Avaliação da composição florística invasora do regadio do Baixo Limpopo

Abstract

Invasive species represent a major threat to biodiversity worldwide. These invasions are threatening biodiversity conservation by displacing native species and modifying ecosystem functioning. In Mozambique, they are present, but there are few published studies. Thus, the present study aimed to characterize the floristic and phytosociological characteristics of the Lower Limpopo Irrigation Area in Gaza Province, seeking to assess the situation of the invasive plants present. 660 inventories were carried out with a 1m2 grid, at 66 points randomly distributed along the Irrigation roads, at an equidistance of 2 km to 3 km, depending on accessibility. To collect information on herbaceous vegetation, the study areas were classified according to the type of use, namely agricultural area, abandoned agricultural area, pasture and roadside. The registered plants were identified and classified as invasive and non-invasive, and their respective phytosociological indices were then determined: frequency, abundance, coverage and importance value index. The analyses were performed using Excel 2007 and the results show that 155 species distributed in 98 genera belonging to 34 families were identified in the study area. Of these species, 105 are native and 50 are invasive. The Poaceae, Fabaceae and Asteraceae families were the ones that recorded the largest number of species overall. The Cynodon dactylon species was the one that presented the highest frequency and importance value index, with 12.13% and 15.3%, respectively. The species Striga asiatica, Sporobolus indicus, Senecio madagascariensis, Mariscus hemisphaericos, Conyza canadensis and Cynodon dactylon had greater abundance and, in terms of coverage value, the species Oxalis latifolia had greater coverage. The pasture area had the highest number of invasive species (40), and presented greater species richness compared to the other areas(TRADUÇÃO NOSSA)