Urban streams in Latin America: Current conditions and research needs
Introduction: Latin America is a highly urbanized region, with most of its population living in cities and urban centers. While information about urban streams in Latin America is rather limited, streams are expected to experience similar environmental impacts and conservation issues as urban streams in parts of the globe, including habitat loss, channelization, sewage discharge, trash, and loss of riparian habitats. Objective: We surveyed a network of researchers from approximately 80% of the countries in Latin America to obtain information on the condition, state of knowledge, and threats to urban streams in the region. Methods: Most participants were reached via the Macrolatinos@ network (www.macrolatinos.net). Results: We obtained 104 responses from researchers in 18 of the 23 Latin American countries. Most urban streams are impacted or degraded, and inputs of contaminants and wastewater discharges were considered major drivers of stream degradation. Most respondents indicated that stream channelization is common, with some streams completely channelized or buried. Sewage and rainfall runoff management were identified as a major factor degrading streams, with most respondents suggesting that streams are a primary destination for wastewater discharge, much of which is untreated. Major limitations to urban stream conservation in Latin America are the result of limited ecological knowledge, lack of citizen interest or political will to protect them. There are isolated efforts to restore urban streams and riparian zones, but these are initial steps that need further development. Conclusions: Our research network of Latin American scientists proved to be a valuable tool to assess a large number of urban rivers in a relatively understudied region. Urban streams in Latin America face a diversity of stressors and management challenges, and we propose three areas that would benefit from further research to improve our understanding and management of these systems: (1) Studies should focus on the watershed, rather than isolated reaches, (2) researchers should strive to attain a better understanding of ecosystem function and the services provided by urban streams to justify management and restoration efforts, and (3) studies that integrate economic models where downstream users pay for upstream protection and restoration could prove beneficial for many Latin American cities in attempting to address water conservation issues.