Wednesday, March 22, 2023

Excessive Horse Grazing Destructive to Grasslands


In my travels around the greater Placitas area, I have noticed that a lot of the area has bare soil or sparse grass, shrubs, and weeds.

Some people may think that is the natural condition of the desert, that that’s how it's supposed to be. However, this land is capable of growing abundant grass and wildflowers, if given the chance, and some rain.

One can see the productivity that is possible in protected areas, such as the Placitas Open Space, or the Strip Mine trails. These photos show the dense, tall grass growing there. This is what the whole area could look like.

According to my rough mapping, about 10,000 acres are impacted by horse grazing and
trampling, not including the Buffalo Tract.

Grass has evolved over millions of years to be grazed. The growing buds are near the ground. Every time a grass plant is bitten off, the roots use their stored energy to grow new leaves. Then the leaves do photosynthesis and replenish the roots. The grass creates seeds to reproduce itself. If the leaves are bitten off again before the roots are replenished, the plant will struggle to grow back, won’t go to seed, and will eventually die. Repeated grazing will kill off grass plants.

Without grass to hold the soil in place, sheet erosion will turn into rills, which turn into small gullies, which lead to larger arroyos. These gullies concentrate floodwater, deepen the arroyos, hasten runoff, and rob the uplands of water infiltration. Runoff will carry debris, which will block culverts, and undermine road and other structures. Organic matter will wash away.

Without grass to shade the soil, the soil will dry out faster. Plant roots support all kinds of microorganisms, which are the foundation of the wildlife food web. Without plants, there is less wildlife at every level.

There can be enough grass to support native wildlife, but it doesn’t grow fast enough to
support 168 800-pound horses. I urge you to take a look at plants and soil in the protected areas. See how rich, productive and beautiful our Sandia foothills can be.

Susan Harrelson is a supervisor with the Coronado Soil and Water Conservancy District and a retired range conservationist and wildlife biologist.


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