Hill Country Naturalist

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  • A male Blackbuck Antelope stares back at me.
    A male Blackbuck Antelope stares back at me.
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In the 1700s, Spaniards introduced a number of exotic animals to what is present day Texas and Mexico, including cattle, horses, sheep, goats and pigs. None of these animals were native to the Western hemisphere. When the settlers of northern European ancestry began moving into the Hill Country in the early to mid-1800s, they brought more of these animals with them, all things we now refer to as livestock. An exotic animal is one that is not native to the region, or even to adjacent regions.

Beginning in the 1930s, and continuing today, many species of exotic ungulates have been introduced throughout the US, but with the highest populations in the Edwards Plateau. My dictionary defines an ungulate as “a hoofed, typically herbivorous, quadruped mammal.” Think mostly cattle, antelope, deer, sheep and goats.

The most common such exotics include axis, fallow and sika deer, blackbuck antelope and aoudad sheep. But there are as many as 200 species of exotic animals in Texas, mostly native to Asia or Africa. It is estimated that there are at least 400,000 individual exotic animals confined to Texas ranches, and maybe a fourth or a fifth that many more that are free-ranging, and these numbers don’t include feral hogs.

There is a fundamental difference between the exotics brought to this county by settlers as livestock, and these more recent arrivals of exotic ungulates. The former were readily domesticated, and could be easily herded, handled, moved, kept inside low ranch fences, and their numbers controlled. And, they provided food, fiber and milk for the settlers, as they do for all of us today.

On the other hand, these newer exotic arrivals are not domesticated, or in most cases domesticatable. They are wild, hard to herd or handle, and most of them can jump regular low ranch fences. The purpose for which they were brought here is not to provide food or fiber, but primarily to be hunted as trophy animals. (Some small numbers are currently being kept as pets, and in a few cases of endangered species, raised to protect the species).

In Texas, native game animals (white-tailed deer, pronghorn, quail, turkey, etc.) are considered property of the state, wherever they exist, and the state therefore regulates the where, when, how and how many can be taken by hunters. Exotic animals, on the other hand, are not property of the state and are in fact considered livestock and the property of the landowner.

Most exotic ungulates eat like goats, meaning they can thrive on browse (woody plant leaves), forbs (broadleaf herbaceous plants) or grass, and therefore they compete with our usual livestock species as well as with white-tailed deer for food. This is particularly troublesome for our white-tailed deer since they cannot survive on a diet of only grass.

This was demonstrated conclusively at Kerr Wildlife Management Area when an equal number of sika deer and white-tailed deer were placed in a high-fenced pasture and left there. After a few years, the white-tailed deer had all died out, but the sika population had increased dramatically. In the beginning, both species ate a lot of browse, but when all of the browse was eaten, as well as the forbs, the sika did fine living on grass. However, the white-tailed deer couldn’t survive.

So the existence of these exotics means they are in competition with both our native wildlife and, if livestock are on the same property, with livestock as well. It is essential, therefore, that the numbers of all three types of animals, livestock, native white-tailed deer, and exotics be controlled to within the carrying capacity of the land, or the health and productivity of the land and the animals will decline.

The most serious problem is that not all exotics have been/are being confined to their owner’s property, but have become feral (free-ranging) and are therefore damaging properties throughout the Hill Country. We have seen that controlling white-tailed deer numbers is difficult because hunting is not a very efficient or effective population control method, and we are now seeing the same problem with exotics.

The overpopulation of whitetailed deer and feral exotics is overbrowsing the Hill Country with the result that there are too few, if any, replacement hardwoods surviving to become mature. The diversity of the habitat is declining and the productivity is decreasing. Controlling these animal numbers is an important problem that has yet to be solved.

Until next time… Jim Stanley is a Texas Master Naturalist and the author of the books “Hill Country Ecology,” “Hill Country Landowner’s Guide” and “A Beginner’s Handbook for Rural Texas Landowners.” He can be reached at <jstmn@ktc.com>. Previous columns can be seen at <www. hillcountrynaturalist.org>, or at Riverside Nature Center at <https://riversidenaturecenter. org/past-blogs-from-a-friend/>.