}, language = {en} } @article{SchiffersTielboergerTietjenetal.2011, author = {Schiffers, Katja and Tielboerger, Katja and Tietjen, Britta and Jeltsch, Florian}, title = {Root plasticity buffers competition among plants theory meets experimental data}, series = {Ecology : a publication of the Ecological Society of America}, volume = {92}, journal = {Ecology : a publication of the Ecological Society of America}, number = {3}, publisher = {Wiley}, address = {Washington}, issn = {0012-9658}, pages = {610 -- 620}, year = {2011}, abstract = {Morphological plasticity is a striking characteristic of plants in natural communities. In the context of foraging behavior particularly, root plasticity has been documented for numerous species. Root plasticity is known to mitigate competitive interactions by reducing the overlap of the individuals' rhizospheres. But despite its obvious effect on resource acquisition, plasticity has been generally neglected in previous empirical and theoretical studies estimating interaction intensity among plants. In this study, we developed a semi-mechanistic model that addresses this shortcoming by introducing the idea of compensatory growth into the classical-zone-of influence (ZOI) and field-of-neighborhood (FON) approaches. The model parameters describing the belowground plastic sphere of influence (PSI) were parameterized using data from an accompanying field experiment. Measurements of the uptake of a stable nutrient analogue at distinct distances to the neighboring plants showed that the study species responded plastically to belowground competition by avoiding overlap of individuals' rhizospheres. An unexpected finding was that the sphere of influence of the study species Bromus hordeaceus could be best described by a unimodal function of distance to the plant's center and not with a continuously decreasing function as commonly assumed. We employed the parameterized model to investigate the interplay between plasticity and two other important factors determining the intensity of competitive interactions: overall plant density and the distribution of individuals in space. The simulation results confirm that the reduction of competition intensity due to morphological plasticity strongly depends on the spatial structure of the competitive environment. We advocate the use of semi-mechanistic simulations that explicitly consider morphological plasticity to improve our mechanistic understanding of plant interactions.}, language = {en} } @article{MayGrimmJeltsch2009, author = {May, Felix and Grimm, Volker and Jeltsch, Florian}, title = {Reversed effects of grazing on plant diversity : the role of below-ground competition and size symmetry}, issn = {0030-1299}, doi = {10.1111/j.1600-0706.2009.17724.x}, year = {2009}, abstract = {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.}, language = {en} } @article{MoloneyHolzapfelTielboergeretal.2009, author = {Moloney, Kirk A. and Holzapfel, Claus and Tielb{\"o}rger, Katja and Jeltsch, Florian and Schurr, Frank Martin}, title = {Rethinking the common garden in invasion research}, issn = {1433-8319}, doi = {10.1016/j.ppees.2009.05.002}, year = {2009}, abstract = {In common garden experiments, a number of genotypes are raised in a common environment in order to quantify the genetic component of phenotypic variation. Common gardens are thus ideally suited for disentangling how genetic and environmental factors contribute to the success of invasive species in their new non-native range. Although common garden experiments are increasingly employed in the study of invasive species, there has been little discussion about how these experiments should be designed for greatest utility. We argue that this has delayed progress in developing a general theory of invasion biology. We suggest a minimum optimal design (MOD) for common garden studies that target the ecological and evolutionary processes leading to phenotypic differentiation between native and invasive ranges. This involves four elements: (A) multiple, strategically sited garden locations, involving at the very least four gardens (2 in the native range and 2 in the invaded range); (B) careful consideration of the genetic design of the experiment; (C) standardization of experimental protocols across all gardens; and (D) care to ensure the biosafety of the experiment. Our understanding of the evolutionary ecology of biological invasions will be greatly enhanced by common garden studies, if and only if they are designed in a more systematic fashion, incorporating at the very least the MOD suggested here.}, language = {en} } @misc{WeiseAugeBaessleretal.2020, author = {Weise, Hanna and Auge, Harald and Baessler, Cornelia and B{\"a}rlund, Ilona and Bennett, Elena M. and Berger, Uta and Bohn, Friedrich and Bonn, Aletta and Borchardt, Dietrich and Brand, Fridolin and Jeltsch, Florian and Joshi, Jasmin Radha and Grimm, Volker}, title = {Resilience trinity}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {4}, issn = {1866-8372}, doi = {10.25932/publishup-51528}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515284}, pages = {14}, year = {2020}, abstract = {Ensuring ecosystem resilience is an intuitive approach to safeguard the functioning of ecosystems and hence the future provisioning of ecosystem services (ES). However, resilience is a multi-faceted concept that is difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough. We suggest a conceptual framework, resilience trinity, to facilitate management based on resilience mechanisms in three distinctive decision contexts and time-horizons: 1) reactive, when there is an imminent threat to ES resilience and a high pressure to act, 2) adjustive, when the threat is known in general but there is still time to adapt management and 3) provident, when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. Resilience has different interpretations and implications at these different time horizons, which also prevail in different disciplines. Social ecology, ecology and engineering are often implicitly focussing on provident, adjustive or reactive resilience, respectively, but these different notions of resilience and their corresponding social, ecological and economic tradeoffs need to be reconciled. Otherwise, we keep risking unintended consequences of reactive actions, or shying away from provident action because of uncertainties that cannot be reduced. The suggested trinity of time horizons and their decision contexts could help ensuring that longer-term management actions are not missed while urgent threats to ES are given priority.}, language = {en} } @article{WeiseAugeBaessleretal.2020, author = {Weise, Hanna and Auge, Harald and Baessler, Cornelia and B{\"a}rlund, Ilona and Bennett, Elena M. and Berger, Uta and Bohn, Friedrich and Bonn, Aletta and Borchardt, Dietrich and Brand, Fridolin and Jeltsch, Florian and Joshi, Jasmin Radha and Grimm, Volker}, title = {Resilience trinity}, series = {Oikos}, volume = {129}, journal = {Oikos}, number = {4}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {0030-1299}, doi = {10.1111/oik.07213}, pages = {445 -- 456}, year = {2020}, abstract = {Ensuring ecosystem resilience is an intuitive approach to safeguard the functioning of ecosystems and hence the future provisioning of ecosystem services (ES). However, resilience is a multi-faceted concept that is difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough. We suggest a conceptual framework, resilience trinity, to facilitate management based on resilience mechanisms in three distinctive decision contexts and time-horizons: 1) reactive, when there is an imminent threat to ES resilience and a high pressure to act, 2) adjustive, when the threat is known in general but there is still time to adapt management and 3) provident, when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. Resilience has different interpretations and implications at these different time horizons, which also prevail in different disciplines. Social ecology, ecology and engineering are often implicitly focussing on provident, adjustive or reactive resilience, respectively, but these different notions of resilience and their corresponding social, ecological and economic tradeoffs need to be reconciled. Otherwise, we keep risking unintended consequences of reactive actions, or shying away from provident action because of uncertainties that cannot be reduced. The suggested trinity of time horizons and their decision contexts could help ensuring that longer-term management actions are not missed while urgent threats to ES are given priority.}, language = {en} }