The Herpetological Journal

pp.1-8

Authors: John M. R. Baker

Abstract: A population of great crested newts ( Triturus cristatus) in central England was monitored from 1 988- 1995. Recognition of individuals was used to quantify population dynamics. Adult annual survival varied from 31-100%. Long-term members of the breeding population had a significantly higher rate of annual survival (65%) than individuals breeding for the first time (57%). The population showed variable patterns of recruitment. A period of six years with little recruitment was followed by a rapid increase in population size, more than three-fold, over two years. The change in the population characteristics coincided with a crash in the population of predatory three-spined sticklebacks (Gasterosteus aculeatus), raising the possibility that newt recruitment was held in check by predation. Juveniles were rarely captured, but their recapture rate between years ( 49%) indicated that the rate of annual survival for juveniles in this population could be relatively high (estimated as 59%). Most juveniles matured at two years of age. The study population thus consisted of long-lived adults, showing variable survival, and erratic recruitment. The longevity of adults enabled the population to persist under adverse conditions until beneficial circumstances could be exploited by rapidly increasing the population size. These demographic traits may be common in T. crislatus populations.

Keywords: Triturus cristatus, population dynamics, mark-recapture

pp.9-13

Authors: Tamotsu Kusano, Kazuko Maruyama And Shigenori Kanenko

Abstract: A breeding population of Japanese toads, Bufo japonicus formosus was studied at two ponds in Yamakita-machi, Kanagawa Prefecture, Japan, during the three breeding seasons of 1992-1994. The movement of toads between the ponds was monitored by mark-recapture studies. Although the two ponds were only 30 m apart, most toads did not switch ponds within or between years. A binomial test and bootstrap simulation rejected the null hypothesis that individual toads selected their breeding ponds randomly from year to year. Mating success and other ecological and behavioural characteristics were compared between male toads that exhibited site fidelity and those that switched ponds during the study period, but we could not detect any significant differences between them. This study demonstrated strong site fidelity in B.j.formosus, but failed to show quantitative advantages or disadvantages of returning annually to the same pond.

Keywords: Bufo japonicus formosus, site fidelity, movement between ponds, mating success

pp.15-20

Authors: Adrian Hailey And Ian M. Coulson

Abstract: Five thread-trailed hingeback tortoises (Kinixys spekii) were observed continuously for a total of 260 hr on four hot days (at intervals of 1 -2 weeks) in the rainy season. Activity occurred in all hours from 06.00-19.00 hr; the population daily activity period was 13 hr. The daily duration of surface activity of individuals was on average 8.2 hr day·' between first and last daily movement. The daily time budget included 1 .95 hr locomotion, 0.86 hr feeding, and 5.2 hr stationary above ground (including long periods in indistinct surface refuges). There were no significant differences in total activity between individual tortoises or study days. Combining the daily activity period of the population and data from single sightings would greatly overestimate the amount of time spent active; observations over complete days are necessary for a true time budget. Increasing the number of days of observation of each individual decreased the variability of the data only slightly.

Key words: Kinixys, tortoise, time budget, activity pattern

pp.21-27

Authors: C. Diaz-paniagua And J. A. Mateo

Abstract: Body size of newts from five populations of Triturus boscai was measured and the age of the newts was estimated using skeletochronology. Variation in adult body size was observed throughout the range of the species, with largest individuals of the southernmost populations being smaller than the smallest adults of the northern localities. Sexual dimorphism in body size was detected in all populations studied. A tendency towards older mean ages was also observed from southern to northern populations. The age of youngest breeders, modal age at which growth slows, and mode of the age structure showed geographic variation, with the greatest differences in life-history traits being between northernmost and southernmost populations, survival being optimized in the north by delaying either the age of maximum reproductive output or sexual maturity. The variation observed may have been due to evolutionary changes, though more extensive information on genetic and morphological interpopulational differences is needed to support a taxonomic differentiation.

Keywords: geographical variation, newt, life history, Triturus boscai

pp.29-32

Authors: José A. Ródar And Juan M. Pleguezuelos