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The Impact of Eucalypts Plantation on Soil Moisture and Ground Vegetation Cover at St. Michaels in the Roma valley, Lesotho

IWRA World Water Congress 2017 - Cancun Mexico
5. Water ecosystems and physical regimes
Author(s): Tsepo Stephen Tiisetso Sekaleli
Adesola Olaleye

Tsepo Stephen Tiisetso Sekaleli
Ministry of Forestry, Range and Soil Conservation
Adesola Olaleye
MIST Innovate Inc.

Keyword(s): Soil moisture, Ground vegetation, Forest plantation, Indigenous forest


The main aim of the present study was to assess the impact of Eucalyptus rubida plantation on soil moisture and ground vegetation cover in lesotho. Since forestry is about the people as well as the environment, the methodology that was adopted in this study included questionnaire survey, soil moisture monitoring and vegetation survey. Local people between the ages of 40 to over 70 years were interviewed and the assumption was that people in these age category know better the impacts of the eucalypts in the area over the years. Three land-use types (eucalypts plantation, indigenous forest and grassland/rangeland) on the same topography, aspect and soil type were identified and studied and the results of soil moisture status after a rainfall event (over 5 days period) and ground vegetation cover were compared. The indigenous forest comprised of a mixture of tree species that include Leucosidea sericea, Buddleja salviifolia, Rhus dentata, Rhus divaricata, Rhmnus prinoides, Euclea coriacea and Olea Africana while the rangeland was mainly eragrostis/aristida  grassland. The rate of soil moisture decrease between the three land-use types was significant and was in the following order: eucalypts plantation (3.37% per day) > indigenous forest (1.63% per day) > grassland/rangeland (1.56% per day). The high rate of soil moisture decrease of 3.37% per day could be attributed to high evapotranspiration rate of the eucalypts plantation. The frequency of ground flora of forbs, grasses and brush was found to be highest under the grassland followed by the indigenous forest and then eucalypts plantation. The land under the eucalypts plantation was mostly bare and had the highest frequency of litter and rockiness compared to both the indigenous forest and the grassland/rangeland. The presence of invader species such as Chrysocoma cilliata, Anthanasia thodei, Gnaphalium undulatum, Scabiosa columbaria, Aster fillifolis, Passerina montana, Erica maesta and Artemisia afra under the eucalypts plantation was also an indication of degradation while the high presence of litter and rockiness could be due to anthropogenic pressures such as human movement which could have limited the growth of ground flora.

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