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Previous issue date: 2012-02-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The decomposition process exercises an extensive control over the carbon cycle, affecting its availability and nutrient cycling in terrestrial ecosystems. The understanding of leaf decomposition patterns above the soil and fine roots decomposition below the soil is necessary and essential to identify and quantify more accurately the flow of energy and matter in forest systems. There is still a lack of studies and a large gap in the knowledge about what environmental variables act as local determinants over decomposition drivers. The knowledge about the decomposition process is still immature for Brazilian semiarid region. The aim of this study was to analyze the decomposition process (on leaves and fine roots) of a mixture of three native species for 12 months in a semiarid ecosystem in Northeast Brazil. We also examined whether the rate of decomposition can be explained by local environmental factors, specifically plant species richness, plant density and biomass, soil macro-arthropods species richness and abundance, amount of litterfall and fine root stock. Thirty sampling points were randomly distributed within an area of 2000 m x 500 m. To determine the decomposition rate, the litterbag technique was used and the data analysis were made with multiple regressions. There was a high degradation of dead organic matter along the experiment. Above ground plant biomass was the only environmental local factor significantly related to leaf decomposition. The density of vegetation and litter production were positively and negatively related to decay rates of fine roots, respectively. The results suggest that Caatinga spatial heterogeneity may exert strong influences over the decomposition process, taking into account the action of environmental factors related to organic matter exposure of and the consequent action of solar radiation as the decomposition process main controller in this region / A decomposi??o exerce um amplo controle sobre o ciclo do carbono, disponibilidade e ciclagem de nutrientes nos ecossistemas terrestres. A compreens?o sobre os padr?es de decomposi??o foliar acima do solo e das ra?zes finas abaixo do solo ? necess?ria e essencial para identificar e quantificar com mais precis?o os fluxos de energia e mat?ria nos sistemas florestais. Ainda h? car?ncia de estudos e uma grande lacuna no conhecimento sobre quais vari?veis ambientais atuam como determinantes locais sobre os controladores da decomposic?o. O conhecimento sobre o processo de decomposi??o ainda ? incipiente para o semi?rido brasileiro. O objetivo do presente estudo foi analisar o processo de decomposi??o (folhas e ra?zes), de uma mistura de tr?s esp?cies nativas durante 12 meses em um ecossistema semi?rido do Nordeste Brasileiro. Tamb?m foi analisado se a taxa de decomposi??o pode ser explicada por fatores ambientais locais, especificamente riqueza de esp?cies, densidade e biomassa a?rea vegetal, riqueza de esp?cies e abund?ncia de macro-artr?podes do solo, produ??o de serrapilheira e estoque de ra?zes finas. Trinta pontos amostrais foram distribu?dos aleatoriamente dentro uma ?rea de 2000 m x 500 m. Para determina??o das taxas de decomposi??o foi utilizada a t?cnica de bolsas de serapilheira (litterbags) e para as an?lises dos dados foram utilizadas regress?es m?ltiplas. Houve uma alta degrada??o da mat?ria org?nica morta. A biomassa a?rea vegetal foi o ?nico fator ambiental local significativamente relacionado ? decomposi??o foliar. A densidade da vegeta??o e a produ??o da serrapilheira foram, respectivamente, positiva e negativa significativamente relacionadas com as taxas de decaimento de ra?zes finas. Os resultados sugerem que a heterogeneidade espacial da Caatinga pode exercer fortes influ?ncias no processo de decomposi??o, tendo em vista a atua??o de fatores ambientais relacionados ? exposi??o da mat?ria org?nica e a consequente atua??o da radia??o solar como controlador do processo de decomposi??o nessa regi?o
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/14029 |
| Date | 22 February 2012 |
| Creators | Costa, Uirande Oliveira |
| Contributors | CPF:96425601434, http://lattes.cnpq.br/8396727262741273, Amado, Andr? Megali, CPF:08699632797, http://lattes.cnpq.br/4312158184208542, Vasconcellos, Alexandre |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ecologia, UFRN, BR, Bioecologia Aqu?tica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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