The sagebrush steppe ecosystem is vulnerable to multiple, increasing threats including excessive land use, invasive species and wildfire. Much is known about the effects of individual impacts, but it is unknown how these threats may interact to alter ecosystem dynamics. Therefore, in my thesis research I aim to investigate how two threats, wildfire and recreation disturbance, may have interactive or additive effects on predator-prey interactions in the sagesteppe and, as a consequence, predator reproduction. Specifically, I am studying nesting Golden Eagles (Aquila chrysaetos) and their prey in southwestern Idaho.
Golden Eagles are top predators of the sagesteppe, and rely on limited nest sites and healthy shrub habitat that supports shrub-reliant prey, including leporids (rabbits and hares) and sciurids (squirrels). Golden Eagles are negatively affected by both wildfire and human disturbance, however, it is unknown how these impacts may interact. Recreation may decrease in burned areas and increase in unburned areas, resulting in poor nesting success across all territories, or recreation patterns may remain consistent and have additive negative effects on nesting success in burned areas.
My study area includes historical nesting territories along the Owyhee front, which is also a popular site for outdoor recreation. In 2015, the Soda Fire significantly burned half of these territories and the rest remained unburned. To address my research questions, I will use a before-after-control-impact design, leveraging data taken in 2017 and 2018 with data collected in the same territories from 2013-2014 on recreation volume and eagle occupancy and productivity. Territories in burned and unburned areas will be compared at varying recreation volumes. Eagle diets will also be assessed through the installation of motion-activated cameras at nests.
In our changing world, it is critical that we understand not only direct effects of human threats but their interactive effects on ecosystems so that we can make well-informed decisions about how to manage recovery in post-fire wildlands.