Wildlife Connectivity

Sprawl Development Can Hurt Wildlife

Roads and large urban and agricultural developments can be major barriers to all kinds of wildlife, from fish and frogs to mountain lions and elk. Without proper planning, they can lead to fragmented habitats that constrain wildlife movement.

This hurts wild animals and plants. Habitat fragmentation limits their movement, impairing some animals’ ability to find food, shelter and mates. Populations get isolated, sensitive species go locally extinct, and key ecological processes like plant pollination can be lost.

If populations are isolated for too long, inbreeding can increase the risk of birth defects, reproductive problems, and vulnerability to disease. Meanwhile it reduces resilience to stress, lowering the population’s chances of survival.

In the 1990s Florida panthers had a population of fewer than 30 individuals due to decades of hunting and habitat loss. Suffering from genetic defects, disease and low reproductive success, they were expected to go extinct in 20 years. But after the introduction of eight female mountain lions from Texas, a gene pool historically connected with Florida panthers, the population has shown some recovery [1], with an estimated 230 individuals in 2017 [2]. The Center continues to fight to protect important habitat for these big cats.

Roads fragment habitats and can lead to vehicle-wildlife collisions that kill or injure animals and motorists, which can result in high costs due to property damage and healthcare needs.

According to the UC Davis Road Ecology Center, in 2016 more than 7,000 wildlife-vehicle collisions on state highways were reported to the California Highway Patrol (mostly involving deer, but also coyotes, bears, elk and mountain lions). This cost Californians about $276 million in damages [3] — and is likely highly underestimated, since it does not include unreported incidents or the tens of thousands of roadkill animals Caltrans disposes of from state highways yearly.

Habitat Connectivity Is Key

Wildlife corridors and crossings are important linkages between at least two significant habitat areas, enabling migration, (re)colonization and breeding opportunities for flora and fauna.

Wildlife corridors/connections come in different shapes and sizes and can consist of existing and intact swaths of habitat, created crossings, restored linkages or a mix. They can be overpasses or underpasses, and their positive effects have been observed in many places, from highways in Colorado to salamander tunnels in Massachusetts.

Preserving wildlife corridors and connecting habitats save wildlife from being killed by cars and trucks and save people from the often serious harm those collisions can cause.

Current Projects Involving Wildlife Corridors and Connectivity:

Altair Development in Temecula, CA
In January 2018 the Center, along with the Sierra Club, Mountain Lion Foundation and Cougar Connection, sued the city of Temecula for approving a 270-acre development that would further isolate an already dwindling mountain lion population in the Santa Ana Mountains, destroying designated lion habitat that connects that mountain population with a more diverse one in the Eastern Peninsular Mountain Range.

NorthLake Development in Santa Clarita, CA
In June 2018 L.A. County’s Planning Commission approved an isolated housing development that will destroy more than 1,300 acres of important wildlife habitat that connects the Angeles and Los Padres national forests while generating more traffic and air pollution. The Center is in the process of appealing the approval.

Mid County Parkway in Riverside County, CA
The Center, along with the Sierra Club and Friends of the Northern San Jacinto Valley, filed suit in 2015 and 2016 against the construction of the Mid County Parkway Project. The project is a proposed six-lane, 16-mile freeway in the San Jacinto Valley that would fragment wildlife preserves and open space, cut through low-income housing, and worsen air pollution. In July 2018 we reached a multimillion-dollar settlement to protect wildlife and habitat connectivity, reduce pollution from truck traffic, and improve safety on Southern California freeways.

1. UC Davis Road Ecology Center (2017). Impact of Wildlife-Vehicle Conflict on Drivers and Animals.

2. Johnson et al. (2010) Genetic Restoration of the Florida Panther. Science 329(5999):1641-1645. DOI 10.1126/science.1192891

3. Florida Fish and Wildlife Conservation Commission (2017) Florida panther population estimate updated. http://myfwc.com/news/news-releases/2017/february/22/panther-population/


Photo of desert tortoise crossing road (in Joshua Tree National Park) by Brad Sutton/National Park Service