The influence of catchment geology on the longitudinal distribution of macroinvertebrate assemblages in a groundwater dominated river
✍ Scribed by C. E. Cannan; P. D. Armitage
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 219 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0885-6087
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✦ Synopsis
Macroinvertebrate fauna were collected from 15 reaches along the length of the River Frome, a lowland groundwater-dominated river in Dorset, southern England. The Frome arises in Upper Greensand and Gault Clay before ¯owing through Chalk and ®nally Tertiary deposits of gravel and sand. Sampling took place in the summer of 1995 and identi®cation was taken to family level. The relation between longitudinal changes in the faunal assemblages and geology in the catchment was examined using multivariate methods. A preliminary classi®cation of all sites was carried out using TWINSPAN analysis. The 15 sites separated into four distinct groups with all three replicates from any one site always found in the same group. Group I (comprising only the headwater site) and Group IV were associated with the mixed Upper Greensand geology, Group II with Chalk and Group III with the Tertiary gravels. These data were supported by a separate correspondence analysis and would appear to show a pattern between geology in the catchment and the distribution of fauna. However, because the geological changes along the Frome valley occur sequentially downstream, it is not possible to separate geological eects from factors related to position downstream.