Abundance, distribution and ecological impacts of invasive plant species in Maputo Special Reserve, Mozambique

Abstract

With a few exceptions, comprehensive assessment of invasive plants species (IPSs) list that invade Maputo Special Reserve’s natural ecosystems is lacking. Some available data are either preliminary or localised, or focus on agricultural weeds that leave an ecological gap about IPSs. In order to establish this gap, a study was conducted to asses the impact of IPSs in Maputo Special Reserve. A stratified random sample was used to allocate five land use and land cover strata. Plots of 20 m diameter formed by two replicates were established in transects within plot of 160 m × 80 m and each invasive plants species number were counted and recorded. At every 10 km distance of the road side in different reserve directions, field plots of 10 m × 10 m were also established location and coordinates where invasive plants species occur recorded. With the ARCGIS 10.3 software, IPSs location coordinates were positioned on the map to create location. Data analysis was through calculation of diversity and evenness indices (Shannon-wiener (H') and Simpson (D'). Student’s t -test was used to compare diversity differences between the invaded and un-invaded sites. The result indicated the occurrence of 26 IPSs across all strata with Lantana camara and Eucalyptus sp being dominant. Settlement stratum recorded the highest level of invasive plants compared to other strata. Student t test on differences in Shannon-wiener diversity (H‘) between invaded and un-invaded areas showed that there was significant difference in species diversity (t 0.05(2) 170 =1.84 0.05< P< 0.10). The threat of IPSs is increasing at an alarming rate, thus control methods have to be designed to stop further spreading into Maputo Special Reserve.   Key words: Biological invasions, environmental damage, species diversity, ecosystem services.