Habitat descriptions are provided in survey reports. G. angulata occur in streams of all sizes and less frequently in lakes. They are found mainly in low to mid-elevation watersheds. They often share habitat with M. falcata throughout much of the Pacific Northwest, but their range rarely extends into high elevation headwater streams where M. falcata may occur. Like other stream-dwelling species, they are more common in stable stream reaches and tend to avoid areas with shifting sediments or areas prone to scour or frequent dewatering. However, G. angulata seem to be more tolerant of fine sediments than M. falcata and may occupy depositional habitats and banks. For example, in the Salmon River, Idaho, where both species co-occur, G. angulata dominated in sand and gravel bars, comprising 97.1 percent of overall mussel density, but in more stable, boulder-dominated reaches nearby, M. falcata comprised 94.9 percent of overall mussel density. Thus, distinct habitat preferences allow for habitat partitioning in streams where M. falcata and G. angulata co-occur. Unlike M. falcata, G. angulata also occurs in impoundments and natural lakes, including nutrient-rich waterbodies and in soft substrates to water depths of ten feet.
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