Relative importance of carbon sources for macroinvertebrates in a Rocky Mountain stream

摘要: Estimates of carbon sources, as determined from ratios stable isotopes, were used in conjunction with estimates secondary production to determine the relative contribution algal macroinvertebrate across a gradient elevation Rocky Mountain stream (North St. Vrain Creek, Colorado). The was then compared availability carbon. Although accounted for less than 2‐40% combined sources organic matter North annual ranged approximately 40% at subalpine site nearly 80% more open foothills. Thus, proportional consumer greatly exceeded Creek. Despite disproportionate importance consumers, most macroinvertebrates Creek some vascular plant abundance terrestrial detritus shaded headwater streams has led ecologists conclusion that generally supports growth primary consumers small, streams. often is lower nutritional value other, abundant food (e.g., algae), microbial colonization and processing increase its (Cummins Klug 1979). Algae are known support desert streams; Minshall 1978), but it accepted canopied depend largely on Analyses gut contents consistent main source nutrition