Land use and the ecology of benthic macroinvertebrate assemblages of high‐altitude rainforest streams in Uganda

Abstract

1. In sub-Saharan Africa, tropical forests are increasingly threatened by accelerating rates of forest conversion and degradation. In East Africa, the larger tracts of intact rainforest lie largely in protected areas surrounded by converted landscape. Thus, there is critical need to understand the functional links between large-scale land use and changes in river conditions, and the implications of park boundaries on catchment integrity. 2. The objective of this study was to use the mosaic of heavily converted land and pristine forest created by the protection of the high-altitude rainforest in Bwindi Impenetrable National Park, Uganda to explore effects of deforestation on aquatic systems and the value of forest in buffering effects of adjacent land conversion. A set of 16 sites was selected over four drainages to include four categories of deforestation: agricultural land, deforested upstream (of the park boundary), forest edge (park boundary) and forest. We predicted that forest buffer (downstream or on the edge) would moderate effects of deforestation. To address this prediction, we quantified relationships between disturbance level and both physicochemical characters and traits of the macroinvertebrate assemblages during six sampling periods (February 2003 and June 2004). 3. Results of both principal components analysis and cluster analyses indicated differences in limnological variables among deforestation categories. PC1 described a gradient from deforested sites with poor water quality to pristine forested sites with relatively good water quality. Agricultural sites and deforested upstream sites generally had the highest turbidity, total dissolved solids (TDS), and conductivity values and low transparency values. Forest sites and boundary site groups generally exhibited low turbidity, TDS, and conductivity values and high water transparency values. Sites also clustered according to deforestation categories; forest and forested edge sites formed a cluster independent of both agricultural land and deforested-upstream. 4. Water transparency, water temperature, and pH were the most important factors predicting benthic macroinvertebrate assemblages. Sensitive invertebrate families of Trichoptera, Ephemeroptera, Plecoptera, and Odonata dominated forested sites with high water transparency, low water temperature, and low pH while the tolerant families of Ephemeroptera, Diptera, Hemiptera, and Coleoptera were abundant in agriculturally impacted sites with low water transparency, high water temperature, and high pH. 5. This study provides support for the importance of riparian buffers in moderating effects of deforestation. Forest and forested edge sites were more similar in both limnological and

Understanding the Impact of Intensive Horticulture Land-Use Practices on Surface Water Quality in Central Kenya

“…These indicators commonly identify processes related to human disturbances such as farming, erosion, and movement of suspended materials and contaminants into rivers [46]. In our analysis, the changes in EC, TDS, and salinity ( Figure 2) to high spikes at sites 13,14,15,29,36 correspond to zones of increased pollutant discharge into river system from adjoining land activities.…”

“…The field raw data consisting of all 14 measured variables for all 38 sites were log transformed to make sure the data follow an approximate normal distribution [46] prior to principal component analysis (PCA). The resulting single matrix consisted of 14 parameter measurements of concentrations (mg/L, EC (µS/cm), pH, water temperature (°C)).…”

Longitudinal patterns of macroinvertebrate communities in relation to environmental factors in a Tibetan-Plateau river system

“…Globally speaking, macroinvertebrate biodiversity patterns in high altitude running waters have been intensely described from temperate regions [see special issues of Freshwater Biology 46 (12), 2001, and Hydrobiologia 562 (1), 2006] to tropical South America (Jacobsen et al, 2003(Jacobsen et al, , 2010Ríos-Touma et al, 2011) and Africa (Kasangaki et al, 2008), and especially in glacial systems (e.g. Ward, 1994;Maiolini and Lencioni, 2001).…”

Diet of Astyanax paranae (Characidae) in streams with different riparian land covers in the Passa-Cinco River basin, southeastern Brazil

“…Land cover in riparian zone streams is strongly related to the physical and chemical characteristics of water (ometto et al, 2000;sutherland et al, 2002;meador & Goldstein, 2003;diana et al, 2006) and the characteristics of the substrate (Waters, 1995;sponseller et al, 2001;allan, 2004;Ferreira & casatti, 2006). The absence of riparian forest may result in a greater transference of sediment to water bodies, increasing turbidity with subsequent habitat loss via sedimentation (Ferreira & casatti, 2006;silVa et al, 2007;KasanGaKi et al, 2008).…”