Recreation in the sagebrush-steppe ecosystem

At any one time, there are numerous research projects being undertaken in the Morley Nelson Snake River National Conservation Area. After hearing from some of the researchers during our virtual speaker program for the 2021 Snake River Raptor Fest, we wanted to learn more about their research and share it with our audience, who we know all have a place in their hearts for this very special piece of land and the species who dwell within it. First up, we spoke to Madeline Aberg, a Researcher at the Intermountain Bird Observatory. After hearing Madeline’s fascinating talk about the impacts of outdoor recreation on horned lark breeding, we asked her to give us an update on her research and how things were going. A huge thank you to Madeline for finding the time to share this with us. Now, over to Madeline…

Madline Aberg conducting her research in the NCA

Multiple-use public lands, like the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA), support important habitat for conservation and human use. One popular human use of public lands is outdoor recreation, which provides opportunities for people to connect with nature and enjoy the landscape. Outdoor recreational use has increased in recent years, especially at sites like the NCA that are located near rapidly growing urban areas (Boise, Idaho, in this case).

As recreation increases in the NCA, it’s important to consider how it impacts the ecosystem, including the raptors that the NCA was founded to protect, their prey, and other birds that breed at the site. Understanding the impacts of recreation can help to balance recreational use of a site like the NCA with the conservation goals of the area.

A photographer recreating in the Morley Nelson Snake River NCA (C) BLM Idaho

Outdoor recreation can impact wildlife in several ways. The effects of recreation can be direct, through harvesting wildlife or disturbing their behavior, or indirect, through changing the habitat or altering the relationships between species.

We are investigating the impact of recreation on multiple species in the sagebrush-steppe ecosystem at the NCA. This area of the NCA, away from the Snake River, includes native shrubs and grasses, as well as invasive grasses and forbs. The sagebrush-steppe ecosystem is important habitat for breeding birds and the prey hunted by foraging raptors. Specifically, we want to know how recreation impacts Piute ground squirrels (Urocitellus mollis), raptors and ravens, mammalian scavengers, and ground-nesting birds.

In the sagebrush-steppe portion of the NCA, the most popular types of recreation are off-highway vehicle (OHV) use and recreational shooting, which includes shooting targets or live animals like the Piute ground squirrel. The roads and trails used to access the site and walk or drive OHVs might reduce the amount of habitat available and the connectedness of the habitat, as well as providing easy paths for predators to use. As a result, the density of breeding birds and the number of chicks they successfully fledge from the nest may decrease. Recreationists walking or driving past wildlife might disturb their behavior and cause them to spend less time on important activities. Recreational shooting could impact prey populations, as they are targeted during the activity, and supplement scavenger species with carcasses left after shooting events. Carcasses left behind might attract avian and mammalian scavengers, which are also predators for ground-nesting birds.

The Idaho sagebrush habitat within the Orchard Combat Training Center (C) USFWS - Pacific Region

We selected sites across the NCA with high or low recreational use, then measured ground squirrel abundance, raptor and raven abundance, mammalian scavenger density, and ground-nesting bird breeding density and nest success. Mammalian scavengers included American badgers (Taxidea taxus) and coyotes (Canis latrans) and ground-nesting birds were long-billed curlews (Numenius americanus) and horned larks (Eremophila alpestris).

American badgers are one of the many species that live within the sagebrush habitats of the NCA (C) Eric Ellingson

Our goal is to better understand how recreation impacts the sagebrush-steppe ecosystem to balance the uses of the site and facilitate the coexistence of outdoor recreation and conservation at the NCA.

We’re looking to hear more about Madeline and her team’s research over time as we all work together to conserve this unique habitat, for humans and animals alike. More coming soon!