Ecological Significance of Aquatic Macroinvertebrates in Headwater Streams

Headwater streams are the starting points of river ecosystems, that consist of an array of unique microhabitats. Most of these stream segments are first-order streams and these aquatic ecosystems provide habitats for many macroinvertebrates including arthropods, mollusks, annelids, nematodes, and turbellarians. These species play a significant role in maintaining the ecological integrity of the river ecosystem. Specifically, their feeding habits of scraping, collecting, shuddering, and predating make a significant contribution to maintaining stable food webs within the stream ecosystems. These macroinvertebrates are highly sensitive to environmental changes and consequently, they have been used as indicators of environmental quality. Although the aquatic macroinvertebrates play a crucial role in headwater streams, they face stresses caused either by nature itself or man leading to their extinction on certain occasions. Global warming, acidification, deforestation, forest fires, industrialization, intensive agriculture, and livestock farming practices have been identified as potential stresses behind the extinction and biodiversity losses of macroinvertebrates in headwater streams. Therefore, the abundance and distribution of macroinvertebrates in headwater streams need to be critically considered in developing criteria for development projects, agricultural practices, and other environmental management strategies to protect and conserve these unique environmental creatures.