Genetic diversity of Brachystegia boehmii Taub. and Burkea africana Hook. f. across a fire gradient in Niassa National Reserve, northern Mozambique

Abstract

Miombo woodlands constitute the most important type of vegetation in southern Africa, covering about 70% of the Zambezian phytoregion. This ecosystem, dominated by the genera Brachystegia , Julbernardia and Isoberlinia , has an immeasurable socio-economic and environmental value, playing a key role in formal and informal economies and in energy, water and carbon balances. Anthropogenic fires represent one of the major threats, compromising the stability of miombo. In this study we report on the usefulness of ISSR markers to assess, for the first time, the genetic diversity in two typical miombo species, Brachystegia boehmii Taub. and Burkea africana Hook. f. across a fire gradient in the Niassa National Reserve (NNR). According to our data, ISSR seem to be a suitable molecular marker's system for biodiversity studies in both species, generating high levels of polymorphisms coupled with a convenient resolving power. The results point to a link between fire-tolerance and genetic diversity, as judged by the higher diversity levels observed in B. africana (fire-tolerant) and by the evolutive fire response of B. boehmii . Although fire differentially affects the biodiversity in each species, in general, the overall genetic diversity was high and their survival does not seem to be compromised by the frequency of fires, agreeing with the fact that NNR is one of the least disturbed areas of deciduous miombo. ► We report on the assessment of the genetic diversity in two miombo species. ► There is a correlation between fire-tolerance and genetic diversity. ► There is a good genetic potential for Burkea africana and Brachystegia boehmii. ► The current fire frequency is affecting differently miombo species.