Although deforestation rates in the Brazilian Amazon are well known, the extent of the area affected by forest degradation is a notable data gap, with implications for conservation biology, carbon cycle science, and international policy. We generated a long-term spatially quantified assessment of forest degradation for the entire Brazilian Amazon from 1992 to 2014. We measured and mapped the full range of activities that degrade forests and evaluated the relationship with deforestation. From 1992 to 2014, the total area of degraded forest was 337,427 square kilometers (km2), compared with 308,311 km2 that were deforested. Forest degradation is a separate and increasing form of forest disturbance, and the area affected is now greater than that due to deforestation.

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RESUMOEstudos de ciclagem de nutrientes no bioma Caatinga podem contribuir para o melhor entendimento dos processos ecológicos nesse ecossistema. Dessa forma, o presente estudo buscou ampliar as informações sobre o aporte do material formador da serapilheira, sua composição química e velocidade de decomposição em uma área de Caatinga no município de Santa Luz, PI. A produção de serapilheira foi coletada mensalmente (dezembro de 2010 a novembro de 2011), utilizando-se 10 coletores. Parte do material coletado foi utilizada para análise de N, K, P, lignina e tanino. A decomposição foi avaliada utilizando litter bags. Os resultados deste estudo indicam que a redução da precipitação levou ao aumento da deposição de serapilheira, principalmente a fração folhas. O nitrogênio apresentou o maior aporte dentre os nutrientes. Os elevados teores de lignina e tanino na serapilheira da Caatinga reduzem a velocidade da decomposição da serapilheira.Palavras-chave: ciclagem de nutrientes, floresta tropical seca, material decíduo. Litter Contribution and Decomposition in the Caatinga inSouthern Piauí State, Brazil ABSTRACTStudies on nutrient cycling in the Caatinga biome can support a better understanding of the ecological processes in that ecosystem. This study aimed to improve information related to the amount of organic material for litter formation, its chemical composition and required time for decomposition in a study area located in the Caatinga biome, municipality of Santa Luz, Piaui state, Brazil. The litterfall production was monthly collected between December 2010 and November 2011 using 10 collectors. The collected material was partially used as samples for soil analysis (N, K, P, lignin and tannin). The decomposition was assessed using litter bags.Our results indicate that litter deposition increases as precipitation decreases, mainly the leaf fraction. The greatest soil nutrient content was Nitrogen. It seems that the high concentrations of lignin and tannin in the Caatinga litter were responsible for decreasing the decomposition rate of the leaf litter.