BENTHIC INVERTEBRATES IN A NORTH‐FLOWING STREAM AND A SOUTH‐FLOWING STREAM, BROOKS RANGE, ALASKA¹

Abstract

Benthic invertebrate faunas were compared to two fifth‐order streams, the Atigun River flowing northward and the Dietrich River flowing southward. Sixty‐eight taxa were collected, forty‐nine from each stream. Aquatic insects comprised 88% of the taxa and 97% of the individuals from the Dietrich River and 73% of the taxa and 97% of the individuals from the Atigun River. Diptera, especially Chironomidae, were most abundant. Plecoptera, Ephemeroptera, Oligochaeta, Acarina, and Collembola were significant. In both streams the headwaters were dominated by the subfamily Diamesinae which was replaced by Orthocladiinae downstream. Diversity seemed to increase with stream order. Cluster analysis showed a high degree of resemblance between the benthic faunas of the rivers. Faunal resemblance decreased with increasing distance between stations, both within and between the streams. Although some taxa may occur in only one stream, the evidence for faunal resemblance is stronger than for faunal differences. Other studies have shown that differences in total radiation associated with valley aspect affect local climate, hydrology, and distribution of terrestrial plants and animals. However, the benthic faunas of Atigun and Dietrich Rivers were remarkably similar. Factors which operate independently of aspect, possibly freezing solid in winter, may control the occurrence of species in these streams.

Characteristics of Lotic Ecosystems and Consequences for Future Research Directions

“…(After data from Baumgartner and Reichel 1975;Czaya 1981;Forge et al 1977;Kopelke 1981;Lehmann 1979;MJ. MUller 1979;Ringe 1974;Sandrock 1978;Slack et al 1979;Statzner 1976;Zwick 1976;and pers. observations) ties.…”

Classification of Wetlands and Deepwater Habitats of the United States

“…Examples of Dominance Types for the Marine and Estuarine Systems are the mussels Modiolus and Mytilus, the brittle star Amphipholis, the soft-shell clam Mya, and the Venus clam Saxidomus. Examples for the Lacustrine, Palustrine, and Riverine Systems are the midge Diamesa, stonefly-midge Nemoura-Eukiefferiella (Slack et al 1977), chironomid midge-caddisfly-snail Chironomus-Hydropsyche-Physa (Krecker and Lancaster 1933), the pond snail Lymnaea, the mayfly Baetis, the freshwater sponge Eunapius, the oligochaete worm Lumbriculus, the scud Gammarus, and the freshwater mollusks Anodonta, Elliptio, and…”

“…Dominance Types for Rock Bottoms in the Marine and Estuarine Systems were taken primarily from Smith (1964) and Ricketts and Calvin (1968), and those for Rock Bottoms in the Lacustrine, Riverine, and Palustrine Systems from Krecker and Lancaster (1933), Stehr and Branson (1938), Ward and Whipple (1959), Clarke (1973), Hart and Fuller (1974), Ward (1975), Slack et al (1977), and Pennak (1978).…”

Initial Quantification of Suspended Sediment Loads for Three Alaska North Slope Rivers

“…Vegetation in the foothills includes sedges, dwarf shrubs, and willows, and some alders along the river valleys [23]. In the mountains, no vascular vegetation is found at elevations over 900 m; at these elevations, the vegetation mat is mainly lichens and sedges, and the plant cover is open [24].…”