The objective of this study was to evaluateudthe response of stream diatom assemblages to changesudin water quality in different land-use settings. Waterudquality sampling and benthic diatom community dataudwere collected in April and September 2013 at 95udsampling stations in the Manyame Catchment, Zimbabwe.udThe data collected were subjected to multivariateudstatistical techniques; CCA and clusterudanalysis to determine environmental gradients alongudwhich the diatom species were distributed as well as toudelucidate hypothesized differences in communityudstructure per land-use type. Three land-use categoriesudwere identified in this study: commercial agricultural,udcommunal agricultural and urban-mining areas inudorder of increasing human disturbance. No significantuddifferences in physical and chemical variables wereudrecorded between the two sampling periods. Studyudsites were grouped into roughly three broad categoriesudbased on CCA and cluster analysis. As pollution increased, low to moderate pollution tolerant speciesudsuch as Cocconeis placentula, Surirella linearis andudSurirella robusta were replaced by high pollutionudtolerant species such as Pinnularia braunii, Tryblionellaudcoarcata, Luticola goeppertiana and Stauroneisudsmithii. This shows that diatom assemblages areudpotential indicators of changes in water quality due toudchanges in catchment land-use.
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