Conservation of catchments: some theoretical considerations and case histories from Rio de Janeiro

Abstract

Conservation has developed along two lines: protection of species and communities, and preservation of natural resources. Catchments provide the natural unit for conservation since they are the fundamental unit of terrestrial ecosystems and account for most of the flow of materials. Urban streams of the city of Rio de Janeiro are generally well protected in their headwaters by the large urban parks in steep terrain. However, the lower reaches are often very heavily impacted by sewage, channelling, etc. Fauna that require estuarine habitats for part of their life history are excluded from such streams. Ecosystem functioning in urban streams is probably changed through the loss of strongly-interacting shrimp. Leaf decomposition was found to be reduced in urban streams compared to pristine streams in one study. Conservation entities in the state of Rio de Janeiro tend to protect the mountainous areas; piedmont and coastal plain habitats are generally impacted by agriculture and habitation. Many attempts are being made to conserve catchments in the state of Rio de Janeiro; we discuss 4 case histories, which have different constraints and employ different strategies for management and conservation.

Key words: connectivity, catadromous shrimp, conservation planning and management.