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Universidade Federal do Rio Grande do Norte (UFRN) 2022

Desempenho de espécies nativas e da composição de comunidades plantadas ao longo de 5 anos de restauração na caatinga

Fonseca, Luan Souza da

Titre : Desempenho de espécies nativas e da composição de comunidades plantadas ao longo de 5 anos de restauração na caatinga

Auteur : Fonseca, Luan Souza da

Université de soutenance : Universidade Federal do Rio Grande do Norte (UFRN)

Grade : Mestrado em Ecologia 2022

Résumé
The restoration of ecosystems is the focus of this decade, seeking to reverse the degradation of environments such as the Caatinga, which is part of the dryland forest environments that cover 47% of the land surface and include a high diversity distributed over 912,000km² of Brazilian territory. The aim of this work was to identify species and community compositions that can ensure greater restoration success in the Caatinga. For this, we analysed for five years the first cohort of the BrazilDry experiment located in Açú National Forest (Rio Grande do Norte, Brazil), an experiment that manipulates species richness and composition. We tested which species and communities exhibit : (1) stability in mortality of the first cohort (species only) in terms of percent survival, (2) mean height, (3) mean annual growth, (4) photosynthesizing biomass production, and (5) aboveground diameter (DAS). All investigated variables were significantly different among species. We found that only Amburana cearensis did not present survival of specimens from the first cohort after 5 years and 12 species showed some stability in the cohort survival curve. The Mimosa tenuiflora was the species that presented the highest averages in all variables analysed. For species compositions within planted communities, only survival and photosynthesizing biomass differed significantly, where the monoculture of M. tenuiflora presented the highest means. The survival curve of some species presents some stability between 2 and 4 years, however we cannot consider stability in all of them. The survival of the compositions presents good results, not only among monocultures of species with high survival, but planted in communities with different levels of diversity. The photosynthesizing biomass in the communities was driven by the presence of the specie M. tenuiflora, due to its high leaf production over the years. Thus, the genetic identity of species and their successional stages may explain the accumulation of photosynthesizing biomass over time within communities. This work brings a selection of native species and communities that perform well over 5 years of restoration in the Caatinga, presenting their potentials in the recovery of degraded areas.

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