Spatial and temporal distribution of non-biting midge larvae assemblages in streams in a mountainous region in southern Brazil.
The spatial and temporal structure of non-biting midge (Diptera: Chironomidae) larvae assemblages and some environmental factors that affect their distribution were analyzed in a montane river and its tributaries in a temperate climate region of southernmost Brazil. In total, 69 taxa were recorded after four seasonal samplings (winter, spring, summer, and autumn). The dominant taxa were Rheotanytarsus sp. 1, Rheotanytarsus sp. 2, Cricotopus sp. 2, and Polypedilum (Polypedilum) sp., although dominance varied among the four sampling sites. The variations in dominance, abundance, and richness among the different sites were affected by environmental characteristics, such as the presence of marginal vegetation and a heterogeneous substratum, and also by human activities. Strictly environmental factors, such as altitude, and factors related to annual weather patterns, such as mean temperature and precipitation, influenced the spatial and temporal distribution of certain taxa and the structure of faunal assemblages. The influence of the riparian vegetation and riverbed heterogeneity on the composition, richness, and abundance of the chironomid larvae assemblages indicates that human activities, such as deforestation and the construction of dams, constitute a serious threat to the conservation of these insects and to the fauna that depends on them for food.
1 Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria. Faixa de Camobi km 9, 97105-900, Santa Maria, RS, Brazil.
Elzira Cecília Serafini
EC
Floss
Elisangela
E
Secretti
Carla Bender
CB
Kotzian
Marcia Regina
MR
Spies
Mateus Marques
MM
Pires
D000818:Animals; D058448:Biota; D001938:Brazil; D002683:Chironomidae / Q000254:growth & development / Q000502:physiology*; D004777:Environment; D007814:Larva / Q000502:physiology; D045483:Rivers; D012621:Seasons; D062206:Spatial Analysis