2022/12/02 by Duke, Samuel, Kaare-Rasmussen, Jakob, Tan, Skylar +1
#artificial stream #invertebrate #invertebrate drift #macrophyte #stream health
paper · doi:10.21973/n37d44
Macrophytes, or aquatic plants, are generally associated with high invertebrate abundance because they provide invertebrates with high quality habitat. Macrophytes also change other local abiotic aspects of a stream, like flow rate. It remains unclear what the direct effects of macrophytes on invertebrates are, when other abiotic changes are controlled for. In this study we used the Sierra Nevada Aquatic Research Laboratory replicate stream channels to study the effects of macrophytes on invertebrates within stream pools. We collected and counted invertebrates from 30 unmanipulated stream sites and estimated the macrophyte cover. We also added macrophyte cover to 12 stream sites and removed macrophyte cover from 12 stream sites and collected and counted the invertebrates from these sites after two days. We found no difference between unmanipulated sites with high macrophyte cover (>35%) and low macrophyte cover (<35%). We also found no difference between sites where macrophytes were removed and sites where macrophytes were added. Furthermore, there were significantly more invertebrates in unmanipulated sites than in manipulated sites. This finding contradicts many previous studies regarding the relationship between macrophytes and invertebrates, demonstrating the limitations of generalizing these patterns across streams and to all seasons. This study also demonstrates the need to better understand drift on the interface between natural and concrete streams.