A Coupled Human and Natural Systems Approach to Studying Recreation on Public Lands
Authors: Aberg Madeline C. 
Published: September 2023

Outdoor recreational use has increased rapidly in the western United States in recent years, which provides more people with opportunities to enjoy public lands and benefit from recreation. However, increased recreation can lead to negative social and ecological impacts that degrade both natural resources and the recreation experience. I used a Coupled Human and Natural Systems (CHANS) approach to study recreational use at the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA) in southwest Idaho. This approach considers the human and natural systems, feedbacks within the systems, and effects from telecoupled influences outside of the site, which gives a more complete view and helps to predict how the system may change in the future. The human system at the NCA includes recreationists, management agencies, biologists, recreation organizations, military training, agriculture, and infrastructure. Recreational shooting – shooting inanimate targets or unprotected mammals – is a popular recreational activity at the NCA and was a primary focus of my efforts within the social system. The natural system includes a river with steep cliffs and the surrounding sagebrush-steppe along with raptors, ravens, mammalian scavengers and predators, ground-nesting birds, and small mammals. I used the CHANS framework to identify and investigate questions about the feedbacks within and between the human and natural systems.

In Chapter 1, I focused on how the human and natural systems affect the expected and observed spatiotemporal patterns of recreation at the NCA. I
used a multidimensional survey of recreationists and observational survey routes to characterize the site use of individual recreational shooters
and the larger spatiotemporal patterns of recreational use, respectively. Recreational shooters reported a strong preference for sites with natural
backstops and generally avoided other groups of recreationists. More experienced shooters placed greater importance on vegetation type and less
importance on the presence of other recreationists. Motivation and activity type also affected preference, as individuals who were motivated to
view wildlife or hunting unprotected mammals reported a stronger preference for sites with a greater abundance of the most common target species,
Piute ground squirrels (Urocitellus mollis). Observed spatial patterns of all recreation showed a concentration of recreational
use in northern portions of the site and along major access roads with little overlap between shooting and other recreational activities.
Observations of recreational use were higher on weekends, earlier in the year, later in the day, on warmer days but not the hottest days, and
during the COVID-19 pandemic. These results help to understand the site needs of recreational shooters and how recreational use is currently
distributed across the NCA, as well as how these patterns might change in the future as environmental and social conditions change.

In Chapter 2, I examined interactions within social groups associated with the NCA. I asked recreationists, managers, and biologists about their perceptions of recreation impacts, challenges, and management using multidimensional surveys and semi-structured interviews. I focused on recreational shooters, the most common type of recreationists at the site, and birdwatchers, who rely on the natural resources at the site. Recreational shooters were primarily concerned with trash, crowding, and safety, whereas managers and biologists listed a variety of concerns focused on wildlife, habitat, safety, illegal killing of protected wildlife, lead, and trash. I assessed standards of quality for three levels of trash and crowding that represent conditions at the site, then compared ratings of acceptability between groups using an ordered logistic regression model. Recreational shooters rated low and medium trash conditions as more agreeable than managers, while biologists and birders did not differ from managers. Conversely, recreational shooters rated all crowding conditions as less acceptable than the other groups. Recreational shooters and birdwatchers placed the highest responsibility for enforcing rules on individuals and law enforcement but disagreed on the role of management agencies. Recreational shooters were supportive of educational management interventions whereas birdwatchers supported management changes, recreation participation, and limits on recreational use. Managers and biologists suggested a variety of management actions, including closures, increased law enforcement, and designated shooting areas. From these results, I identified opportunities for improving recreation at the site.

In Chapter 3, I investigated the impact of recreation on multiple trophic levels of the ecological system. I selected 10 paired 1-km2
sites, with half in areas of high recreation and half in areas of low recreation. I used observational driving survey routes to collect locations
of recreational use, mapped a kernel density estimate of recreation locations, then extracted the estimate as a measure of recreation intensity for
specific areas and time periods. I assessed the effect of recreational use intensity on the abundance of a keystone prey species (Piute ground
squirrels), the abundance of avian and mammalian predators that rely on ground squirrels, and the breeding density and nesting success of
ground-nesting birds at the NCA. The abundance of ground squirrels had a positive relationship with recreation use intensity, potentially due to
recreationists selecting sites with squirrels. The presence of native shrub cover had a stronger positive relationship with ground squirrel
abundance. The abundance of avian scavengers, particularly common ravens (Corvus corax), was positively related to recreational
intensity, as well as power lines and development. The density of a common mammalian scavenger, American badgers (Taxidea taxus),
was positively related to recreational intensity. Breeding bird density and nesting success of ground-nesting birds were negatively related to
recreational intensity, with the nest success of a more sensitive species, long-billed curlews (Numenius americanus), being most
strongly affected. Together, my results highlight the importance of considering variation in recreation intensity, the effect of recreation
relative to other conservation threats, and the outcomes for multiple levels of the ecosystem.

Together the results of these chapters give insight into the interactions and feedbacks within and between the coupled human and natural system of recreation at the NCA. This provides a more complete view of the full system to balance the needs of the human and natural systems into the future.