Movement models and simulation reveal highway impacts and mitigation opportunities for a metapopulation-distributed species
CITATION:
Aiello CM, Galloway NL, Prentice PR, Darby NW, Hughson D, Epps CW (2023) Movement models and simulation reveal highway impacts and mitigation opportunities for a metapopulation-distributed species. Landsc Ecol https://doi.org/10.1007/s10980-023-01600-6
Aiello CM, Galloway NL, Prentice PR, Darby NW, Hughson D, Epps CW (2023) Movement models and simulation reveal highway impacts and mitigation opportunities for a metapopulation-distributed species. Landsc Ecol https://doi.org/10.1007/s10980-023-01600-6
Summary |
By: Christina Aiello
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Many human developments like towns, roads, and railroads, can prevent wildlife from moving through their habitat and accessing the resources they need to survive and thrive. This occurs throughout the desert bighorn metapopulation. Previous research shows that various human-made structures act like barriers to bighorn and limit their ability to interact and share genetic material with neighboring populations. In this study, the authors dug deeper into how nearby bighorn move and use habitat along two major interstate highways in Southern California – I-15 and I-40. By attaching GPS collars to track the movements of near-highway bighorn, the authors sought to learn more about which habitat they prefer to use and which areas they tended to avoid using movement models called step selection functions (See our research page for more info).
The authors then compared the amount and characteristics of the habitat currently reachable by bighorn to that predicted to be reachable during no-highway simulations. They found that without highways, bighorn could reach anywhere from 7 – 138% more habitat during typical annual movements (depending on what range they live in). In some locations, the habitat reachable without highways included higher elevations – habitat that can be critical to long-term bighorn persistence in these harsh desert regions.
This study provides a glimpse into how bighorn could use this landscape if they were free to move and choose the habitat they prefer. The simulation results help us measure how much impact the highway has on the species, and how much the species might benefit if we improve movement across highways. We can use the data from this study to answer questions like: where should we build a wildlife crossing (overpass) that bighorn sheep would benefit from and use most? And, where should we not disturb land because it would interfere with movements that bighorn currently make to access habitat and interact with other bighorn? This information is particularly important in desert habitats that continue to see new development proposals related to large-scale solar power production, transportation, and urban expansion, as well as increased visitation and use of National Parks in the region. Meanwhile, limited resources make movement and access to diverse habitat especially important to wildlife survival in desert ecosystems.
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Management Implications
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