Mapping potential connections between Southern Africa’s elephant populations

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Authors

Huang, Ryan M.
Van Aarde, Rudi J.
Pimm, Stuart L.
Chase, Michael
Leggett, Keith

Journal Title

Journal ISSN

Volume Title

Publisher

Public Library of Science

Abstract

Southern Africa spans nearly 7 million km2 and contains approximately 80% of the world’s savannah elephants (Loxodonta africana) mostly living in isolated protected areas. Here we ask what are the prospects for improving the connections between these populations? We combine 1.2 million telemetry observations from 254 elephants with spatial data on environmental factors and human land use across eight southern African countries. Telemetry data show what natural features limit elephant movement and what human factors, including fencing, further prevent or restrict dispersal. The resulting intersection of geospatial data and elephant presences provides a map of suitable landscapes that are environmentally appropriate for elephants and where humans allow elephants to occupy. We explore the environmental and anthropogenic constraints in detail using five case studies. Lastly, we review all the major potential connections that may remain to connect a fragmented elephant metapopulation and document connections that are no longer feasible.

Description

DATA AVAILABILITY STATEMENT : Telemetry data cannot be shared publicly because they contain the locations of an endangered and highly poached species. The environmental and human data necessary for reproducing our results are available at: https://osf.io/eyanr/. Much of these data have also been published under Loarie et al (2009).
SUPPLEMENTARY MATERIAL : S1 Table. Telemetry sample size. Table of the number of males and female elephants providing telemetry data broken down by conservation cluster of occurrences. Included are the major protected areas in each cluster. https://doi.org/10.1371/journal.pone.0275791.s001
S2 Table. Area of layer intersection. Table providing amount of area considered suitable within each country of interest for each data layer used in addition to the combined data. https://doi.org/10.1371/journal.pone.0275791.s002
S1 Fig. Map of suitable landscapes. High resolution map showing areas that are both environmentally suitable for elephants and currently experience low human activity. https://doi.org/10.1371/journal.pone.0275791.s003
S2 Fig. Distribution of slope across conservation clusters. Histogram of elephant telemetry points at various slopes for each metapopulation cluster. The red dashed line indicates the threshold (3°) of preference for suitability. https://doi.org/10.1371/journal.pone.0275791.s004
S3 Fig. Distance to rivers across conservation clusters. Accumulation curve of area within a conservation cluster as the distance increases away from rivers of varying flow orders. https://doi.org/10.1371/journal.pone.0275791.s005
4 Fig. Distribution of crop probability across conservation clusters. Histogram of elephant telemetry points at various cropland probabilities for each metapopulation cluster outside of protected areas. The red dashed line indicates the threshold (25%) of preference for suitability. https://doi.org/10.1371/journal.pone.0275791.s006
S5 Fig. Distribution of human population density across conservation clusters. Histogram of elephant telemetry points at various human population densities for each metapopulation cluster outside of protected areas. The red dashed line indicates the threshold (25 people per km2) of preference for suitability. https://doi.org/10.1371/journal.pone.0275791.s007
S6 Fig. Elephant interactions with cattle. A) Histogram of elephant telemetry points at various cattle densities for each metapopulation cluster outside of protected areas. The red dashed line indicates the threshold (5 cattle per km2) of preference for suitability. B) A map of elephant telemetry points illustrating how spill over from protected areas leads to interactions with areas of high cattle density. https://doi.org/10.1371/journal.pone.0275791.s008

Keywords

Elephants, Conservation science, Rivers, Africa, Mozambique, Livestock, Malawi, Surface water, African elephant (Loxodonta africana)

Sustainable Development Goals

Citation

Huang, R.M., Van Aarde, R.J., Pimm, S.L., Chase, M.J. & Leggett, K. (2022) Mapping potential connections between Southern Africa’s elephant populations. PLoS One 17(10): e0275791. https://doi.org/10.1371/journal.pone.0275791.