Invasive Plants

Invasive plants are among the most common management issues for public and private rangelands. Each region in the United States has its own problem species. Some areas have issues with non-native species coming in and outcompeting the native plants, disrupting the ecosystem. But on rangelands in the U.S., you'll often find native plants that have invaded due to changes in the way land was managed after it was settled by European colonizers. As an example, there has been a suppression of wildfires; while it protected people and their livelihoods, it also took away a vital piece of the ecological puzzle.

Mesquite History

Mesquite is a native shrub or tree (depending on the ecoregion) with big sharp spines and bean like seed pods, which is historically found here in low numbers. These lightly scattered woody plants provide some cover for wildlife when needed as well as fixing nitrogen from the atmosphere into the soil as most legumes do (think peanuts and beans). We have two different species of mesquite on the ranch, one called Honey mesquite and one called Western mesquite. As it is a woody plant, its slower growing than grass and takes longer to recover and regrow from damage. So as grasslands burned in natural wildfires, grasses remained the dominant group of vegetation for hundreds of thousands of years, while shrubs expansion was limited by the frequency and intensity of the fires.

How It Began

As people built towns and fences, they also found ways to control and limit the destructive wildfires indispensable to the area. Over just a hundred and thirty years of reducing fire frequency, shrubs like mesquite were able to proliferate beyond their natural density, crowding out grasses and changing the structure of the landscape. Without the original vegetation structure, vital wildlife and insect populations that evolved with the grasslands drop without enough food and habitat. Additionally, the grass on which we produce most of the world's beef, dwindles to nearly nothing, barely able to support a few hundred cattle.

Strategies

To return our ranch to a more functional grassland, we manage projects that aim to reduce mesquite density. Any area on the ranch with a density of 20% or higher is suffering significantly enough to treat, and on top of that we cross check these areas with where the most productive soils lie. If we treat these priority areas we will see the greatest improvements and a more productive ranch to support greater cattle production. Because mesquite is a resprouting species, hiding its growth points underground in its roots, it's roots must die or be removed in order to eradicate the plant. As we have two types of mesquite, our ranch uses a mixture of the chemical herbicides Remedy and Sendero sprayed onto the plants via plane, which kills the shrub's roots over the span of a few years.