Acid-tolerance
Guides
Cambarus bartonii bartonii
Common Crayfish
Cambarus bartonii bartonii is a subspecies of freshwater crayfish native to eastern North America. It is a secondary burrowing species found in streams and other aquatic habitats, with documented physiological tolerance to acidic conditions. The subspecies exhibits agonistic behavioral contests between males, particularly during reproductive periods when males adopt Form I morphology with enlarged claws. It has been observed using terrestrial microhabitats for overwintering.
Cambarus robustus
Big Water Crayfish, robust crayfish
Cambarus robustus, commonly known as the Big Water Crayfish or robust crayfish, is a freshwater crayfish species in the family Cambaridae. It is native to eastern North America, ranging from several U.S. states to Ontario, Canada. The species has been studied extensively as a surrogate for federally endangered crayfish species due to its close phylogenetic relationships and similar ecological requirements. Research indicates it demonstrates significant acid tolerance compared to sympatric Orconectes species, exhibits complex agonistic behaviors with distinct initiation acts predicting contest outcomes, and occupies a partitioned trophic position in multi-species crayfish communities.
Paracapnia
small winter stoneflies
Paracapnia is a genus of small winter stoneflies in the family Capniidae, native to North America. The genus contains at least five described species, including the angulate snowfly (Paracapnia angulata) and the northeastern snowfly (Paracapnia opis). Members of this genus are notable for their tolerance of acidic stream conditions, with some species increasing in abundance in waters affected by acid precipitation.
Paracapnia angulata
angulate snowfly
Paracapnia angulata is a small winter stonefly in the family Capniidae. The species occurs in headwater streams across eastern North America, with documented populations in Appalachian streams affected by acid precipitation. Research indicates it tolerates a wide pH range (4.5–7.5) and can achieve high secondary production in acidic conditions due to increased abundance and biomass, despite lower individual growth rates. Nymphs serve as prey for steelhead trout.