Results
Stream temperatures varied across habitats based on latitude and elevation, as expected (Figs. 1, 2). Maximum stream temperatures were lower at latitudes above than latitudes below 35°N, but minimum stream temperatures were similar across latitudes (Fig. 1, Table 1a,b). Thermal breadths were lower at latitudes above compared to latitudes below 35°N (Fig. 1, Table 1c). We did not observe broad categorical elevation trends with any stream temperature metric (Fig. 2, Table 1 d.e, and f ). Importantly, geographic information was not included for 74.8% of totaln = 229 records of stream maximum and minimum temperatures and calculated thermal breadths (Figs. 1, 2). Maximum stream temperature and thermal breadth were linearly related to habitat elevation (Fig. 3a Table 2 s), whereas minimum stream temperature was not related to elevation (Fig. 3a, Table 2). In contrast, stream latitude was not linearly related with any stream habitat temperature variable (Fig. 3b, Table 2).
We found that habitable maximum temperatures varied across voltinism and among functional feeding guilds of species (Table 3, Figs. 4a-4c). Specifically, multivoltine taxa had higher maximum stream temperatures than univoltine and semivoltine taxa (Fig. 4a). Collector-gatherers tended to have higher maximum stream temperatures (Fig. 4b), however, effects of stream temperature among taxonomic Order were not clearly evident (Fig. 4c, Table 3, 4). We detected significant interactions among voltinism and feeding guilds (Table 3), however, we did not detect differences in maximum temperatures and thermal breadth among interactions with functional feeding guilds, voltinism, or taxonomic Order (Figs. 4a-4c).