Climate Change 2001:
Working Group II: Impacts, Adaptation and Vulnerability
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5.4.3.1.2. Changes in timing (phenology)

Invertebrates: Warmer conditions during autumn and spring adversely affect the phenology of some cold-hardy species. Experimental work on spittlebugs (Philaenus spumarius) found that they hatched earlier in winter-warmed (3°C above ambient) grassland plots (Masters et al., 1998).

Amphibians: Two frog species, at their northern range limit in the UK, spawned 2-3 weeks earlier in 1994 than in 1978 (Beebee, 1995). These changes were correlated with temperature, which also showed increasing trends over the same period.

Birds: Changes in phenology, or links between phenology and climate, have been noted for earlier breeding of some birds in Europe, North America, and Latin America (see Table 5-3). Changes in migration also have been noted, with earlier arrival dates of spring migrants in the United States (Ball, 1983; Bradley et al., 1999), later autumn departure dates (Bezzel and Jetz, 1995), and changes in migratory patterns in Europe (Gatter, 1992).

5.4.3.1.3. Changes in morphology, physiology, and behavior

Amphibians and Reptiles: Correlations between temperature and calling rates have been found in Egyptian frogs (Akef Mamdouh and Schneider, 1995). Indian tree frogs show differences in behaviors that depend on their level of hydration (Lillywhite et al., 1998). Painted turtles grew larger in warmer years, and during warm sets of years turtles reached sexual maturity faster (Frazer et al., 1993). Physiological effects of temperature, primarily sex determination, also can occur while reptiles are still within their eggs (Gutzke and Crews, 1988).

Birds: Spring and summer temperatures have been linked to variations in the size of eggs of the Pied Flycatcher (Ficedula hypoleuca). Early summer mean temperatures explain ~34% of the annual variation in egg size between the years 1975 and 1994 (see Figures 5-3 to 5-5; Jarvinen, 1996).

Mammals: Body size is correlated with many life-history traits, including reproduction, diet, and size of home ranges. North American wood rat (Neotoma spp.) body weight has shown a significant decline that is inversely correlated with a significant increase in temperature over the past 8 years (Smith et al., 1998). Juvenile red deer (Cervus elaphus) in Scotland grew faster in warm springs, leading to increases in adult body size (Albon and Clutton-Brock, 1988).



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