Drivers of habitat availability for terrestrial mammals: Unravelling the role of livestock, land conversion and intrinsic traits in the past 50 years

The global decline of terrestrial species is largely due to the degradation, loss and fragmentation of their habitats. The conversion of natural ecosystems for cropland, rangeland, forest products and human infrastructure are the primary causes of habitat deterioration. Due to the paucity of data on the past distribution of species and the scarcity of fine-scale habitat conversion maps, however, accurate assessment of the recent effects of habitat degradation, loss and fragmentation on the range of mammals has been near impossible. We aim to assess the proportions of available habitat within the lost and retained parts of mammals' distribution ranges, and to identify the drivers of habitat availability. We produced distribution maps for 475 terrestrial mammals for the range they occupied 50 years ago and compared them to current range maps. We then calculated the differences in the percentage of 'area of habitat' (habitat available to a species within its range) between the lost and retained range areas. Finally, we ran generalized linear mixed models to identify which variables were more influential in determining habitat availability in the lost and retained parts of the distribution ranges. We found that 59% of species had a lower proportion of available habitat in the lost range compared to the retained range, thus hypothesizing that habitat loss could have contributed to range declines. The most important factors negatively affecting habitat availability were the conversion of land to rangeland and high density of livestock. Significant intrinsic traits were those related to reproductive timing and output, habitat breadth and medium body size. Our findings emphasize the importance of implementing conservation strategies to mitigate the impacts caused by human activities on the habitats of mammals, and offer evidence indicating which species have the potential to reoccupy portions of their former range if other threats cease to occur.This study investigates the impact of habitat degradation on terrestrial mammal species. By comparing historic and current distribution maps for 475 species, we found that 59% of them have less available habitat in their lost ranges, suggesting habitat loss contributed to range declines. Factors like land conversion to rangeland and high livestock density negatively affected habitat availability. Intrinsic traits such as reproductive timing, habitat breadth and medium body size also played a role. The study underscores the need for conservation efforts to mitigate human-induced habitat threats and identifies species that could potentially reclaim lost range if threats are addressed.imag

Range maps for terrestrial mammals in the 1970s-1980s for the paper "Drivers of habitat availability for terrestrial mammals: unravelling the role of livestock, land conversion and intrinsic traits in the past 50 years"

Range maps of terrestrial mammals for the years 1970s-1980

Data from: Natal foraging philopatry in eastern Pacific hawksbill turtles

The complex processes involved with animal migration have long been a subject of biological interest and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry (NFP). Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry

Supplemental Table 1 from Natal foraging philopatry in eastern Pacific hawksbill turtles

Results (mean % ± 95% confidence intervals in parentheses) from the Bayesian mixed stock analysis from hawksbill rookeries ranked by location to the four regional foraging grounds (RFGs). The two rookeries in RFG2 were combined into a single regional estimate for the regional analysis due to their proximity and genetic similarity

Supplemental Figure 1. from Natal foraging philopatry in eastern Pacific hawksbill turtles

Results of the principal components analysis of the eight foraging grounds with sample sizes ranging from n = 20-117 showing the four clusters that determined the four regional foraging grounds (RFGs). Samples from neighboring foraging grounds with sample sizes ranging from n = 1-7 were pooled into each RFG for the Bayesian mixed stock analysis