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Anurans in the semi-arid Caatingas: convergence, divergence, and implications for global warming

Anurans in the semi-arid Caatingas: convergence, divergence, and implications for global warming Carlos A. Navas Universidade de São Paulo - Brazil. I - Why caatingas, why anurans. Projections of Climate Change in North Eastern Brazil for 2010-2100*

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Anurans in the semi-arid Caatingas: convergence, divergence, and implications for global warming

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  1. Anurans in the semi-arid Caatingas: convergence,divergence, and implications for global warming Carlos A. Navas Universidade de São Paulo - Brazil

  2. I - Why caatingas, why anurans • Projections of Climate Change in North Eastern Brazil for 2010-2100* • Rainfallreduction, more intenseby 2071-2100. • - Increasein airtemperatureby 2-3 C in 2010-2040, andby more than 4 C by 2071-2100. • - Increasein thefrequencyof hot daysandnights, andheatwaves. • - Waterdeficitsvaryingbetween 2-3 mm/day in 2010-2040 and 6-9 mm/dayby 2071-2100. • - Aridization andpossibledesertification in partsofthesemiaridland Brazilian Institute for Geography and Statistics * According to models by J. Marengo et al., CCST/INPE - Brazil

  3. More rain Two-month period Less rain Models by J. Marengo et al., CCST/INPE - Brazil Year Interval for prediction

  4. Despite its semi-arid nature , the Caatinga is home to 40+ anuran species Rhinella granulosa Phyllomedusa nordestina Scinax eurydice Dermatonotus muelleri Proceratophrys cristiceps Physalaemus gracilis Corythomantis greeningi Adenomera sp. Leptodactylus ocellatus Dendropsophus minutus Rhinella jimi Pseudis bolbodactyla

  5. Likely, anurans have colonized the Caatinga via permanence during a process of aridization lasting 10000 years After further aridization? Before aridization After aridization

  6. So, why Caatingas, why anurans… • Caatingas are a recent semi-arid biome, present only in Brazil and in great risk due to climate change. Anurans are expected to be at particular risk in the predicted scenarios. • The anuran community of the Caatingas reflects a diverse and evolutionarily-recent subset of lineages derived from Cerrado, Atlantic Forest and Amazonian Rainforest. • We do not know if these species and populations differ from related stock from more moderate biomes.

  7. What is next? How to start? Why Caatinga anurans are vulnerable to climate warming and eventually… Why semi-arid anurans are vulnerable to climate warming

  8. Can we propose valid generalizations for anurans is the Caatinga? • Do Caatinga anuran species share enough aspects of natural history as to propose valid generalizations about how they will be affected by climate change? • Valid generalizations: common consequences of climate change due to shared aspects of natural history and physiology.

  9. Conservation of habits and physiology? Leptodactylus ocellatus

  10. Some species displays integrated physiology and behavior that result in keen ability to detect humid microhabitats Specialization on microhabitat selection and sensorial physiology? Corytomantis greeningi Humid cotton fluff RH= 40% 1 cm. Navas, Jared et al. 2002

  11. Habitat generalist specialized on water uptake? Bufo jimmi Prates & Navas, 2009

  12. Behavioral conservation and physiological specialization? Juvenile R. jimmi and R. granulosa B. granulosus, C. Jared > 45 °C B. Boreas (Wildherps) B. americanus, Lookoutnow B. alvarius, J.P. Clare B. calamita, M. Emmers B. marinus, R. Shine

  13. Behavioral conservation and physiological specialization? Juvenile Bufo jimmi and B. granulosus 120 100 80 R. granulosa (juvenile) CS residual activity (% of normal at 30oC) 60 40 R. granulosa R. icterica 20 R. jimi 0 0 10 20 30 40 50 60 70 Incubation time at 50oC (min) Navas, Carvalho et al., 2007

  14. Is water proofing enough? Phyllomedusa P. distinctaAtlantic forest P. burmeisteri Semi-deciduous forest P. azureaChaco, Cerrado P. nordestinaCaatingas P. bicolorAmazonian forest P. ayeaye Cerrado (restricted) hypochondrialisgroup ? burmeisteri group

  15. Aestivation seems diverse among Caatinga anurans Bufo jimmi, no aestivation? Pleurodema, Atypical aestivation? Bufo granulosus, facultative aestivation? Proceratophrys, Dermatonotus and others, Typical aestivation?

  16. Possible specialization: Aestivation with vertical migration in Pleurodema 125.0 100.0 75.0 Depth (cm) 50.0 25.0 0.0 4 6 9 Time after last rain (months) 30.0 Soluble Protein concentration (mg/g of humid tissue) 24.0 18.0 12.0 6.0 0.0 Rains Drought Speed (m/s) 0.50 0.40 0.30 0.20 90% RH 0.10 0.00 Active Aestivating Pereira et al., não publicado

  17. Conclusions • Anuran life in the Caatinga involves behavioral, ecological and physiological traits that vary in relative importance among lineages. • Due to microhabitat choice and behavior, species are likely to differ in the type and magnitude of physiological challenges.

  18. Proposal • Given this diversity, it is difficult to generalize about consequences of climate change for Caatinga anurans. • The most productive generalizations regarding impact of climate change on semi-arid anurans may be based on ecological convergence across lineages. Predicted climatic change Expected highest impact • Rainfall reduction Microhabitat specialists • Increase in air temperature by 2-4 C Spp. with diurnal juveniles • Water deficits (longer dry seasons) Typical aestivators • Aridization and possible desertification Refugia specialists

  19. Research Program on Global Climate Change Cited collaborators Carlos Jared (Butantan) Marta Antoniazzi (Butantan) Fernando R. Gomes (UNESP) Jose E. Carvalho (UNESP) Hanna Suzuki (Butantan) Titon Braz Jr. (UNESP) Monique Simon (USP) Isabel C. Pereira (USP) Ivan Prates (I. Butantan) Field assistance Francisco de Assis Rodriguez

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