Multiple stressors in the neotropical region: Environmental impacts in biodiversity hotspots

The Neotropical Region is highly diverse geographically, climatically, and biologically. Freshwater ecosystems are impacted by many stressors with impacts that remain poorly understood. While we know the status and the effects of some stressors on certain fish and invertebrate species, whole ecosystem effects are yet to be understood. We describe the status and general trends of 10 stressors: variation in rainfall due to climate change; changes in forest cover (e.g., logging, deforestation, and afforestation); agriculture and livestock; impervious cover (e.g., urban areas); mining operations; flow regulation; loss of riparian zones and floodplains; overfishing; and the introduction of exotic species. Agriculture, mining, and increase in impervious cover due to urbanization are the major stressors for neotropical freshwater ecosystems. Although information is limited the local extinctions of freshwater populations and the loss of ecosystem functions and services are common and likely to increase given the limited conservation measures applied in the region.