Effects of disturbance and a dominant consumer on stream community assembly: Experimental and observational evidence

• Main Author: Martin, Haley Marie
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2012
• Subjects: Ecology; Environmental science; Hydrologic sciences; Limnology
• ISBN: 9781267882141; 126788214X

Without understanding changes in aggregate and compositional properties, it is possible to misinterpret mechanisms driving community variability. Changes in patterns of variability can be caused by independent and interactive effects of biotic and abiotic drivers. In an experimental study, I manipulated the presence of a dominant detritivore (P.gentilis) and disturbance (drying). I found that disturbance lowered aggregate variability and the presence of P.gentilis lowered compositional variability, but only in the absence of disturbance. In an observational study, I created an index describing relative likelihood of disturbance (system-level drought) for multiple watersheds and tested the impacts of the likelihood of disturbance and the presence of P.gentilis on aggregate and compositional variability. Disturbance tended to increase aggregate variability and decrease compositional variability, but only in the absence of P.gentilis. The results of both studies indicate that there may be an interaction between biotic and abiotic drivers that can significantly change community dynamics.