Moyo, Hloniphani Peter Mthunzi2026-08-132026-08-132010Moyo, Hloniphani Peter Mthunzi. 2010vital:11173http://hdl.handle.net/10353/d1001011Plant-water relationshipsAcacia mearnsiiWater tableWattles (Plants) -- South Africa -- Eastern CapeStreamflow -- South Africa -- Eastern CapeGroundwater -- South Africa -- Eastern CapeGroundwater recharge -- South Africa -- Eastern Capehttp://hdl.handle.net/20.500.11837/4648ABSTRACT Invasion of rangelands by trees such as Acacia mearnsii threaten native vegetation and their habitats because invasive trees compete with native vegetation for resources such as water, nutrients and the sun. The non-indigenous trees have higher evapotranspiration rates that eventually lead to reduction in stream and river flows. Acacia mearnsii also have inhibitory effects on growth of underneath vegetation through exudates from either their roots or leaves that prevent either the germination or the full establishment of native vegetation. The purpose of this study was to investigate (1) the effects of Acacia mearnsii on water table; and (2) the effect of Acacia mearnsii on soil and vegetation properties in the Eastern Cape Province, South Africa. Water table was measured using HOBO data loggers in plots where A. mearnsii was cleared and where it was not. There was significantly higher (p < 0.05) recharge in plots where trees were cleared (-8.7m) compared to where they were not (-9m). Soil samples were collected from inside and outside Acacia mearnsii canopies and analyzed for pH, soil organic carbon, soil aggregate stability, electrical conductivity and nitrogen content. Soil from under A.mearnsii canopies was more acidic (3.05) compared to that from outside (5.47). Nitrogen content was significantly higher in soils from under the canopies (0.52 mg kg-1) compared to those from outside (0.21 mg kg-1). Soil aggregate stability was not significantly different (p > 0.05) between soils from inside and those from outside canopies. Total herbaceous production was measured using the dry-weight method. Total herbaceous production was significantly higher (p < 0.05) in the plots that were cleared (290 kg ha-1) than in those that were not (22 kg ha-1). Soil samples were collected from inside and outside canopies, incubated in the greenhouse to determine the seed bank botanical composition and the seed bank size. Soils from outside canopies had higher seed bank size (p < 0.05) (59% of total seedling emergence) than soils from under the canopies (41%). Acacia mearnsii contributed 5% of total seedling emergence in trays while forbs contributed 50%, showing that in the absence of A.mearnsii, germination increases. It is concluded that Acacia mearnsii significantly reduces groundwater recharge, soil pH, biomass production and native vegetation seed bank whilst increasing soil nitrogen and soil organic carbon under its canopies.xiv, 89 leavespdfEnglishUniversity of Fort HarePlant-water relationshipsAcacia mearnsiiWater tableWattles (Plants) -- South Africa -- Eastern CapeStreamflow -- South Africa -- Eastern CapeGroundwater -- South Africa -- Eastern CapeGroundwater recharge -- South Africa -- Eastern CapeThesis