Towards improving biodiversity assessments for mammals and birds within the Neotropics

Global change is greatly affecting biodiversity and the vital ecosystem functions and services it provides. Biodiversity hotspots, areas with high levels of diversity that are under strong anthropogenic pressures, are especially prevalent in the tropics, making them conservation priorities. However, these areas often lack comprehensive data on species spatial distributions and functional traits, hindering our ability to perform biodiversity assessments and assess species and ecosystem vulnerability. Species distribution models (SDMs) can help delineate species ranges and inform conservation decisions. Yet, SDMs often solely focus on local environmental factors and overlook filtering processes occurring at broader-scales. Further, conservation efforts have mainly emphasized taxonomic diversity (TD), assuming equal species importance, but a more comprehensive approach should consider the diversity of roles species play in ecosystems –functional diversity (FD). To develop robust FD metrics across broad geographic regions, we need improved trait data that fills gaps and harmonizes existing datasets. Overcoming these challenges demands improved methods, data availability, and embracing multiple dimensions of biodiversity.To address the need to consider FD alongside TD, and the issue of data paucity in the Neotropics, I compiled an open-access functional trait dataset, containing ecological, life-history, morphological, and geographical traits for frugivorous birds and mammals within Neotropical moist forests called Frugivoria (Chapter 1). This open and accessible dataset and workflow enables practitioners and researchers to investigate patterns of FD for taxa performing the essential ecosystem function of seed dispersal. To enhance the capacity of SDMs to more fully capture the distributions of species and to better incorporate environmental filtering processes that influence species occurrence, I generated scale-dependent geodiversity variables (Chapter 2) and incorporated them into SDMs for Colombian mammals. Models incorporating geodiversity variables generally performed better than those constructed without. This finding demonstrates the utility of geodiversity variables for generating robust geographic estimates useful for species risk assessments.In Chapter 3, I aimed to develop a more comprehensive perspective on diversity that extends beyond traditional TD and considers the roles of species in sustaining ecosystem function. To achieve this, I used the Frugivoria dataset to explore spatial alignments and mismatches between TD and FD, the extent to which protected areas (PAs) encompassed TD and FD, and assessed the distribution of Functionally Unique, Specialized, and Endangered (FUSE) species. The results identified strong spatial mismatches and few areas of alignment between dimensions of diversity for mammals and birds, with only ~30% protected. Further, many areas with high proportions of FUSE species remain unprotected. FD was also found to be higher in community-managed lands. This finding emphasizes the importance of including community-managed lands in strategies aimed at achieving biodiversity targets.The concluding chapter discusses potential ways to use Frugivoria data to inform conservation practice and policy. It further discusses how to apply the framework for testing geodiversity variables to improve SDMs to other regions and taxa. Lastly, it highlights priorities for conservation when considering the spatial tradeoffs of TD, FD, and FUSE species distributions. By integrating these different elements, this dissertation improves our ability to understand the distribution of bird and mammal biodiversity and will therefore help generate better-informed species risk assessments and set more inclusive spatial conservation priorities within the Neotropics.