Using network theory to prioritize management in a desert bighorn sheep metapopulation
CITATION:
Creech TG, Epps CW, Monello RJ, Wehausen JD. (2014) Using network theory to prioritize management in a desert bighorn sheep metapopulation. Landsc Ecol doi.org/10.1007/s10980-014-0016-0
Creech TG, Epps CW, Monello RJ, Wehausen JD. (2014) Using network theory to prioritize management in a desert bighorn sheep metapopulation. Landsc Ecol doi.org/10.1007/s10980-014-0016-0
Summary |
By: Risa Bellak
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Wildlife populations benefit from and depend on the genetic diversity that can result from habitat connectivity. So habitats are often managed to promote gene flow, with research informing what actions help protect or improve critical connections. One tool that researchers use to evaluate gene flow among populations is called a network graph - these diagrams map connections among populations that can be analyzed to identify important areas or links that improve or maintain flow throughout the entire network. Network graphs are comprised of individual points (“nodes”) that are connected by lines (“edges”) and are used to evaluate systems including transportation and social media networks, disease outbreaks, and wildlife habitat. In this study, the network graph “nodes” are habitat patches that support populations of desert bighorn sheep in Southern California. The “edges” connect habitat patches that are close enough for desert bighorn sheep to travel among.
The two metrics used to describe connectivity were associated with measured genetic diversity in bighorn populations. As these network metrics increase, it is likely that genetic diversity will increase as well. The authors identified four high-priority habitat features and at a minimum, two features ranked in the top five across all four combinations of network metric and connectivity type. These habitat patches and connecting pathways play a critical role in the maintenance of connectivity within the entire network and are high priority for protection. While some patches and pathways are not currently functional due to habitat fragmentation or local extinctions, their restoration could improve network connectivity. The authors suggest increasing connectivity across major interstates such as I-10, I-15, and I-40. Based on their findings, they recommend several priorities for managing bighorn habitat to promote a well-connected and functional metapopulation. These restoration actions would involve landscapes managed by multiple agencies and would require collaboration and action on protected and unprotected lands.
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Management Implications
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