Terrestrial invertebrates: functional roles in ecosystems and utility as vital signs in the Sierra Nevada

Holmquist, PhD, Jeff

The Sierra Nevada Network initiated an agreement with White Mountain Research Station to assess invertebrates as indicators of meadow change. Meadows are of high interest for monitoring as they concentrate resources, provide critical habitat for both resident and transient animals, and have been identified as key ecosystem elements in the Sierra Nevada Network parks. A powerful indicator of the status of meadow ecosystems is found in the invertebrate assemblages that use meadows for all or part of their life cycles. Meadow invertebrates are potentially ideal candidates for monitoring, because these animals 1) include representatives of several trophic levels and are important food resources and processors of organic material, 2) represent a “crossroads” for ecological flows, e.g., aquatic-terrestrial, 3) are easy to sample quantitatively, and 4) are sensitive to a variety of stresses and in turn are capable "vectors" for cascading disturbances. This report will describe some of the ecosystem roles, utility as vital signs, and functional responses of invertebrates, or as E.O. Wilson describes them, “the little things that run the world” (Wilson 1987). Some sections will emphasize our research group’s current efforts, in part because relatively little is known about some invertebrate processes in the Sierra and other alpine meadow systems.