Abstract:
Currently, biological invasions constitute the greatest threat of biodiversity loss in the world, in addition to causing damage to the economy and risks to human health. In Mozambique, these threats are already evident, given the presence of Prosopis juliflora, a species classified as one of the 100 worst invasives in the world. Despite this fact, there are no studies in the country on its real distribution and impacts, whether economic or ecological. Thus, the present research was carried out, with the aim of investigating the distribution and impacts of this species on plant species in the district of Chókwè.
For this purpose, 143 points along the district roads, at an equidistance of 2-3 km, depending on accessibility. At each point, a sample plot of 1000 m 2 was established for the collection of information on P. juliflora, and 10 squares of 1 m 2 for the herbaceous vegetation located under the canopy of this plant. The analysis variables for P. juliflora were: frequency, abundance, diameter, height, number of individuals and for herbaceous vegetation, the frequency relative, relative abundance, relative coverage, importance value index, richness, Shannon and Simpson diversity.
Maxent v.3 was used to assess areas prone to invasion by P. juliflora using its presence data. The results indicated a frequency of P. juliflora of 67%, with an abundance ranging from low to very abundant, with coverage from 5% to over 75%. A high number of individuals with a diameter of less than 5 cm was recorded; presence of P. juliflora in all types of soil and vegetation, with the exception of sandy and dense forest, respectively. The invaded areas had a great expansion over time, probably beginning in 2013, with residential areas as the main points of dispersion. Currently, the area potentially prone to invasion by this species in the country is estimated at around 54.6%, and could reach up to 63.9% in 2080, if measures are not taken to control it. As for the impact on vegetation, the study revealed a reduction in species when comparing non-invaded areas (51) with invaded (16), with a Shannon-Wiener index of 28.65 against 12.91, respectively (TRADUÇÃO NOSSA)
