Temperature threshold models for benthic macroinvertebrates in Idaho wadeable streams and neighboring ecoregions

Abstract

Water temperatures are warming throughout the world including the Pacific Northwest, USA. Benthic macroinvertebrates are one of the most important and widely used indicators of freshwater impairment; however, their response to increased water temperatures and their use for monitoring water temperature impairment has been hindered by lack of knowledge of temperature occurrences, threshold change points, or indicator taxa. We present new analysis of a large macroinvertebrate database provided by Idaho Department of Environmental Quality from wadeable streams in Idaho that is to be used in conjunction with our previous analyses. This new analysis provides threshold change points for over 400 taxa along an increasing temperature gradient and provides a list of statistically important indicator taxa. The macroinvertebrate assemblage temperature change point for the taxa that decreased with increased temperatures was determined to be about 20.5 °C and for the taxa assemblage that increased with increased temperatures was about 11.5 °C. Results of this new analysis combined with our previous analysis will also be useful for others in neighboring regions where these taxa occur.

Identifying Key Stressors Driving Biological Impairment in Freshwater Streams in the Chesapeake Bay Watershed, USA

“…In the absence of any other stressors (contaminants, flow alteration, etc. ), rising stream temperatures due to climate change is a likely stressor for cold-water dependent benthic organisms (Richards et al 2018 ; Rice and Jastram 2015 ) and may also cause shifts in benthic community composition in reference streams across the region in the future.…”

“…Leveraging common study designs that are more likely to provide evidence needed to support stressor identification is also necessary (Orr et al 2020 ). For example, studies following stressor gradients facilitate the identification of ecological thresholds for individual stressors (Richards et al 2018 ). Complicating these studies, however, is often the presence of multiple stressors along the same gradient (for example, Yuan et al 2003 ) and more work is needed to explicitly test for stressor interactions in gradient-based studies (Kreyling et al 2018 ).…”

A method for evaluating sediment-induced macroinvertebrate community composition changes in Idaho streams

“…Samples were collected with a 500 µm mesh Hess sampler and composited and preserved with ≥70% ethanol in the field. Samples were identified to the lowest practical taxonomic level (typically to genus or species) and enumerated by EcoAnalysts Inc. following methods described in Richards et al (2018). The same laboratory and methods were used across years.…”

Analysis of the Spatio-Temporal Variation of the Thermal Pattern of River Ganges in Proximity to Varanasi, India

“…In recent times, climate change has been a concern for the environmentalist in the global arena. With the rise in the temperature globally, the water temperature is also warming worldwide (Richards et al, 2018 ; Schindler, 2001 ; Sinokrot et al, 1995 ). Some degree of global warming seems to be inevitable due to the climate change in the environment.…”