Coupling African elephant movement and habitat modeling for landscape availability-suitability-connectivity assessment in Kruger National park, South Africa

Wenjing Xu, Richard Fayrer-Hosken, Marguerite Madden, Chenay Simms, Lan Mu, Andrea Presotto

Abstract


Making an appropriate conservation decision often requires understanding the functional connectivity of the landscape for focal species. Graph theory and continuous surface methods have become powerful tools to quantify landscape connectivity for animal movement. However, a key limitation of these methods is the use of thresholding to define either habitat patches or links between patches.
We explore how to incorporate African elephants' (Loxodonta africana) movement data into an "Availability-Suitability-Connectivity (ASC)" framework which integrates habitat suitability modeling and graph-based network analysis, and how to implement connectivity results to inform conservation management that addresses locally intensive habitat utilization by elephants. In our ASC analysis, node availability was identified by satellite imagery classification and node suitability was estimated by MaxEnt model. Links were determined by effective movement between nodes in three days. Differences of Integrative Index of Connectivity (dIIC) and its fractions were calculated to prioritize patch importance, which were then used for mapping an example landscape management zones to reduce elephant local ecological impact. In total, 544 nodes and 1345 links were identified in the landscape graph. Although suitable nodes were spread across the landscape, elephants intensively used habitat at the central area. Our zone map demonstrates areas for landscape management that can facilitate elephant range expansion. The integrative framework quantified the ASC interactions between animal movement and landscape features. The results highlight the potential for coupling geographic and ecological methods to effectively identify and focus conservation efforts.

Keywords


African elephants, connectivity model, animal movement and Kruger National Park

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