By Bill Ward
Published in The Boerne Star on December 24, 2002
“Take Only Photos; Leave Only Footprints” is a familiar admonition at state and national parks and nature preserves. Do not disturb Nature; let it take its own course. Is that really being a good steward of the land?
Dr. Steven Windhager, Director of Ecological Reconstruction at the Lady Bird Johnson National Wildflower Center, urges that we reconsider that way of “protecting” the natural environment.
Certainly, in many places we want to leave Nature undisturbed to prevent further loss of natural habitat, the world’s leading cause of decrease in biodiversity. However, sometimes Nature can use our help in maintaining the natural ecology.
This is true because for thousands of years man has played an insidious trick on Nature.
We have introduced many species into areas where they do not occur naturally. Some of these exotic species inevitably upset Nature’s balance, to the detriment of indigenous species. Ecologists tell us that the second leading cause of decrease in biodiversity is the spread of exotic species. Sometimes it is the invasion of exotic species, not destruction by man, which destroys the natural habitat. In those cases, perhaps we can step in to help alleviate the problem. If we do nothing, will we be pleased with the course Nature takes on its own? Probably not.
The Cibolo Nature Center is a local example of where invasive exotic plants are interfering with the attempt to preserve the natural setting for future generations. Chinese tallow, ligustrum, chinaberry, Japanese honeysuckle, and periwinkle (vinca) are competing with native species in the riparian habitat along Cibolo Creek.
In some spots the invasive exotics are winning the competition. When the non-native plants take hold, it is not only the native-plant population that is changed. Also, the birds, mammals, reptiles, insects., even soil microbes are affected.
When native vegetation is reduced along a stream, there are likely to be physical changes in the system too.
For example, loss of native plants could cause increased erosion of the banks, thus increasing flood damage and possibly creating stream-flow problems.
At any rate, removal of exotic species along Cibolo Creek might help preserve, or even restore, the riparian habitat.
On Dec. 14 a large group of members of the Boerne Chapter of the Native Plant Society of Texas, Master Naturalists, and other volunteers from the Boerne community enthusiastically cooperated in cutting down exotic plants from the banks of Cibolo Creek.
We treated the stumps with a systemic herbicide (an ecologically safe one) and mapped the stumps for future monitoring.
The invasion of alien species along the creek is worse than I thought. In two and a half hours, the teams of volunteers cut down 36 Chinese tallows, 81 ligustrums, and six chinaberries. And that was in only a little more than half a mile of creek along one bank, only one-quarter of the total creek bank on Cibolo Nature Center land.
Several tallows had trunk diameters of 6-8 inches; one was over a foot in diameter. Several ligustrums were 6-10 inches in diameter, and all the chinaberries were large trees.
Those large exotics were crowding out a lot of the canopy space. Numerous smaller tallows and ligustrums were the dominate understory vegetation in several places. As fast as Chinese tallow and ligustrum grow, I can visualize a creek trail in the near future leading through dense thickets of nothing but ligustrum and tallow. Not a pretty vision. The natural vegetation is so much prettier and diverse.
I think we did Mother Nature a big favor on Dec. 14. We took more than photos, and we left more than footprints. And we’ll do it again Jan. 11. Everyone is invited to help. Call Suzanne at (830) 249-4616.
