Remote sensing applications for modeling human impacts on the ecological properties of wetland and aquatic environments in the Solimões/Amazon floodplain

Abstract

The Amazon floodplain is characterized by extreme natural fluctuation in the water level of its rivers with an alternation between excess and lack of water known as "flood pulse", sensu Junk (1989). The flood pulse is the principal ecological driving force acting in the floodplain ecosystem; it is largely responsible for the behavior of biogeochemical cycles and demands specific adaptations of the regional biota (Adis e Junk, 2002; Simone et al., 2003; Parolin 2010; Piedade 1997; Arraut 2008). The floodplain aquatic systems are relatively little known and studied when compared to the Amazon terrestrial ecosystems. Estimations made by Sippel et al. (1992) indicate the existence of more than 10 000 lakes with an area larger than one hectare (1 ha), of which less than 1% have been properly investigated. Recent forecasts about the effects of climate change in the Amazon region suggest an increase in the temperature and in the frequency and intensity of extreme events (droughts and floods), with a range of consequences for the local biota and biogeochemistry (Foley et al. 2002; Pachauri, 2007; Malhi et al., 2008; Marengo et al., 2011; Toomey et al., 2011). This proposal is based on the previous efforts of the team (FAPESP - 2002/00785-3, 2003/00785-3, 2004/1406-5, 2007/07867-9, 2008/07537-1; CNPq - 477885/2007-1, 304929/2007-7, 550373/2010-1; and GEOMA Thematic Network) and aims to conduct an integrated study of the various ecosystem components of the Amazon floodplain, at multiple scales, considering the current and future combined effects of the environmental changes caused by global climate change and human activities in the Amazon floodplain. This integration will be achieved from four main research lines in which the group has worked in the last decade: 1 - Expansion of knowledge about the impacts of human presence and use of wetland ecosystems on the Amazon floodplain; 2 - Expansion of knowledge about the impact of natural factors and global climate change on the functioning of the floodplain environment; 3 - Evaluation of potential interactions and possible synergistic effects between climate change and anthropogenic increase; 4 - Generation of knowledge and strategic human resources needed for the implementation and future integration of data from the new generation of orbital spectroscopic imagers, scheduled to be launched by the end of this decade. To do so, the project team plans to continue working in two study areas covered by the FAPESP Project 2008/07537-1: a preserved wetland and a wetland heavily impacted by human activities. The preserved area is formed by the RDSM floodplain, which has been the subject of two PhD theses (Arraut, 2008; Affonso, 2011) where the integration of remote sensing and in situ data was essential for the understanding of Manatee migration processes (Arraut et al., 2010) and the study of the relationship between the characteristics of the floodplain habitats and the abundance of pirarucu (Affonso, 2011). The most impacted area is represented by the Curuai Lake, which, according to Reno and Novo (2008), Reno et al. (2011), has undergone an intense deforestation process between the late 1970's and 2008 due to jute cultivation and livestock on the floodplain. (AU)