**1. Introduction**

162 Biodiversity Loss in a Changing Planet

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During the past decade it has been documented that the average of earth temperature increased 6 °C in a period of 100 years. The higher amount of this phenomenon has been recorded between 1910 and 1945 and, from 1976 to present date (Jones, 1999; Kerr, 1995; Oechel et al., 1994; Thomason, 1995). From 1976 to present the temperature rising has been the faster recorded in the last 10,000 years (Jones et al., 2001; Taylor, 1999; Walther et al., 2002), and this caused the maximum daily temperature increase in the southern hemisphere (Easterling et al., 2000), as well as a significant temperature increase in the tropical forest areas (Barnett et al., 2005; Houghton et al., 2001; Santer et al., 2003; Stott, 2003). According to projections, the average temperature of earth may increase up to 5.8 °C (Intergovernmental Panel on Climate Change IPCC, 2007) at the end of current century, which actually represents and enormous threat for biodiversity (Mc Carty, 2001; Parmesan & Yohe, 2003).

Although the historical data describes a changing climate during the last 350 million years of amphibians and reptiles history (Duellman & Trueb, 1985), the abrupt rising of the temperature during the last century could have a great impact on ectotherm organisms, which depend of environmental temperature to achieve physiological operative body temperatures (Walter et al., 2002; Zachos et al., 2001). Thus, the accelerated grow of earth temperature could affect physiological, reproductive, ecological, behavioral, and distribution traits among amphibians and reptiles (Cleland et al., 2006; Dorcas et al., 2004; Pough, 2001; Gvozdik & Castilla, 2001). In this context, a review of the published studies is necessary to evaluate and summarize the evidence of climate change effects in amphibians and reptiles. This review should provide an overview that should be helpful for researches, students, and policy makers, in order to address how climate change affects amphibians and reptiles, and the possible responses of these organisms to climate change.

Due to the available published information are not equal for amphibians and reptiles, the present chapter are divided in two: amphibians and reptiles. In each chapter subdivision a physiological, reproductive, and distribution effects are issued as long as information was available. Additional information in amphibians such as synergic effects of environmental factors due climate change, and evolutionary adaptations are addressed. At the end of the chapter a conclusion section is added in order to summarize the most important trends addressed in this review.

Effects of Climate Change in Amphibians and Reptiles 165

2) the increase of the dry season length, 3) decrease of soil moisture (due changes of precipitation and temperature rise), and 4) increase in rainfall variation. This would affect organisms at population and community levels. As an example Carey & Bryant (1995) found that the individual growth rate, reproductive effort, and life span could change, with a

The increase of temperature and thermal variation are the basic signal for emergence and reproduction in anurans, particularly in species from temperate zone (Duellman & Trueb, 1986; Jorgensen, 1992). Climate change linked with other factors such as photoperiod (Pancharatna & Patil, 1997) may affect the breeding patterns of amphibians. Amphibians in Canada are affected by the precipitation decrease and increased temperatures during summer (Herman & Scott, 1992; Ovaska, 1997). In The United Kingdom there has been evidence of early oviposition in *Bufo calamita*, *Rana sculenta* and *Rana temporaria* between 1978 and 1994, which is correlated with the increase of spring temperatures during the last 20 years (Beebee, 1995; Forchhammer et al., 1998). Also, an earlier beginning in the oviposition period (2 to 13 days between 1846 and 1986) in *Rana temporaria* in Finland has been recorded and correlated to changes in air and water temperature (Terhivou, 1988). Historical and recent climate data from Ithaca, New York suggest that the temperature rising during the 20th century has changed the matting patterns of *Pseudacris crucifer*, *Lithobates sylvaticus*, *Lithobates catesbeianus*, and *Hyla versicolor*, by promoting the vocalization behavior for 10 to 13 days earlier than the expected

In addition, it has been proposed that the change in precipitation patterns (Duellman & Trueb, 1985) can affect the reproductive phenology of amphibian species that breed in ponds. If ponds are filled latter in the season, then the short water permanence should lead to an increase in competition and a higher predation rate. Meanwhile organisms are concentrated in the remaining ponds and they are more vulnerable diseases outbreaks. Changes on amphibian's phenology could present complex effects over populations, changing the population structure, and then a rapid decline of sensitive populations

It has been suggested that climate change is the cause of species migration to higher altitudes and latitudes, and then the subsequent shrinkage or loss of amphibian populations and distribution (Pounds et al., 1997). Exploring the relationship between current amphibian distribution and the possible effects of global warming on species distribution in order to build distribution models based on different algorithms such as GARP or MAXENT (Stockwell & Peters, 1999), neural networks, and generalized lineal models (Thuiller, 2003), It would possible to model for the basic conditions for the species to survive. General models of amphibians in Europe suggest that a large portion of species could expand its distribution along Europe if they are able to disperse unlimited, but if species are not capable to disperse, the distribution range of most of the species could be drastically reduced. This scenario could be the most likely because the current levels of habitat fragmentation and degradation, especially in the aquatic habitats. According to the projections of Araujo et al. (2006) the majority of the amphibian species from Europe could lost most of their distribution areas for 2050. This supports the hypothesis that climate

parallel change in the activity patterns, microhabitat use, and thermoregulation.

**2.1.2 Reproductive biology and phenology** 

from historical data (Gibs & Breisch, 2000).

(Donelly & Crump, 1998).

**2.1.3 Distribution** 

### **2.1 Amphibians**

Amphibians are very susceptible to environmental variation since they have permeable skin, eggs without shell (not amniotic eggs), and a complex life cycle that expose them to changes in both the aquatic and terrestrial environment (Blaustein, 1994; Blaustein & Wake, 1990, 1995; Vitt et al., 1990), also they are particularly sensitive to changes in temperature and humidity, as well as to exposure to large doses of UV radiation (Blaustein & Bancroft, 2007). During the last twenty years a decline o of more 500 populations of frogs and salamanders has been documented (Stuart, 2004; Vial & Saylor, 1989). The reasons for this decline stills unclear because of the factor complexity and their interactions (Alford & Richards, 1999; Blaustein & Kiesecker, 2002; Kiesecker et al., 2001). However many cases of species decline share ecological traits, life histories or demographic traits such as: 1) high habitat specialization, 2) reduced population size, 3) long generation time, 4) fluctuating abundance, 5) low reproductive rate, and 6) complex life cycles. These characteristics suit species more vulnerable to threats (Reed & Shine, 2002; Williams & Hero, 1998). The traits alone may not cause the decline, but cause that organisms become more vulnerable after an initial perturbation like the rise of environmental temperature (Lips et al., 2003). Climate change may have adverse effects by itself on the survival, distribution, reproductive biology, ecology, physiological performance, and immune system of organisms when they are exposed to higher environmental temperatures or dryness (beyond their threshold of tolerance). Also, the effects of climate change could act in synergy with various biotic and abiotic agents like diseases and infections, intense UV radiation, habitat loss, exotic species (competitors and depredators), and chemical pollution (Young, 2001, as cited in Lips et al., 2003).
