Vulnerability of stream biota to climate change in mediterranean climate regions: A synthesis of ecological responses and conservation challenges

Abstract

Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate It is change. expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human In this development. article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological We also responses. discuss current knowledge gaps and conservation Expected climate challenges. alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and Recent observations fires., which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental Accurate forecasts changes. of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding Long hydrology.-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate Investments should change. focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Scientists Africa., policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge. © 2012 Springer Science+Business Media B.V.