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Title: “Individual, population and community responses to spatial subsidies: effects of ungulate supplementary feeding on brown bears".


Period: 2009-2012.


Project leader: Nuria Selva.


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Summary: Supplementary feeding of game animals has a deeply rooted and long tradition in Europe, and particularly in Poland. This artificially provided food represents a drastic change in the natural temporal and spatial distribution of food resources: it is localized in space (hunting towers), continuously supplied and available during periods of shortage of natural foods. Considering also the magnitude of the artificial food provided annually in the forestry districts, we can expect the ecological effects of this practice to be drastic and complex, and to have important implications for wildlife conservation and management. The general goal of this project is to evaluate the ecological impacts of supplementary feeding at individual, population and community levels in the Bieszczady mountains. One of the non-target species more directly affected there by ungulate baiting is the brown bear Ursus arctos.

We specifically aim at:

1. Determine the dynamics of the artificial resource subsidy, i.e., their amount, spatial distribution and availability through time, as well as the animal species exploiting it,


2. Assess the patterns of bait use by different species, especially by individual bears in relation to age/sex class, reproduction and hibernation patterns, and test whether baiting sites can be acting as an ecological trap for bears,


3. Quantify bait contribution to the diet of the direct consumers, specifically for (a) individual bears, (b) the bear population, and (c) ungulates, in relation to the distance to baited points and control areas in Bieszczady National Park. The fact that corn, one of the main components of baits, is a C4 plant will allow us accurate estimations and tracking its clear isotopic signature (high δ13C) spatially (in a C3 landscape) and through the food web via stable isotope analysis,


4. Assess the changes produced in the spatial distribution and local abundance of species, and their consequences in the structure of animal communities. Special attention will be put on the indirect effects on non-consumers of the subsidy, like ground-nesting birds, predators or vegetation.

The methodology includes photo-trapping of animals at baiting sites and control areas, mapping baiting points, collection and stable isotope analysis of animal and vegetal tissue samples and censuses of animals in plots. This project will represent an important contribution to the scientific knowledge on the ecology of spatially subsidized communities in terrestrial systems. Additionally, disentangling the ecological impacts of supplementary feeding will have important implications for conservation biology, specifically for the brown bear in Poland and generally for the preservation of biodiversity and ecological processes in the Carpathian mountains.










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