Birds and stream quality

Posted on March 4, 2011

The ecological quality of stream environments is typically assessed using condition indices that reflect bed and bank stability, habitat structure, and the diversity and abundance of instream organisms such as macroinvertebrates and fish.  Riparian bird communities have been used less often as indicators of stream condition, even though bird surveys are more cost-effective than other biotic indicators of stream quality and the fact that birds are sensitive to terrestrial processes that affect the instream environment.  To explore relationships between community patterns and ecological processes, data on riparian birds, stream macroinvertebrates and local land-use were collected from 37 stream reaches in centralItaly.  Published information was used to classify bird species by functional traits related to life-history, breeding and feeding.  Multivariate analysis revealed that bird species in disturbed habitats tended to feed on plants and breed in herbs or shrubs, while species in less modified habitats tended to be smaller, feed more on insects and other small animals, and breed in trees.  There was a close correlation between bird-based indicators of stream condition and a standard macroinvertebrate-based index of biotic integrity.  Because birds occupy a number of niches and habitats, riparian bird communities respond to the effects of land use over a range of spatial scales, and the high mobility of birds makes them rapid indicators of disturbance. 

Reference:  Larsen, S., Sorace, A. & Mancini, L.  2010.  Riparian bird communities as indicators of human impacts along Mediterranean streams.  Environmental Management 45, 261–273.