Advisor(s)
Abstract(s)
Droughts can change the distribution and
alter the behaviour, phenology and physiology of
many species, leading in extreme cases to high
mortalities or even extirpation. In this study, a
before/after comparison was performed in two Portuguese
river basins (Rabac¸al and Tuela) to assess the
possible effects of an extreme drought on the abundance
and size structure of two pearl mussel Margaritifera
margaritifera populations, a Critically
Endangered species in Europe. The hydrological year
of 2017 was extremely dry in Portugal and this
situation was responsible for a major reduction of the
river flow and rapid decrease in the water levels during
summer. One year after the drought, a significant
reduction in abundance was observed (i.e. 27.6% for
the Rabac¸al and 38.7% for the Tuela basin populations).
However, no differences were detected in the
size structure of the two pearl mussel populations.
Droughts are predicted to increase in number and
intensity and it is crucial to monitor M. margaritifera
populations, given the low resistance (and possibly
low resilience) of this species to these extreme
conditions. Management measures that could help
the conservation of pearl mussels are discussed.
Description
Keywords
Climate change Conservation Extreme climatic events Mortality Resilience Resistance
Citation
Nogueira, Joana Garrido; Lopes-Lima, Manuel; Varandas, Simone; Teixeira, Amílcar; Sousa, Ronaldo (2019). Effects of an extreme drought on the endangered pearl mussel Margaritifera margaritifera: a before/after assessment. Hydrobiologia. ISSN 0018-8158. p. 1-11