The Herpetological Journal

Authors: Perry, Gad; Bertoluci, Jaime; Bury, Bruce; Hansen, Robert W.; Jehle, Robert; Measey, John; Moon, Brad R.; Muths, Erin & Zuffi, Marco A. L.

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Authors: Walker, Ryan C.J.

Abstract: Understanding the range of threatened species is important for developing sound conservation initiatives. However, different survey methods can yield varying results when applied to cryptic vertebrates. Here, I established detection probabilities and compare detection rates of time-dependent searches against line-transect sampling for a rare, small and cryptic spider tortoise (Pyxis arachnoides) in the coastal dry forests of southwest Madagascar. The detection probability was 1.00 for field surveys undertaken during periods of highest tortoise activity. Significant differences in mean detection rates of 4.15 and 2.29 tortoises per man hour were recorded for time-constrained searching and line-transect sampling, respectively. Only time-constrained searches detected tortoises at all survey sites. There was no size-dependent variation in tortoise detection for either method. A GIS-based spatial model revealed that 12.54% of the range detected through timed searching would have been missed if transect sampling alone was applied. Higher detection rates for the timed search method are probably a result of surveyors applying greater effort to the species preferred microhabitat. Dependent on the desired output of the study, time-dependent searches or a combination of time-dependent searching and linear transect sampling is suggested.

Keywords: PYXIS ARACHNOIDES, LINE-TRANSECT SAMPLING, CRYPTIC SPECIES, ARID FOREST ENVIRONMENTS, DISTRIBUTION MAPPING, TIME-CONSTRAINED SEARCH

pp. 13-21
Authors: Plăiaşu, Rodica and Băncilă, Raluca and Samoilă, Ciprian and Hartel, Tibor and Cogălniceanu, Dan

Abstract: Rural landscapes in central and eastern Europe provide valuable ecosystem services and support high levels of biodiversity. These landscapes face an increasing pressure from human development and changes in agricultural practices. Pond-breeding amphibians and their breeding habitats are especially vulnerable to land-use changes. We studied waterbody use by amphibians in a rural landscape from Haţeg Geopark, Central Romania, a region where large areas are still under traditional land use. We surveyed 55 waterbodies, characterized them and their surrounding terrestrial habitats with 22 variables. Amphibians were more sensitive to waterbody-related variables than to landscape parameters. Man-made waterbodies had lower species richness than natural ones, but often represent the only breeding habitats available. The low importance of the landscape variables for amphibians is the result of traditional and environment-friendly land management, which maintains a mosaic landscape where the optimal terrestrial habitats for amphibians are still well represented.

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pp. 23-32
Authors: Yetman, Caroline A.; Mokonoto, Peter J. & Ferguson, Willem H.

Abstract: Nothing is known about the age of wild Giant Bullfrogs (Pyxicephalus adspersus); yet this information has important conservation implications for this regionally threatened species. We quantified and compared the age, body size and body condition of adult male and female P. adspersus caught during spawning events at peri-urban breeding sites in Diepsloot and at Glen Austin and Bullfrog pans in Gauteng Province, South Africa. Age was estimated from lines of arrested growth (LAG) counted in cross-sections of animal phalanges. Males and females from all three sites possessed 6±2 (max. 16) and 4±1 (max. 11) LAG, respectively, suggesting shorter female longevity. Individuals with <3 LAG were not encountered at the breed ing sites, implying that newly metamorphosed P. adspersus require at least three years to reach sexual maturity. There was no significant difference in the LAG counts of same-sex animals between the three sites. However, mean male snout-vent length, mass, and body condition was greatest at Glen Austin Pan, and lowest at Bullfrog Pan. The latter is possibly explained by chemical contamination of Bullfrog Pan from an adjacent disused landfill. At Glen Austin Pan males and females sampled in 2004-06 for this study were significantly shorter than those sampled at the same site in 1992-93 for a different study. Our results suggest that male P. adspersus may live for 20 years or more in the wild, but at some peri-urban breeding sites adult life expectancy is declining. Juvenile P. adspersus are most threatened by terrestrial habitat transformation because they take ≥3 years to mature, during which period they may move great distances from their natal site. Differences in the size and condition of P. adspersus between the study sites suggests that the species requires site-specific management in addition to conservation at larger spatial scales.

Keywords: SOUTH AFRICA, POPULATION, ANURAN, SKELETOCHRONOLOGY, POLLUTION

pp. 33-42
Authors: Boretto, Jorgelina M.; Jahn, Graciela A.; Fornés, Miguel W.; Cussac, Víctor E. & Ibargüengoytía, Nora R.

Abstract:  Phymaturus zapalensis inhabits harsh thermal environments in the steppe of Patagonia, Argentina, characterized by climate conditions that impose constraints on reproduction, providing an appealing model to study the role of steroid hormones in the regulation of seasonal reproductive events. Males of P. zapalensis exhibited a postnuptial spermatogenic cycle with spermiation in mid-spring in synchrony with female ovulation time when mating occurs, followed by testicular recrudescence, but do not show sperm reservoir during hibernation period in winter. Females of P. zapalensis can reproduce annually or biennially. Here, we studied the steroidogenic functions of testicular compartments of P. zapalensis by analysing serum testosterone and ultrastructure related to steroidogenic activity in Sertoli and Leydig cells, as a possible mechanism for the synchronization of male and female reproductive cycles. The testosterone cycle resembles the gonadal cycle in P. zapalensis previously described by morphology and histology of testes. Testosterone concentration is highest in mid-spring and lowest in early summer, with an initial recovery at the beginning of a new spermatogenic cycle in late summer and early autumn. Ultrastructural morphological features indicative of steroidogenic activity in Leydig and Sertoli cells were observed during the spermatogenic cycle. Evidence of temporal asynchrony in steroidogenic activity between compartments were found in males captured in summer and autumn, while synchronous activity was found during mating in spring. Temporal separation of steroidogenic activity serves to synchronize male and female cycles in P. zapalensis and assures the adjustment of reproductive activity to physiological and environmental constraints.

Keywords: TESTICULAR FUNCTION, TESTOSTERONE, LEYDIG AND SERTOLI CELLS, LIZARD, STEROIDOGENESIS

pp. 43-49
Authors: Naimi, Mohamed; Znari, Mohammed; Lovich, Jeffrey E.; Feddadi, Youssef & Baamrane, Moulay Abdeljalil Ait

Abstract: We examined the relationships of clutch size (CS) and egg size to female body size (straight-line carapace length, CL) in a population of the turtle Mauremys leprosa from a polluted segment of oued (river) Tensift in arid west-central Morocco. Twenty-eight adult females were collected in May–July, 2009 and all were gravid. Each was weighed, measured, humanely euthanized and then dissected. Oviductal shelled eggs were removed, weighed (egg mass, EM) and measured for length (EL) and width (EW). Clutch mass (CM) was the sum of EM for a clutch. Pelvic aperture width (PAW) was measured at the widest point between the ilia bones through which eggs must pass at oviposition. The smallest gravid female had a CL of 124.0 mm. Mean CS was relatively large (9.7±2.0 eggs, range: 3–13) and may reflect high productivity associated with polluted (eutrophic) waters. Regression analyses were conducted using log-transformed data. CM increased isometrically with maternal body size. CS, EW and EM were all significantly hypoallometric in their relationship with CL. EL did not change significantly with increases in CL. EW increased at a hypoallometric rate with increasing CL but was unconstrained by PAW since the widest egg was smaller than the narrowest PAW measurement when excluding the three smallest females. Smaller females may have EW constrained by PAW. As females increase in size they increase both clutch size and egg width in contradiction to predictions of optimal egg size theory.

Keywords: CLUTCH SIZE, MOROCCO, OPTIMAL EGG SIZE, TURTLE, CONSTRAINT

pp. 51-58
Authors: Meek, Roger

Abstract: Amphibian road-kills were monitored over a six-year period (2005–2010) on a series of low traffic volume roads in Ven dée, Western France. Most road-kill was found in the common toad Bufo bufo (39% of all mortalities) and agile frog Rana dalmatina (25.4%). Three species of urodeles constituted 26% of the sample. Lowest road-kill was found in Pelophylax lessonae (4%), which was attributed to a sedentary lifestyle around ponds. Road-kill had a strong temporal aspect and was associated mostly with migratory movements. Significantly higher than expected road-kill was found on low traffic roads bordered by woodland and/or wetlands in R. dalmatina, Lissotriton helveticus and B. bufo and in urban areas greater than expected in Triturus marmoratus, P. lessonae and B. bufo. Less than expected road-kill was found next to monocultures in all species tested. Road-kill was more numerous following rainfall but during dry weather relatively more frequent in R. dalmatina and P. lessonae. This was attributed to foraging activity in R. dalmatina and movement due to pond desiccation during late summer in P. lessonae. Synchronized patterns of road-kill were found in three species of urodeles suggesting similar patterns of movement behaviour. Traffic intensity and road-kill on different roads was not correlated and hence traf fic volume was not a good predictor of road-kill. However, in a regression analysis, road-kill showed a strong association (r ²=0.87) with extent of migratory distances.

Keywords: AMPHIBIANS, TRAFFIC VOLUMES, MOVEMENT BEHAVIOUR, ROAD-KILL, HABITAT

pp. 59-62
Authors: Ferreira, Eduardo; Rocha, Rita Gomes; Malvasio, Adriana & Fonseca, Carlos

Abstract: We evaluated the usefulness of arboreal pipe refuges for studying Neotropical herpetofauna, by quantifying the effects of microhabitat variables and pipe colouration on pipe occupancy rates. We used fifty five sets of refuges that each comprised three pipes with different colours (white, grey and black). We recorded 122 occupancy events by four hylid and one scincid species. Refuge colour did not significantly affect occupancy rates. Environmental data explained a significant portion (10.6%) of the total variance of occupancy, with vegetation type and height of opening being most important.

Keywords: PVC REFUGIA, SCINCIDAE, HYLIDAE, HEIGHT, VEGETATION TYPE

pp. 63-66
Authors: Walker, Ryan C.J.; Luiselli, Luca; Woods-Ballard, Andy J. & Rix, Charlotte E.

Abstract: We studied microhabitat use by the threatened Malagasy endemic spider tortoise (Pyxis arachnoides) during the wet and the dry season of Madagascar's Southern Dry Forest. In total, 282 tortoises were captured and marked. Microhabitat selection was dependent on the interaction term 'age × sex' (with curved carapace length as a covariate), but neither dependent on season, sex and age taken independently. Juveniles favoured areas of denser vegetation cover than more mature animals, which typically selected the microhabitat types in relation to their relative availability. Controlling the subsistence harvest of fuel wood within the region is an important conservation initiative to increase the recruitment of reproductively mature tortoises into the population.

Keywords: SPIDER TORTOISE, MADAGASCAR, MICROHABITAT, ECOLOGY

pp. 67-70
Authors: Kacoliris, F. P. & Williams, J. D.

Abstract: The goal of this work was to assess escape behaviour in individuals of sand dune lizards (Liolaemus multimaculatus) varying in degree of research disturbance. When searching for individuals in the field, the distance between the observer and the lizard before it started escaping (AD) and the distance between the lizards and the closest shelter (DCS), were compared in a disturbed and an undisturbed site. Disturbance was caused by three years research in which lizards were captured, marked and recaptured. The AD averaged 186 cm at the disturbed site and 330 cm at the undisturbed site, whereas the DCS averaged 1,609 cm at the disturbed site and 2,008 cm at the undisturbed site. Both variables showed significant differences between sites (p<0.05). This study supports the idea that research activities that involve manipulation of animals can affect their behaviour.

Keywords: APPROACH DISTANCE, ESCAPE BEHAVIOUR, SAND DUNE LIZARD, RESEARCH DISTURBANCE, DISTANCE TO SHELTER