@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{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}
}
@article{EstherGroeneveldEnrightetal.2008,
  author    = {Esther, Alexandra and Groeneveld, J{\"u}rgen and Enright, Neal J. and Miller, Ben P. and Lamont, Byron B. and Perry, George L. W. and Schurr, Frank Martin and Jeltsch, Florian},
  title     = {Assessing the importance of seed immigration on coexistence of plant functional types in a species-rich ecosystem},
  issn      = {0304-3800},
  doi       = {10.1016/j.ecolmodel.2008.01.014},
  year      = {2008},
  abstract  = {Modelling and empirical studies have shown that input from the regional seed pool is essential to maintain local species diversity. However, most of these studies have concentrated on simplified, if not neutral, model systems, and focus on a limited subset of species or on aggregated measures of diversity only (e.g., species richness or Shannon diversity). Thus they ignore more complex species interactions and important differences between species. To gain a better understanding of how seed immigration affects community structure at the local scale in real communities we conducted computer simulation experiments based on plant functional types (PFTs) for a species-rich, fire-prone Mediterranean-type shrubland in Western Australia. We developed a spatially explicit simulation model to explore the community dynamics of 38 PFTs, defined by seven traits - regeneration mode, seed production, seed size, maximum crown diameter, drought tolerance, dispersal mode and seed bank type - representing 78 woody species. Model parameterisation is based on published and unpublished data on the population dynamics of shrub species collected over 18 years. Simulation experiments are based on two contrasting seed immigration scenarios: (1) the 'equal seed input number' scenario, where the number of immigrant seeds is the same for all PFTs, and (2) the 'equal seed input mass' scenario, where the cumulative mass of migrating seeds is the same for all PFTs. Both scenarios were systematically tested and compared for different overall seed input values. Without immigration the local community drifts towards a state with only 13 coexisting PFTs. With increasing immigration rates in terms of overall mass of seeds the simulated number of coexisting PFTs and Shannon diversity quickly approaches values observed in the field. The equal seed mass scenario resulted in a more diverse community than did the seed number scenario. The model successfully approximates the frequency distributions (relative densities) of all individual plant traits except seed size for scenarios associated with equal seed input mass and high immigration rate. However, no scenario satisfactorily approximated the frequency distribution for all traits in combination. Our results show that regional seed input can explain the more aggregated measures of local community structure, and some, but not all, aspects of community composition. This points to the possible importance of other (untested) processes and traits (e.g., dispersal vectors) operating at the local scale. Our modelling framework can readily allow new factors to be systematically investigated, which is a major advantage compared to previous simulation studies, as it allows us to find structurally realistic models, which can address questions pertinent to ecological theory and to conservation management.},
  language  = {en}
}
@article{KoernerJeltsch2008,
  author    = {K{\"o}rner, Katrin and Jeltsch, Florian},
  title     = {Detecting general plant functional type responses in fragmented landscapes using spatially-explicit simulations},
  issn      = {0304-3800},
  doi       = {10.1016/j.ecolmodel.2007.08.002},
  year      = {2008},
  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{PoppDomptailBlaumetal.2009,
  author    = {Popp, Alexander and Domptail, Stephanie and Blaum, Niels and Jeltsch, Florian},
  title     = {Landuse experience does not qualify for adaptation to climate change},
  issn      = {0304-3800},
  doi       = {10.1016/j.ecolmodel.2008.11.015},
  year      = {2009},
  abstract  = {The need to implement sustainable resource management regimes for semi-arid and arid rangelands is acute as non- adapted grazing strategies lead to irreversible environmental problems such as desertification and associated loss of economic support to society. In these sensitive ecosystems, traditional sectoral, disciplinary approaches will not work to attain sustainability: achieving a collective vision of how to attain sustainability requires interactive efforts among disciplines in a more integrated approach. Therefore, we developed an integrated ecological-economic approach that consists of an ecological and an economic module and combines relevant processes on either level. Parameters for both modules are adjusted for an arid dwarf shrub savannah in southern Namibia. The economic module is used to analyse decisions of different virtual farmer types on annual stocking rates depending on their knowledge how the ecosystem works and climatic conditions. We used a dynamic linear optimisation model to simulate farm economics and livestock dynamics. The ecological module is used to simulate the impact of the farmers' land-use decision, derived by the economic module, on ecosystem dynamics and resulting carrying capacity of the system for livestock. Vegetation dynamics, based on the concept of State-and-transition models, and forage productivity for both modules is derived by a small- scale and spatially explicit vegetation model. This mechanistic approach guarantees that data collected and processes estimated at smaller scales are included in our application. Simulation results of the ecological module were successfully compared to simulation results of the optimisation model for a time series of 30 years. We revealed that sustainable management of semi-arid and arid rangelands relies strongly on rangeland managers' understanding of ecological processes. Furthermore, our simulation results demonstrate that the projected lower annual rainfall due to climate change adds an additional layer of risk to these ecosystems that are already prone to land degradation.},
  language  = {en}
}
@article{MeyerRaudnitschkaSteinhauseretal.2008,
  author    = {Meyer, Jork and Raudnitschka, Dorit and Steinhauser, J. and Jeltsch, Florian and Brandl, Roland},
  title     = {Biology and ecology of "Thallomys nigricauda" (Rodentia, Muridae) in the Thornveld savannah of South Africa},
  issn      = {1616-5047},
  doi       = {10.1016/j.mambio.2006.11.002},
  year      = {2008},
  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{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{PfeiferSchatzPicoetal.2009,
  author    = {Pfeifer, Marion and Schatz, Bertrand and Pic{\´o}, F. Xavier and Passalacqua, Nicodemo G. and Fay, Michael F. and Carey, Pete D. and Jeltsch, Florian},
  title     = {Phylogeography and genetic structure of the orchid "Himantoglossum hircinum" (L.) Spreng. across its European central-marginal gradient},
  issn      = {0305-0270},
  doi       = {10.1111/j.1365-2699.2009.02168.x},
  year      = {2009},
  abstract  = {Aim This study aims to link demographic traits and post-glacial recolonization processes with genetic traits in Himantoglossum hircinum (L.) Spreng (Orchidaceae), and to test the implications of the central-marginal concept (CMC) in Europe. Location Twenty sites covering the entire European distribution range of this species. Methods We employed amplified fragment length polymorphism (AFLP) markers and performed a plastid microsatellite survey to assess genetic variation in 20 populations of H. hircinum located along central-marginal gradients. We measured demographic traits to assess population fitness along geographical gradients and to test for correlations between demographic traits and genetic diversity. We used genetic diversity indices and analyses of molecular variance (AMOVA) to test hypotheses of reduced genetic diversity and increased genetic differentiation and isolation from central to peripheral sites. We used Bayesian simulations to analyse genetic relationships among populations. Results Genetic diversity decreased significantly with increasing latitudinal and longitudinal distance from the distribution centre when excluding outlying populations. The AMOVA revealed significant genetic differentiation among populations (F-ST = 0.146) and an increase in genetic differentiation from the centre of the geographical range to the margins (except for the Atlantic group). Population fitness, expressed as the ratio N-R/N, decreased significantly with increasing latitudinal distance from the distribution centre. Flower production was lower in most eastern peripheral sites. The geographical distribution of microsatellite haplotypes suggests post-glacial range expansion along three major migratory pathways, as also supported by individual membership fractions in six ancestral genetic clusters (C1-C6). No correlations between genetic diversity (e.g. diversity indices, haplotype frequency) and population demographic traits were detected. Main conclusions Reduced genetic diversity and haplotype frequency in H. hircinum at marginal sites reflect historical range expansions. Spatial variation in demographic traits could not explain genetic diversity patterns. For those sites that did not fit into the CMC, the genetic pattern is probably masked by other factors directly affecting either demography or population genetic structure. These include post-glacial recolonization patterns and changes in habitat suitability due to climate change at the northern periphery. Our findings emphasize the importance of distinguishing historical effects from those caused by geographical variation in population demography of species when studying evolutionary and ecological processes at the range margins under global change.},
  language  = {en}
}
@article{BlaumSeymourRossmanithetal.2009,
  author    = {Blaum, Niels and Seymour, Colleen and Rossmanith, Eva and Schwager, Monika and Jeltsch, Florian},
  title     = {Changes in arthropod diversity along a land use driven gradient of shrub cover in savanna rangelands : identifcation of suitable indicators},
  issn      = {0960-3115},
  doi       = {10.1007/s10531-008-9498-x},
  year      = {2009},
  abstract  = {Shrub encroachment linked to heavy grazing has dramatically changed savanna landscapes, and is a major form of rangeland degradation. Our understanding of how shrub encroachment affects arthropod communities is poor, however. Here, we investigate the effects of shrub encroachment on abundance and diversity of ground-dwelling (wingless) arthropods at varying levels of shrub cover in the southern Kalahari. We also ascertain if invertebrate assemblage composition changes with habitat structure and identify which aspects of habitat structure (e.g., grass cover, herbaceous plant cover, shrub density) correlate most strongly with these changes. Ant, scorpion and dung beetle abundance increased with shrub cover, whereas grasshoppers and solifuges declined. Spider and beetle abundance exhibited hump-shaped relationships with shrub cover. RTU richness within orders either mirrored abundances, or exhibited no trend. Shrub density was the habitat component most correlated with similarities between invertebrate assemblages. Ground-dwelling arthropods showed clear shifts in species assemblage composition at a similarity level of 65\% according to shrub density. Changes in indicator species showed that within the Tenebrionidae (darkling beetles), certain species respond positively to shrub thickening, replacing other species within the Family. Small-bodied, wingless Scarabaeidae (dung beetles) tended to increase with increased shrub density and three species emerged as significant indicators of more thickened habitats, although this might be a response to greater dung availability, rather than habitat structure itself. We conclude that because ground- dwelling invertebrates showed such clear responses in species assemblage composition, they present excellent candidates for use as indicator species in further studies into bush encroachment.},
  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}
}
@article{PoppBlaumJeltsch2009,
  author    = {Popp, Alexander and Blaum, Niels and Jeltsch, Florian},
  title     = {Ecohydrological feedback mechanisms in arid rangelands : simulating the impacts of topography and land use},
  issn      = {1439-1791},
  doi       = {10.1016/j.baae.2008.06.002},
  year      = {2009},
  abstract  = {The interaction between ecological and hydrological processes is particularly important in arid and semi-arid regions. Often the interaction between these processes is not completely understood and they are studied separately. We developed a grid-based computer model simulating the dynamics of the four most common vegetation types (perennial grass, annuals, dwarf shrubs and shrubs) and related hydrological processes in the region studied. Eco-hydrological interactions gain importance in rangelands with increasing slope, where vegetation cover obstructs run-off and decreases evaporation from the soil. Overgrazing can influence these positive feedback mechanisms. In this study, we first show that model predictions of cover and productivity of the vegetation types are realistic by comparing them with estimates obtained from field surveys. Then, we apply a realistic range in slope angle combined with two land use regimes (light versus heavy grazing intensity). Our simulation results reveal that hydrological processes and associated productivity are strongly affected by slope, whereas the magnitude of this impact depends on overgrazing. Under low stocking rates, undisturbed vegetation is maintained and run-off and evaporation remain low on flat plains and gentle slope. On steep slopes, run-off and evaporation become larger, while water retention potential decreases, which leads to reduced productivity. Overgrazing, however, reduces vegetation cover and biomass production and the landscape"s ability to conserve water decreases even on flat plains and gentle slopes. Generally, the abundance of perennial grasses and shrubs decreases with increasing slope and grazing. Dominance is shifted towards shrubs and annuals. As a management recommendation we suggest that different vegetation growth forms should not only be regarded as forage producers but also as regulators of ecosystem functioning. Particularly on sloping range lands, a high percentage of cover by perennial vegetation insures that water is retained in the system.},
  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{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{GrimmRevillaGroeneveldetal.2005,
  author    = {Grimm, Volker and Revilla, Eloy and Groeneveld, J{\"u}rgen and Kramer-Schadt, Stephanie and Schwager, Monika and Tews, J{\"o}rg and Wichmann, Matthias and Jeltsch, Florian},
  title     = {Importance of buffer mechanisms for population viability analysis},
  year      = {2005},
  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{WiegandSchmidtJeltschetal.2000,
  author    = {Wiegand, K. and Schmidt, H. and Jeltsch, Florian and Ward, D.},
  title     = {Linking a spatially-explicit model of acacias to GIS and remotely-sensed data},
  year      = {2000},
  language  = {en}
}
@article{JeltschWeberDeanetal.2000,
  author    = {Jeltsch, Florian and Weber, Gisela and Dean, W. R. J. and Milton, Sue J. and VanRooyen, N. and O'Connor, Terry and Moloney, Kirk A.},
  title     = {Entstehung und Bedeutung r{\"a}umlicher Vegetationsstrukturen in Trockensavannen : Baum-Graskoexistenz und Artenvielfalt},
  year      = {2000},
  language  = {de}
}
@article{TielboergerKadmonMuelleretal.2000,
  author    = {Tielb{\"o}rger, Katja and Kadmon, Ronen and M{\"u}ller, Monika and Jeltsch, Florian},
  title     = {Raum-zeitliche Populationsdynamik von einj{\"a}hrigen W{\"u}stenpflanzen},
  year      = {2000},
  language  = {de}
}
@article{TielboergerKadmonMuelleretal.2000,
  author    = {Tielb{\"o}rger, Katja and Kadmon, Ronen and M{\"u}ller, Monika and Jeltsch, Florian},
  title     = {Populationsdynamische Funktionen von Ausbreitung und Dormanz},
  year      = {2000},
  language  = {de}
}
@article{JeltschWeberParueloetal.2000,
  author    = {Jeltsch, Florian and Weber, Gisela and Paruelo, J. and Dean, W. R. J. and Milton, Sue J. and VanRooyen, N.},
  title     = {Beweidung als Degradationsfaktor in ariden und semiariden Weidesystemen},
  year      = {2000},
  language  = {de}
}
@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{JeltschWeberGrimm2000,
  author    = {Jeltsch, Florian and Weber, Gisela and Grimm, Volker},
  title     = {Ecological buffering mechanisms in savannas : a unifying theory of long-term tree-grass coexistence},
  year      = {2000},
  language  = {en}
}
@article{WiegandWardThulkeetal.2000,
  author    = {Wiegand, K. and Ward, D. and Thulke, Hans-Hermann and Jeltsch, Florian},
  title     = {From snap-shot information to long-term population dynamics of Acacias by a simulation model},
  year      = {2000},
  language  = {en}
}
@article{WiegandJeltschWard2000,
  author    = {Wiegand, K. and Jeltsch, Florian and Ward, D.},
  title     = {Do spatial effects play a role in the spatial distribution of desert dwelling Acacias?},
  year      = {2000},
  language  = {en}
}
@article{WiegandJeltsch2000,
  author    = {Wiegand, T. and Jeltsch, Florian},
  title     = {Long-term dynamics in arid and semi-arid ecosystems : synthesis of a workshop},
  year      = {2000},
  language  = {en}
}
@article{WeberJeltsch2000,
  author    = {Weber, Gisela and Jeltsch, Florian},
  title     = {Long-term impacts of livestock herbivory on herbaceous and woody vegetation in semiarid savannas},
  year      = {2000},
  language  = {en}
}
@article{JeltschStephanWiegandetal.2001,
  author    = {Jeltsch, Florian and Stephan, T. and Wiegand, T. and Weber, G. E.},
  title     = {Arid rangeland management supported by dynamic spatially-explicit simulation models},
  year      = {2001},
  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{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{WichmannJeltschDeanetal.2002,
  author    = {Wichmann, Matthias and Jeltsch, Florian and Dean, Richard and Moloney, Kirk A. and Wissel, Christian},
  title     = {Does climate change in arid savanna affect the population persistence of raptors?},
  year      = {2002},
  language  = {en}
}
@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{JeltschHansenTackmannetal.2003,
  author    = {Jeltsch, Florian and Hansen, Frank and Tackmann, K. and Thulke, Hans-Hermann},
  title     = {K{\"o}derauslageintervalle und Dauer der Bek{\"a}mpfung des Kleinen Fuchsbandwurms : eine Modellierstudie},
  year      = {2003},
  language  = {de}
}
@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{JeltschWichmannDeanetal.2003,
  author    = {Jeltsch, Florian and Wichmann, Matthias and Dean, W. R. J. and Moloney, Kirk A. and Wissel, Christian},
  title     = {Implications of climate change for the persistence of raptors in arid savannah},
  year      = {2003},
  language  = {en}
}
@article{JeltschWichmannJohstetal.2003,
  author    = {Jeltsch, Florian and Wichmann, Matthias and Johst, J. and Moloney, Kirk A. and Wissel, Christian},
  title     = {Extinction risk in periodically fluctuating environments},
  year      = {2003},
  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}
}
@article{JeltschHansenTackmannetal.2003,
  author    = {Jeltsch, Florian and Hansen, Frank and Tackmann, K. and Wissel, Christian and Thulke, Hans-Hermann},
  title     = {Controlling Echinococcus multilocularis - ecological implications of field trials},
  year      = {2003},
  language  = {en}
}
@article{WiegandJeltschWard2004,
  author    = {Wiegand, K. and Jeltsch, Florian and Ward, D.},
  title     = {Minimum recruitment frequency in plants with episodic recruitment},
  year      = {2004},
  abstract  = {There is concern about the lack of recruitment of Acacia trees in the Negev desert of Israel. We have developed three models to estimate the frequency of recruitment necessary for long-term population survival (i.e. positive average population growth for 1,000 years and <10\% probability of extinction). Two models assume purely episodic recruitment based on the general notion that recruitment in and environments is highly episodic. They differ in that the deterministic model investigates average dynamics while the stochastic model does not. Studies indicating that recruitment episodes in and environments have been overemphasized motivated the development of the third model. This semi-stochastic model simulates a mixture of continuous and episodic recruitment. Model analysis was done analytically for the deterministic model and via running model simulations for the stochastic and semi-stochastic models. The deterministic and stochastic models predict that, on average, 2.2 and 3.7 recruitment events per century, respectively, are necessary to sustain the population. According to the semi-stochastic model, 1.6 large recruitment events per century and an annual probability of 50\% that a small recruitment event occurs are needed. A consequence of purely episodic recruitment is that all recruitment episodes produce extremely large numbers of recruits (i.e. at odds with field observations), an evaluation that holds even when considering that rare events must be large. Thus, the semi- stochastic model appears to be the most realistic model. Comparing the prediction of the semi-stochastic model to field observations in the Negev desert shows that the absence of observations of extremely large recruitment events is no reason for concern. However, the almost complete absence of small recruitment events is a serious reason for concern. The lack of recruitment may be due to decreased densities of large mammalian herbivores and might be further exacerbated by possible changes in climate, both in terms of average precipitation and the temporal distribution of rain},
  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}
}
@article{JeltschTewsMoloney2004,
  author    = {Jeltsch, Florian and Tews, J{\"o}rg and Moloney, Kirk A.},
  title     = {Modelling seed dispersal in a variable environment : a case study of the fleshy-fruited savanna shrub Grewia flava},
  year      = {2004},
  abstract  = {In ecology much attention has been paid towards seed dispersal of fleshy-fruited plants, however, knowledge is lacking about the Iona-term demographic consequences of variation in dispersal distance and fruit removal rate, particularly given the natural variability of the environment the organism lives in. In this study we used a spatially explicit, two-level stochastic computer model to simulate population dynamics of a fleshy-fruited shrub living in the sub-canopy of solitary savanna trees. On the landscape level we implemented three realistic scenarios of savanna landscape dynamics for a period of 500 years with equal inter-annual mean of environmental variables. The first scenario is representative of a relatively constant environment with normal variability in precipitation, constant tree density and random tree recruitment pattern. The second and third scenarios represent positive auto-correlated, cyclic patterns with alternating phases of tree cover increase and decrease corresponding with favorable and unfavorable rain phases. Our simulation experiments show that when fruit removal rate is extremely low, population persistence is enhanced under relatively constant rain conditions, while alternating rain phases of the cyclic scenarios lead to a significant population decrease. This result confirms previous findings that periodically fluctuating environments may increase local extinction risk. However, when dispersal distance is a limiting factor (whilst removal rate was sufficiently high), tree clumps typically forming in wet phases of both cyclic scenarios compensated for the negative effect of low dispersal distances, while the constant scenario with random tree pattern and larger inter-tree distances resulted in a significant population decline. (C) 2003 Elsevier B.V. All rights reserved},
  language  = {en}
}
@article{JeltschHansenTackmannetal.2004,
  author    = {Jeltsch, Florian and Hansen, Frank and Tackmann, K. and Staubach, C. and Thulke, Hans-Hermann},
  title     = {Processes leading to a spatial aggregation of Echinococcus multilocularis in its natural intermediate host Microtus arvalis},
  year      = {2004},
  abstract  = {The small fox tapeworm (Echinococcus multilocularis) shows a heterogeneous spatial distribution in the intermediate host (Microtus arvalis). To identify the ecological processes responsible for this heterogeneity, we developed a spatially explicit simulation model. The model combines individual-based (foxes, Vulpes vulpes) and grid- based (voles) techniques to simulate the infections in both intermediate and definite host. If host populations are homogeneously mixed, the model reproduces field data for parasite prevalence only for a limited number of parameter combinations. As ecological parameters inevitably vary to a certain degree, we discarded the homogeneous mixing model as insufficient to gain insight into the ecology of the fox tapeworm cycle. We analysed five different model scenarios, each focussing on an ecological process that might be responsible for the heterogeneous spatial distribution of E multilocularis in the intermediate host. Field studies revealed that the prevalence ratio between intermediate and definite host remains stable over a wide range of ecological conditions. Thus, by varying the parameters in simulation experiments, we used the robustness of the agreement between field data and model output as quality criterion for the five scenarios. Only one of the five scenarios was found to reproduce the prevalence ratio over a sufficient range of parameter combinations. In the accentuated scenario most tapeworm eggs die due to bad environmental conditions before they cause infections in the intermediate host. This scenario is supported by the known sensitivity of tapeworm eggs to high temperatures and dry conditions. The identified process is likely to lead to a heterogeneous availability of infective eggs and thus to a clumped distribution of infected intermediate hosts. In conclusion, areas with humid conditions and low temperatures must be pointed out as high risk areas for human exposure to E. multilocularis eggs as well. (C) 2004 on behalf of Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved},
  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{JeltschTews2004,
  author    = {Jeltsch, Florian and Tews, J{\"o}rg},
  title     = {Climate change impacts woody plant population dynamics in arid savanna},
  year      = {2004},
  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{JeltschTewsBroseetal.2004,
  author    = {Jeltsch, Florian and Tews, J{\"o}rg and Brose, Ulrich and Grimm, Volker and Tielb{\"o}rger, Katja and Wichmann, Matthias and Schwager, Monika},
  title     = {Animal species diversity driven by habitat heterogeneity/diversity : the importance of keystone structures},
  year      = {2004},
  abstract  = {In a selected literature survey we reviewed studies on the habitat heterogeneity-animal species diversity relationship and evaluated whether there are uncertainties and biases in its empirical support. We reviewed 85 publications for the period 1960-2003. We screened each publication for terms that were used to define habitat heterogeneity, the animal species group and ecosystem studied, the definition of the structural variable, the measurement of vegetation structure and the temporal and spatial scale of the study. The majority of studies found a positive correlation between habitat heterogeneity/diversity and animal species diversity. However, empirical support for this relationship is drastically biased towards studies of vertebrates and habitats under anthropogenic influence. In this paper we show that ecological effects of habitat heterogeneity may vary considerably between species groups depending on whether structural attributes are perceived as heterogeneity or fragmentation. Possible effects may also vary relative to the structural variable measured. Based upon this, we introduce a classification framework that may be used for across-studies comparisons. Moreover, the effect of habitat heterogeneity for one species group may differ in relation to the spatial scale. In several studies, however, different species groups are closely linked to 'keystone structures' that determine animal species diversity by their presence. Detecting crucial keystone structures of the vegetation has profound implications for nature conservation and biodiversity management.},
  language  = {en}
}
@article{JeltschWichmannDean2004,
  author    = {Jeltsch, Florian and Wichmann, Matthias and Dean, W. R. J.},
  title     = {Global change challenges the Tawny Eagle (Aquila rapax) : modelling extinction risk with respect to predicted climate and land use changes},
  year      = {2004},
  language  = {en}
}
@article{SchurrDeanMiltonetal.2004,
  author    = {Schurr, Frank Martin and Dean, W. R. J. and Milton, Sue J. and Jeltsch, Florian},
  title     = {A conceptual model linking demography of the shrub species Grewia flava to the dynamics of Kalahari savannas},
  year      = {2004},
  abstract  = {Environmental heterogeneity is a major determinant of plant population dynamics. In semi-arid Kalahari savannas, heterogeneity is created by savanna structure, i.e. by the spatial arrangement and temporal dynamics of woody plant and open grassland microsites. We formulate a conceptual model describing the effects of savanna dynamics on the population dynamics of the animal-dispersed shrub Grewia flava. From empirical results we derive model rules describing effects of savanna structure on several processes in Grewia's life cycle. By formulating the model, we summarise existing information on Grewia demography and identify gaps in this knowledge. Despite a number of such gaps, the model can be used to make certain quantitative predictions. As an example, we apply the model to investigate the role of seed dispersal in Grewia encroachment on rangelands. Model results show that cattle promote encroachment by depositing substantial numbers of seeds in open areas, where Grewia is otherwise dispersal-limited. Finally, we draw some general conclusions about Grewia's life history and population dynamics. Under natural conditions, concentrated seed deposition under woody plants appears to be a key process causing the observed association between Grewia and other woody plants. Furthermore, low rates of recruitment and high adult survival result in slow-motion dynamics of Grewia populations. As a consequence, Grewia populations interact with savanna dynamics on long temporal and short to intermediate spatial scales.},
  language  = {en}
}
@article{WichmannGroeneveldJeltschetal.2005,
  author    = {Wichmann, Matthias and Groeneveld, J{\"u}rgen and Jeltsch, Florian and Grimm, Volker},
  title     = {Mitigation of climate change impacts on raptors by behavioural adaptation : ecological buffering mechanisms},
  issn      = {0921-8181},
  year      = {2005},
  abstract  = {The predicted climate change causes deep concerns on the effects of increasing temperatures and changing precipitation patterns on species viability and, in turn, on biodiversity. Models of Population Viability Analysis (PVA) provide a powerful tool to assess the risk of species extinction. However, most PVA models do not take into account the potential effects of behavioural adaptations. Organisms might adapt to new environmental situations and thereby mitigate negative effects of climate change. To demonstrate such mitigation effects, we use an existing PVA model describing a population of the tawny eagle (Aquila rapax) in the southern Kalahari. This model does not include behavioural adaptations. We develop a new model by assuming that the birds enlarge their average territory size to compensate for lower amounts of precipitation. Here, we found the predicted increase in risk of extinction due to climate change to be much lower than in the original model. However, this "buffering" of climate change by behavioural adaptation is not very effective in coping with increasing interannual variances. We refer to further examples of ecological "buffering mechanisms" from the literature and argue that possible buffering mechanisms should be given due consideration when the effects of climate change on biodiversity are to be predicted. (c) 2004 Elsevier B.V. All rights reserved},
  language  = {en}
}
@article{GrimmRevillaBergeretal.2005,
  author    = {Grimm, Volker and Revilla, Eloy and Berger, Uta and Jeltsch, Florian and Mooij, Wolf M. and Railsback, Steven Floyd and Thulke, Hans-Hermann and Weiner, Jacob and Wiegand, Thorsten and DeAngelis, Donald L.},
  title     = {Pattern-oriented modeling of agend-based complex systems : lessons from ecology},
  year      = {2005},
  abstract  = {Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity},
  language  = {en}
}
@article{WichmannJohstSchwageretal.2005,
  author    = {Wichmann, Matthias and Johst, Karin and Schwager, Monika and Jeltsch, Florian and Blasius, Bernd},
  title     = {Extinction risk, coloured noise and the scaling of variance},
  year      = {2005},
  abstract  = {The impact of temporally correlated fluctuating environments (coloured noise) on the extinction risk of populations has become a main focus in theoretical population ecology. In this study we particularly focus on the extinction risk in strongly autocorrelated environments. Here, in contrast to moderate autocorrelation, we found the extinction risk to be highly dependent on the process of noise generation, in particular on the method of variance scaling. Such variance scaling is commonly applied to avoid variance-driven biases when comparing the extinction risk for white and coloured noise. In this study we found an often-used scaling technique to lead to high variability in the resulting variances of different time series for strong auto-correlation eventually leading to deviations in the projected extinction risk. Therefore, we present an alternative method that always delivers the target variance, even in the case of strong temporal correlation. Furthermore, in contrast to the earlier method, our very intuitive method is not bound to auto-regressive processes but can be applied to all types of coloured noises. We recommend the method introduced here to be used when the target of interest is the effect of noise colour on extinction risk not obscured by any variance effects.},
  language  = {en}
}
@article{WichmannGroeneveldJeltschetal.2005,
  author    = {Wichmann, Matthias and Groeneveld, J{\"u}rgen and Jeltsch, Florian and Grimm, Volker},
  title     = {Mitigation of climate change impacts on raptors by behavioural adaption : ecological buffering mechanism},
  year      = {2005},
  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{WichmannDeanJeltsch2006,
  author    = {Wichmann, Matthias and Dean, W. R. J. and Jeltsch, Florian},
  title     = {Predicting the breeding success of large raptors in arid southern Africa : a first assessment},
  year      = {2006},
  abstract  = {Raptors are often priorities for conservation efforts and breeding success is a target measure for assessing their conservation status. The breeding success of large raptors in and southern Africa is thought to be higher in years of high rainfall. While this correlation has been found in several studies, it has not yet been shown for data from a wider geographical area. In conservation research, it is important to explore the differences between spatially- separated populations to estimate and to compare their conservation status, and to deduce specific management strategies. Using a theoretical approach, we develop a simplistic model to explain the breeding success-rainfall relationship in large African raptors at larger spatial scales. Secondly, we validate this model and we show that the inclusion of field data leads to consistent predictions. In particular, we recommend that the average size of the 'effective territory' should be included in the relationship between annual rainfall and breeding success of raptors in and southern Africa. Accordingly, we suggest that breeding success is a function of precipitation and inter- nest distance. We present a new measure of territory quality depending on rainfall and territory size. We suggest that our model provides a useful first approach to assess breeding success in large raptors of and southern Africa. However, we strongly emphasise the need to gather more data to further verify our model. A general problem in conservation research is to compare the status of populations assessed in different study areas under changing environmental conditions. Our simplistic approach indicates that this problem can be overcome by using a weighted evaluation of a target measure (i.e. breeding success), taking regional differences into account},
  language  = {en}
}
@article{TewsEstherMiltonetal.2006,
  author    = {Tews, J{\"o}rg and Esther, Alexandra and Milton, Sue J. and Jeltsch, Florian},
  title     = {Linking a population model with an ecosystem model : assessing the impact of land use and climate change on savanna shrub cover dynamics},
  doi       = {10.1016/j.ecolmodel.2005.11.025},
  year      = {2006},
  abstract  = {In semiarid savannas of Southern Africa current land use practices and climate change may lead to substantial changes of vegetation structure in the near future, however uncertainty remains about the potential consequences and the magnitude of change. In this paper we study the impact of climate change, cattle grazing, and wood cutting on shrub cover dynamics in savannas of the southern Kalahari. We use an established savanna ecosystem model to simulate landscape dynamics in terms of rainfall, fire and distribution of the dominant tree Acacia erioloba. We then incorporate these data into a spatial population model of the common, fleshy-fruited shrub Grewia flava and investigate shrub cover dynamics for a period of 100 years. Depending on the intensity of commercial wood cutting practices tree removal of A. erioloba led to a strong decline of the G. flava population, as shrub recruitment is concentrated in tree sub-canopies due to bird-mediated seed dispersal. Under climate change shrub cover slightly decreased with decreasing precipitation and was unchanged with increase in precipitation variability. Contrarily, grazing by cattle strongly increased shrub cover and facilitated shrub encroachment because of cattle-induced distribution of G. flava seeds into the matrix vegetation. Knowledge of the latter process is particularly important because shrub invasion is a major concern for conservation and savanna rangeland management as a result of its adverse effects on livestock carrying capacity and biodiversity},
  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}
}
@article{HennenbergFischerKouadioetal.2006,
  author    = {Hennenberg, K. J. and Fischer, Franka and Kouadio, K and Goetze, D and Orthmann, B and Linsenmair, KE and Jeltsch, Florian and Porembski, Stefan},
  title     = {Phytornass and fire occurrence along forest-savanna transects in the Comoe National Park, Ivory Coast},
  issn      = {0266-4674},
  doi       = {10.1017/S026646705003007},
  year      = {2006},
  abstract  = {In tropical West Africa, distribution patterns of forest islands in savannas are influenced by fires which occur regularly in the grass stratum. Along continuous forest-savanna transects in the Comoe National Park, the change in the amount and composition of non-woody phytomass was investigated from savanna to forest interior. This was correlated with the cover of vegetation strata above, soil depth, and the occurrence of seasonal surface fires. Phytomass mainly consisted of leaf litter in the forests (about 400 g m(-2) at the end of the rainy season, and about 600 g m(-2) at the end of the dry season) and of grasses in the savanna (about 900 g m(-2)). Low grass biomass appeared to be primarily the result of suppression by competing woody species and not of shallow soil. The occurrence of early dry-season fires seemed to be determined mainly by the amount of grass biomass as fuel because fires occurred in almost all savanna plots while forest sites remained unaffected. However, late dry-season fires will encounter higher amounts of leaf litter raising fire probability in forests. Due to the importance of the amount of combustible phytomass, fire probability and intensity might increase with annual precipitation in both savanna and forest},
  language  = {en}
}
@article{SchwagerJohstJeltsch2006,
  author    = {Schwager, Monika and Johst, Karin and Jeltsch, Florian},
  title     = {Does red noise increase or decrease extinction risk? Single extreme events versus series of unfavorable conditions},
  year      = {2006},
  abstract  = {Recent theoretical studies have shown contrasting effects of temporal correlation of environmental fluctuations ( red noise) on the risk of population extinction. It is still debated whether and under which conditions red noise increases or decreases extinction risk compared with uncorrelated ( white) noise. Here, we explain the opposing effects by introducing two features of red noise time series. On the one hand, positive autocorrelation increases the probability of series of poor environmental conditions, implying increasing extinction risk. On the other hand, for a given time period, the probability of at least one extremely bad year ("catastrophe") is reduced compared with white noise, implying decreasing extinction risk. Which of these two features determines extinction risk depends on the strength of environmental fluctuations and the sensitivity of population dynamics to these fluctuations. If extreme ( catastrophic) events can occur ( strong noise) or sensitivity is high ( overcompensatory density dependence), then temporal correlation decreases extinction risk; otherwise, it increases it. Thus, our results provide a simple explanation for the contrasting previous findings and are a crucial step toward a general understanding of the effect of noise color on extinction risk},
  language  = {en}
}
@article{RossmanithGrimmBlaumetal.2006,
  author    = {Rossmanith, Eva and Grimm, Volker and Blaum, Niels and Jeltsch, Florian},
  title     = {Behavioural flexibility in the mating system buffers population extinction: lessons from the Lesser Spotted Woodpecker (Picoides minor)},
  doi       = {10.1111/j.1365-2656.2006.01074.x},
  year      = {2006},
  abstract  = {In most stochastic models addressing the persistence of small populations, environmental noise is included by imposing a synchronized effect of the environment on all individuals. However, buffer mechanisms are likely to exist that may counteract this synchronization to some degree. We have studied whether the flexibility in the mating system, which has been observed in some bird species, is a potential mechanism counteracting the synchronization of environmental fluctuations. Our study organism is the lesser spotted woodpecker Picoides minor (Linnaeus), a generally monogamous species. However, facultative polyandry, where one female mates with two males with separate nests, was observed in years with male-biased sex ratio. We constructed an individual-based model from data and observations of a population in Taunus, Germany. We tested the impact of three behavioural scenarios on population persistence: (1) strict monogamy; (2) polyandry without costs; and (3) polyandry assuming costs in terms of lower survival and reproductive success for secondary males. We assumed that polyandry occurs only in years with male-biased sex ratio and only for females with favourable breeding conditions. Even low rates of polyandry had a strong positive effect on population persistence. The increase of persistence with carrying capacity was slower in the monogamous scenario, indicating strong environmental noise. In the polyandrous scenarios, the increase of persistence was stronger, indicating a buffer mechanism. In the polyandrous scenarios, populations had a higher mean population size, a lower variation in number of individuals, and recovered faster after a population breakdown. Presuming a realistic polyandry rate and costs for polyandry, there was still a strong effect of polyandry on persistence. The results show that polyandry and in general flexibility in mating systems is a buffer mechanism that can significantly reduce the impact of environmental and demographic noise in small populations. Consequently, we suggest that even behaviour that seems to be exceptional should be considered explicitly when predicting the persistence of populations},
  language  = {en}
}
@article{SchiffersSchurrTielboergeretal.2008,
  author    = {Schiffers, Katja and Schurr, Frank Martin and Tielb{\"o}rger, Katja and Urbach, Carsten and Moloney, Kirk A. and Jeltsch, Florian},
  title     = {Dealing with virtual aggregation : a new index for analysing heterogeneous point patterns},
  issn      = {0906-7590},
  doi       = {10.1111/j.0906-7590.2008.05374.x},
  year      = {2008},
  language  = {en}
}
@article{ThieleJeltschBlaum2008,
  author    = {Thiele, T. and Jeltsch, Florian and Blaum, Niels},
  title     = {Importance of woody vegetation for foraging site selection in the Southern Pied Babbler (Turdoides bicolor) under two different land use regimes},
  issn      = {0140-1963},
  year      = {2008},
  language  = {en}
}
@article{KoechyMathajJeltschetal.2008,
  author    = {K{\"o}chy, Martin and Mathaj, Martin and Jeltsch, Florian and Malkinson, Dan},
  title     = {Resilience of stocking capacity to changing climate in arid to Mediterranean landscapes},
  doi       = {10.1007/s10113-008-0048-6},
  year      = {2008},
  abstract  = {Small livestock is an important resource for rural human populations in dry climates. How strongly will climate change affect the capacity of the rangeland? We used hierarchical modelling to scale quantitatively the growth of shrubs and annual plants, the main food of sheep and goats, to the landscape extent in the eastern Mediterranean region. Without grazing, productivity increased in a sigmoid way with mean annual precipitation. Grazing reduced productivity more strongly the drier the landscape. At a point just under the stocking capacity of the vegetation, productivity declined precipitously with more intense grazing due to a lack of seed production of annuals. We repeated simulations with precipitation patterns projected by two contrasting IPCC scenarios. Compared to results based on historic patterns, productivity and stocking capacity did not differ in most cases. Thus, grazing intensity remains the stronger impact on landscape productivity in this dry region even in the future.},
  language  = {en}
}
@misc{KoechyMathajJeltschetal.2008,
  author    = {K{\"o}chy, Martin and Mathaj, Martin and Jeltsch, Florian and Malkinson, Dan},
  title     = {Resilience of stocking capacity to changing climate in arid to Mediterranean landscapes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18720},
  year      = {2008},
  abstract  = {Small livestock is an important resource for rural human populations in dry climates. How strongly will climate change affect the capacity of the rangeland? We used hierarchical modelling to scale quantitatively the growth of shrubs and annual plants, the main food of sheep and goats, to the landscape extent in the eastern Mediterranean region. Without grazing, productivity increased in a sigmoid way with mean annual precipitation. Grazing reduced productivity more strongly the drier the landscape. At a point just under the stocking capacity of the vegetation, productivity declined precipitously with more intense grazing due to a lack of seed production of annuals. We repeated simulations with precipitation patterns projected by two contrasting IPCC scenarios. Compared to results based on historic patterns, productivity and stocking capacity did not differ in most cases. Thus, grazing intensity remains the stronger impact on landscape productivity in this dry region even in the future.},
  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. <hr> Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.},
  language  = {en}
}
@inproceedings{PoppBlaumDomptailetal.2006,
  author    = {Popp, Alexander and Blaum, Niels and Domptail, Stephanie and Herpel, Nicole and Gr{\"o}ngr{\"o}ft, Alexander and Hoffman, T. T. and J{\"u}rgens, Norbert and Milton, Sue and Nuppenau, Ernst-August and Rossmanith, Eva and Schmidt, Michael and Vogel, Melanie and Vohland, Katrin and Jeltsch, Florian},
  title     = {From satellite imagery to soil-plant interactions},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7302},
  year      = {2006},
  abstract  = {Decisions for the conservation of biodiversity and sustainable management of natural resources are typically related to large scales, i.e. the landscape level. However, understanding and predicting the effects of land use and climate change on scales relevant for decision-making requires to include both, large scale vegetation dynamics and small scale processes, such as soil-plant interactions. Integrating the results of multiple BIOTA subprojects enabled us to include necessary data of soil science, botany, socio-economics and remote sensing into a high resolution, process-based and spatially-explicit model. Using an example from a sustainably-used research farm and a communally used and degraded farming area in semiarid southern Namibia we show the power of simulation models as a tool to integrate processes across disciplines and scales.},
  language  = {en}
}
@inproceedings{JeltschSchroederEsselbachBlaumetal.2006,
  author    = {Jeltsch, Florian and Schr{\"o}der-Esselbach, Boris and Blaum, Niels and Badeck, Franz-Werner},
  title     = {Einsatz der Fernerkundung in der {\"O}kologie},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7075},
  year      = {2006},
  abstract  = {Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006},
  language  = {de}
}
@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{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}
}
@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}
}