Resource Division in an Understory Herb Community: Responses to Temporal and Microtopographic Gradients

Abstract

Although light and other environmental factors may be important to the distributions of understory species, microtopography is probably the major influence on the occurrence of clumps of the dominant herbaceous species [Phacelia, Dicenta, Dentaria, Erythronium, Stellaria, Osmorhiza, Caulophyllum, Laportea, Cimicifuga, Sedum, Mitella, Hepatica, Dryopteris, Polystichum, bryophytes] in the Cove Forest plot at Porters Flat [Tennessee, USA]. Microtopography and seasonal change are responsible for much of the niche differentiation between the herbs and thus largely account for the species diversity of this rich herb stratum. Species present at different seasons show similar responses to microtopographic factors. Therefore these species may be grouped into guilds, and the distributions of species in relation to 2 distinct resource gradients may not be independent.