The worst invasive plants are natives of warm climates — South America, mostly — and have limited tolerance to cold temperatures. Freezing temperatures kill them — particularly the floating plants such as hyacinth and salvinia.
“A good hard freeze can kill a lot more (invasive aquatic plants) than our crews ever could with herbicides,” [Howard Elder, of Texas Parks and Wildlife Department's inland fisheries division] said.
And East Texas, where water hyacinth and giant salvinia have established colonies that cover thousands of acres of water, got a good hard freeze this past week.
“It was down to 16 degrees, here. And it lasted for three days. There was ice everywhere. That’s going to help us a whole lot,” said Elder, based in Jasper.
The same thing can be said for the freeze’s impact on invasive fish species that have thrived, to the detriment of native fish, in some local waterways.
Bayous, streams and other waterways in and around Houston are infested with large and growing populations of invasive fish such as tilapia and armored catfish — species that compete with native fish and, in the case of armored catfish, burrow into banks and accelerate erosion.
Like the invasive plants, the invasive fish are natives of tropical or semi-tropical areas and can’t handle truly cold temperatures.
Every little bit helps. If only it had had the same effect on the mosquitoes.