Integrating field sampling, spatial statistics and remote sensing to map wetland vegetation in the Pantanal, Brazil

Abstract

Wetland ecosystems are among the habitats most threatened by climatic change, due to their high sensitivity to the hydrological regime (Junk, 2002). They form transitional habitats between aquatic and terrestrial systems and embody different kinds of habitats such as mangroves, peatlands, freshwater swamps and marshes (Mitsch et al., 2009). The ecological importance of these habitats has been recognized worldwide as well 10 as the urgent need to preserve them, as stressed in the Cuiaba´ Declaration on Wetland elaborated during the 8 International Wetlands Conference of INTECOL, Brazil. However, lack of knowledge about the complex natural dynamics of wetlands may lead to arbitrary management decisions (Junk et al. 2006). To improve the protection of wetlands, it is imperative to have a thorough understanding of the structuring elements 15 and of the identification of efficient methods to describe and monitor them. Vegetation communities have distinct spatial and temporal patterns. Understanding the mechanisms that determine these patterns has been an important issue in ecology for decades (e.g., Connell and Slatyer, 1977; Svenning et al., 2004). Two factors play a key role: spatial interactions in ecological processes (e.g. competition), and 20 environmental factors (e.g. flooding duration) (Tilman, 1988). Ecological processes include interactions between individuals, which may cause particular spatial patterns in the distribution of plants. Spatial variation in environmental factors causes spatial patterns in vegetation communities due to the differences of species requirements. These two factors do not usually operate independently but act together at different 25 spatio-temporal scales (Turner, 1989; Svenning et al., 2004). This multi-scale interaction may lead to complex spatial patterns that are continuously changing (Wagner and Fortin, 2005).