How Wildlife Behavior May be Impacted by Visitors

Visits to national parks have grown steadily over the last decade, and these protected areas are often key venues for outdoor recreation and activities such as wildlife viewing. But what level of human activity in these protected areas is “too much” for wildlife? How can we measure this? And is there some threshold level of human activity above which the human activity displaces wildlife?

Caught on camera. Wildlife camera traps were deployed at 10 sites to detect wildlife use rates.

Glacier Bay National Park in southeast Alaska offers us the unique opportunity to answer those questions. Glacier Bay has very low levels of on-land tourism (most people come by boat and often don’t ever go to shore)—making it a particularly interesting place to identify a lower level of outdoor recreation that changes wildlife behavior. In this study, we used remote cameras to measure how brown bears, black bears, wolves and moose use areas of high, concentrated human activity versus areas visitors use less. By controlling where and when humans could access certain areas of Glacier Bay and then measuring wildlife responses to the differing levels of human activity, we identified two important thresholds.

First, we did not detect the any of the four species on the remote cameras more than five times per week unless human activity was absent. Second, in backcountry areas, wildlife detections on the cameras dropped to zero per week once outdoor recreation levels reached the equivalent of about 40 visitors per week. For context, some of the most highly visited national parks in the United States receive upwards of 200,000 people per week.

But it’s unreasonable to expect that protected areas like national parks will be completely devoid of human activity—especially as the number of people seeking to visit wild places increases—and it’s up to managers of these areas to balance the desires of humans to view wildlife with the likely impacts. A combination of management techniques, including concentrating human use in certain areas to limit the areal extent of human impacts, or limiting the time of year or day that people are allowed to visit specific areas, might be the best way to promote coexistence between people and wildlife in protected areas.

Low levels of outdoor recreation alter wildlife behaviour

Abstract

1. Public interest in nature-based recreation is growing, including visitation to protected areas. However, the level of recreation in these areas that causes detectable changes in wildlife behaviour remains unknown, and many studies that investigate wildlife responses to humans do so in high-visitation areas.
2. We used camera traps to investigate the spatial and temporal responses of brown bears (Ursus arctos), black bears (Ursus americanus), moose (Alces alces) and wolves (Canis lupis) to experimentally manipulated levels of human activity in Glacier Bay National Park, Alaska during summers 2017 and 2018. Human activity was restricted at some sites and concentrated at others, and these human impact treatments were swapped mid-season. The park has very low on-land visitation (~40,000 on-land tourists per year), making it a unique study system to investigate wildlife responses to low levels of human activity.
3. Detections did not exceed five per week for any species unless human activity was absent (zero photos of humans were taken). However, spatial and temporal patterns of wildlife activity in relation to human activity were nuanced and species specific. Moose shifted their activity patterns to better align with when people were most active. Black bears were more likely to be detected in areas of high human activity but used high-use areas less intensely than low-use areas. Wolves used areas of high human impact more intensely, but shifted their activity to be more strongly nocturnal.
4. Our results highlight the importance of considering both spatial and temporal responses of wildlife to human activity. Additionally, and arguably most importantly, we detected changes in wildlife behaviour in response to humans in a national park with relatively low tourism. Although natural processes may dominate in protected areas, our results indicate that even low levels of human activity can alter wildlife behaviour.
5. Synthesis and applications. We demonstrated that nearly any level of human activity in a protected area may alter wildlife behaviour. However, it is unreasonable to expect protected areas to be completely devoid of human activity. Thus, management of these areas will need to balance the desires of humans to view wildlife with the likely impacts.

Sytsma, M. L. T., T. Lewis, B. Gardner, and L. R. Prugh. 2022. Low levels of outdoor recreation alter wildlife behaviour. People and Nature 00: 1-13.