East Texas Naturalist Blog

Earlier this year, a group of volunteers from the Cypress Basin chapter of the Texas Master Naturalists helped distribute weevils in an effort to combat the invasive giant salvinia on Caddo Lake.

Under the direction of Lee Eisenberg, 45 large plastic totes were filled with weevil-infested salvinia from the Morley Hudson Greenhouse, loaded onto several boats then transported to Willowson's Woodyard where they were released.

The empty totes were then filled with fresh salvinia to replenish the greenhouse supply where weevils continue to reproduce.

During this time of year, some of us are eager to see more green in the rather barren east Texas woods of winter.  Sometimes the green we see is not as welcome as we might first believe. While there are many pleasant shades of green out there that come from several types of evergreen trees and vines, there is one shade of green that my eye is particularly trained upon: Japanese Climbing Fern.  

The Japanese Climbing Fern is native to Asia and tropical Australia.  Like many other invasive species, it was introduced here due to its striking appearance and its ease of cultivation in local gardens.  After its introduction in the 1930's, it became a very popular garden addition.  Unfortunately, while it may make a particular corner of a garden "pop" with its striking leaves and healthy growth, its escape into our natural habitats can be disastrous.  Japanese Climbing Fern can form dense mats, twining and climbing over anything in its way: trees, shrubs, telephone poled, etc.  The dense growth shades out native species and reduces diversity in a habitat.  

Being a fern, it does not produce a flower and does not reproduce via seed.  It thrives and colonizes by rhizomes and spreads rapidly by wind dispersed spores.  Those tiny powder-like spores are dispersed not only via the wind but also by any conveyance they can hitch a ride including the mud in your shores, your clothing, your pets and, of course, with free roaming wildlife.  Another way it is moved from place to place is in pine straw bales used for mulching your landscape. That is another reason you should insist that any pine straw used to mulch your beds be weed free.  You should be leery of what pine straw mulch may bring into your garden as several non-native invasive species can travel the U.S. in these bales.

I wrote recently about all of the water hyacinths that were appearing in large clumps all over the lake after recent heavy rains.  The heavy rains caused the lake level to rise rapidly causing the lighted moored water hyacinths to break loose and float downstream.  Many people who lived in the south part of the lake were not used to seeing these floating islands and some were not sure what was happening. 

If they were really surprised by the large number of plants that floated down, just wait.  Right now there is approximately 5 or 6 acres of water hyacinths pressed up against the Highway 155 bridge.  Little by little they are squeezing through and floating downstream as the ones a couple of weeks ago did.  This time, after the recent rain last week that caused the lake to rise another five or more feet, there are many more water hyacinths headed their way.

We may get a good cold front that could slow the progress for the plants do not do well in cold weather.  With prolonged times of freezing weather, much of the mass of plants may sink below the surface and not continue its migration.  Many of those growths will actually die in the deeper water.  If we do not get the cold weather, then these plants will eventually make their way under the bridge.  Winds and boat traffic will free the "logjam" that now exists.  

No, this is not a joke.  

It does show once again the dangers that arise with the importation of non-native species. Far too often, with no natural predators, their populations get out of control and the damage they do to the local ecosystems can be devastating. 

 The article below is from the Houston Chronicle.  http://www.chron.com/sports/outdoors/article/Warthogs-invade-South-Texas-6671689.php 

Within the past couple of weeks, Lake O' the Pines has been inundated with clumps of floating plants.  Some of these clumps are more like floating islands, up to twenty feet across.  Most are smaller a foot or two up to three of four feet across but there are so many of them.  It is astounding.  Some old time residents said they had never seen anything like it here before.

So what are all these clumps of plants and where did they come from?  

It turns out that they are water hyacinths, Eichornia crassipes, and are an invasive species native to tropical and sub-tropical South America.  These plants are one of the worse invaders in many countries through out the world.  They were widely introduced in North America, New Zealand, Africa, Asia and Australia.  In many areas they caused serious damage.