South America has a large proportion of wetlands compared with other continents. While most of these wetlands were conserved in a relatively good condition until a few decades ago, pressures brought about by land use and climate change have threaten their integrity in recent years. The aim of this article is to provide a bibliometric analysis of the available scientific literature relating to the remote sensing of wetlands in South America. From 1960 to 2015, 153 articles were published in 63 different journals, with the number of articles published per year increasing progressively since 1990. This rise is also paralleled by an increase in the contribution of local authors. The most intensively studied regions are the wetland macrosystems of South American mega-rivers: the Amazon and Paraná Rivers, along with the Pantanal at the headwaters of Paraguay River. Few studies spanned more than two countries. The most frequent objectives were mapping, covering all types of wetlands with optical data, and hydrology, focusing on floodplain wetlands with microwave data as the preferred data source. The last decade substantial growth reflects an increase in technological and scientific capacities. Nevertheless, the state of the art regarding the remote sensing of wetlands in South America remains enigmatic. Fundamental questions and guidelines which may contribute to the understanding of the functioning of these ecosystems are yet to be fully defined and there is considerable dispersion in the use of data and remote-sensing approaches.

This study assesses the change in fish exploitation patterns of the sábalo fisheries of the lower Paraná River basin based on hydrological, biological, and fishery indicators. From historical catch records, we recorded a shift from a lightly and moderate exploited status before 2001 to a heavily exploited one, as a result of the development of sábalo exports from 2001 onwards. Channel and floodplain connectivity indices demonstrated that the Paraná exhibited highly favorable hydrological conditions between 1972 and 1999 but more adverse conditions from 1999 to 2009, as a consequence of flood pulses reduction coincident with a fishing mortality increment. A total catch of 15,000 tons, including local consumption, regional market, informal sales, and exportation volumes, was estimated as the maximum sustainable catch. That level was instead exceeded 3 fold in 2004, in parallel with a decrease in the mean fish length from 48 to 42 cm, along with a reduction in both the mesh size from 16 to 12 cm and megaspawner proportion, and an increase of fishing mortality. Although growth overfishing was not noted, an analysis of the spawning potential ratio trend indicated that recruitment overfishing took place during 2005, since the fishing mortality rate was 4 times greater than the natural mortality rate. These observations suggest that less favorable hydrological conditions after 1999 coupled with a coincident high fishing pressure could have impacted the sábalo population biomass. Management of sábalo fisheries requires to set aside a single economic vision of the resource use moving to an ecosystem-oriented approach that incorporate, among others components, the hydrological regime, species life history traits, fishing impacts on other species, and main stakeholders socioeconomic requirements as key elements for the preservation of fishery sustainability.