Assessment of impacts of removing Eucalyptus species on natural regeneration of native species at Gishwati-Mukura national park

Abstract

The aim of this research was to assess the impacts of removing the Eucalyptus species on the natural regeneration of native species at Gishwati-Mukura National Park. The eighteen study sites were selected from the Eucalyptus species removed and non-removed areas, with three and five randomized plots in each site of Mukura and Gishwati sides respectively to identify the native and non-native plant species regenerated, the number of E. stumps regenerated, and E. seedlings germinated. A quadrat of 1m 2 was used for the herbs species identification, 25m

and 100m 2 for the identification of the woody species (shrubs and trees) having less than 2m and greater or equal to 2cm of diameter at breast height correspondently. A straight line of 100m long from the edge of the buffer zone was drawn in and out the Park to identify the distribution potential of Alnus inside and outside of the Park. A quadrat of 1m used for quantification of the number of Alnus seeds and seedlings germinated at 0, 5, 15, 30, 50, 75 and 100m distances. The plants species abundance, diversity indices, evenness and the coppiced stumps abundance were analyzed with the Excel sheet, pivot table and bioproffessional software. The total of 20 Eucalyptus stumps were coppiced among 197 E. stumps counted in the whole study area and 3 E. seedlings were identified. The estimated number of herbs species were highly abundant at E. removed area at 60 herbs species compare to 13 herbs species in non-E. removed areas per 1m 2 at Mukura side. Gishwati side was 57 herbs species in E. removed area compare to 16 herbs species in non E. removed area per 1m 2 with high dominance of the Coelachne africana, Phyllanthus nummulariifolius herbs in both study sides. The areas were highly dominated by the pioneer woody species such as Macaranga kilimandscharica, Maesa lanceolata, Dombeya torida, Bothriocline ruwenzoriensi, Xymalos monospora, and low abundance of climax species like Carapa grandiflora, Podocarpus falcatus, Syzygium guinens in the whole study area. The results shown that the E. species had numerous influence on the native species regeneration by competing with native species, the E. leaves litter and chemical substances inhibiting the regeneration of native species in the nature area