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The impact of severe drought on survival, fecundity and population persistence in an endangered amphibian

February 2016
Ecosphere 7(2)

DOI:10.1002/ecs2.1246

License
CC BY 3.0

Authors:

Hugo Cayuela

Claude Bernard University Lyon 1

Dragan Arsovski

Macedonian Ecological Society

Eric Bonnaire

Office National des Forêts

Rémi Duguet

Alcedo Conseil

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Climate is globally changing. In Europe, studies have highlighted an increasing trend in both the frequency and magnitude of droughts. Abrupt changes in the frequency, location, or intensity of extreme heatwaves and droughts can have direct and severe effects on wild populations. Amphibians are the planet's most threatened group of vertebrates, with over 40% of known species considered in decline. To date, researchers have mainly focused on the influence of repeated droughts on species occurrence and community composition; however, evidence of the direct impact of climatic factors on the demographic parameters of amphibians is currently not well documented. Further investigation of this issue is therefore of critical importance in order to optimize local and global wildlife conservation policies in the context of a changing climate. This study used capture–recapture data to investigate the impact of severe drought on the survival and fecundity of a threatened amphibian, the yellow-bellied toad (Bombina variegata, L.), as well as to predict how potential changes in the frequency of droughts might influence the population growth rate. By developing multievent capture-recapture models, we showed that severe drought has a negative impact on fecundity and postmetamorphic survival at different ontogenetic stages. Then, using stochastic matrix population models, we predicted that changes in drought frequency negatively influence the population growth rate, which is a warning sign for population persistence. Direct conservation actions are then proposed to mitigate the detrimental effects of drought on population dynamics.

Variation in precipitation levels during the active period (April to September) of Bombina variegata in a population in southern France between 2010 and 2014: in blue, “standard” years; in orange, drought.

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Demographic parameters (mean and 95% CI) in a population of Bombina variegata in southern France: (a) recapture probability: circle = juvenile, triangle = subadult, cross = adult female, square = adult male, (b) breeding probability: empty circle = probability of a male breeding two consecutive times, empty square = probability of a female breeding two consecutive times, full circle = probability of a male skipping breeding two consecutive times, full square = probability of a female skipping breeding two consecutive times, (c) survival probability at three ontogenetic stages (J = juvenile, S = subadult, A = adult) in standard conditions (blue) and during a drought (orange), (d) Fecundity in standard conditions (blue) and during a drought (orange), (e) predicted population growth rate according to drought frequency (from 1 drought every year to 1 drought every 10 yr).

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v v Article e012461v

IntroductIon

     -

       -

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     



       

        

     -

      

      -

       

       -



     





†23412

1UMR 5023 LEHNA, Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés,

CNRS, Université Lyon 1, 69100 Villeurbanne, France

2CEFE UMR 5175, CNRS – Université de Montpellier – Université Paul-Valéry Montpellier – EPHE, Laboratoire

Biogéographie et Ecologie des Vertébrés, 1919 Route de Mende, 34293 Montpellier Cedex 5, France

3Oce National des Forêts, Agence de Verdun, 55100, Verdun, France

4Alcedo Faune Flore, Quartier Le Fez, 07110, Sanilhac, France

Citation:





Abstract.

-





    

      -







Bombina varie-

gata-





  

-



Key words:Bombina variegata

Received

† E-mail:



v v Article e012462 v www.esajournals.org

CAYUELA ET AL.

-



     

       



      -

       







     





      



 

-



-



 -

  

   

Bufo bufo

    Triturus cristatus   

  

 T. cristatus

Ambysto-

ma tigrinum



Rana sevosaAmbystoma

opacum

Gyrinophilus porphy-

riticus



     

     

  

     

      

     

       



 



      





    Bombina varie-

gata 

      

      



       

        

    



-



       



    -

     B variegata  



        -

 



     -

 



     

      -

       



      -

-



    

      -

      

      -

     

-





Methods

Study area and ﬁeld sampling

      

of B variegata     -

    -

       

       

      



   

      

       

    

      

       

v v Article e012463 v www.esajournals.org

CAYUELA ET AL.

      -

     

     

      -

      

         



       

       



      

      

      

  

 

-

  



       

    



-

       



 

-

        

    

-

     



    

       

       

      



       

       

    

     





    -

-



Multievent capture–recapture model

       

       

       

     

         

     

      

     

     -

     

        

     -

    

      

       

       

      

        

          

      

       

       -

       

      



 -

      -

     

    

       -

      

       

       

       

  



 

     

       Bombina

variegata





v v Article e012464 v www.esajournals.org

CAYUELA ET AL.

-





     

   αα 



α

ββββ



 -

    



 

     

     

      -





 φ φ

  φφ  φφ 

       

      



     

  -

-

      

     

  -

    

       

    -





-



⎛⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎝

1−𝛼

0𝛼

JM 0 0 0 0 0 000

01−𝛼JF 0𝛼JF

0 0 0 0 000

00𝛽JM 01−𝛽JM

0 0 0 000

0 00𝛽JF 01−𝛽JF

0 0 000

0 0 00 𝛽SM 01−𝛽SM

0 000

0 0 00 0 𝛽SF 01−𝛽SF

000

0 0 0 0 0 0 1 0 000

0 0 0 0 0 0 0 1 000

0 0 0 0 0 0 0 0 100

0 0 0 0 0 0 0 0 010

0 0 0 0 0 0 0 0 001

⎞⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎠

⎛⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎝

10 0 0 0 0 0 0 0 0 0

01 0 0 0 0 0 0 0 0 0

00𝜙JM 000 0 0 0 0 1−𝜙JM

00 0 𝜙JF 0000 0 0 1−𝜙JF

00 0 0 𝜙SM 000 0 01−𝜙SM

00 0 0 0 𝜙SF 00 0 01−𝜙SF

00 0 0 0 0 𝜙BM 0 0 01−𝜙BM

00 0 0 0 0 0 𝜙BF 0 01−𝜙BF

00 0 0 0 0 0 0 𝜙NBM 01−𝜙NBM

00 0 0 0 0 0 0 0 𝜙NBF 1−𝜙NBF

00 0 0 0 0 0 0 0 0 1

⎞⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎠

(2)

(1)

v v Article e012465 v www.esajournals.org

CAYUELA ET AL.



   γγ 

γγ 



sensu

    -

-





(4)

      

-



Biological scenarios using the E- SURGE program

    

      

     

     -

   

    

 -

      

 α ϕ   γ p(-

        



      

    -

  



 

     -

       

      -

       

-

       



      

     



-





     -

     -



     

t

   t       



     

  

  -





Simulation matrix model

      



  

⎛⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎝

100000 0 0 0 0 0

010000 0 0 0 0 0

001000 0 0 0 0 0

000100 0 0 0 0 0

000010 0 0 0 0 0

000001 0 0 0 0 0

000000 𝛾BM 01−𝛾BM

000000 0 𝛾BF 01−𝛾BF 0

0000001−𝛾NBM 0𝛾NBM

000000 0 1−𝛾NBF 0𝛾NBF 0

000000 0 0 0 0 1

⎞⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎠

⎛⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎝

1 00 00

1−pJM pJM

000

1−pJF pJF

000

1−pSM 0pSM

1−pSF 0pSF

1−pBM 00pBM 0

1−pBF 000pBF

1 00 00

⎞⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎠

(3)

v v Article e012466 v www.esajournals.org

CAYUELA ET AL.

    

   



(5)

     1 

2

      

-



     t  

female at t   

      -

  



    

       

-

      -

        -

    



         

     k 

      

     

tkt0k

       





result

        

      

      

(00F

∗

S2S3)



 

α 

α 

β 

β 

β 

β 

φ 

φ 

φ 

φ 

φ 

φ 

φ 

φ 



γ tt

γ tt

γ 



γ 



p 



p 



p 



p 



p 



p 



v v Article e012467 v www.esajournals.org

CAYUELA ET AL.

      -

       



       

       

        

        

        

      

  

     α

φγ p  





    

        -

     

      

       

       



       -

      

  

 

       -

     

  

Bombina variegata

rk-



      



r    kDev 

1  YEAR  24  

2  YEAR  22  

3  YEAR  21  

4  YEAR    

5 DRY  YEAR  18  

6 DRY  YEAR  20  

7  YEAR  17  

8  YEAR    

   YEAR YEAR 21  

10   YEAR YEAR   

11   YEAR YEAR 18  

12   YEAR YEAR 16  

13 DRY  YEAR YEAR 15  

14 DRY  YEAR YEAR 17  

15   YEAR YEAR 14  

16   YEAR YEAR 16  

17   YEAR  21  

18   YEAR    

   YEAR  16  

20   YEAR  18  

21 DRY  YEAR  15  

22 DRY  YEAR  17  

23   YEAR  14  

24   YEAR  16  

25   YEAR  17  

26   YEAR  15  

27   YEAR  14  

28   YEAR  12  

 DRY  YEAR  11  

30 DRY  YEAR  13  

31   YEAR  10  

32   YEAR  12  

v v Article e012468 v www.esajournals.org

CAYUELA ET AL.

 

      



     

       



       



dIscussIon



       

     B. variegata

     



      

    

Fecundity is impacted by drought events

      

     

      

     



       

   B variegata  

      

Bombina variegata

         

             

   











v v Article e01246 v www.esajournals.org

CAYUELA ET AL.



  

        



 

    

    

      

  

       -



      

      -

       

       -

       

       

        

      -

      

         



Survival probability is impacted by age and drought

       -

      

      

      

        

       

         

     

  



       -

        -

 

       

 B variegata     



     

     

      

    -

    

     



     

      

     



       

      

 B variegata     -

     

      

      

     

      

     

      



Population growth rate is impacted by

drought frequency

     

     

      



       

      

       

     

      -

 

        

         

          

      

        B variegata

     

      

        

     

     -

  

      

     

     -

     

Conservation recommendations

      



for B. variegata    -

      

     

       -

     



    -

      

v v Article e0124610 v www.esajournals.org

CAYUELA ET AL.

      -

      

Bombina variegata



-





      

    

 -

     -

     





-



       

     

      

    

  

       

       

 

      -

       





-

-

 



      -



 

     

      -



       

        

     

      -



 



 

     -

   



-

      -

  

      

     

      

     

      -

     



-

      

      

-

       



     

B. variegata

AcknowledgMents

       

   

       

       

      

  

      

 

lIterAture cIted



   



-

  

(Rana sylvatica

       

Bombina

variegata

       

     

       

     



-

     -



         

        

      Bombina

variegata







v v Article e0124611 v www.esajournals.org

CAYUELA ET AL.

-



        

  

-

      



         







   

      -

   in   

   

    



-



    Ambystoma tigri-

num

-

-







-



-

  

  -



 -

       

    in     

-

       -

  

-

      -



      

    





-

 -

  



          

      -

     





      -

      





  -

 



        

   

   



          

    

  -









   

-



     Bombina Pelo-

phylaxRana

-

   





        

  Bombina variegata   

       





         

      







      

    



  -

        -

    Bombina variegata -

    





      

    



     





     

    

  



v v Article e0124612 v www.esajournals.org

CAYUELA ET AL.

       

     

Bombina variegata et Bufo calamita



         

-

    

 -

-



     -



-



        -

 Bombina variegata

      



    -



 

      Bombi-

na variegata    





-



        -



    



           

     

Rana sevosa

-



          

      -

      







     

-











           

     -

    



         

       

-



          -







        





-



  -





 

   

-

    









     -



  -

-



 

       -

      



        





   

     

  -

    



Complex Organisms Must Deal with Complex Threats: How Does Amphibian Conservation Deal with Biphasic Life Cycles?

Article

Full-text available

May 2023

Simple Summary Programs to conserve biphasic amphibians may fail if threats at different life stages are not addressed. Anthropogenic threats, such as altered hydroperiods and water pollution, exacerbate the already high natural rates of mortality at the aquatic egg and larval stage, while the terrestrial life stage is threatened by disease and habitat destruction. Threats at both of these life stages influence population viability. However, our examination of the literature suggests that studies rarely address threats to both life stages, and conservation actions rarely attempt to manage threats across the life cycle. The conservation of biphasic amphibians may thus be substantially improved by applying multiple conservation actions that deal with specific anthropogenic threats across all life stages. Abstract The unprecedented rate of global amphibian decline is attributed to The Anthropocene, with human actions triggering the Sixth Mass Extinction Event. Amphibians have suffered some of the most extreme declines, and their lack of response to conservation actions may reflect challenges faced by taxa that exhibit biphasic life histories. There is an urgent need to ensure that conservation measures are cost-effective and yield positive outcomes. Many conservation actions have failed to meet their intended goals of bolstering populations to ensure the persistence of species into the future. We suggest that past conservation efforts have not considered how different threats influence multiple life stages of amphibians, potentially leading to suboptimal outcomes for their conservation. Our review highlights the multitude of threats amphibians face at each life stage and the conservation actions used to mitigate these threats. We also draw attention to the paucity of studies that have employed multiple actions across more than one life stage. Conservation programs for biphasic amphibians, and the research that guides them, lack a multi-pronged approach to deal with multiple threats across the lifecycle. Conservation management programs must recognise the changing threat landscape for biphasic amphibians to reduce their notoriety as the most threatened vertebrate taxa globally.

Severe wildfires promoted by climate change negatively impact forest amphibian metacommunities

Article

Full-text available

Apr 2023
DIVERS DISTRIB

Aim Changes to the extent and severity of wildfires driven by anthropogenic climate change are predicted to have compounding negative consequences for ecological communities. While there is evidence that severe weather events like drought impact amphibian communities, the effects of wildfire on such communities are not well understood. The impact of wildfire on amphibian communities and species is likely to vary, owing to the diversity of their life‐history traits. However, no previous research has identified commonalities among the amphibians at most risk from wildfire, limiting conservation initiatives in the aftermath of severe wildfire. We aimed to investigate the impacts of the unprecedented 2019–2020 black summer bushfires on Australian forest amphibian communities. Location Eastern coast of New South Wales, Australia. Methods We conducted visual encounter surveys and passive acoustic monitoring across 411 sites within two regions, one in northeast and one in southeast New South Wales. We used fire severity and extent mapping in two multispecies occupancy models to assess the impacts of fire on 35 forest amphibian species. Results We demonstrate a negative influence of severe fire extent on metacommunity occupancy and species richness in the south with weaker effects in the north—reflective of the less severe fires that occurred in this region. Both threatened and common species were impacted by severe wildfire extent. Occupancy of burrowing species and rain forest specialists had mostly negative relationships with severe wildfire extent, while arboreal amphibians had neutral relationships. Main Conclusion Metacommunity monitoring and adaptive conservation strategies are needed to account for common species after severe climatic events. Ecological, morphological and life‐history variation drives the susceptibility of amphibians to wildfires. We document the first evidence of climate change‐driven wildfires impacting temperate forest amphibian communities across a broad geographic area, which raises serious concern for the persistence of amphibians under an increasingly fire‐prone climate.

Corridor quality buffers extinction under extreme droughts in experimental metapopulations

Article

Full-text available

Jun 2023

Corridors with good-quality habitats maintain the spatial dynamics of metapopulations by promoting dispersal between habitat patches, potentially buffering populations, and communities against continued global change. However, this function is threatened by habitats becoming increasingly fragmented, and habitat matrices becoming increasingly inhospitable, potentially reducing the resilience and persistence of populations. Yet, we lack a clear understanding of how reduced corridor quality interacts with rates of environmental change to destabilize populations. Using laboratory microcosms containing metapopulations of the Collembola Folsomia candida, we investigate the impact of corridor quality on metapopulation persistence under a range of simulated droughts, a key stressor for this species. We manipulated both drought severity and the number of patches affected by drought across landscapes connected by either good- or poor-quality corridors. We measured the time of metapopulation extinction, the maximum rate of metapopulation decline, and the variability of abundance among patches as criteria to evaluate the persistence ability of metapopulations. We show that while drought severity negatively influenced the time of metapopulation extinction and the increase in drought patches caused metapopulation decline, these results were mitigated by good-quality corridors, which increased metapopulation persistence time and decreased both how fast metapopulations declined and the interpatch variability in abundances. Our results suggest that enhancing corridor quality can increase the persistence of metapopulations, increasing the time available for conservation actions to take effect, and/or for species to adapt or move in the face of continued stress. Given that fragmentation increases the isolation of habitats, improving the quality of habitat corridors may provide a useful strategy to enhance the resistance of spatially structured populations.

Influence of landscape connectivity on newt’s response to a warmer climate

Article

Full-text available

May 2023
LANDSCAPE ECOL

Context Climate change and habitat fragmentation exert considerable pressures on biodiversity. The spatial distribution of microclimatic refuges in the landscape can influence species responses to warming climates. Objectives Using a semi-natural experiment, we investigated the potential synergetic effects of climate warming and habitat connectivity on a single amphibian species. Methods We monitored populations of the palmate newt, Lissotriton helveticus, under two climate treatments, a warmer climate (+ ~ 2 °C) or a present-day climate, in mesocosms either isolated or connected to the other climatic conditions. We assessed the abundance and phenotype (snout-vent length, body condition and skin coloration: darkness and redness) of juvenile and adult newts, and the dispersal propensity of juveniles. Results Over the 4 years of climatic manipulation, populations tended to increase more in the present-day than in the warmer climate. Warmer climates decreased the abundance of adult newts and altered the phenotypic composition of populations with darker and less red newts. However, connectivity between the two climates cancelled out the effect of a warmer climate on abundance and reversed the effects on phenotype composition. We further found that juvenile newts from the present-day climate treatment tended to emigrate more from warmer conditions during our laboratory dispersal assay and that population isolation disrupted a common covariation between emigration propensity and body size, leg length and skin darkness. Conclusions Our results point to a synergetic effect of climate warming and fragmentation on the demography of newt populations and emigration decisions of juveniles, suggesting that microclimate refuges and their accessibility play a key role in buffering the impacts of climate warming, with potential implications for amphibian diversity at a regional scale.

Drought, fire, and rainforest endemics: A case study of two threatened frogs impacted by Australia's “Black Summer”

Article

Full-text available

May 2023

Deepening droughts and unprecedented wildfires are at the leading edge of climate change. Such events pose an emerging threat to species maladapted to these perturbations, with the potential for steeper declines than may be inferred from the gradual erosion of their climatic niche. This study focused on two species of amphibians-Philoria kundagungan and Philoria richmondensis (Limnodynastidae)-from the Gondwanan rainforests of eastern Australia that were extensively affected by the "Black Summer" megafires of 2019/2020 and the severe drought associated with them. We sought to assess the impact of these perturbations by quantifying the extent of habitat affected by fire, assessing patterns of occurrence and abundance of calling males post-fire, and comparing post-fire occurrence and abundance with that observed pre-fire. Some 30% of potentially suitable habitat for P. kundagungan was fire affected, and 12% for P. richmondensis. Field surveys revealed persistence in some burnt rainforest; however, both species were detected at a higher proportion of unburnt sites. There was a clear negative effect of fire on the probability of site occupancy, abundance and the probability of persistence for P. kundagungan. For P. richmondensis, effects of fire were less evident due to the limited penetration of fire into core habitat; however, occupancy rates and abundance of calling males were depressed during the severe drought that prevailed just prior to the fires, with the reappearance of calling males linked to the degree of rehydration of breeding habitat post-fire. Our results highlight the possibility that severe negative impacts of climate change for montane rainforest endemics may be felt much sooner than commonly anticipated under a scenario of gradual (decadal-scale) changes in mean climatic conditions. Instead, the increased rate of severe stochastic events places these narrow range species at a heightened risk of extinction in the near-term.

Amphibian Ecophysiology

Chapter

Apr 2023

Habitat connectivity buffers extinction under extreme droughts in experimental metapopulations

Preprint

Jan 2023

Connectivity maintains the spatial dynamics of metapopulations by promoting dispersal between habitat patches, potentially buffering populations and communities against continued global change. However, this function is threatened by habitats becoming increasingly fragmented, and habitat matrices becoming increasingly inhospitable, potentially reducing the resilience and persistence of populations. Yet, we lack a clear understanding of how reduced connectivity interacts with rates of environmental change to destabilise populations. Using laboratory microcosms containing metapopulations of the Collembola Folsomia candida , we investigate the impact of habitat connectivity on metapopulation persistence under a range of simulated droughts, a key stressor for this species. We manipulated both drought severity and the number of patches affected by drought across landscapes connected by either good or poor-quality corridors. We measured the time of population extinction, the maximum rate of population decline, and the variability of abundance among patches as criteria to evaluate the persistence ability of metapopulations. We show that whilst drought severity and number of drought-affected patches negatively influenced population persistence, these results were mitigated by increased habitat connectivity, which increased population persistence time and decreased both how fast populations declined and the variability in abundance among patches. Our results suggest that enhancing spatial connectivity can increase the persistence of metapopulations, increasing the time available for conservation actions to take effect, and/or for species to adapt or move in the face of continued stress. Given that fragmentation increases the isolation of habitats, improving habitat connectivity by using good quality corridors may provide a useful strategy to enhance the resistance of spatially structured populations.

Reproductive ecology of Anuran Amphibians: Effects of internal and external factors

Article

Full-text available

Jun 2023

This research paper examines the influence of internal factors (female body weight, body condition) and external ecological factors on the reproductive parameters of females, as well as on the reproductive ecology of adult individuals of anuran amphibians. Among the most significant reproductive characteristics of females are the number of eggs in a clutch, the proportion of reproductive products to female body weight (contribution to reproduction), and the average weight of eggs. The body weight of the female and the ecological (meteorological) conditions of her activity during the year preceding spawning, as well as the hibernation conditions, have the greatest impact on the quantitative expression of these parameters. The proportion of reproductive products to female body weight in anuran amphibians usually ranges from 13 to 30%. Climate warming can directly affect the reproductive parameters of females, the survival of metamorphs, and the phenology of the spawning period.

Review of Various Impacts of Climate Change in South Asia Region, Specifically Pakistan

Chapter

Full-text available

Feb 2023

Climate change is a dire and increasing crisis worldwide in South Asian region, especially Pakistan. This region is highly vulnerable to climate change, while awareness of climate change issues and adaptation strategies is very low. Pakistan faces a perpetual threat in its ecosystem, biodiversity, and oceans. Much of the country’s threats stem from poverty, a lack of financial resources, and natural disasters. Pakistan endures ongoing seasonal changes, including extreme climate events, an ongoing shortage of water, pest diseases, human health issues, and more. The country has a low adaptive capacity to these threats, given its ongoing economic struggles and varying living conditions from season to season. The likely effects of climate change on the common Pakistani citizens are devastating, especially for local animals like lions, tortoises, dolphins, and vultures. These animals, regardless of their small global impact, will face extinction. In fact, the effects on local people, such as the per capita impact on global greenhouse gas emissions, are severe. The findings of this review support the theory that GHG emissions cause climate change. The effects of this global phenomenon have been seen in Pakistan in agriculture, livestock, precipitation and temperature trends and patterns, food and energy reliability, water resources, and community. According to a recent sectorial assessment, this review evaluates climate change alleviation and adaptation techniques in the sectors mentioned above, which caused a huge economic loss in Pakistan every year. A new study finds that governmental intervention is necessary for recent climate policy development. The research suggested that strict accountability of resources and regulatory actions are vital to creating climate policy.

Rôle écologique des bassins d’orage routiers pour les amphibiens

Thesis

Full-text available

Sep 2022

Antonin Conan

Les bassins d’orage routiers (BO) sont retrouvés le long des routes afin de dépolluer les eaux de chaussée avant rejet dans l’environnement. Malgré la pollution, ces BO sont colonisés par les amphibiens. Dans le Bas-Rhin, paysage très modifié avec peu de zones humides naturelles, les amphibiens se reproduisent dans des sites de substitution comme les BO. Durant ma thèse, je me suis intéressé à l’utilisation des BO par les grenouilles vertes & le Crapaud vert, afin d’évaluer leur rôle écologique. Les résultats indiquent que les BO du Bas-Rhin sont des pièges écologiques, mais uniquement en présence d’une forte densité de sangsues prédatrices de têtards, et non pas à cause de la pollution. Cloisonner ces BO afin d’en interdire l’accès par les amphibiens n’est toutefois pas pertinent. En effet, même si cette thèse a démontré l’efficacité de différentes clôtures pour empêcher la majorité des amphibiens de traverser une route, elle a aussi souligné le rôle relais des BO à la connectivité paysagère, évitant l’isolement des populations étudiées. Dans les paysages très modifiés, il est alors préférable d’améliorer les BO en réalisant une gestion adaptée en fonction des amphibiens.

Régression de Bombina variegata (Linné, 1758) en France par l’analyse de sa répartition passée et actuelle

Article

Full-text available

Jan 2011

The classification history of European Bombina is recalled. The past distribution of Bombina variegata in France is related: its range expanded until the Landes, Pyrénées-Orientales, Bouches-du-Rhône, Bretagne sides and Nord department. B. variegata was never reported in the following departments: Alpes-Maritimes, Var, Ariège, Hautes-Pyrénées, Lot-et-Garonne, Gers, Tarn, Tarn-et-Garonne, Aveyron, Morbihan, Finistère, Côtes d’Armor, Ille-et-Vilaine, Manche, Hautsde- Seine, Seine-Saint-Denis, Oise, Pas-de-Calais. It was erronneously reported from Lozère and Pyrénées-Atlantiques. It does not reach the Nord and Pas-de-Calais seaside. Its decline, started in the 19th century, increased during the last forty years.

Interactions between climate and habitat loss effects on biodiversity: a systematic review and meta‐analysis

Article

Full-text available

May 2013
GLOBAL CHANGE BIOL

MASSEMIN D. et CHEYLAN M. (2001) - Eléments bibliographiques sur le statut passé et actuel du sonneur à ventre jaune Bombina variegata (L.) (Anura ; Discoglossidae) en région méditerranéenne française. Bull. Soc. Herp. Fr. 97 : 41-47.

Article

Full-text available

Jan 2001

Highlighting the effects of land-use change on a threatened amphibian in a human-dominated landscape

Article

Full-text available

Apr 2015

In Western Europe, habitat loss and landscape fragmentation has led to significant population decline in various animal groups, including amphibians. The extinction of the last natural populations of the yellow-bellied toad in Belgium, Luxembourg and several regions of southern and western France suggests a widespread decline. By using site-occupancy models and adding covariates corresponding to the human-influenced features of the landscape, we tried to identify the relative effects of different land-use types on the species’ distribution pattern in a man-made environment (the Alsatian Rhine floodplain in France). We recorded presence-absence data in 150 forest sample plots (300 × 300 m) and then modeled species distribution while taking into account detection errors in the field. Land-use was recorded on two spatial scales: within the forest sample plots and in a 1500 m radius buffer area around the forest plots. In the forest plots, toad occurrence was negatively correlated with loss of forest cover to agricultural land. In contrast, occurrence is positively correlated with the density of human-made rutted dirt paths and tracks, which provide semi-natural breeding sites. In the 1500 m radius buffer zones around forest plots, toad occurrence was negatively correlated with the density of urbanization and road networks. These results can be used to plan conservation strategies for amphibians in human-dominated landscapes.

A scanning electron microscopic study of the surface morphology of nuptial pads in male amphibians (Genus: Bombina, Pelophylax, Rana)

Article

Full-text available

Jun 2012

The fine structure of nuptial pad surface of the anuran amphibians Bom-bina variegata, Pelophylax epeiroticus, Pelophylax ridibundus and Rana dalmatina, was examined by scanning electron microscopy. Nuptial pads are cutaneous second-ary sexual characters of males that appear during the breeding season and disappear afterwards following an annual cycle. In males of P. epeiroticus, P. ridibundus and R. dalmatina, nuptial pads were observed on the ventrolateral aspect of the first digit (the thumb) as darkish and remarkably keratinized papillae. In males of B. variega-ta nuptial pads were almost black and very visible on the thumb, the second and the third digit of the front legs. They also extended on the ventral surface of the forearms. Under scanning electron microscope numerous small papillae were observed rising above pad's surface. In P. epeiroticus, P. ridibundus and R. dalmatina, these papillae were almost rounded at the base while at the dome shaped top they had many micro-processes organised in groups, thus assuming the shape of a "flower" which differed slightly among these three ranid species. In B. variegata the protuberances were coni-cal with heavily keratinized hooks without microprocesses. Our results show that sur-face morphology of nuptial pads is unique for each species and could be considered as a species-specific character.

Decline of an endangered amphibian during an extreme climatic event

Article

Full-text available

Nov 2012

Climate change is a poorly understood, emerging threat to many amphibian species. One of the ways climate change is likely to affect amphibians is through increased recruitment failure associated with more frequent climatic extremes. To understand the risk posed by this threat, we combined 13 years of annual monitoring and multi-scaled habitat modelling at the site (n=60), pool (n=105) and nest (n=170) levels to investigate the decline of the endangered northern corroboree frog (Pseudophryne pengilleyi), during the most severe drought on record in southern Australia. We documented the local extinction of 42% of P. pengilleyi breeding sites during the climatic extreme. Using logistic regression we investigated habitat variables associated with extinction sites. We found that locally extinct sites now resemble historically absent sites, with fewer pools, less water, and drying-related tree invasion. Extended periods of limited water availability at extinction sites is likely to have restricted breeding, contributing to localised extinctions. Habitat variables recorded at the pool and nest level did not significantly influence P. pengilleyi presence/absence, indicating that site level wetness had an overriding effect. We anticipate that increasing climate variability is likely to disproportionately threaten seasonal pool-breeding amphibian species, exacerbating the global amphibian biodiversity crisis. However, our work with P. pengilleyi suggests there are a range of simple habitat manipulations that could help to ameliorate the impacts.

ESTIMATING TEMPORARY EMIGRATION USING CAPTURE–RECAPTURE DATA WITH POLLOCK’S ROBUST DESIGN

Article

Mar 1997

Climate change 2001: Impacts, adaptation, and vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC)

Article

Jan 2001
GLOBAL ECOL BIOGEOGR

Landscape context influences chytrid fungus distribution in an endangered European amphibian

Article

Apr 2015
ANIM CONSERV

Wildlife disease is an emerging threat to biodiversity. The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis, has been documented in over 500 amphibian species globally. Understanding conditions under which amphibians are vulnerable to Bd is important for evaluating species risk and developing surveillance strategies. Here, we investigate the spatial distribution of Bd infection in the ephemeral pond-breeding yellow-bellied toad Bombina variegata, a species of high conservation concern in the European Union. We sampled 550 toads from 60 ponds in a traditional agricultural landscape in Southern Transylvania, Romania. Overall, Bd prevalence was low in B. variegata, but infected toads were widely dispersed through the landscape and were found in a quarter of all sampled ephemeral ponds. At the pond level, increased Bd occurrence was associated with short distances to perennial water sources and high forest cover. These findings suggest that perennial water sources may act as source habitat for Bd, with amphibian movements resulting in Bd spillover into ephemeral ponds. Increased Bd occurrence in ponds surrounded by high levels of forest cover is likely related to cooler and wetter conditions that are more favourable for Bd. Throughout the study landscape, patchy environmental suitability for Bd appears to restrict the pathogen to a subset of B. variegata habitat. Ephemeral ponds in open landscapes, without nearby perennial habitat, likely provide an environmental refuge from Bd, where the risk of infection is low. From a conservation perspective, these findings highlight the importance of maintaining ephemeral ponds in open landscapes, but these are currently threatened by land-use change.

The effects of climate change and land-use change on demographic rates and population viability

Article

Aug 2014
BIOL REV

Understanding the processes that lead to species extinctions is vital for lessening pressures on biodiversity. While species diversity, presence and abundance are most commonly used to measure the effects of human pressures, demographic responses give a more proximal indication of how pressures affect population viability and contribute to extinction risk. We reviewed how demographic rates are affected by the major anthropogenic pressures, changed landscape condition caused by human land use, and climate change. We synthesized the results of 147 empirical studies to compare the relative effect size of climate and landscape condition on birth, death, immigration and emigration rates in plant and animal populations. While changed landscape condition is recognized as the major driver of species declines and losses worldwide, we found that, on average, climate variables had equally strong effects on demographic rates in plant and animal populations. This is significant given that the pressures of climate change will continue to intensify in coming decades. The effects of climate change on some populations may be underestimated because changes in climate conditions during critical windows of species life cycles may have disproportionate effects on demographic rates. The combined pressures of land-use change and climate change may result in species declines and extinctions occurring faster than otherwise predicted, particularly if their effects are multiplicative.