Estudo da ocorrência e estado de conservação da Raphia australis Oberm. Strey na Reserva Botânica de Bobole

Abstract

This project was carried out in the Bobole Botanical Reserve (RBB) with the aim of discovering the current conservation status of the Raphia australis species. This species is quasi-endemic in Mozambique and lives associated with different forms of flora and fauna, constituting habitat, food and nutrient cycling for various epiphytes, ferns, microfauna and other living beings. R.australis is under extreme threat, as it is located in an area with great agricultural potential, attracting surrounding communities to cut it down for agricultural practice. RBB was created in 1945 with an area of ​​200 ha, the destruction of this forest was initiated by itinerant farmers, who began to cut it down to carry out subsistence crops in the place where it was implanted. Subsequently, business agriculture, namely banana and rice, accelerated the destruction of the forest. RBB currently has only 12 ha of area. To achieve the objective of this work, a mapping of R. australis patches in its area of ​​occurrence within the RBB was carried out, using the following instruments: GPS, Computer with Arcgis 9.3 software, aerial photographs of the RBB in a scale of 1: 5000, RBB topographic chart in 1:5000 scale. A survey of seed abundance, natural regeneration, non-fruiting adults and fruiting adults was also carried out, where a total of 13 transects were established. Each transect consisted of 30 squares of 10X10 m (100 m 2 ). This methodology was adopted in order to compare the results of this study with that of Sambane (1999). Regarding the analysis of the conservation status of R. australis, the factors that influence the species survival were described, namely: local biophysical conditions, moisture and soil organic matter content, and the current status of the reserve was characterized; using the following instruments: soil survey probe and 8 pF rings with a volume of 100 cm 3 . The average humidity was 45% and the average organic matter content was 5.68%, both factors showed enormous amplitudes.

The coverage of the R.australis patches occupied an area of ​​0.44 ha equivalent to 4% of the total area of ​​the reserve, the remaining 96% are occupied by agricultural plots, native and exotic vegetation and grass. presented greater abundance in the value of 901.8 seeds/ha, followed by natural regeneration with 147. 7 ind/ha, non-fruiting adults with 31.5 ind/ha and fruiting adults with 7.7 ind/ha. Compared to the study by Sambane (1999), the abundance of adult individuals (with and without fruit) decreased from 160 ind/ha to 39 ind/ha, corresponding to a decrease of 64% in percentage terms, which is aggravated by the fact that the species to be monocarpic bearing only once and dying soon after. Conservation measures for the species R. australis in its area of ​​occurrence and distribution were analyzed under four main aspects, namely social, ecological, legal and scientific-recreational. For all these aspects, it is recommended that more studies related to the species be carried out (studies related to germination and association of R. australis with other species) in the RBB, greater community involvement, urgent intervention by competent authorities for a rehabilitation plan for the area (TRADUÇÃO NOSSA)