A influência da matriz adjacente e dos efeitos de borda sobre a regeneração natural de uma floresta de terra firme na Amazônia Central

Abstract

The edge effect is one of the main consequences of deforestation in the Amazon forest, causing microclimatic changes that lead to structural changes in the remaining forests, thus impacting the community of regenerating individuals, as well as their leaf functional characteristics that are associated with ecological strategies of the plants. In this context, the individuals that make up natural regeneration can provide an answer to the changes occurring in a forest community, as they are very sensitive indicators of the forest's capacity to recover over time. Therefore, the understanding of how these impacts affect ecophysiological processes in forest edges influenced by different types of adjacent matrices is still poorly understood and may elucidate the magnitude of these effects in relation to land use change processes over the decades. The work aims to evaluate the impact of the edge effect on natural regeneration in a terra firme forest in Central Amazonia under the influence of different adjacent matrices. The study was carried out at the Experimental Farm of the Federal University of Amazonas, in areas of continuous forest under edge effect established for more than 20 years with distinct adjacent matrices of pasture and forest in regeneration. Three plots of 100 x 100m were installed, two perpendicular to the adjacent edge arrays and one inside the native forest without the edge effect. In these plots, microclimatic variables (air temperature and relative humidity, vapor pressure deficit, light transmittance), structural (canopy opening) and leaf collection from regenerating individuals were collected for the analysis of functional variables (leaf area, specific leaf area, leaf dry mass content and chlorophyll fluorescence a) It was found that, depending on the adjacent matrix, the microclimatic variables and the efficiency responses in the use of light in the edge-center gradient behave differently, highlighting the first meters to the edge. In addition, the edge effect directs the regenerating community's ecological strategies towards the development of competing traits, but with notable participation of stress-tolerant traits. It is concluded that even after 47 years of established edge, its effects are still present, being partially mitigated by an adjacent regenerating forest, when compared to a grassland edge, it can be verified in the structure of the community and in the ecophysiological responses of regenerating individuals.