Functional connectivity and ecological sustainability of European ecological networks: a case study with the brown bear.

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2017

End date

12/31/2021

Budget

437,880 EUR

Fundings

Abstract

Europe is a landscape mosaic shaped by human activities. Protected areas are small and spatially disconnected, and <3% of Europe is considered natural. Nevertheless, Europe still harbors high biological diversity and populations of large carnivores (LC). Most LC populations currently subsist in small and isolated populations in fragmented habitats but are expanding again in many parts of Europe due to favorable management policies. This, however, exposes LC to conflicts with humans and new environmental conditions due to changes in land use and climate. Management of LC is difficult, since they require large territories that overlap with human activities, and because their persistence heavily depends on the ability for the exchange of genes among remaining subpopulations. Conservation and management efforts therefore must expand to the landscape scale and consider protected areas together with non-protected parts of the human-dominated landscape. This is crucial for designing coherent ecological networks that enable LC to fulfil their role in the ecosystem while minimizing human conflicts. We use the brown bear to investigate if existing ecological networks ensure landscape connectivity and ecological sustainability in Europe and provide recommendations for their improvement. The bear is a species of high conservation interest for which connectivity issues are recognized as priority. We focus on movement, dispersal, gene flow, range and food web dynamics, as key processes for species persistence and adaptation, and for maintenance of ecosystem services. The project team has developed a data base that integrates GPS telemetry and genetic data from all European countries with bear populations into a common database. This data base now contains several million GPS relocations as well as genetic data from several thousand brown bear individuals from all over Europe. The project team has developed a framework to look large scale connectivity among bioregions in Europe and which large mammal species are most appropriate to use to evaluate large scale connectivity. Brown bears, but also other species, such as red deer, have been evaluated as good species for connectivity modelling between bioregions. Manuscripts on these topics have been submitted for scientific publication. This framework was also evaluated at a stakeholder workshop in fall 2019, where we have used the Carpathian Ecoregion as example to test and illustrate this framework. Data from brown bears in Scandinavia is used for more detailed analyses on brown bears dispersal and settlement patterns across the landscape. In the first paper, we have focused on female bears and modeled post-natal settlement patterns of as a function of various variables, including the presence of the mother, related females, familiar females (i.e. all spatially overlapping females in the natal range independent of their relatedness), and female population density. We found that female bears were more likely to be philopatric with an increasing number of surrounding, familiar females. High female population density in the natal range resulted in females settling in areas with lower overlap of their natal range. We also found that older females settle in areas with less overlap of their natal range. An understanding of female dispersal and settlement patterns is crucial for population development and expansion, and thus for population management. A manuscript is currently under preparation. In a next manuscript we have evaluated the importance of human infrastructure on movement of male bears. We contrasted dispersing males with resident males, i. males with an established home range. The results suggest that resident bears avoid areas clos to public roads and buildings. In comparison, dispersing males were more ambivalent in their response to human infrastructure. They did not exhibit significant selection for or against any roads and avoided areas with higher building density only at local scale. In fact, dispersing males did not select for any features in the landscape, which likely is explained by the novelty of the landscape and their naivety towards it. Data from dispersers provide more realistic models for population reconnecting than if data were derived from resident animals alone. Data from Scandinavia were also used to evaluate how harvest, i.e. hunting, affects the genetic structure of bear populations. We found that high harvest decreased the fine-scale genetic structure of bear matrilines in central Scandinavia, i.e. female dispersal distances decreased and male reproductive success was less skewed. These findings indicate a crucial role of regulated harvest in shaping the fine-scale genetic structure of wild populations, potentially altering evolutionary trajectories. The project team has organized a workshop on population connectivity at the International Conference on Bear Research and Management in Montana, USA, in September 2021.