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The conservation of elephants is increasingly crucial in southern Africa, where urban development and habitat degradation are restricting these majestic animals to protected areas like game reserves. This situation raises concerns about potential genetic isolation within elephant populations, which could make them more susceptible to diseases and shifts in their environment.
A collaborative study conducted by the University of Illinois Urbana-Champaign and the University of Pretoria in South Africa brings attention to possible solutions for this issue. The researchers have developed a comprehensive map that illustrates how conservation managers can establish and enhance elephant movement corridors across a seven-nation region. This initiative is aimed at fulfilling the habitat requirements of elephants while encouraging gene flow between isolated populations.
Lead author Alida de Flamingh, who completed this research as part of her PhD in the Department of Animal Sciences at the University of Illinois, noted, “While previous studies have amalgamated genetic and spatial data, our research stands out as it covers a broader geographic area, making it the first of its kind for southern African elephants.” She has since transitioned to a postdoctoral role at the Carl R. Woese Institute for Genomic Biology.
The vast territory that African elephants traverse—sometimes extending up to 11,000 square kilometers (over 2.7 million acres)—is a significant factor in this research. Capturing this expansive scale for analysis is a formidable task, as elephants often deviate from direct paths to navigate through varied habitats.
“This research demanded extensive effort,” de Flamingh explained. “In collaboration with the Conservation Ecology Research Unit at the University of Pretoria, we collected non-invasive DNA samples from elephant dung throughout the elephants’ range. CERU also provided valuable data from GPS collars placed on 80 elephants, capturing nearly 54,000 location points.”
While GPS data effectively tracks elephant movements across landscapes, it does not inherently reveal gene flow, whereas DNA data confirms gene interactions without demonstrating the movement patterns. Merging these datasets necessitated a landscape genetics approach.
“Our landscape genetics methodology incorporates concepts from electrical circuit theory to explore how elephants may traverse and achieve gene flow,” co-author Nathan Alexander explained. “Our framework assesses the various resistances or costs associated with elephant movement through the landscape. This allows us to understand how to optimize pathways for successful migration and connectivity between populations.”
Challenges such as steep inclines, arid regions devoid of vegetation, heavily populated human areas, and locations far from water sources contribute to the costs elephants face while moving. Combining this environmental data with DNA insights allowed the researchers to pinpoint essential routes to enhance gene flow between protected habitats.
De Flamingh highlighted that the relationship between habitat suitability and elephant movement is not straightforward. “We discovered a significant nonlinear relationship, revealing that the most unsuitable habitats impose the greatest restrictions on elephant distribution. Fortunately, elephants show resilience and can navigate through intermediate habitats, which is encouraging for their conservation.”
Particularly adverse habitats have been identified, including the barren Makgadikgadi salt pans in Botswana and regions with dense human populations. Establishing connections that help elephants sidestep these areas may not only facilitate their movement but also mitigate human-elephant conflicts, a significant threat facing these animals.
The findings of this study can serve as valuable resources for government bodies and NGOs working toward effective conservation practices in southern Africa. “Given that southern Africa holds the largest elephant population in the continent, conservation efforts here can significantly impact the survival of these species, especially strategies that minimize human-elephant interactions,” stated senior author Al Roca, a professor of animal sciences at Illinois. Collaborative efforts with partners like CERU, along with support from the International Fund for Animal Welfare and the African Elephant Conservation Fund, are vital for the success of these initiatives.
The research, titled “Integrating habitat suitability modeling with gene flow improves delineation of landscape connections among African savanna elephants,” has been published in Biodiversity and Conservation. The paper honors the memory of co-author Rudi van Aarde, whose leadership at CERU was instrumental in initiating this research before his passing during its development.
Roca retains connections with the Carl R. Woese Institute for Genomic Biology, the Illinois Natural History Survey, and the School of Information Sciences at the University of Illinois.
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