**3. General conclusions**

172 Biodiversity Loss in a Changing Planet

Virginia, where the sand temperature is lower and produces a higher proportion of males compared with those in Florida (Heppell et al., 2003). According to the IPCC (2001), Florida could experience a significant increase in temperature, so there is a high possibility of bias in the sex ratios, and a complete feminization of the setting of these the vast majority of the United Estates populations (Shoop & Kenney, 1992). The results indicates that an increase of 2° C is sufficient to cause feminization of clutches, and an increase of 3° C should drive to lethal incubation temperatures. As an alternative to temperature increase, turtles could potentially alter their nesting specific environment, looking for areas covered by vegetation, with greater proximity to the sea or groundwater. If turtles alter their oviposition season just a few days may be adapted to 1° C warming and if they did around a week, they could avoid the most extreme scenario (3° C); and this strategy could be the most viable adaptive

mechanism for marine turtles in response to climate change (Hawkes et al., 2007).

and then the probability that the population becomes extinct.

(Janzen, 1994).

In addition, evidence from genetic and behavioral analysis of the Painted Turtle populations *Chrysemis picta* in southeastern United States indicates that this turtle may disappear if do not develops traits that determine whether a balanced sex ratio, which directly affects their population dynamics (Girondot et al., 2004). Studies like those of Girondot et al., (2004) shows that species with temperature sex determination could be very sensitive to even modest variations (≤ 1 °C) in their local thermal environment. A slight increase in temperature could produce a high bias towards production of females (39° C). Such bias towards females results in a highly unequal sex ratio among adults and therefore if there are no males, females may lay eggs unfertilized eggs, and annual cohorts of offspring could lost

The analysis of seasonal temperature variation and nesting behavior in *Chrysemis picta* suggest that pre-oviposition could mitigate climate change impacts on local populations located in less boreal latitudes and allow the production of males (Hays et al., 2001). Such nesting behavior modification may reduce the impact of local climatic variation, but may be insufficient for the populations living further north, since the young individuals may be low ability to survive the warm summer temperatures. It is believed that the metapopulation structure of these turtles among in the Mississippi River basin could help to mitigate the bias in sex ratio of the population caused by climate change if there is enough variation in both the thermal structure of suitable nesting areas, and migration rate between populations

In contrast, among the rhyncocephalians, lizards, and snakes with temperature sex determination, the threatened by global warming is higher in the tuatara (*Sphenodon punctatus*); a long generation time (which indicating limited potential to respond to rapid climate change), and extreme low temperature variation toward sex determination, with less than 1 °C drive the difference for the production of males or females (Nelson et al., 2004). Climate projections predict a significant increase among 1.4-5.8 °C in a very short period of time over the next 100 years (IPCC, 2001). Under this scenario reptiles may have four options to endure global warming: 1) modify its geographical range, 2) develop a genetic sex determination, 3) change their nesting behavior or 4) simply disappear (Janzen & Paukstis, 1991; Morjan, 2003). The tuatara may successfully manipulate the sex ratio of offspring by selecting the nesting site accord to vegetation, but apparently deeper nests in warm years to avoid bias toward males, which supports the proposition that the most viable strategy to deal with the effects of climate change is search sites with vegetal cover to nest. In the case Global climate change has influenced many aspects of the biology and ecology of amphibians and reptiles, which in some cases was caused the decline of their populations or serious threats. However evidence suggest that the phenomenon itself does not directly affect the organisms, but acts in combination with biotic and abiotic factors increasing its effects, as we illustrated in the case of diseases and infections the drying aquatic habitats draying up, the invasion of competing species, and the diminishing of the immune system due thermal stress regarding to the reproductive biology of organisms suggests that climate change affects several aspects among the most visible traits: phenology, survivorship and fecundity. However, it remains unclear if global warming will alter population dynamics of all populations or some one would be balanced due areas with suitable conditions for distribution and survival of organisms, mainly in the case of amphibians, whose survival depends largely on the presence of moisture and healthy aquatic habitats. However, there are non or very few data and projections turtles and crocodiles, comparing with lizards, which has been suggested that around of 50% of the Mexican *Sceloporus* lizards would disappear for 2080, since if maximum environmental temperature continues rising constantly due a overcome of physiological threshold of tolerance and the reduction of their daily activity times, which would cause an energetic shortfall as a consequence of low food intake (Sinervo et al., 2010).

Some potential adaptive responses already has bee suggested in different traits (behavior, physiology and morphology) among species affected by climate change. To test the likelihood of change in this traits due climate change requires the use of tools such as statistical analysis that incorporate phylogenetic hypotheses for the organisms under study, also an accurate estimate of the trait change rate both amphibians and reptiles is needed to understand the speed of the extraordinary rising of global environmental temperatures and their effects in biodiversity.

It is certain that climate global change will affect amphibians and reptiles around the world due synergic effects with other abiotic and biotic conditions. Our efforts should be concentrate in save as many populations and species we can, but first them all to understand the synergic effects and implement strategies to buffer them in regions when populations and species would be in the highest risk. It is quite possible that we cannot do anything against global warming and climate change, but we still can decide based on scientific evidence what, when and how to do about it.

Effects of Climate Change in Amphibians and Reptiles 175

Blaustein A.R., Hokit D.G., O' Hara R.K. & Holt, R.A. 1994b. Pathogenic fungus contributes

Blaustein, A. R, & Wake, D.B. 1995. The puzzle of declining amphibian populations. *Scientific American*, Vol. 272, No 4 (April, 1995), pp. 52-57. ISSN: 0036-8733. Blaustein, A.R., Kiesecker, J.M., Chivers, D.P., Hokit, D.P., Marco, D.G., Belden, A., & Hatch,

Blaustein, A. R. & Kiesecker J.M. 2002. Complexity in conservations: Lessons from the global

Blaustein, A.R. & Belden, L.K. 2003. Amphibian defenses against ultraviolet-B radiation. *Evolution & development*, Vol.5, No 1 (January, 2003), pp.89-97. ISSN: 1525-142X. Blaustien A.R. & Bancroft B.A. 2007. Amphibian populations declines: evolutionary

Bradford, A.F. 2002.Amphibian declines and environmental change in the eastern Mojave

Bosch J., Carrascal,L. M., Durán, Walker, L, S. & Fisher, M. C. 2007. Climate Change and

Carey, C. & Bryant, C.J. 1995. Possible interrelations among environmental toxicants,

Health Perspectives, Vol. 103, No 4 (May, 1995), pp13-17. ISSN: 0091-6765. Carey, C., Cohen N., & Rollins-Smith L. 1999. Amphibian declines an immunological

Chamaillè-Jammes, S., Massot, M., Aragon P. & J., Clobert 2006. Global warning and

Christy, J. R., Clarke, R. A., Gruza, G. V., Jouzel, J., Mann, M. E., Oerlemans, J., Salinger, M.

Cleland, E.E., Chiariello, N.R., Loarie, S.R., Mooney, H.A. & Field, C.B., 2006. Diverse

3, pp. 251-254. ISSN: 0006-3207

608. ISSN: 1461-0248.

(December 2001), pp. 1804-1809. ISSN: 0888-8892.

Cultural Resources of the intermountain region pp7.

1607 (Jan. 22, 2007), pp. 253-260. ISSN: 1471-2954.

1999), pp. 459-472. ISSN: 0145-305X.

Cambridge University Press.

1354-1013.

to the amphibians looses in the Pacific Norwest. *Biological Conservation*, Vol.67, No

L.K. 1998. Effects of ultraviolet radiation on amphibians: field experiments. *American Zoologist*, Vol. 38, No 6 (December, 1998), pp. 799-812. ISSN: 0003-1569. Blaustein, A. R., Belden L.K., Olson, D.H., Green D.M., Root, T.L. & Kiesecker, J.M. 2001.

Amphibian breeding and climate change. *Conservation Biology*, Vol. 15, No 6

decline of amphibians populations. *Ecology Letters*, Vol. 5, No 4 (July, 2002), pp. 587-

considerations. *Biosciences*, Vol. 57, No 5 (May, 2007), pp. 437-444. ISSN: 0006-3568.

Desert. Conference Proceedings. Spring-fed Wetlands: Important Scientific and

Outbreaks of Amphibian Chytridiomycosis in a Montane Area of Central Spain; Is There a Link? Proceedings of The Royal Society Biological Sciences, Vol. 274, No.

amphibian development and decline of amphibian populations. Environmental

perspective. *Developmental and Comparative Immunology*, Vol. 23, No 6 (September,

positive fitness response in mountain populations of common lizards *Lacerta vivipara*. *Global Change Biology*, Vol. 12, No 2 (February, 2006), pp. 392-402. ISSN:

J., Wang, S. W. 2001. Observed Climate Variability and Change. In: *Climate change 2001: the scientific basis. Contributions of working group I to the third assessment report of the Intergovernmental Panel on Climate Change.* Houghton, J. T., Ding, Y., Griggs, D. J., Noguer, M., Van der, P. Linden, J. & Xiaosu, D. Published for the Intergovernmental Panel on Climate Change, pp. 99-184, ISBN: 0521014956,

responses of phenology to global changes in a grassland ecosystem. *Proceedings of* 
