Strengthening the conservation of biodiversity at local and regional scales

The protection of biodiversity in an era of rapid environmental change is a challenge that requires strengthening research to provide insights that match on-the-ground conservation efforts. In this dissertation, I have addressed this challenge over three chapters that advance the science of conservation for applications at the local and regional scales. The three chapters are unified by using birds as study organisms and the application of spatial analysis for determining conservation priorities:In Chapter 1, I analyzed 100 years of land-use change impacts on a single mountain tropical community: the birds of San Antonio, a cloud forest site in the western Andes of Colombia. Here, I investigated three key topics for local-scale conservation that transcended this case-study: (1) community dynamics in response to land-use change; (2) spatial patterns of species extirpations; (3) vulnerability to climate disruption. The results showed unequivocal species losses and changes in community structure and abundance. Furthermore, I found that species were extirpated after habitat loss and fragmentation, but forest recovery stopped extirpations and helped some species repopulate. Land-use change legacies increased species vulnerability to climate change, but the results suggest that reversing landscape transformation can help restore biodiversity and improve resistance to future threats. In Chapter 2, I developed a data-driven geospatial workflow to map species distributions from primary biodiversity data, starting from Extent of Occurrence (EOO) to Area of Habitat (AOH) within the estimated species range map. The range maps are produced with an inverse distance weighted interpolation procedure of presences and absences. Tested on 723 resident forest birds in the Americas (North, South, Central America, and the Caribbean), the results showed the geospatial workflow generated range maps with higher overall accuracy and fewer errors of omission and commission than traditional expert-drawn range maps. This improved the calculation of species Area of Habitat (AOH) for conservation planning and decision-making at local and regional scales. The workflow has the advantage that it is straightforward, reproducible, and can be incorporated into species risk assessments. In Chapter 3, I evaluated species responses to climate change in the tropical Andes by incorporating subspecies within a hierarchical modeling framework to account for intraspecific variation. I found these models had improved performance and projected fewer negative declines in species abundances than models that ignored subspecies. Notwithstanding, the variation within species is fragile. Some subspecies constitute a small fraction of the global population size and are vulnerable to future threats based on low relative abundances. Moreover, one in every four subspecies analyzed is at a potential risk of extinction based on small range sizes, and most of the threatened subspecies inhabit isolated regions of the northern Andes. I conclude that protecting subspecies could buffer against the impacts of climate change. In summary, this dissertation contributed to the field of conservation biology by strengthening science that supports the protection of biodiversity at the local and regional scales.