Browsing by Author "Shear, T. H."

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Compositional gradients of plant communities in submontane rainforest of Eastern Tanzania
(ResearchGate, 2007-01) Wentworth, T; Munishi, P. K. T.; Shear, T. H.; Temu, R. A. P. C.
This study classified plant communities and examined the environmental correlates of community compositions in two submontane rainforests on the ranges of Eastern Arc Mountains, Tanzania. Using agglomerative cluster analysis, indicator species analysis and non-metric multidimensional scaling (NMS) ordination, based on importance value of tree species, five distinct plant communities were identified in the Usambara and six in the Uluguru mountains. The communities corresponded closely to variations in topography and soil physical and chemical properties. The different communities occurred on clay soils in lower elevations and on sandy-clay to sandy-clay-loam soils in higher elevations. Two topographic and 14 edaphic factors were significant correlates of plant community composition. Elevation was the strongest correlate of community composition on individual mountain range followed by percent clay and soil pH. Landform index and soil Na concentration were the major factors in separating plant communities on the west Usambara and Uluguru Mountains. There were appreciable variations in plant community compositions and patterns on the two mountain ranges. The results suggest that plant community patterns in the Eastern Arc Mountains vary from one range to another and are influenced by a complex of local heterogeneity in topographic and edaphic factors. The complex of factors influencing plant distribution can have a big bearing in species restoration and biodiversity conservation in the Eastern Arc Mountains.
Rainfall interception and partitioning in afromontane rain forests of the Eastern arc mountains, Tanzania: implications for water conservation.
(Forest Research Institute Malaysia, 2003-05) Munishi, P. K. T.; Shear, T. H.
The aboveground components of the hydrologie cycle of rain forest are important processes that determine the hydrologie behaviour and dynamics of these ecosystems. Precipitation, throughfall, stem flow, canopy interception and streamflow were measured and modelled in two afromontane rain forests of the Eastern Arc Mountains of Tanzania. Measurements were made daily for 50 months in the Ulugurus and 56 months in the Usambaras. Throughfall was 76% of the gross rainfall in the Usambaras and 79% in the Ulugurus. Stemflow was less than 2% of rainfall. Both parameters were correlated with gross rainfall (r2 = 0.97, 0.99, 0.86 and 0.94). Canopy interception was 22% of rainfall for the Usambaras and 20% for the Ulugurus. Streamflow was best modelled using five months running mean rainfall in the Ulugurus (r = 0.67) and three to four months in the Usambaras (r = 0.72). A high proportion of the gross rainfall is delivered as net precipitation. There is effective partitioning of rainfall on the forest canopy providing reasonable dumping effect of rainstorms. The slow response in streamflow to rainfall events shows the efficiency of the forests to mitigate storm water impacts and thus ensuring continuous water supply. Further studies in effects of forest harvesting on water yield are pertinent to enable adequate planning of forest utilization.