Responses of an endangered brown bear population to climate change based on predictable food resource and shelter alterations

Abstract

The survival of an increasing number of species is threatened by climate change: 20%–30% of plants and animals seem to be at risk of range shift or extinction if global warming reaches levels projected to occur by the end of this century. Plant range shifts may determine whether animal species that rely on plant availability for food and shelter will be affected by new patterns of plant occupancy and availability. Brown bears in temperate forested habitats mostly forage on plants and it may be expected that climate change will affect the viability of the endangered populations of southern Europe. Here, we assess the potential impact of climate change on seven plants that represent the main food resources and shelter for the endangered population of brown bears in the Cantabrian Mountains (Spain). Our simulations suggest that the geographic range of these plants might be altered under future climate warming, with most bear resources reducing their range. As a consequence, this brown bear population is expected to decline drastically in the next 50 years. Range shifts of brown bear are also expected to displace individuals from mountainous areas towards more humanized ones, where we can expect an increase in conflicts and bear mortality rates. Additional negative effects might include: (a) a tendency to a more carnivorous diet, which would increase conflicts with cattle farmers; (b) limited fat storage before hibernation due to the reduction of oak forests; (c) increased intraspecific competition with other acorn consumers, that is, wild ungulates and free‐ranging livestock; and (d) larger displacements between seasons to find main trophic resources. The magnitude of the changes projected by our models emphasizes that conservation practices focused only on bears may not be appropriate and thus we need more dynamic conservation planning aimed at reducing the impact of climate change in forested landscapes.

Habitat-partitioning improves regional distribution models in multi-habitat species: a case study with the European bilberry

“…Therefore, the achievement of accurate spatial products informing on spatial and temporal variation of key trophic resources is essential for developing realistic conservation strategies at regional scale. Comparing our results with a recent prediction made for the target species in the study area on the basis of forestry occurrence and climatic data (Penteriani et al 2019), we found that using habitat predictors (including habitat maps or remote sensing data) in partitioned models allowed for achieving spatial products with higher spatial precision at regional scale. While the use of remote sensing data reflects more accurately the local area of occupancy (Álvarez-Martínez et al 2018), the use of habitat maps and bedrock layers allows for removing limestone-dominated areas, which could have been overlooked when using only topo-climatic variables.…”

“…These climatic features, together with the uneven topography and the historical land management, have resulted in a highly heterogeneous landscape that host a wide variety of ecosystems, habitats and endemic species. In these mountains, that have been recognized as a hotspot of biodiversity (Worboys et al 2010;García-Llamas et al 2016, bilberry has a regional interest as a trophic resource for endangered species, such as the Cantabrian Capercaille (Blanco-Fontao et al 2009) and the Cantabrian Brown Bear (Rodríguez et al 2007;Penteriani et al 2019). The species mainly occurs in acidic vegetation related to northern exposures and can be found across three habitats: acidic woodlands, Atlantic heathlands and alpine dwarf-shrublands (Table 1 and Annex 1 of the Supplementary material).…”

Seasonality, local resources and environmental factors influence patterns of brown bear damages: implications for management

“…(Martínez Cano et al ., 2016) and the mountain range has an Atlantic climate, characterized by mild winters and rainy summers (Pato & Obeso, 2012). Forests of oak ( Quercus petraea , Quercus pyrenaica and Quercus robur ), beech ( Fagus sylvatica ), chestnut ( Castanea sativa ) and white birch ( Betula pubescens ) are dominant, alternating with pastures and brushwoods and subalpine scrubs (Penteriani et al ., 2019; Zarzo‐Arias et al ., 2019). The western Cantabrian subpopulation, estimated to hold around 280 bears (2017), inhabits an area of more than 7.000 km 2 with an average human population density of 10.9 inhabitants/km 2 and a road density of more than 0.5 km/km 2 , while the eastern subpopulation, with around 50 bears (2017), occupies around 4.000 km 2 with c .…”

Denning in brown bears

“…(a) climate change may severely reduce the available spring food resources (Holden, Kasworm, Servheen, Hahn, & Dobrowski, 2012;Inouye, Barr, Armitage, & Inouye, 2000;Penteriani, Zarzo-Arias, Novo-Fernández, Bombieri, & López-Sánchez, 2019;Roberts, Nielsen, & Stenhouse, 2014) or produce a temporary change in its availability (Deacy et al, 2017); and/or (b) if bears exit dens earlier, vegetation production may still not be sufficient to support their food requirements. This may be more important for populations that exhibit a lower altitudinal difference between denning and spring foraging habitat.…”