Functional connectivity – the extent to which landscapes actually facilitate species movement – is key for designing effective corridors that benefit wildlife. While it’s easier to identify structural barriers to connectivity, identifying factors that disrupt functional connectivity requires a more detailed understanding of how species use a landscape.
For species bordering urban areas, exposure to human activity may impede functional connectivity. Urbanization creates structural barriers to species movement, but also increases exposure to sensory pollution, such as artificial light and noise.
Ditmer, M.A., Carter N.H., Hersey K.R., Leclerc M., Wittemyer G., and Stoner D.C. 2023. Navigating the wildland-urban interface: Sensory pollution and infrastructure effects on mule deer behavior and connectivity. Basic and Applied Ecology 73: 62-71.
At the same time, urban and agricultural areas may provide novel foraging opportunities for some species, creating a tradeoff between human contact and foraging rewards. These tradeoffs may impact how species maintain connectivity at the urban-wildland interface.
Recent research looked at how urbanization, artificial light, and vegetation availability influence corridor use in Utah. In 2012-2018, researchers tracked the movement of 43 mule deer using GPS collars. They used the GPS locations to characterize how mule deer were moving across the landscape and compared this to vegetation availability, artificial light, and development in the study location.
The study found that multiple factors of urbanization influenced mule deer corridor use. As expected, roads and housing development were structural barriers, decreasing corridor use. Mule deer also moved through corridors faster when there was less vegetation and more artificial light, indicating that these areas were used for quick movements rather than foraging.
In developed areas with high levels of artificial light, mule deer used corridors less intensively, even if there was vegetation for foraging. In contrast, in less developed areas, mule deer used areas more intensively when there was relatively high artificial light. These results point to a tradeoff for mule deer – in urban areas, artificial light is avoided due to light pollution and human activity, but in rural areas, artificial light may provide protection from cougar predation.
These results are notable because they show that urbanization affects not only whether a corridor is used, but how it is used as well. For species at the wildland-urban interface, understanding how a species responds to human activity will guide management decisions. Incorporating a species’ functional use of landscapes will strengthen effective corridor design.
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