TY - JOUR
T1 - Genetic connectivity and population structure of African savanna elephants (Loxodonta africana) in Tanzania
AU - Lohay, George G.
AU - Weathers, Thomas Casey
AU - Estes, Anna B.
AU - McGrath, Barbara C.
AU - Cavener, Douglas R.
N1 - Funding Information:
We thank the Wildlife Conservation Society, the Cleveland Metroparks Zoo and the Huck Institutes of the Life Sciences of the Pennsylvania State University for funding this research. We thank the Tanzania Wildlife Research Institute, Tanzania National Parks Authority, the Ngorongoro Conservation Area Authority, and Tanzania Wildlife Authority for providing permission to conduct research in protected areas. We also thank the Cleveland Metroparks Zoo for providing elephant fecal samples that were used to develop our methods. Thanks to Dr. Ernest Eblate of the Tanzania Wildlife Research Institute for providing us with elephant tissue samples and Mr. Sylvester Temba for preparing buffer solution. Thanks to Dr. John Carlson, Dr. Stephen Schaeffer, Dr. Katriona Shea, and Dr. George Perry for comments on the manuscript. A special gratitude to the Cavener laboratory members especially, Jingjie Hu and Rebecca Bourne for helping in laboratory analyses and Susan Kotikot for making maps for study areas. We thank the Penn State Genomics Core Facility—University Park, PA for genotyping and sequencing elephant samples.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Increasing human population growth, exurban development, and associated habitat fragmentation is accelerating the isolation of many natural areas and wildlife populations across the planet. In Tanzania, rapid and ongoing habitat conversion to agriculture has severed many of the country's former wildlife corridors between protected areas. To identify historically linked protected areas, we investigated the genetic structure and gene flow of African savanna elephants in Tanzania using microsatellite and mitochondrial DNA markers in 688 individuals sampled in 2015 and 2017. Our results indicate distinct population genetic structure within and between ecosystems across Tanzania, and reveal important priority areas for connectivity conservation. In northern Tanzania, elephants sampled from the Tarangire-Manyara ecosystem appear marginally, yet significantly isolated from elephants sampled from the greater Serengeti ecosystem (mean FST = 0.03), where two distinct subpopulations were identified.Unexpectedly, elephants in the Lake Manyara region appear to be more closely related to those across the East African Rift wall in the Ngorongoro Conservation Area than they are to the neighboring Tarangire subpopulations. We concluded that the Rift wall has had a negligible influence on genetic differentiation up to this point, but differentiation may accelerate in the future because of ongoing loss of corridors in the area. Interestingly, relatively high genetic similarity was found between elephants in Tarangire and Ruaha although they are separated by >400 km. In southern Tanzania, there was little evidence of female-mediated gene flow between Ruaha and Selous, probably due to the presence of the Udzungwa Mountains between them. Despite observing evidence of significant isolation, the populations of elephants we examined generally exhibited robust levels of allelic richness (mean AR = 9.96), heterozygosity (mean µHE = 0.73), and effective population sizes (mean Ne = 148). Our results may inform efforts to restore wildlife corridors between protected areas in Tanzania in order to facilitate gene flow for long-term survival of elephants and other species.
AB - Increasing human population growth, exurban development, and associated habitat fragmentation is accelerating the isolation of many natural areas and wildlife populations across the planet. In Tanzania, rapid and ongoing habitat conversion to agriculture has severed many of the country's former wildlife corridors between protected areas. To identify historically linked protected areas, we investigated the genetic structure and gene flow of African savanna elephants in Tanzania using microsatellite and mitochondrial DNA markers in 688 individuals sampled in 2015 and 2017. Our results indicate distinct population genetic structure within and between ecosystems across Tanzania, and reveal important priority areas for connectivity conservation. In northern Tanzania, elephants sampled from the Tarangire-Manyara ecosystem appear marginally, yet significantly isolated from elephants sampled from the greater Serengeti ecosystem (mean FST = 0.03), where two distinct subpopulations were identified.Unexpectedly, elephants in the Lake Manyara region appear to be more closely related to those across the East African Rift wall in the Ngorongoro Conservation Area than they are to the neighboring Tarangire subpopulations. We concluded that the Rift wall has had a negligible influence on genetic differentiation up to this point, but differentiation may accelerate in the future because of ongoing loss of corridors in the area. Interestingly, relatively high genetic similarity was found between elephants in Tarangire and Ruaha although they are separated by >400 km. In southern Tanzania, there was little evidence of female-mediated gene flow between Ruaha and Selous, probably due to the presence of the Udzungwa Mountains between them. Despite observing evidence of significant isolation, the populations of elephants we examined generally exhibited robust levels of allelic richness (mean AR = 9.96), heterozygosity (mean µHE = 0.73), and effective population sizes (mean Ne = 148). Our results may inform efforts to restore wildlife corridors between protected areas in Tanzania in order to facilitate gene flow for long-term survival of elephants and other species.
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U2 - 10.1002/ece3.6728
DO - 10.1002/ece3.6728
M3 - Article
C2 - 33144949
AN - SCOPUS:85092200540
VL - 10
SP - 11069
EP - 11089
JO - Ecology and Evolution
JF - Ecology and Evolution
SN - 2045-7758
IS - 20
ER -