Efeito do fogo na estrutura e nos padrões de distribuição das formações vegetais no Parque Nacional do Limpopo

Abstract

The present study was carried out in Limpopo National Park (LNP), a conservation area located in Gaza Province. Th e main aim of the study was to evaluate the fire frequency (FF) on the landscape as the effects of fire on vegetation is less known by Society in general and by scientist society in particular. The study was executed in two (2) major prespectives namely, R emote Sensing and Floristic assessment. The Mapping results classify the LNP in 14 floristics communities. The community with largest extension was an open forest represented by Terminalia sericea , Combretum apiculatum, Guibourtia conjugata e Colophospermu m mopane species, which represent 24.4 % of LNP. There were also selected three (3) types of soil namely, Lebombo No rth (LN) , Nwambia Sandveld (NS) and Calcrete , linked each one with two (2) FF (high and low). Woody and grass survey were carried in circula r plot making up 12 samplings. In the grass survey were analysed biomass and tuft distance (TD) while in woody survey were analysed the density, Importance Value Index (IVI) and Shannon Index. The results proved that grass biomass is highly affected (p<0.0 1) by the interaction between soil and FF while the TD was not significant (p=0.864). Woody density (p=0.537) and Phytomass (p=0.484) was not signicantly affected by the interaction between FF and soil type. C. apiculatum and C. mopane were mostly represen tative in all soil types with IVI greater than 100 %. C alcrete showed greater grass diversity ( 2.6) than the other s and this was in high FF areas. In the woody component , high FF decreases the diversity of species and thus, the LN showed the greater divers ity (1.85 ) . Although the fire does not affect the woody density and phytomass, LNP managers should be recommended to control the fire use by the communities who live inside the park so as avoid the alteration of current fire regime which can cause damage t o the floristic biodiversity.(TRADUÇÃO NOSSA)