TY - JOUR A1 - Franz, Kamila W. A1 - Romanowski, Jerzy A1 - Johst, Karin A1 - Grimm, Volker T1 - Ranking landscape development scenarios affecting natterjack toad (Bufo calamita) population dynamics in Central Poland JF - PLoS one N2 - When data are limited it is difficult for conservation managers to assess alternative management scenarios and make decisions. The natterjack toad (Bufo calamita) is declining at the edges of its distribution range in Europe and little is known about its current distribution and abundance in Poland. Although different landscape management plans for central Poland exist, it is unclear to what extent they impact this species. Based on these plans, we investigated how four alternative landscape development scenarios would affect the total carrying capacity and population dynamics of the natterjack toad. To facilitate decision-making, we first ranked the scenarios according to their total carrying capacity. We used the software RAMAS GIS to determine the size and location of habitat patches in the landscape. The estimated carrying capacities were very similar for each scenario, and clear ranking was not possible. Only the reforestation scenario showed a marked loss in carrying capacity. We therefore simulated metapopulation dynamics with RAMAS taking into account dynamical processes such as reproduction and dispersal and ranked the scenarios according to the resulting species abundance. In this case, we could clearly rank the development scenarios. We identified road mortality of adults as a key process governing the dynamics and separating the different scenarios. The renaturalisation scenario clearly ranked highest due to its decreased road mortality. Taken together our results suggest that road infrastructure development might be much more important for natterjack toad conservation than changes in the amount of habitat in the semi-natural river valley. We gained these insights by considering both the resulting metapopulation structure and dynamics in the form of a PVA. We conclude that the consideration of dynamic processes in amphibian conservation management may be indispensable for ranking management scenarios. Y1 - 2013 U6 - https://doi.org/10.1371/journal.pone.0064852 SN - 1932-6203 VL - 8 IS - 5 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Becher, Matthias A. A1 - Osborne, Juliet L. A1 - Thorbek, Pernille A1 - Kennedy, Peter J. A1 - Grimm, Volker T1 - Towards a systems approach for understanding honeybee decline - a stocktaking and synthesis of existing models JF - Journal of applied ecology : an official journal of the British Ecological Society N2 - 1. The health of managed and wild honeybee colonies appears to have declined substantially in Europe and the United States over the last decade. Sustainability of honeybee colonies is important not only for honey production, but also for pollination of crops and wild plants alongside other insect pollinators. A combination of causal factors, including parasites, pathogens, land use changes and pesticide usage, are cited as responsible for the increased colony mortality. 2. However, despite detailed knowledge of the behaviour of honeybees and their colonies, there are no suitable tools to explore the resilience mechanisms of this complex system under stress. Empirically testing all combinations of stressors in a systematic fashion is not feasible. We therefore suggest a cross-level systems approach, based on mechanistic modelling, to investigate the impacts of (and interactions between) colony and land management. 3. We review existing honeybee models that are relevant to examining the effects of different stressors on colony growth and survival. Most of these models describe honeybee colony dynamics, foraging behaviour or honeybee - varroa mite - virus interactions. 4. We found that many, but not all, processes within honeybee colonies, epidemiology and foraging are well understood and described in the models, but there is no model that couples in-hive dynamics and pathology with foraging dynamics in realistic landscapes. 5. Synthesis and applications. We describe how a new integrated model could be built to simulate multifactorial impacts on the honeybee colony system, using building blocks from the reviewed models. The development of such a tool would not only highlight empirical research priorities but also provide an important forecasting tool for policy makers and beekeepers, and we list examples of relevant applications to bee disease and landscape management decisions. KW - Apis mellifera KW - colony decline KW - feedbacks KW - integrated model KW - multiple stressors KW - predictive systems ecology KW - review Y1 - 2013 U6 - https://doi.org/10.1111/1365-2664.12112 SN - 0021-8901 VL - 50 IS - 4 SP - 868 EP - 880 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Bailleul, Frederic A1 - Grimm, Volker A1 - Chion, Clement A1 - Hammill, Mike T1 - Modeling implications of food resource aggregation on animal migration phenology JF - Ecology and evolution N2 - The distribution of poikilotherms is determined by the thermal structure of the marine environment that they are exposed to. Recent research has indicated that changes in migration phenology of beluga whales in the Arctic are triggered by changes in the thermal structure of the marine environment in their summering area. If sea temperatures reflect the spatial distribution of food resources, then changes in the thermal regime will affect how homogeneous or clumped food is distributed. We explore, by individual-based modelling, the hypothesis that changes in migration phenology are not necessarily or exclusively triggered by changes in food abundance, but also by changes in the spatial aggregation of food. We found that the level of food aggregation can significantly affect the relationship between the timing of the start of migration to the winter grounds and the total prey capture of individuals. Our approach strongly indicates that changes in the spatial distribution of food resources should be considered for understanding and quantitatively predicting changes in the phenology of animal migration. KW - Animal migration KW - food structuring KW - global change KW - individual-based model KW - polar environment Y1 - 2013 U6 - https://doi.org/10.1002/ece3.656 SN - 2045-7758 VL - 3 IS - 8 SP - 2535 EP - 2546 PB - Wiley-Blackwell CY - Hoboken ER -