Landscape connectivity informs critical linkage zones for the conservation of African savanna elephant (Loxodonta africana) in Tanzania

The populations of African savanna elephants have declined by an estimated 60% since the 1970s, which can be attributed to a mixture of poaching and habitat loss. Human activities and environmental changes have caused unprecedented loss and fragmentation of elephant natural habitats, resulting in the isolation of elephant populations. Preserving habitat connectivity is thus increasingly important to conserve remaining elephant populations and maintain ecological functions. Using species distribution modeling (SDM) and graph-based landscape connectivity modeling, we aimed to understand population connectivity and target vital corridors across Tanzania, one of the most important elephant range states. However, mapping such a vast extent poses a great challenge due to data availability constraints. To tackle this issue, we developed an integrated modeling approach that leverages multiple, publicly available occurrence datasets, which vary in format and quality, with a multi-scale SDM to estimate spatial suitability of African savanna elephants. Two SDMs based on polygon-based observations and presence-only occurrences were calibrated separately and then ensembled using Bayes fusion. A set of landscape metrics was generated from a land cover map with a high resolution of ~5 m and employed to describe the detailed landscape structure needed to explain the distribution of elephants. We then used the modeled environmental suitability to map landscape connectivity using circuit theory with Circuitscape. Our results indicated that both long-distance and short-distance connectivity are currently facing significant threats from intensive human activities (e.g. agriculture) in Tanzania. In addition, our study identifies critical linkage zones that should be targeted for connectivity conservation efforts and provides new insights to help inform broader efforts to balance development and conservation objectives.