Where Are the Young Umbuzeiros? How Managed Areas Influence the Recruitment of Spondias tuberosa Câm. (Anacardiaceae) in Northeastern Brazil
Déborah Oliveira1, Patrícia Melo1, Arne Cierjacks2, Jarcilene Almeida-Cortez1
1Federal University of Pernambuco, Dept. of Botany, Brazil
Spondias tuberosa Arr. Cam. is an endemic fruit-bearing tree of the Brazilian semiarid region with great socio-economic and environmental importance. This species is a source of sustenance for local people and small farmers, especially during the dry season. S. tuberosa also provides food for wild and domesticated animals, playing an important role to environment. However, there is a lack of seedling recruitment in their natural environment, which has been attributed to seed predation, low seed germination and establishment, and the irregularity of rainfall in the region. Furthermore, land use change and overexploitation have been hypothesized to cause a risk of extinction in this species. In this study, we aimed to assess the population trends, seed production and predation, as well as the germination in greenhouse, of S. tuberosa from agricultural (AGR) and protected (PA) areas in a seasonal tropical dry forest of northeastern Brazil. We selected 25 adult individuals and from each tree we measured the diameter. Under the canopy, we counted and collected the seeds of the current season. In a greenhouse, these seeds were germinated and had their growth accompanied. Our results showed that in AGR all the diameter size-class were represented while in PA the first two size-class showed a lack of individuals. The production of seeds was not different between these two areas although the number of seed m-2 was higher in AGR. Trees located in AGR usually occurred isolated, which may explain the fact that the rate of seed predation was more intense in these areas. Seed size also was bigger in AGR and the seedlings from these seeds were more vigorous than the ones from PA. We found seedlings exclusively in agricultural areas, probably due to abundance of water and soil nutrients and to absence of wild or domesticated animals. Our results clearly show that somehow the species depends on human action for its regeneration. Thus, researchers and stakeholders (local people) should combine efforts to develop strategies for species conservation.
Keywords: Brazilian seasonal tropical dry forest, population dynamics, regeneration
Contact Address: Déborah Oliveira, Federal University of Pernambuco, Dept. of Botany, 50740-330 Recife, Brazil, e-mail: deborahalanigmail.com