Influência topoedafoclimática na produção primária bruta no semiárido

O relevo influencia a precipitacao, a producao de biomassa e a producao primaria bruta ( Gross Primary Production -GPP). Em ecossistemas secos qualquer variacao GPP tem importância cientifica uma vez que sao ecossistemas bastante vulneraveis devido a alta variabilidade espacial e temporal do clima. Alem disso, avaliar a relacao entre o relevo e GPP em ecossistemas secos se torna mais facil por existir um periodo bem definido com zero de precipitacao. O estudo objetivou avaliar a influencia do relevo, da altitude, da precipitacao e do solo na Gross Primary Production -GPP no Bioma Caatinga. Foram utilizados os produtos MOD17 (GPP), sensor MODIS do satelite Terra e dados de precipitacao para os anos de 2015 e 2016, com a aplicacao de estatisticas descritivas e multivariadas para identificar correlacoes e similaridades entre areas e amostras. Ocorreu grande variacao espacial e temporal da GPP em areas de Caatinga, devido ao relevo, clima e solo. A quantificacao da GPP nas areas de maiores altitudes apresentou medias de 46,87 e 55,84 gC m -2 e menores valores de GPP, de 2,49 e 3,75 gC m -2 , em 2015 e 2016, respectivamente. Nas areas planas, as maiores medias foram 46,03 e 55,84 gC m -2 e as menores 3,75 e 2,49 gC m-², em 2015 e 2016, respectivamente. Ocorreu uma diferenca de quase 40% para os menores valores de GPP, quando comparados aos relativos as areas mais altas e mais baixas. Foi possivel avaliar a influencia do relevo na GPP devido existir um periodo seco bem definido e de precipitacao zero. Os anos de maiores precipitacao tem forte influencia nos menores valores de GPP das areas planas. Assim, no periodo chuvoso e mais dificil identificar a influencia de outros fatores, que nao sejam a precipitacao, na GPP. Esses resultados sao de grande importância para mitigar ou avaliar os efeitos das mudancas climaticas sobre os ecossistemas secos. Palavras-Chave: relevo, sensoriamento remoto, producao primaria bruta, sensor MODIS Edapho-topo-climatic Influence on gross primary production in semi-arid A B S T R A C T Relief influences formation, biomass production and gross primary production (Gross primary production-GPP). In dry ecosystems any GPP variation is of scientific importance since they are very vulnerable ecosystems due to the high spatial and temporal variability of the climate. In addition, assessing the relationship between relief and GPP in dry ecosystems makes it easier to have a well-defined period with zero special. The study aimed to evaluate the influence of relief, altitude, exclusion and soil in the Primary Gross Production-GPP in the Caatinga Biome. The products MOD17 (GPP), MODIS sensor from the Terra satellite and capacity data for the years 2015 and 2016 were used, with the application of descriptive and multivariate statistics to identify correlations and similarities between areas and accounts. There was a great spatial and temporal variation of the GPP in Caatinga areas, due to the relief, climate and soil. Quantification of GPP in areas of higher altitudes showed averages of 46.87 and 55.84 gC m -2 and lower values of GPP, of 2.49 and 3.75 gC m -2 , in 2015 and 2016, respectively. In the flat areas, the highest averages were 46.03 and 55.84 gC m -2 and the lowest 3.75 and 2.49 gC m -2 , in 2015 and 2016, respectively. There was a difference of almost 40% for the lowest values of the GPP, when compared to those related to the highest and lowest areas. It was possible to evaluate the influence of the relief on the GPP because there is a well-defined dry period with zero capacity. The years of greater capacity have a strong influence on the lower values of GPP in flat areas. Thus, in the rainy season, it is more difficult to identify the influence of factors other than exclusion on GPP. These results are of great importance to mitigate or assess the effects of climate change on dry ecosystems. Keywords: relief, remote sensing, gross primary production, MODIS sensor