Lurking in the Litter

One of the most important but least appreciated aspects of a good yard wildlife habitat is the ground surface. Most people would consider this the proper place for grass or to be kept swept clean of debris. However to have healthy wildlife habitat in your yard you must have a substantial litter layer. This provides habitat for a community of critters, both invertebrate and vertebrate that add biodiversity and interest to your yard and provide foraging territory for birds (such as a hermit thrush which spent the winter in our yard). Whereas the average yard would be kept clean of leaves with mulch around flower beds, our yard is surrounded by broad areas of leaf litter, with leaf mulch around shrubs and flowers. Leaves have substantial advantages over commercial mulch, especially the much-touted melaleuca variety. They provide natural food and cover for a wide variety of creatures, whereas exotic mulch may be quite sterile.

Let’s look at some critters found in our Florida yard leaf litter. My favorite is the giant whip scorpion or vinegaroon which is not uncommon on Manasota Key. It lives in shallow burrows under debris and while scary looking is harmless, unless you are a small roach or cricket. It catches small creatures with a downward movement of its two fearsome pincers, but unlike its arachnid relative the true scorpion, has no venom- only a gland that sprays vinegar or acetic acid from the base of its whip-like “tail.”

A neighboring invertebrate predator of the litter is the southeastern five-lined skink which has a bright blue tail when young. These blue-tailed skinks apparently have such an advertisement for two purposes- first to direct the attack of a color vision predator (birds) towards the tail which can be broken off to allow the lizard to escape, and second to warn predators of a toxin. Although the toxic nature of such skinks has long been known in woods folklore (large skinks are called scorpions in many areas of the south), it is only recently that herpetologists have known that these skinks are toxic to predators and cats have been known to become paralyzed after eating one. But blue is such an unusual color to have been selected for this purpose since red is the typical warning coloration for toxicity (for example the red eft stage of the newt or coral snakes).

Another lizard which resembles a snake since it has no legs is the so-called glass lizard which has a very long tail which will break off when a predator attacks. But you can see that it is a lizard since it has tiny external ears, eyelids, a rigid body, and a tongue characteristic of lizards. This invertebrate predator “swims” in the litter and hunts its invertebrate prey.

An exotic snake which few people are aware of has made its entry to Florida in the dirt of imported potted plants. This Brahminy “blind” snake has much reduced eyes and lives in the litter or surface dirt layer and feeds on invertebrates. It resembles a worm and only upon closer inspection can you see that it has scales and a snake tongue.

These are just a few of the marvelous inhabitants of the unseen world of the litter. They are all beneficial in maintaining a balance among the sometimes obnoxious ground-living invertebrates that enter our houses and make themselves unwelcome. I find that the best defense is a line of invertebrate and vertebrate predators which act as biocontrol agents and add considerable interest to the biodiversity of wildlife in our yards.

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