Horses are picky eaters, they will choose the best tasting, most nutritious grass and with their mouth structure they can eat those grasses nearly down to the dirt with their front teeth. Cattle on the other hand must use their tongues to eat forage which does not allow them to eat forage close to the ground.
Effects of Unmanaged Wild Horse Grazing on Riparian Ecosystems and Wildfire on the Devil’s Garden Plateau, Modoc County, California
by Laura K. Snell
Working with public land managers in Northeastern California on USFS and BLM land, the University of California Cooperative Extension has been conducting research on wild horse impacts of springs, seeps, and vegetation. This study, started in 2015, has provided thousands of trail camera photos showing the behavior of wild horses, livestock, and wildlife around natural riparian areas.
In otherwise arid sage steppe rangelands, springs provide critical watering sources as well as wildlife habitat for sage grouse, deer, elk, pronghorn, waterfowl etc. These riparian areas also provide habitat for fish, aquatic insects, and plants, some of which are threatened or endangered. Properly functioning riparian areas include a raised water table and dense and diverse vegetation that protect stream banks from erosion and protect the water from evaporation, sediment, temperature fluctuations, and buffer high flow.
Above is an example of a properly functioning riparian area providing a natural fire break during a wildfire on the Modoc National Forest in the summer of 2017. This is an active livestock grazing allotment where grazing is managed for multi-use of rangeland resources. Notice the dense and diverse vegetation, extended water table, and covered stream banks. This area is outside of the Devil’s Garden wild horse territory and not yet utilized by wild horses.
Horses differ from cattle in many ways including the type of forage they can consume. Horses are picky eaters, they will choose the best tasting, most nutritious grass and with their mouth structure they can eat those grasses nearly down to the dirt with their front teeth. Cattle on the other hand must use their tongues to eat forage which does not allow them to eat forage close to the ground. Highly nutritious grasses are located in riparian areas and meadows where horses will choose to congregate all year long without movement and management. This can be seen on the Devil’s Garden Wild Horse Territory in Modoc County, CA.
This picture illustrates the congregation of horses near a natural riparian area in Northeastern California. The horses have eaten all the vegetation under the trees and nearly all the vegetation that is needed to stabilize the spring banks around the riparian area. The water quality suffers as the plants that would provide shade to the water are eaten, causing the water temperature to rise. Vegetation that would provide habitat for aquatic insects, nesting bird species, and many small mammals is gone. A 20% streambank alteration is allowed in livestock grazing situations, when this picture was taken, the alteration was nearly 100%. Livestock are managed and would have been moved from this pasture weeks ago but wild horses are left to graze unmanaged 365 days a year.
Here is another example of a natural spring that has been overgrazed by wild horses. You will notice that there is very little grass and therefore wildfire would most likely not burn this area. The caveat is that wildfire would not likely burn this are in the first place with good riparian management and managed grazing. The wild horses have degraded the water quality, streambanks, vegetation, and the entire workings of the riparian ecosystem. With management, the water table in this valley would be higher, promoting more native grasses which stay green and pliable later in the growing season which in turn also shade the ground, allowing the ground to stay wetter longer. If a wildfire approached this area, it would most likely die out on its own.
Horses do not choose to walk long distances to eat invasive annual grasses that are the fuel of wildfires in the western United States. Horses instead will choose to stay in these riparian areas and eat every bit of green grass. Only when all the green grass is gone will they walk as short as possible to find other feed.
Wildfires are a natural part of this ecosystem and although there are unnatural fire regimes and fire return intervals at play here and across the west, is allowing wild horses to degrade the rangeland at the cost of every other species a trade-off to decreasing wildfire risk?
On the left is another example of a highly degraded spring on federal land from unmanaged wild horse use. The right is private land that has been managed with livestock grazing for generations. This picture was taken August 15, 2017 and you can see on the right that the bottoms of the vegetation are still green and the vegetation is dense and diverse. A healthy riparian area can function as a fire barrier and also provide for multiple uses from wildlife habitat, to aesthetics.
Managed grazing can be an important tool to fire depression and resource management. Livestock are used throughout California to maintain road ditches, power line right-aways and even private and public lands. There are nearly 4000 horses on the Devil’s Garden Plateau currently and the established Appropriate Management Level is 206-402. Horses are within the wild horse territory, outside of the territory, and on private and tribal lands. They are spreading outside of their allotted area as their numbers increase nearly unchecked creating additional issues including public safety concerns on highways and moving into developments. Management is the key to solving this problem, saving our riparian areas, and continuing to have public land for multi-use.
Laura K. Snell started working for the University of California Agriculture and Natural Resource Division in spring 2015 after working for the University of Nebraska-Lincoln. She is the county director and livestock and natural resource advisor for Modoc County based out of Alturas, California. Her research interests include range ecology and management, fire ecology, livestock production, and wild horses. Laura focuses on collaborative research with public and private land managers utilizing the nearly 70 percent of land in Modoc county that is publically owned. When she is not conducting research, she spends most of her time exploring the public land surrounding Alturas and training her dog, Zuri.
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