Monday, March 29, 2010

Ant Mound Plants

Each spring, many of the ant mounds at Blue Jay Barrens take on a cloak of plants. Most of the plants are annuals that flower and produce seed early in the spring.

I haven’t found any evidence that the ants have any special relationship with these plants. As the ants expand their nest chambers, they bury the plants, but before they are completely buried, the plants mature and scatter a new generation of seeds on the mound. Many annuals colonize disturbed ground. I believe the ants just provide a continuing area of disturbed soil that perfectly suits the needs of the plants.

The spacing of the plants almost makes the mound appear to have been professionally landscaped. The plants must also enjoy a certain degree of protection by the ants. Anything unlucky enough to disturbed the plants would quickly be chased away or taken as food. The fallen seeds would also be protected and would benefit by being covered with soil excavated by the ants.

The most abundant plant on the mounds is this Perfoliated Pennycress, Thlaspi perfoliatum, a Eurasian species that has established itself across a wide area of North America. Although non-native, this species doesn’t seem to pose a threat to any native plant populations. At least it has the courtesy to display both fruit and flower at the same time, making identification much easier.

This is most likely Field Mustard, Brassica rapa, another non-native. This plant also requires disturbed ground in which to grow and is one of the plants responsible for turning broad areas of cropland fields yellow in the spring.

Oxeye Daisy, Chrysanthemum leucanthemum, is a non-native perennial that is defined by Ohio law as a noxious weed. This plant is found practically everywhere in Ohio, but the scary part is the fact that Ohio law allows county and township officials to enter onto private property to eradicate noxious weeds. I don’t know of any practical way to begin eliminating this species without also destroying the native plants growing with it and I doubt protecting natives would even be a concern of elected officials.

At last, here’s a native plant living on the ant mounds. This is Small-flowered Bitter Cress, Cardamine parviflora, another annual that thrives in disturbed soil. There are several native annuals that should thrive on the mounds and I wonder why I don’t see them here. Since my pot cultured Leavenworthia uniflora are promising to produce an abundance of seed, I think I’ll plant a bunch of the seed into one of the ant mounds and see what happens. It sounds like it out to work.

No comments:

Post a Comment