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Recent climate change has been shown to affect phenotypic traits, such as body size and fecundity, in some animals. It is important to assess the response of a species to climate change for predicting a population’s future. We compared historic and contemporary body size and clutch size measurements in the lentic breeding salamander, Hynobius tokyoensis, collected from a wide range of latitudes in its geographical range and concluded that the species has gone through significant increases in body size and clutch size over the last four decades. Although a decrease in body size due to climate change is well documented for other species, reports of an increase in body size are rare. In addition, we found that increases in temperature and precipitation were constant regardless of latitude, but that the ratios of increase in body size and clutch size were greater in high-latitude populations. Our results suggest that, even within a species, the magnitude of the response to climate change depends on the geography of the population.

Many amphibian populations worldwide have declined rapidly and been threatened with extinction in the past few decades because of human impacts on the environment. It is well known that urbanization reduces the genetic diversity of isolated populations. The concept that a reduction in genetic diversity leads to lower reproductive fitness has been predominantly supported by studies involving laboratory organisms, but has rarely been tested in wild populations. Here we examined whether genetic diversity affected hatchability, a population parameter related to reproductive success, in the populations of two pond-breeding amphibian species (Hynobius tokyoensis and Rana ornativentris) affected by urbanization. We surveyed 81 populations in the southwestern Kanto region of Japan. Mean hatchability of the populations was determined and genetic diversities were estimated via mitochondrial or microsatellite DNA analyses. Firstly, Random Forests (an ensemble machine learning method) models were applied to clarify the effects of environmental factors on both hatchability and genetic diversity. Subsequently, the relationships among environmental factors, genetic diversity, and mean hatchability were evaluated using path analysis. Mean hatchability was significantly affected by both urbanization and genetic diversity. This result shows that loss of genetic diversity may decrease a population’s reproductive success in the field.

Populations of the montane brown frog, Rana ornativentris, endemic to Japan, have been declining abruptly due to habitat loss and destruction by land development, and thus genetic diversity of this species is needed for clarifying the demographic status and conservation measures of this species. However, there were no appropriate genetic markers to elucidate such genetic diversities in population and individual level. We therefore developed microsatellite markers of R. ornativentris utilizing Ion PGM™ sequencing. As a result of the screening, a total of 23 polymorphic markers were developed. To test the usefulness of these markers for population genetic analysis, we genotyped two regional populations: an eastern population (Akiruno-shi, Tokyo) and a western population (Kita-hiroshima-cho, Hiroshima Pref.). The total number of alleles and expected heterozygosities per locus ranged from 3 to 11 and 0.000 to 0.875, respectively. The markers described here will be useful for studying population gene...

Biological responses to climate change have been widely documented across taxa and regions,but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. We reviewed 10,090 abstracts and extracted 71 studies from 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focused on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. According to a theoretical model, the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.

Bufo japonicus formosus (Eastern-Japanese common toad) is endemic to Eastern Japan. As with many Japanese amphibians, little is known about its terrestrial life, especially during the nonbreeding season. This species persists even in highly disturbed urban areas where many other amphibian species have already been extirpated. An understanding of how such species use habitats within remnant landscapes may help to inform management strategies for the conservation of urban ecosystems. We examined the nightly movement patterns, distance traveled, movement range, and microhabitat selection of non-breeding adult B. j. formosus at an urbanized site, using fluorescent powder tracking. We evaluated the usefulness of this tracking method through this survey. We found that the nightly distances traveled by these toads varied greatly among individuals and nights. No sexual differences in movement pattern, distance traveled, and movement range were detected. However, body size significantly affected distance traveled and movement range. We found that toads tended to use areas covered with grasses and mosses more frequently than expected, and to avoid paved areas. Fluorescent powder tracking was effective for the elucidation of movement patterns and habitat selection of amphibians. Our results provide useful information for the conservation of amphibians, especially for species inhabiting urbanized areas.

The breeding activity of the Japanese common toad, Bufo japonicus formosus, was monitored in Yamakita-machi, Kanagawa Prefecture and Minami-osawa, Hachioji-shi, Tokyo, during 1992–1994 and 2011–2013. The breeding activity began in late February-mid March, and lasted for one to three weeks. The number of breeding toads captured per day varied, and the effects of the lunar phase on the breeding activity were analyzed using circular statistics. Rao's spacing test indicated that large reproductive events were not uniformly distributed along the lunar cycle (U=166.1, n=46, P

Salamanders are expected to differentiate genetically among local populations due to their low dispersal ability, and are potentially susceptible to loss of genetic diversity if the population is isolated by habitat fragmentation. The salamander Hynobius tokyoensis is a lowland lentic breeder and endemic to a narrow area of central Japan. In this urban area, H. tokyoensis habitats are extensively fragmented and several populations are threatened with extinction, but information on genetic divergence and loss of genetic diversity is scarce. We performed mitochondrial (cyt b) and microsatellite (five loci) DNA analyses of 815 individuals from 46 populations in 12 regions across their entire distribution range. As a result, populations were clearly separated into northern and southern groups, and genetic differentiation among the 12 regions was also evident. Regional differentiation appears to be affected by a complex geographical history, but the genetic diversity of each population may have also been affected by recent habitat fragmentation. There were positive correlations between the mitochondrial and microsatellite DNA diversities. Some populations have lost genetic diversity in both mitochondrial and microsatellite DNAs; all such populations were at the peripheral edges of the species distribution range. Thus, even in attempts to restore genetic diversity in a small population by the transfer of outside individuals, efforts must be made to avoid genetic pollution.

Adult sex ratio is considered to be a key factor in understanding sexual selection, mating behavior, life history and population dynamics. Following Fisher (1930), a general consensus was formed that sex ratio tends to be largely balanced. However, gainsaying this, large variations in sex ratio have been reported among populations and species of amphibians. There is little information on sex ratio in natural populations of Japanese hynobiid salamanders. To help fill this gap, we conducted a long-term census of a population of Hynobius tokyoensis from 1976 to 1985 and estimated the adult sex ratio (the proportion of males within the population) at 0.578 from data gathered during eight non-breeding seasons. The bootstrap 95% confidence interval was 0.516–0.641. The study showed that the adult sex ratio was significantly biased toward males in the population studied; it was nearly 1.5:1 (males:females). Age at first reproduction is 1 year later in females, which suggests that the most likely factor driving the unbalanced sex ratio is the differential maturation rate between the sexes.

The body size and age structure of a breeding population of the Japanese common toad, Bufo japonicus formosus, was studied at Yamakitamachi in Kanagawa Prefecture for three breeding seasons from 1992 to 1994. Yearly variation in snout-vent length (SVL) was not significant, but the difference in SVL between the sexes was highly significant; the mean SVL of males and females was 125.8 and 134.2 mm, respectively. The breeding adults were aged successfully by skeletochronology using phalanges. The breeding adults were 1-8 yr old. The mean and median ages were 4.5 and 4 yr in males, and 5.2 and 5 yr in females, respectively. The males were estimated to begin to breed when one to four yr old, with a mean of 2.4 yr, while the females were estimated to breed when two to four yr old, with a mean of 2.7 yr. Age at first reproduction was significantly younger for males than females. We discuss the sexual size dimorphism of B. j. formosus in relation to the difference in age structure of the breeding popula...

Body size and age structure were studied for two breeding populations of the salamander, Hynobius tokyoensis, in the southern Kanto plain of Honshu, Japan. The mean snout-vent lengths (SVLs; measured from the tip of snout to the posterior end of cloaca) of males and females were 64.1 and 66.5 mm at Habu in Tokyo, and 63.1 and 65.3 mm at Isumi in Chiba prefecture, respectively. The differences in SVL were not significant between sexes or populations. The breeding adults, successfully aged by skeletochronology using phalanges, were 4–21 years old. The median age was significantly older in the Habu population (eight years) than in the Isumi population (five years), and the age at first reproduction estimated from the age at which the growth of individuals was greatly retarded was two to six years. The modal age at first reproduction was four years for both sexes in both populations except for males at Isumi (three years). In the latter, age at first reproduction was significantly younger than in the...

Embryonic mortality and clutch size of the foam-nesting treefrog Rhacophorus arboreus were observed in early summer of 2000 and 2001 at a small pond in a secondary forest on the campus grounds of Tokyo Metropolitan University. A total of 24 foam nests were monitored from just after spawning. When hatchlings emerged, the foam nests were collected and examined for embryonic mortality and clutch size. Embryonic mortality, averaging 0.233 (0.036–0.616, SD=0.173), varied markedly among nests. Logistic regression showed that the date of spawning had a significant effect on embryonic mortality: the nests constructed late in the season suffered higher mortality. Clutch size varied from 272 to 872 (x=522.1, SD=134.0). Multiple regression analysis showed that year and date of spawning had no significant effect on clutch size. A significant correlation was detected between clutch size and height of the nesting position (r=−0.563, P=0.004): those nests constructed higher above the pond water tended to have smaller clutches. Factors affecting egg mortality and clutch size are discussed.

Diel activity ofJesogammarus spinopalpus was monitored by an actograph using infra-red beams. The overall level and diel pattern of activity differed between males and females, and between the single and precopula phases. Single males were more active during the dark period (night) (153 intercepts/h) than during the light period (daytime) (50 intercepts/h), showing a clearly nocturnal habit, whereas the activity of single females was very low both at night (18 intercepts/h) and in the daytime (8 intercepts/h). The activity pattern of precopula pairs was nocturnal, but the level of activity was lower than that of single males (48 intercepts/h at night and 6 intercepts/h in the daytime). The sexual difference in activity level may reflect behavioral tactics during reproduction.

Testes size was compared among 19 species of Japanese anurans in relation to their breeding systems. Although the mean body mass of the species examined varied markedly between 1.8 and 116 g, the mean proportion of testes mass to body mass was fairly constant at 0.2 to 0.4% across all species except the rhacophorid species. Foam-nest building rhacophorids had relatively large testes constituting more than 1% of their body mass. Among them, Rhacophorus arboreus had the largest, exceeding 5% of the body mass. Multi-male breeding, where a female is grasped by two or more males during spawning, occurs frequently in these rhacophorids, especially in R. arboreus. This close association between large testes size and multi-male breeding strongly suggests that sperm competition is an important factor affecting the evolution of relative testes size in Japanese anurans.

A breeding population of Rana japonica was studied at a marsh on the campus of Hiroshima University in Higashi-Hiroshima during the five years 1995-1999. The mark-recapture study showed that the size of the breeding population varied from year to year, and increased more than twofold in 1999 in comparison with the preceding years. The sex ratio of the breeding population (male/female) was from nearly 1.0 to 1.6. Frogs of both sexes were estimated to breed for the first time at the age of one or two years, and their maximum age was four years according to skeletochronology using phalanges and mark-recapture. Modes of the estimated ages were one year for males during the study years except 1997, but one or two years for females. Two thirds of breeding frogs, irrespective of their sex, were estimated to breed only once throughout their lives.

Recently, declines in amphibian populations all over the world have been reported. Global warming has the potential to become one of the most important causes for those declines, because reproductive activities of amphibians are affected severely by temperature and rainfall. It has been reported that climate warming has promoted a long-term tendency toward earlier breeding among amphibian populations in Europe and North America. However, some studies have not supported such a long-term change in the timing of amphibian breeding in those areas. We analyzed long-term data sets (12- to 31-year period) on the date of first spawning for four populations of three Japanese amphibians (Hynobius tokyoensis, Rana ornativentris, and Rhacophorus arboreus) in the suburbs of Tokyo and detected a significant trend toward earlier breeding in all populations examined. We also detected that the date of first spawning was correlated strongly with the mean monthly temperature just before the breeding season for each population examined. Given that the long-term trend of warming in the study district was significant, our investigation demonstrated that climate warming has affected the timing of breeding in at least some species or populations of amphibians in East Asia.

In long-lived species such as amphibians, age determination of individual animals is important in elucidating population dynamics and life histories. Although four methods have been used for aging amphibians, only skeletochronology and mark-recapture are reliable (see Halliday and Verrell, 1988). Markrelease-recapture potentially provides the most reliable data on age, but this method is very labor-intensive and takes a long time to yield a result. On the other hand, skeletochronology using phalanges has proved to be an excellent tool to investigate population age structure. Although this method has potential problems (such as endosteal resorption of periosteal bone which may alter the early year rings), many studies have been conducted successfully using skeletochronology in anurans (e.g., Hemelaar and van G lder, 1980; Gibbons and McCarthy, 1983; Hemelaar, 1985). In this paper, we report on the age structure, age at first reproduction, and growth rates of Rana saku aii as determined by skeletochronology. The stream frog, Rana sakuraii, is distributed in central Honshu from the Kanto to Kinki districts, Japan (Matsui and Matsui, 1990). The frogs inhabit mountain forests in summer and appear in streams in late autumn, overwintering under submerged stones. Breeding begins in February-March, and breeding activity lasts for a few weeks to a month (Kusano and Fukuyama, 1987, 1989). Specimens were collected in an upper tributary of the Bonbori River (35?42'N, 139?11'E), at 380 m, about 37 km west of the Tokyo metropolitan area. This stream is located in a mountainous region covered with planted coniferous forests of Cryptomeria japonica and Chamaecyparis obtusa and secondary deciduous forest. From 1988 to 1990, we collected breeding adults by hand during February-March. The frogs were sexed u ing secondary sexual characteristics such as thumbpad development, and snout-vent length (SVL) was measured to the nearest 0.5 mm with a slide caliper. Th fourth toe of the right or left hind leg was clipped off each frog and stored in separate vials containing 10% buffered formalin. Only the third phalanx of each toe was used for this study. Overwintering juveniles were collected from the stream during December-April. They were measured, and then some were killed in a 0.1% MS 222 solution and fixed in 10% buffered formalin to determine their

Growth and population density of the larvae,Hynobius nebulosus tokyoensis Tago, were estimated in a small pond within the study site settled in Habu village of Hinodemachi, a suburb of Tokyo City, during the period from 1975 to 1980. The mortality factors which influenced the survival rate of larvae were also evaluated from the ecological point of view. Laboratory experiments on the growth of larvae and predation by newts were conducted in pararell with the field survey. The results showed that growth rate of larvae under the natural condition was very slow, as compared with that under the laboratory condition with sufficient food supply, and mean body size at metamorphosis was negatively correlated with the density at that time. This suggested that food resources were in short supply in the pond, and there occurred a severe intraspecific competition for food among larvae. The mortality rate of larvae was so high, 80–99% in each year, and the density of larvae survived until metamorphosis varied so greatly from year to year that the larval stage was the most important stage throughout the life cycle to the maintenance of a population for this salamander. The most important factors which contributed to this high mortality were the predation by the newt,Triturus pyrrhogaster pyrrhogaster Boie, and cannibalism. From the laboratory experiment, it was found that predators could attack only small larvae successfully, and successful attack rate decreased sharply as larvae grew larger. This relationship resulted in the characteristic L-shaped pattern of survivorship curve of larvae; that is, heavy mortality just after hatching period.

(1) A population of a salamander,Hynobius nebulosus tokyoensisTago was studied at Habu, Hinodemachi, in Tokyo during the breeding seasons from 1976 to 1978. Adults appeared in the pond were captured and marked individually by toe-clipping. Egg sacks were counted and tagged with vinyl tapes for the marking. (2) The annual egg production of this population was found to be constant, about 6500 eggs, and total number of breeding adults appeared in the pond also varied little during three years. (3) The appearance of breeding adults in the pond and oviposition seemed to be influenced by the rise of temperature and rainfall. (4) Males appeared earlier in the pond and stayed there for approximately 10 to 20 days. On the other hand, females appeared later in the pond and left there soon after laying eggs. (5) Mean clutch size and body length of breeding adults appeared in the pond showed a tendency to decrease as time proceeded, which seemed to show that the smaller and younger the salamander was, the later it appeared in the pond. (6) Owing to low temperature, the eggs laid earlier took more time to hatch than those laid later. (7) The survival rate of eggs was 67.2% in 1976, 86.4% in 1977 and 81.2% in 1978. The loss rate of eggs laid in the early and late periods of oviposition was higher than that of eggs laid in the middle period.

The freshwater anisogammarid, Jesogammarus spinopalpus, is a multivoltine annual species. In the present study, the seasonal shifts in clutch variables (clutch size, clutch volume and single egg volume) were examined during the two reproductive seasons from early winter to late spring of 1985 and 1986. The monthly data showed that all clutch variables changed seasonally. Since clutch size and volume showed a positive correlation with female body length, an analysis of covariance was made. The result showed that for females of a certain size, clutch volume was nearly constant during the reproductive season, but females produced a large clutch of small eggs in midwinter and a small clutch of large eggs in late spring. Egg size was positively related to water temperature, which is thus implied as the proximate factor affecting the egg size. Producing larger eggs in the late period is considered to be a life history strategy which increases the parental fitness, since food shortage and a high density of young in late spring would otherwise lead to keen competition particularly for late-hatched juveniles.

natural history of four species of whiptail lizards, Cnemidophorus (Sauria: Teiidae) in Trans Pecos, Texas. Southwest. Natural. 2:105-121. . 1957b. Some aspects of competition in natural populations of whiptail lizards (genus Cnemidophorus). Texas J. Sci. 410-447. MITCHELL, J. C. 1976. Niche overlap and ecology of bisexual and parthenogenetic Cnemidophorus (Sauria: Teiidae). Master's Thesis, Arizona State Univ., Tempe. 145 pp. . 1979. Ecology of southeastern Arizona whiptail lizards (Cnemidophorus): population densities, resource partitioning and niche overlap. Can. J. Zool. 57:1487-1499. OPPENHEIM, R. W. 1968. Color preferences in the pecking response of newly hatched ducks (Anos platyrhynchos). J. Comp. Physiol. Psychol. Monogr., Suppl. 66 (pt. 2):1-17. PIANKA, E. R. 1970. Comparative autecology of the lizard Cnemidophorus tigris in different parts of its geographic range. Ecology 51:703-720. RAND, A. S., G. C. GORMAN, AND W. M. RAND. 1975. Natural history, behavior, and ecology of Anolis agassizi. Smith. Contr. Zool. 176:2738.

Cannibalistic behavior among Hynobius nebulosus larvae living in a small pond was analyzed using a videotape recording system. Maximum and range of victim size increased with cannibal size. Mouth morphology, i.e., the mouth width of a cannibal relative to the head width of the victim, is an important constraint determining maximum victim size. Time required for a cannibal to swallow its victim varied considerably among trials; there was a significant positive correlation between handling time and size ratio in total length of the victim to the cannibal. Factors affecting the rate of cannibalism in natural populations are discussed. ia, 1985(2), p. 472-476