Great Sand Dunes National Park and Preserve: Ungulate use and wetland condition in the ungulate management plan baseline period (2016–2019)
Schweiger EW , Zeigenfuss L , Mosher D, Sherrill K , Witwicki D . 2025. Great Sand Dunes National Park and Preserve: Ungulate use and wetland condition in the ungulate management plan baseline period (2016–2019). Science Report. NPS/SR—2025/258. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2309023
This report presents baseline (2016–2019) results from Ungulate Management Plan (UMP) monitoring of sensitive and important wetlands at Great Sand Dunes National Park and Preserve (GRSA) by the Rocky Mountain Network. At GRSA’s request we also include several management recommendations in the Discussion. Wetlands harbor disproportionately high levels of biodiversity and support iconic species like elk (Cervus canadensis) and bison (Bison bison). We develop Ungulate Use Indices (UUIs) from dung, collar, and camera trap data to quantify elk and bison use of wetlands. We estimate Wetland Condition Indices (WCIs) using bioassessment methods that model a synthetic response in wetland vegetation to ungulate use. WCIs provide a single number that encapsulates the condition or ecological integrity of wetlands used by elk and bison. WCIs stand alone, but we enhance their application via interpretation of their component metrics. We augment WCIs with four hand-picked (HP) metrics. Finally, we develop novel assessment points (APs) in consultation with park resource management staff that place results into classes of the best, intermediate, and worst conditions in the baseline data. WCI models successfully capture a large portion of the variation in wetland condition response to ungulate use—much more than single metrics alone. Baseline condition of many sand sheet wetlands was poor, with almost 40% and 66% of herbaceous and woody sites degraded by elk and bison use, respectively. Two HP metrics, iris (Iris missouriensis) and silverweed (Potentilla anserina) cover in herbaceous sites, and the density of browsed willow and cottonwood (Salicaceae) in woody sites, are emblematic of these poor conditions. Over 50% of sites were in the worst condition classes for these two metrics. However, should the park effectively manage elk and bison into the future and pursue other important restoration goals, our models suggest these and other indicators of wetland condition could improve. Baseline ungulate use and wetland condition will be compared to future UMP wetland monitoring results as GRSA resource management seeks to reduce elk and bison use of wetlands by lowering density and hazing animals. GRSA expects to approach this process in an adaptive way and may add other active and passive ungulate management strategies as warranted. The ability of a WCI to consolidate variation in wetland condition response supports a high statistical power to detect future changes. Its direct connection to park management actions is an important application of ecological monitoring that will assist GRSA resource management into the future.
- Type
- Published Report
- Authors
- Schweiger, E.; Zeigenfuss, Linda; Mosher, Dewane; Sherrill, Kirk; Witwicki, Dana
- Date of Issue
- 2025-03
- Publisher
- National Park Service
- DOI
- 10.36967/2309023
- Units
- GRSA , NRSS , ROMN
- Keywords
- adaptive management, bison, ecological integrity, elk, Great Sand Dunes National Park and Preserve, ungulate use, WEIReport, wetland condition
- Subjects
- Ecological Framework: Water | Hydrology | Groundwater Dynamics , Ecological Framework: Biological Integrity | Focal Species or Communities | Wetland Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Mammals