Cyclones, catchments and coastal streams: disturbing changes in macroinvertebrate assemblages over seven years — ASN Events

Cyclones, catchments and coastal streams: disturbing changes in macroinvertebrate assemblages over seven years (#93)

Judy N Davies 1 , Andrew J Boulton 1 , Darren Ryder 1
  1. University of New England, Armidale, NSW, Australia

In streams draining heavily forested subtropical catchments, leaf-eating macroinvertebrates (often termed ‘shredders’) play a vital role in organic matter dynamics and maintaining the ecological integrity of the in-stream ecosystem. Vegetation structure of the riparian zone of many forested streams along the eastern coast of Australia has now been modified by invasive plants (e.g. camphor laurel) and human activities such as urbanization and flood mitigation. Superimposed on these disturbances are droughts and cyclones, and flows that often fluctuate widely. Our study explored associations between aquatic invertebrate assemblage composition (especially shredders) and the changes in flow regime and riparian inputs over seven years in two subtropical streams with differing riparian zone history. Despite major differences in riparian structure and composition, and the impact of cyclonic floods (e.g. Cyclone Oswald that dumped 380 mm of rainfall in 48 hours), shredder densities and aquatic community composition remained remarkably consistent over the seven years and appeared to recover rapidly from pulse disturbances such as cyclone induced spates.

#ASFBASL2014