Webinar: Programa Doutoral em Ciências da Terra e do Espaço; UC: Seminário I (Física da Atmosfera e do Clima)
Ecological status assessment of intermittent rivers: challenges and new approaches
Maria Helena Novais
Investigadora PostDoc – Cátedra Energias Renováveis (CER), Laboratória da Água e ICT, Universidade de Évora
23 April 2020, 16:00, ZOOM: Register in advance for this meeting:
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Intermittent rivers can be defined as lotic ecosystems in which water sometimes stop flowing and many systems also experience a partial or complete loss of surface water. Estimates on the global occurrence of this phenomenon suggest that more than a half of the channels comprised in river networks periodically cease to flow or dry, reaching 80% of the total watercourses in some regions. In Southern Portugal, these systems are estimated to represent more than 70% of the river network. The study of these systems is therefore a critical and timely issue, due to their worldwide increase triggered by several causes, climate change included.
There is a need for a deep understanding of the way the biota inhabiting intermittent rivers responds to water intermittency and to the longitudinal, lateral and vertical contraction/expansion events, up to the greatest contraction when the entire riverbed is dry.
For a long time, benthic diatoms have been considered good ecolog ical indicators, being currently included in the Water Framework Directive (WFD, Directive, 2000/60/EC) as proxies for biomonitoring the ecological status of rivers. However, only the biota present during the flowing phase is currently considered, leaving out the dry phase and giving an incomplete idea of the habitat quality in these ecosystems. Therefore, additions to current methods for ecological status assessment should be implemented, contributing to the improvement of management practices throughout the year, considering the aquatic regimes and states of the rivers.