Robust Lancetooth: A Furtive Keystone?

By Bruce G. Marcot, Ecology Picture of the Week:

Here is a most common snail of forests and gardens in western North America ... the "robust lancetooth," named after a characteristic of its radula or the rasplike mouth structure found in most mollusks.  

This snail is easily overlooked but is relatively common underfoot.  Its coloration helps it blend into the forest floor, thus making it furtive or hidden and secretive.  In fact, many mollusks and arthropods constitute furtive but ecologically important components of biodiversity and forest ecosystems.

This little snail -- usually no longer than about 21 mm (0.8 inch) -- is actually a predator, preying upon other snails.  Thus, it can be a friend to gardeners ... but also, along with other furtive species, it likely plays a key role in the upper parts of the trophic food chain in forest floor ecosystems.  

In fact, this species might be a keystone in the sense of its effect on maintaining populations of its prey species.  This is largely unstudied in forests, but we know that marine snails play keystone roles in intertidal and subtidal oceanic ecosystems. 

We tend to study large, charismatic wildlife such as elephants and monkeys and falcons, whereas the tiny, furtive, and uncharismatic life forms may be the real keystones to ecosystem function and health. 

  --Bruce G. Marcot

Image and text © Bruce G. Marcot, Ph.D. Research Wildlife Ecologist,
who produces the Ecology Picture of the Week website.