Wildlife Impacts and Public Access: Are there unintended consequences of increasing open space visitation?

By John Baas, PhD

The Shelter in Place (SIP) order has been in effect in the San Francisco Bay area for nearly three months and has implications for how park, recreation, and open space agencies may need to manage public access in response to wildlife impacts.  Last week I saw a juvenile coyote trotting down a residential street in broad daylight. On Youtube, you can see lions napping on a road in Kruger Park, South Africa, an alligator strolling down the street in South Carolina, wild goats occupying a Welsh village, to name a few. Wildlife are on the move. 

People are on the move, too. About 10 days after the Bay Area SIP took effect, I visited one of my favorite local open space areas.  This particular area has a single, narrow access road, a small parking lot that accommodates about 20 cars, and a large (but farther away from the trailhead) overflow parking area that easily accommodates 200 to 250 cars.  On most weekends prior to the SIP order, those parking areas were typically 40 to 50% occupied on weekends.  But during my visit, both locations were at 100% occupancy on Saturday and Sunday, with additional cars parked along the access road. Moreover, I have observed the same effect at staging areas for several other open spaces in the East Bay region as the SIP has extended in to May.

If visitor use is increasing across open space areas throughout the San Francisco Bay area, what effects is it having on wildlife?

WRA, Inc. staff recently published a paper in the California Fish and Wildlife Journal, titled “An assessment of non-consumptive recreation effects on wildlife: current and future research, management implications, and next steps.”

The article summarized research that public access has on wildlife.  For many of the studies we reviewed, the findings were complex and did not offer straightforward answers on the relationship between the two.  Most studies focused narrowly on wildlife behavioral responses in relation to recreation use levels.  In many of these studies “recreation use” was not well defined, and it was difficult to determine what effect recreation use levels (as opposed to recreation use per se) had on wildlife, especially at the population level, since most studies only examined changes in individual behavior.

As part of our review, we found that some researchers have recently taken a more focused look at how the level of visitation might affect wildlife. For example, Larson and her colleagues correlated recreational use levels with habitat occupancy for seven special status species for 18 publicly accessible reserves in San Diego County. This is a thorough research effort that integrates a model to predict recreation use levels with whether habitats for special status species are occupied. Correlation between recreation levels and habitat occupancy is conceived as a level of wildlife species exposure to visitors. Although this study did not attempt to evaluate impacts to wildlife, it is a much-needed improvement in how public access and wildlife studies are conducted.  Indeed, a more comprehensive and robust effort such as this one is needed that extends this type of research to a variety of habitat types and recreational use levels throughout California. 

The continuing effects of the SIP provide a unique opportunity to examine the effects of sustained, increased visitor use on wildlife across the state.  We are hopeful that our colleagues in more research-oriented institutions are able to take advantage of this unique situation to help answer the question of how wildlife are affected by varying levels of recreation use within open space areas.

For more information on the Journal article author, please contact John Baas.