Are we loving our natural areas to death? Most natural areas are set aside for multiple reasons, such as conserving plants and animals, providing places for outdoor recreation, and protecting unique natural features. But we don’t always know if all these purposes can be accomplished simultaneously. Recently, participation in outdoor recreation (such as hiking, mountain biking, and trail running) has been increasing nationally and globally. While this is great news for public health and appreciation of nature, it also raises concerns ranging from car emissions in national parks to soil erosion and the introduction of invasive species. Our lab’s research on this topic focuses on the impacts of recreation on wildlife, particularly threatened species that depend on habitat within natural areas. We hope that with a better understanding of the impacts of recreation on wildlife, we can help design management strategies to minimize them.
Wildlife response to human recreation in San Diego County
San Diego County has a population of over three million people. It is also a hotspot of biodiversity that is home to over 500 vertebrate species, many of which are threatened or endangered. In a collaboration among the Wildlife Conservation Society, Colorado State University, and University of California-Berkeley, we are working to measure and model recreation in San Diego area parks and preserves to assess the risk of disturbance to sensitive wildlife species. As part of this project, we are reviewing the scientific literature to assess what the scientific community knows about the impacts of recreation on wildlife, and find out which species may be particularly vulnerable. We also developed an expert opinion survey and a field study using motion-activated cameras to measure patterns of recreation. Finally, we are constructing a model that will help us understand recreation patterns in San Diego and draw conclusions about the potential impacts to sensitive wildlife species.
Impacts of human recreation activity on Adirondack birds
The Adirondacks receive an estimated 7-10 million visitors per year, the majority (>90%) of whom participate in non-consumptive, nature-based outdoor recreation. The goal of our research is to investigate expanding and intensifying disturbances associated with human recreation as a driver of bird community homogenization. Biotic homogenization refers to a process by which regionally distinct rare, forest interior, and ground-nesting species are gradually replaced by a globally common set of early successional, edge-associated, and generalist species. Possible mechanisms include direct disturbance by humans, indirect disturbance by habitat modification, or indirect disturbance via species interactions.
Traffic levels and motor vehicle noise in a U.S. national forest
Participation in motorized recreation activities has more than doubled in the past 20 years. In a collaboration between The Wilderness Society and the University of California-Berkeley, we investigated the effects of motor vehicle routes, traffic levels, and noise propagation on wildlife communities in a U.S. national forest. We used point counts, track plates, and bioacoustic monitors to survey for birds, mammals, and motor vehicle traffic along paved, gravel, and natural-surface roads and motor vehicle trails over two years. Motor vehicle noise exceeded ambient natural sound levels up to 625 m from the nearest road. Detections of mammalian carnivores increased with distance to road, and the greatest numbers of native species were detected at the most isolated sites with lowest levels of human activity; sites with one-third fewer motor vehicle events produced detections of 3.2 times more native carnivores. We found no effect of distance to road or traffic level on detections or species richness of birds. By integrating information about traffic levels and noise propagation into transportation and recreation planning decisions, scientists and land managers can balance human use with species protection in protected area management.