Environment shapes invertebrate assemblage structure differences between volcanic spring-fed and runoff rivers in northern California
AffiliationUniv Arizona, Sch Nat Resources & Environm
Keywordsvolcanic spring-fed rivers
MetadataShow full item record
PublisherUNIV CHICAGO PRESS
CitationEnvironment shapes invertebrate assemblage structure differences between volcanic spring-fed and runoff rivers in northern California 2016, 35 (3):1010 Freshwater Science
Rights© 2016 by The Society for Freshwater Science.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractFlow variability plays an important role in structuring lotic communities, yet comparatively little is known about processes governing assemblage dynamics in stream ecosystems with stable environmental conditions, such as spring-fed rivers. Volcanic spring-fed rivers (hereafter spring-fed rivers) occur in geologically active landscapes of the western USA and around the globe. We sampled invertebrate assemblages and quantified primary productivity and habitat characteristics of spring-fed and runoff rivers in northern California over 4 seasons. We predicted that abiotic factors would be more stable and nutrient availability greater and that invertebrate density would be greater and diversity lower in spring-fed than in runoff rivers. Runoff rivers exhibited high variability in discharge and temperature, whereas spring-fed rivers were relatively stable with high naturally occurring nutrient levels. On average, NO3- and PO43- concentrations were 40x greater in spring-fed than in runoff rivers. Spring-fed rivers supported nearly 7 to 16x greater densities of invertebrates than runoff systems, depending on season. However, invertebrate species richness was greater in runoff rivers in all seasons. Spring-fed river invertebrate assemblages were strongly correlated with elevated nutrient concentrations and basal C sources, whereas runoff assemblages were associated with discharge variability and median substrate size. We suggest that strong differences in abiotic variability between spring-fed and runoff rivers play an important role in determining invertebrate assemblage structure. Because spring-fed rivers exhibit more stable temperatures throughout the year and lower temperatures during the summer than runoff rivers, they may provide essential refugia for coldwater taxa in a warming climate.
NoteONLINE: May 04, 2016
VersionFinal published version
SponsorsUS Bureau of Reclamation