Investigation of novel methods to predict the distribution, abundance, and connectivity of rare species : a case study for the conservation of Baird’s tapir

Species Distribution Models (SDMs) are statistical tools used to develop continuous predictions of species occurrence. ‘Integrated SDMs’ (ISDMs) are an elaboration of this approach with potential as useful tools that allow for the dual use of opportunistically collected presence-only (PO) data and site-occupancy (SO) data from planned surveys. These models also account for survey bias and imperfect detection through the use of a hierarchical modeling framework that separately estimates the species-environment response and the detection process. This is particularly helpful for conservation applications and predictions for rare species, where data are often limited and prediction errors may have significant management consequences. Despite this potential importance, ISDMs remain largely untested under a variety of scenarios. I applied the ISDM framework to Baird’s tapir (Tapirus bairdii), an endangered large mammal that is found in Mesoamerica. The discrepancy between expert opinion and population estimates from the ISDM suggested further investigation was needed. Using a sensitivity analysis that tested modelling decisions, I found that site area had the strongest effect on the magnitude of population estimates and underlying intensity surface, which was driven by estimates of model intercepts. Selecting a site area that accounted for the individual movements of the species within an average home range led to population estimates that coincided with expert estimates. I used the lessons learned from the sensitivity analysis to employ an ISDM in a Range-wide Conservation Plan (RWCP) for Baird’s tapir. The outputs from this model were combined with a hotspot analysis to delineate habitat patches for the species, and a graph network used to investigate the connectivity between these patches. In light of the results from this exercise, the following actions are recommended to facilitate the conservation of Baird’s tapir: 1) protect existing habitat by strengthening enforcement in areas already under protection, and working with indigenous territories to preserve and enforce their land rights; 2) re-establish connections between habitat patches; 3) conduct additional non-invasive surveys in patches with little or no data on species presence; 4) collect more telemetry data on the species to better estimate home range size and dispersal capabilities; and 5) further develop robust models to more accurately predict true probabilities of presence, connectivity, and viability.Geography and the Environmen