Vegetation and forage
Heavy or concentrated grazing can reduce plant cover and forage available to horses, livestock, and native wildlife.
Ecology & native wildlife
Ecological impacts depend on place and density.
Free-roaming horses interact with vegetation, soils, water, wildlife, and other land uses. Those effects are measurable in some locations, but their severity is not identical across Nevada.
Evidence
What research and agency records describe
Riparian systems
Repeated use around springs and wet areas can affect vegetation, streambanks, soils, and habitat condition.
Wildlife interaction
Research has examined relationships between horse abundance, habitat condition, water access, and native wildlife populations.
Greater sage-grouse
A well-studied Nevada concern
A peer-reviewed study published in The Journal of Wildlife Management examined feral horse abundance in relation to greater sage-grouse population dynamics in the Great Basin.
The researchers reported negative sage-grouse population responses associated with higher horse abundance, adding to evidence that horse density can matter in already stressed sagebrush ecosystems.
Association does not mean every observed sage-grouse decline is caused by horses. Sage-grouse are affected by multiple interacting pressures, including wildfire, invasive plants, development, drought, predation, and habitat fragmentation.
Review the studyAgency assessment
Nevada Department of Wildlife
NDOW has documented concerns involving free-roaming horse and burro populations, including use of water sources, grazing pressure, riparian impacts, and interactions with native wildlife habitat.
An agency assessment represents an informed management position. When possible, NV.Horse also links the underlying scientific studies and federal environmental documents so visitors can examine the evidence independently.
Read NDOW reportImportant distinction
Localized evidence is not automatically statewide evidence.
A degraded spring, overgrazed HMA, or documented wildlife interaction can demonstrate a real ecological effect without proving that the same level of impact occurs everywhere horses are present.
Conversely, healthy conditions observed in one area do not establish that horse populations are ecologically harmless everywhere else.
Density, climate, vegetation, fire history, water, livestock grazing, wildlife use, and management history all influence outcomes.
Last reviewed: August 25, 2026