Can landscape characteristics help explain the different trends of Cantabrian brown bear subpopulations?

Abstract

A central challenge in animal conservation is to understand how a population may respond to different habitat characteristics, which may affect their growth and viability. At the beginning of the 20 th century, the Cantabrian brown bear Ursus arctos population (north-western Spain) was separated into western and eastern subpopulations. Today, brown bears in the Cantabrian Mountains are recovering and the two subpopulations are reconnected. However, the western portion of the population represents ca. 90% of the entire population, the number of females with cubs-of-the-year has also shown a more rapid increase in the western subpopulation than in the eastern one and mean litter size is significantly larger in the west. By comparing the characteristics of the landscape used by brown bears in the western vs. eastern sectors of the population, we intended highlighting focal elements of landscape composition and structure that may help explain the differences in numbers and fecundity of these two subpopulations. We suggest that habitat use alone might not have the expected role in potentially explaining differences between subpopulations. Both the current positive trend of the Cantabrian population and our results seems to show that the dynamics affecting these subpopulations might be more complex than previously believed and cannot be understood on the basis of habitat analyses only. Suspicions may arise around direct human influences (e.g. persistence of poaching and/or bad practices during hunting) on the different trends exhibited by the two sectors of this endangered bear population.

Not exodus, but population increase and gene flow restoration in Cantabrian brown bear (Ursus arctos) subpopulations. Comment on Gregório et al. 2020

“…Brown bears have been continuously present in the eastern Cantabrian Mountains [ 29 ], and a recent habitat assessment has shown that habitat characteristics are similar in both Cantabrian subpopulations [ 30 ]. Under these circumstances, the removal of individuals will produce an attractive sink [ 15 ], as has been specifically suggested for this bear population [ 31 ].…”

“…In addition, the human footprint (i.e. landscape variables associated with humans) of the habitat is also higher in the western subpopulation [ 30 ].…”

“…Gregório et al [ 4 ] presume that bears from the eastern subpopulation “could be forced to flee from areas with higher human disturbance and poaching, which are more intense in the Eastern Cantabrian Mountains”, but there is no evidence supporting this statement beyond the suspicions suggested by Lamamy et al in the Discussion of their paper [ 30 ]. According to the information of our data base, from January 2000 to August 2020, 8 bears have been found illegally killed (verified by official necropsies) in the western subpopulation (3 poisoned, 3 snared and 2 shot) and 4 (3 poisoned and 1 shot) in the eastern one.…”

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

“…The first one, between France and Spain, has been reinforced by translocations of bears from Slovenia since 1996 due to its critical and imminent risk of extinction (Gonzalez et al, 2016; Quenette et al ., 2001; Swenson et al ., 2011). The other bear population inhabits the Cantabrian Mountains, where two subpopulations are recovering and recently interconnected after a long isolation (Gonzalez et al, 2016; Lamamy et al ., 2019; Zarzo‐Arias et al ., 2019). Within their range, bears coexist with several human activities, which may be attractive to them.…”

Relevance of the Cell Neighborhood Size in Landscape Metrics Evaluation and Free or Open Source Software Implementations

“…The value of the cell neighborhood parameter was specified in eight different papers: seven chose a Moore definition [13][14][15][16][17][18][19][20] and one a von Neumann definition [21]. The 16 papers which exclusively employed LecoS [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] used an 8-cells neighborhood rule, as it is the only setting available in the add-on; a similar hypothesis is applicable to the four works which used r.li in GRASS [38][39][40][41], which uses a 4-cells neighborhood definition. The papers which did not specify the definition of the neighborhood in FRAGSTATS are assumed to have used a 8-cells definition, since this is the default setting [42], although it is not possible to prove this assumption.…”