The response of macroinvertebrate communities to habitat fragmentation

Abstract

Aquatic fragmentation may be characterized as a lack of connectivity between upstream and downstream populations or sites (Page et al. 1997). Fragmentation in stream ecosystems occurs when changes in the surrounding landscape (loss/modification of riparian zone vegetation) render the in-stream habitats unsuitable for aquatic organisms. Additionally, Page et al. (1997) suggest that organisms also can be impacted or fragmented by in-stream modifications (dams, bridges) that further eliminate usable aquatic habitat and prevent movement through the aquatic system.

Intact riparian zones are of utmost importance in maintaining a healthy aquatic environment. Riparian zones with abundant vegetative cover serve to shade the stream and prevent unusually high water temperatures. Furthermore, they aid in stabilizing the stream bank, thus reducing erosion and acting as a filter to remove topsoil, pesticides, and fertilizer that would otherwise enter the stream as water drains off the croplands (Page et al. 1997). In Illinois, when modifications in prevailing riparian vegetation occurs in a riverine system it can be expected to bring about changes in the physicochemical and biological nature of the aquatic system (Townsend et al. 1997).

This study was intended to determine 1) the relationship between habitat fragmentation and biotic integrity, as characterized by the invertebrate community, in a riverine system and 2) the amount of riparian zone connectiveness that is needed to maintain a diverse river basin. These findings may lead to new management strategies or changes in restoration protocols used for assessing riparian stream ecosystems.

Date of Award	2006
Original language	American English
Awarding Institution	Eastern Illinois University
Supervisor	Robert Fischer (Supervisor)