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.

Multispecies and Watershed Approaches to Freshwater Fish Conservation

<em>Abstract</em>.—Decision makers are increasingly tasked with developing conservation strategies that incorporate information on current human threats along with projected influences of climate change. In this study, we integrated a current stream habitat condition assessment of the five largest Hawaiian Islands, with information on ecological stream characteristics and projected change in rainfall to support proactive stream conservation. We used the software Zonation to identify reaches of high conservation value, given both current conditions and projected changes in climate. The results of the spatial prioritization show that low-elevation stream reaches with high potential for supporting multiple species and limited current human disturbance may be especially valuable to conservation. In addition, leeward-draining streams may lose value due to reductions in rainfall, underscoring the importance of managing stream base flow in these areas to conserve native stream organisms. Our results provide guidance for conservation planning in Hawaii and highlight the relevance of regionwide assessments when planning proactive management strategies.

Community-based stream conservation initiatives in British Columbia, Canada

British Columbia is a diverse province, with ecosystems ranging from semi-arid deserts to valley glaciers and vast ice fields. By world standards, BC has an abundance of fresh water in its lakes and rivers. However, rivers have been exploited for social and industrial purposes, often to the detriment of the natural values. Community groups and non-government organizations have been active in rehabilitating and restoring waterways. The Outdoor Recreation Council of BC is a provincial non-government organization that has been instrumental in river conservation issues in BC. Three key initiatives have been established by the Council since its formation in 1975. BC Rivers Day has grown into the largest river celebration of its kind in North America, and there is a move to establish a national Rivers Day in Canada based on the model established in BC. Second is the annual Endangered Rivers List compiled by the Council and released each spring. The third initiative is the River Recovery Project in which dams and impoundment structures were evaluated against a set of criteria. A short list of candidates was generated by the project that will be further studied to determine what actions should be taken to alter the management of the structures to restore ecological values of the rivers and streams on which they are built. The three initiatives described rely on local community support. The Outdoor Recreation Council of BC provides coordination, promotion, and publicity as well as some resource materials while local groups and communities take on stewardship roles for their local streams. This model may be useful for other jurisdictions.