Extreme droughts as a threat to a critically endangered species in southern Europe

Date:
2018/06/15

Time:
13:45

Room:
A2 Wivi

Extreme droughts as a threat to a critically endangered species in southern Europe

(Oral)

Ronaldo Sousa
rg.eco.sousa@gmail.com

CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal., Portugal
,
André Ferreira
CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal., Portugal
,
Francisco Carvalho
CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal., Portugal
,
Manuel Lopes-Lima
CIBIO/InBIO - Research Center in Biodiversity and Genetic Resources, University of Porto, Campus Agrário de Vairão, Vairão, Portugal., Portugal
,
Simone Varandas
CITAB-UTAD - Centre for Research and Technology of Agro-Environment and Biological Sciences, University of Trás-os-Montes and Alto Douro, Forestry Department, Vila Real, Portugal., Portugal
,
Amílcar Teixeira
CIMO-ESA-IPB - Mountain Research Centre, School of Agriculture, Polytechnic Institute of Bragança, Bragança, Portugal., Portugal

DOI: 10.17011/conference/eccb2018/107145

SEE PEER REVIEW

Climate change may impair the survival of rare species. In this study we used populations of the critically endangered pearl mussel Margaritifera margaritifera (Linnaeus, 1758) colonizing several rivers in the North of Portugal (the southern limit of their distribution) to assess the effects of future climatic scenarios. Our results, based on empirical and modelling data, showed that future survival is threatened by projected declines in precipitation for the 21st century, with implication on the river flows and water depths that might decrease below the species requirements. This situation could be especially critical during summer conditions since the ecological flows may not be assured and several river stretches may be converted into stagnant isolated pools. Connectivity may also be affected with reverberating effects on the mobility of Salmo trutta, the natural host of M. margaritifera, with consequences in the reproduction and recruitment of pearl mussels. In addition, the occurrence of extreme events such as droughts may also negatively affect pearl mussels. During the extreme 2017 summer drought we assessed the mortality of M. margaritifera in several Portuguese rivers. We found that massive die-offs occurred due to the low water level and mussels were mainly found stranded near the banks. Additionally, in some sites predation by wild boars (Sus scrofa (Linnaeus, 1758)) was also important. In view of future climatic scenarios, several M. margaritifera populations in Iberia (and elsewhere) may now be more at risk and conservation measures should be urgently applied, including: the negotiation of ecological flows with dam promoters, the restoration of riparian vegetation along degraded areas, supplemental stocking of hatchery-raised M. margaritifera individuals, and careful monitoring and translocations to deeper areas or ex-situ facilities to reduce mortality rates during summer extreme droughts.

SEE PEER REVIEW

INTRO:
The authors present a study of the effects of climate change and related periods of extreme drought on pearl mussel populations in the northern Portugal. Expected climate change impacts on this critically endangered species were predicted based both on empirical data and modelling. Results indicated the necessity for urgent conservation measures.
MERITS:
Presented study provides relevant insight in the effects of climate change on pearl mussel, a highly endangered species, and identifies key conservation measures that should be urgently applied. It is an interesting study, and based on the information provided, study seems to be sound and informative for future conservation efforts, both in Portugal and in other regions throughout the species range.
CRITIQUE:
I did not observe anything that would require revision. All elements of the study seem to be sound and well developed.
DISCUSSION:
Discussion is well developed, with a list of specific conservation measures identified based on the obtained results.

- - -
INTRO:
The study assessed effects of future climatic conditions, i.e. increasing droughtness, on populations of the endangrered freshwater pearl mussel, Margaritifera margaritifera, based on empirical and modelling data, in the southern limit of the distribution range of the species.
MERITS:
M. margaritifera population in Iberian Peninsula are already now suffering from droughtness produced by increasing temperatures. Results of the study show that in the future the river flows and water depths that might decrease below the species requirements due to projected declines in precipitation for the 21st century so that the future survival of M. margaritifera is threatened. Thus, the study describes a major challenge for the conservation of the species.
CRITIQUE:
No weaknesses observed
DISCUSSION:
These results are important for the conservation of southern European populations of M. margaritifera. Important conservation measures in terms of restored ecological flows of rivers, monitoring of populations, facilities to reduce summer mortality and captive breeding programmes of the species were proposed.

- - -
INTRO:
The study focuses on the habitat change of the already endangered pearl mussel in rivers in Northern Portugal under climate change scenarios using empirical and modelling data. Results show that a further decline of rainfall, especially during summer months, will negatively affect the survival rates of pearl mussels in many aspects. The mansucript concludes with the statement that conservation measures must urgently be taken in order to secure stable pearl mussel populations.
MERITS:
The study seems to be well thought-through and conducted, yielding results that are important for further management of the thereatened pearl mussel in Portugal.
CRITIQUE:
It would be nice to know a little bit more about the data material on which the study is based
DISCUSSION:
In my opinion, especially studies dealing with water stream availability under future climate change scenarios, are of very high value as they tackle one of the most urgently needed resources of all living organisms. As such, pointing towards the shortening of water supply and change of river bed conditions, not only the implications for the species under question (the pearl mussel), but also for other species can be deduced.

Extreme droughts as a threat to a critically endangered species in southern Europe

Date:2018/06/15

Time:13:45

Room:A2 Wivi

Extreme droughts as a threat to a critically endangered species in southern Europe

(Oral)

SEE PEER REVIEW

SEE PEER REVIEW

Date:
2018/06/15

Time:
13:45

Room:
A2 Wivi