Abstract
The role of disturbance in maintenance of ecological dominance by Tetraphis pellucida Hedw. is examined in field studies and an empirical model. Patterns of compositional change in T. pellucida-dominated communities are summarized in a matrix of transition probabilities. Open substrate patches are most frequently replaced by asexual colonies which gradually change to the sexual state. Most sexual patches persist, or are overcome by competitors, but a significant fraction of the patches experience disturbance. A Markov model is used to predict the effects of varying disturbance frequency on the relative abundance of sexual, asexual, and senescent colonies, as well as on the success ofcompetitors. Experimental reduction in disturbancefrequency causes an increase in competitors and the local extinction of T. pellucida. Tetraphis pellucida maintains ecological dominance by exploiting frequently disturbed microsites. Its dual reproductive modes allow it to perpetuate itself by gemmae in frequent, local disturbances, and to escape to distant disturbances via spore production. Microhabitat preference ofT. pellucida for decayed stumps over adjacent logs may be correlated with differing disturbance frequencies. These findings suggest that disturbance may be an important selective pressure in maintaining dual reproductive modes in this species.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call