A Ramble at Wildflower Preserve 12.21.10

Folks continue to be extremely interested in an old golf course in Charlotte County, FL, now being transformed into a wildlife preserve. We had about 45 people on a nature walk this morning to ramble along the new trails and to look at the remarkable successional changes that have occurred within only about five years since the 78 acre golf course was abandoned. Here are a few interesting bits of natural history observed over several recent visits.

Evidence of foraging by armadillos is common although we do not often see the perpetrator (see photo). We found an aquatic turtle nest that was dug up and the eggs eaten, almost certainly by this persistent digging predator. Although armadillos see poorly, their sense of smell is keen and they are efficient predators on small creatures living in the top few inches of soil. You may not realize that armadillos appear to have been introduced into Florida and have a considerable adverse influence on the ecology of habitats where they forage. Yet there is no outcry to remove them or control their numbers, which would of course be impractical in any case.

While walking in this period of early winter it is interesting that a common and pleasant sound is the incessant buzzing of cicadas (see photo). This is a type of annual cicada, very different in its ecology from the so-called periodical cicadas, the most famous of which may only emerge as adults every 17 years. In this way they can maintain enormous population densities and suffer relatively little predation since they are only available as prey so infrequently. Their numbers during years of emergence are so astounding that their calls actually hurt your ears. The annual cicadas are present in contrast in tiny numbers, but they are found every year.

A poorly known insect to most people is the bagworm moth (see photo). The caterpillar protects itself by surrounding its body with a covering of cut parts of plants tied together with silk. If you are familiar with the aquatic larvae of caddisflies you will immediately recognize the similarity in habits in these two unrelated kinds of insects. Some other caterpillars may protect themselves with irritating spines or retain toxins from food plants; a protective armor made up of pieces of plants might seem an odd form of protection, but it works. Bagworms may sometimes damage plantings, but this one was on dog fennel which is a common weed.

In one of many small constructed ponds I have noticed blue crabs foraging along the edges (see photo). This shows that there is a connection with tidal Lemon Creek, allowing planktonic crab larvae to enter the ponds and grow up in a relatively protected sanctuary, since large fish cannot enter. The water is stained a dark brown but is clear, indicating the presence of dissolved tannins likely derived from the mangrove leaves and bark. This is why “red” mangroves are so named- they have a layer of tannins under the bark. Tannins are phenolic compounds that inhibit the digestion of proteins in the gut of insects and thus protect against herbivory. They are most common in watersheds that are low in dissolved nutrients where plants have a strong incentive to protect their leaves from herbivores. Blue crabs are one of the most important, common (and tasty!) specialized estuarine predators that can tolerate wide fluctuations in salinity. They illustrate the ecological principle that estuaries are low in biodiversity, but can be high in biomass of the few species that are tolerant of the highly variable physical and chemical conditions.

It is interesting that there are common moorhens at Wildflower, especially in the “green ponds” with a surface covering of floating duckweed. I am guessing that the difference between the green and clear ponds is that secondary sewage effluent is flowing selectively through the green ponds from an adjacent treatment plant. Now moorhens have become rather scarce in many places in Florida in recent years (such as Myakka State Park), apparently due to competition from an enormous increase in exotic blue tilapia, that eat the floating vegetation with included invertebrates favored by moorhens. It seems that ponds enriched with nutrients from human sources may be able to maintain some moorhens (and coots), perhaps due to an excessive and unnatural production of food for both birds and fish. So this seems to be a case where mild nutrient pollution may be beneficial to some species.

I continue to find inspiration among the forgotten fairways of the former Wildflower Golf Course. Nature is reasserting herself and this provides hope for the future not only of Wildflower Preserve but of many habitats severely degraded by human activities.

Bill Dunson, Englewood, FL & Galax, VA
wdunson@comcast.net