Friday, November 16th, 2012...7:12 pm
Foreign Invasion
Sometimes, going ‘global’ isn’t always a good thing. In fact, globalization wreaks havoc on the natural community.
Recently, a land manager told me that some places in Austin look more like China than Central Texas.
The sad thing is, he’s right. There’s a hoard of invasive species overtaking the landscape in Austin, especially on public lands, and it’s a huge beast to tackle. Plants like Japanese privet, Chinaberry and Chinese privet are all native to Asia, but came here after people decided that they looked pretty in their yards. These plants are known as ornamentals, and people plant them because they look nice. They also thrive in Austin’s winterless and favorable climate.
![Ligustrum](http://bloximages.newyork1.vip.townnews.com/hilltopviewsonline.com/content/tncms/assets/v3/editorial/e/f5/ef5089bd-46fb-576c-a3b5-7dc1f11bfc27/5050b0a1df808.image.jpg)
This tree is probably the great-grandmother of all ligustrum trees within a mile radius or so. It’s huge. It’s hard to tell, but that tree is full of luscious berries. Birds love that stuff.
In the area around St. Edward’s, Japanese and Chinese privet, also known as ligustrum, is of the greatest concern. It grows all over campus, and is the dominant plant species on the area of campus that is undeveloped and located in between the parking garage and I-35. It’s a lovely looking plant, but it’s also non-native and creates a lot of problems for the native species that are trying really hard to compete for resources like water, sunlight, and real estate, meaning a spot to grow.
Invasive species like ligustrum can be successful and thrive in new habitat for a number of reasons. In this case, ligustrum does really well because its seeds are encased in a small berry-like fruit that hangs in bunches from the branches. So it has a high-dispersal rate, as birds eat the berries and spread the seeds through their excrement. Ligustrum also grows quickly and can adapt well in different types of environments. For example, the tree pictured above is relatively large and looks like a typical tree. In a more untamed environment, ligustrum plants can grow very close together and have a more bush-like appearance.
All of the thin, spindly trunks located to the left and the right of the path are ligustrum plants. Notice how different they look from the large tree pictured in the first photo.
At Blunn Creek Nature Preserve, located across the street from the university, the City of Austin has been heading an ecological restoration project for about 6 years now. It was estimated that 60% of the woody species at the preserve were ligustrum at the beginning of the project. Now, I would bet that it’s still about 20%. But already the preserve looks drastically different.
At this particular location, ligustrum was crowding out the native grass species because it had the ability to grow so much taller and faster, thereby taking all of the light that would normally reach the ground. This led to a lot of erosion problems along the creekbank because there were no more grasses left to hold down the soil, only spindly ligustrum trunks that just don’t hold down the soil in the way that grass roots can.
The difficult thing is that St. Edward’s is right next door, and we’re not really doing much about our ligustrum problem. We’ve cut down a few trees here and there, for maintenance reasons, but we don’t exactly have any sort of initiative in this ‘fight’ against invasive species. The question is, should we? If the City of Austin is spending thousands of dollars trying to eradicate invasives from a nature preserve that was established by a Brother of Holy Cross from St. Edward’s University? Are we being a bad neighbor by not taking part in a restoration project of our own? I mean, we do plenty at Wild Basin, but why not right here at home?