11 research outputs found
Loosening of environmental licensing threatens Brazilian biodiversity and sustainability
Environmental licensing is one of Brazil’s main environmental-policy instruments and is intended to regulate anthropogenic activities and to avoid their impacts on the environment. This licensing is now at risk to being annihilated. Bill 3729/2004 was recently approved by Brazil’s Chamber of Deputies, and if approved by the Senate (as is likely) it would create the so-called ‘general law of environmental licensing’ and a series of changes weakening environmental impact assessments, public participation and supervision by environmental agencies. The changes include creation of a self-declared license in which licenses would be issued automatically without any analysis by technical staff in the environmental agencies. Various types of small and medium-sized projects would be completely exempted from licensing. If approved, the bill would cause irreversible environmental losses to megadiverse Brazilian ecosystems and allow installation of projects with high environmental impact without any impact analysis or measures to minimize or recover from impacts or to provide environmental compensation for them
Dry season limnological conditions and basin geology exhibit complex relationships with δ<sup>13</sup>C and δ<sup>15</sup>N of carbon sources in four Neotropical floodplains
<div><p>Studies in freshwater ecosystems are seeking to improve understanding of carbon flow in food webs and stable isotopes have been influential in this work. However, variation in isotopic values of basal production sources could either be an asset or a hindrance depending on study objectives. We assessed the potential for basin geology and local limnological conditions to predict stable carbon and nitrogen isotope values of six carbon sources at multiple locations in four Neotropical floodplain ecosystems (Paraná, Pantanal, Araguaia, and Amazon). Limnological conditions exhibited greater variation within than among systems. δ<sup>15</sup>N differed among basins for most carbon sources, but δ<sup>13</sup>C did not (though high within-basin variability for periphyton, phytoplankton and particulate organic carbon was observed). Although δ<sup>13</sup>C and δ<sup>15</sup>N values exhibited significant correlations with some limnological factors within and among basins, those relationships differed among carbon sources. Regression trees for both carbon and nitrogen isotopes for all sources depicted complex and in some cases nested relationships, and only very limited similarity was observed among trees for different carbon sources. Although limnological conditions predicted variation in isotope values of carbon sources, we suggest the resulting models were too complex to enable mathematical corrections of source isotope values among sites based on these parameters. The importance of local conditions in determining variation in source isotope values suggest that isotopes may be useful for examining habitat use, dispersal and patch dynamics within heterogeneous floodplain ecosystems, but spatial variability in isotope values needs to be explicitly considered when testing ecosystem models of carbon flow in these systems.</p></div