Variabilidade temporal da biomassa florestal em fragmento de caatinga em regeneração a 40 anos

Abstract

The Caatinga biome has suffered major change in its structure due to anthropogenic activities besides the soil and climatic factors, being necessary studies to assess its dynamics in the face of climate change. The objective of this work was to study the above ground biomass change in arboreal component, in seven years period, in a fragment of secondary vegetation in recover for more than 40 years. It was used for this study data from field measurement from 2009, 2010, 2014 and 2016. As a result, it was quantify 3,075 plants ha-1in 2009, 3,225 plants ha-1in 2010,3.238plants ha-1in 2014and 3,050plants ha-1in 2016. During the studied time period (2009to 2016) it was identified a mortality of 80plants ha-1yr-1and recruitment of 77plants ha-1yr-1, resulting a deficit of 3plants ha-1yr-1. In 2009 the total biomass were estimated in 65.34Mgha-1, in 2010 there were an increase of 7.27Mgha-1adding up to72.61Mgha-1.In 2014 there was a decrease of 17.75Mgha-1reducing biomass to 54.86Mgha-1, this descent was maintained in the following year of 2016 which was of 8.96 Mg ha-1, passing to 45.90 Mg ha-1. This decrease in biomass is connected to the difference between the larger dead individuals and the small gain of new individuals that might be associated with prolonged drought observed during the period 2012-2015. This result shows the sensitivity of the vegetation to climate in particular to precipitation. We conclude that is essential to have a long term monitoring system in the region to better understand the resilience of Caatinga biome to climate interanual variation and future climate change.