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Accueil du site → Master → Afrique du Sud → 2021 → Soil and vegetation recovery following Acacia dealbata clearing in the Tsitsa catchment, Eastern Cape Province of South Africa : implications for ecological restoration

Rhodes University (2021)

Soil and vegetation recovery following Acacia dealbata clearing in the Tsitsa catchment, Eastern Cape Province of South Africa : implications for ecological restoration

Balintulo, Putuma

Titre : Soil and vegetation recovery following Acacia dealbata clearing in the Tsitsa catchment, Eastern Cape Province of South Africa : implications for ecological restoration

Auteur : Balintulo, Putuma

Université de soutenance : Rhodes University

Grade : Master of Science (MS) 2021

Résumé partiel
Invasion by alien plant species in South Africa continues to compromise the stability of ecosystems by causing declines in biodiversity, altering soil nutrients and processes, and subsequently transforming ecosystem functionality. Control of invasive alien plant species has been widely implemented in South Africa to minimize their negative impacts ; however, the legacy effects can persist long after the plant has been removed. The impacts of Acacia dealbata clearing on soil properties and native vegetation recovery remains understudied despite their significance in ecological restoration and monitoring. This comparative study determined the impacts of A. dealbata clearing on both soil physicochemical properties and vegetation in the Eastern Cape Province of South Africa. Soils were collected from three different clearing treatments, namely, cleared, invaded, and uninvaded, on 5 m x 5 m plots over three summer months. The plots were replicated four times for each clearing treatment, making a total of 72 sampling plots. Soils were assessed for soil pH, resistivity, P, C, N, and exchangeable cations as well as soil moisture content, penetration resistance, infiltration rate, hydraulic conductivity, and water repellency. Clearing of A. dealbata did not have any significant effects on most soil nutrients, however, there were variations in soil pH, resistance, and Na. Soil pH was significantly higher in the uninvaded treatments than in the cleared and invaded treatments. Soil moisture content was significantly higher in the cleared treatments than the adjacent invaded and uninvaded treatments, but this was observed in the month of December only. Soil penetration resistance and infiltration rates were significantly higher in the month of December in the cleared treatments. For all clearing treatments, no significant differences were recorded for soil hydraulic conductivity. These results on changes in soil properties following A. dealbata clearing are varied, with some soil properties showing decreases, an indication that removal of A. dealbata has the potential to shift soil properties towards a positive recovery trajectory. This study further assessed whether the clearing of A. dealbata facilitates the recovery of native plant species. Vegetation surveys were conducted in the three above-mentioned treatments and plots. Results showed little recruitment of native grasses and forbs, but the persistence of A. dealbata seedlings in the cleared treatments.

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Page publiée le 12 janvier 2023