Does forest extent affect salamander survival? Evidence from a long‐term demographic study of a tropical newt

Forest loss has been associated with reduced survival in many vertebrates, and previous research on amphibians has mostly focused on effects at early life stages. Paramesotriton hongkongensis is a tropical newt that breeds in streams but spends up to 10 months per year in terrestrial habitats. Populations are threatened by habitat degradation and collection for the pet trade, but the cryptic terrestrial lifestyle of this newt has limited our understanding of its population ecology, which inhibits development of a species‐specific conservation plan. We conducted an eight‐year (2007–2014) mark–recapture study on four P. hongkongensis populations in Hong Kong and used these data to evaluate relationships between forest cover, body size, and rainfall on survival and to estimate population sizes. Hong Kong has been subjected to repeated historic territory‐wide deforestation, and thus, we wanted to determine whether there was a link between forest extent as a proxy of habitat quality and newt demography. Annual survival was positively associated with forest cover within core habitat of all populations and negatively related to body size. Mean annual survival (~60%) was similar to that of other stream‐dwelling amphibians, but varied among years and declined substantially in 2012–2013, perhaps due to illegal collection. Despite the link between forest extent and survival, population sizes declined at the most forested site by 40% and increased by 104% and 134% at two others. Forest protection and consequential secondary succession during recent decades in Hong Kong may have been responsible for persistence of P. hongkongensis populations

Reproductive Biology and Natural History of the White-lipped Pit Viper (\u3cem\u3eTrimeresurus albolabris\u3c/em\u3e Gray, 1842) in Hong Kong

The White-lipped Pit Viper (Trimeresurus albolabris) is broadly distributed through South and Southeast Asia, and very little is known about the natural history of the species. In this study, we report on the ecology, demography, reproductive states, and growth rates of T. albolabris in Hong Kong, China. The sex ratio is even in Trimeresurus albolabris populations. This species displays sexual dimorphism from birth. Females attain larger sizes, and all males, including neonates, displaying a white supralabial stripe on the head and have longer relative tail lengths. Males attain sexual maturity at about 410 mm snout-vent length (SVL). Females reach sexual maturity at about 460 mm SVL, but only begin reproducing at about 520 mm SVL. Mating occurs between August to October, coinciding with the onset of spermatogenesis. Trimeresurus albolabris displays post-nuptial vitellogenesis, and long-term sperm storage in females likely occurs over the winter. Females gestate over the summer and parturition occurs in late July to August. Females reproduce once every two or more years, except for very large females that may reproduce annually. Brumation by females occurs within the first three weeks of December, but snakes will emerge to bask on sunny days. Understanding its demography and reproductive ecology can provide insights into the conservation and management of T. albolabris populations in the region and increase our understanding of sexual dimorphism, reproduction, and evolution of the cryptic Trimeresurus species complex

Responses of a Spotted Turtle (\u3cem\u3eClemmys guttata\u3c/em\u3e) Population to Creation of Early-successional Habitat

The maintenance or creation of early successional habitat is commonly employed by natural resource managers, often for the benefit of native wildlife. In southern New England, USA, forest succession has reduced the amount of early successional habitat on the landscape making the creation of such habitat a management priority in the region. However, questions remain regarding the impacts of the creation of early successional habitat on certain species, especially those that are associated with late successional habitats. We conducted a radio-telemetry study of Spotted Turtles (Clemmys guttata) in Rhode Island, USA, for one year before, and one year after a 3-ha forest clear-cut in close proximity to wetlands known to contain a resident population of the species. The annual home range size of turtles was 18.5% larger post-cut, possibly due to changes in the distribution of resources and suitable habitat after the harvest. However, turtles exhibited fidelity to hibernacula and communal overwintering, despite nearby disturbance, and patterns of activity and habitat use were similar in both years and were generally consistent with those of other Spotted Turtle populations. Our results suggest that timber harvesting of this spatial scale and management approach may not have any short-term effects on the spatial ecology or habitat use of populations of Spotted Turtles, but further research is needed to understand longer-term effects. We strongly recommend that the timing of clear-cut harvesting be restricted to outside of the region-specific activity season of this species and that land managers avoid significant disturbance to wetlands containing Spotted Turtles, especially those containing hibernacula

Reproduction of Endangered Big-Headed Turtle, \u3cem\u3ePlatysternon megacephalum\u3c/em\u3e (Reptilia: Testudines: Platysternidae)

The big-headed turtle (Platysternon megacephalum) is heavily harvested to support tremendous demands from food and pet markets, and thus its ecology remains poorly understood. The presence of self-sustaining populations in Hong Kong (22°09’-22°37’N, 113°50’-114°30’E) provides important opportunities to advance our understanding of this species. We employed mark-recapture surveying, radio-tracking of two gravid females, and directed streamside searches to document the reproductive ecology of the species between September 2009 and June 2011 in Hong Kong. We found seven gravid females between 20-27 June 2010 and 2011, and which subsequently oviposited on average three eggs (range 2-8), with mean length and width of 36 mm and 21 mm, in early July. There was positive correlation between the size of females and clutch sizes. We found one clutch in leaf litter 1.6 m away from the stream, which hatched between 14 to 18 October. The incubation period was estimated to be between 103 and 110 days. The results of this study provide important information to formulate conservation plan for this endangered species

Population demography of Oldham’s leaf turtle (\u3cem\u3eCyclemys oldhamii\u3c/em\u3e) in protected and disturbed habitats in Thailand

Background. Freshwater turtle populations are vulnerable to a range of human activities because of particular life history attributes, and anthropogenic impacts can cause shifts in demographic traits, including survival, density and population structure. Asian freshwater turtles have undergone dramatic population declines in recent decades principally because of collection for food, pet, and traditional medicine markets. Despite this, few studies have been conducted on the population demography of these turtles, thereby limiting our understanding of population trends and the development of conservation actions. Oldham\u27s leaf turtle (Cyclemys oldhamii) is one of the most commonly traded turtles in Asian markets, but previous published studies have focused solely on systematics. Methods. We conducted a mark-recapture study of C. oldhamii at three sites in north-eastern Thailand -- a protected stream, a degraded stream, and human-constructed ponds -- and evaluated differences in survival, density, population structure, and sexual dimorphism among sites. Results. We captured 77 turtles at the protected stream, 67 at the constructed ponds, and two in the degraded stream. Survival was 12% lower and density was 35% lower in the constructed ponds than in the protected stream. Size class structure was skewed toward smaller individuals at the constructed ponds, and both sites exhibited subadult-skewed age class structure. Sex ratios were not statistically different than 1:1 at either site and did not differ between sites. We did not document sexual dimorphism in either population. Discussion. Explanations for lower survival, lower densities, and skewed size class structure at the constructed ponds include collection for consumption or Buddhist prayer release locally, collection for illegal export from Thailand, predation by domestic dogs associated with humans living nearby, or lower habitat quality. Evidence from our study suggests that collection, either for local use or export, is the most likely explanation for differences in demographic characteristics between the two sites. The information gained from this study may contribute to a status assessment for C. oldhamii and development of conservation actions should they become necessary to protect populations in Thailand

A Comparison of the Population Genetic Structure and Diversity between a Common (\u3cem\u3eChrysemys p. picta\u3c/em\u3e) and an Endangered (\u3cem\u3eClemmys guttata\u3c/em\u3e) Freshwater Turtle

The northeastern United States has experienced dramatic alteration to its landscape since the time of European settlement. This alteration has had major impacts on the distribution and abundance of wildlife populations, but the legacy of this landscape change remains largely unexplored for most species of freshwater turtles. We used microsatellite markers to characterize and compare the population genetic structure and diversity between an abundant generalist, the eastern painted turtle (Chrysemys p. picta), and the rare, more specialized, spotted turtle (Clemmys guttata) in Rhode Island, USA. We predicted that because spotted turtles have disproportionately experienced the detrimental effects of habitat loss and fragmentation associated with landscape change, that these effects would manifest in the form of higher inbreeding, less diversity, and greater population genetic structure compared to eastern painted turtles. As expected, eastern painted turtles exhibited little population genetic structure, showed no evidence of inbreeding, and little differentiation among sampling sites. For spotted turtles, however, results were consistent with certain predictions and inconsistent with others. We found evidence of modest inbreeding, as well as tentative evidence of recent population declines. However, genetic diversity and differentiation among sites were comparable between species. As our results do not suggest any major signals of genetic degradation in spotted turtles, the southern region of Rhode Island may serve as a regional conservation reserve network, where the maintenance of population viability and connectivity should be prioritized

Non‐marine turtle plays important functional roles in Indonesian ecosystems

The Southeast Asian box turtle (Cuora amboinensis) is numerically the most important turtle exported from Indonesia. Listed as Vulnerable by the IUCN, this turtle is heavily harvested and exported for food and traditional medicine in China and for the pet trade primarily in the United States, Europe, and Japan. Despite its significance in global markets, relatively little is known about the species’ ecology or importance to ecosystems. We conducted our research in a national park in Sulawesi, Indonesia, and our objectives were to quantify trophic breadth, capacity for seed dispersal between aquatic and terrestrial ecosystems, and whether ingestion of seeds by C. amboinensis enhances germination. We obtained diet samples from 200 individual turtles and found that the species is omnivorous, exhibiting an ontogenetic shift from more carnivorous to more omnivorous. Both subadults and adults scavenged on other vertebrates. In a seed passage experiment, turtles passed seeds for 2‒9 days after ingestion. Radio‐tracked turtles moved, on average, about 35 m per day, indicating that seeds from ingested fruits, given seed passage durations, could be dispersed 70‒313 m from the parent tree and potentially between wetland and upland ecosystems. In a seed germination experiment, we found that ingestion of seeds by turtles enhanced germination, as compared with control seeds, for four of six plant species tested. Of these, two are common in the national park, making up a significant proportion of plant biomass in lowland swamp forest and around ephemeral pools in savanna, and are highly valued outside of the park for their lumber for construction of houses, furniture, and boats. Protection of C. amboinensis populations may be important for maintaining trophic linkages that benefit biodiversity, communities, and local economies

Evolutionary response to global change: Climate and land use interact to shape color polymorphism in a woodland salamander

Evolutionary change has been demonstrated to occur rapidly in human‐modified systems, yet understanding how multiple components of global change interact to affect adaptive evolution remains a critical knowledge gap. Climate change is predicted to impose directional selection on traits to reduce thermal stress, but the strength of directional selection may be mediated by changes in the thermal environment driven by land use. We examined how regional climatic conditions and land use interact to affect genetically based color polymorphism in the eastern red‐backed salamander (Plethodon cinereus). P. cinereus is a woodland salamander with two primary discrete color morphs (striped, unstriped) that have been associated with macroclimatic conditions. Striped individuals are most common in colder regions, but morph frequencies can be variable within climate zones. We used path analysis to analyze morph frequencies among 238,591 individual salamanders across 1,170 sites in North America. Frequency of striped individuals was positively related to forest cover in populations occurring in warmer regions (\u3e7°C annually), a relationship that was weak to nonexistent in populations located in colder regions (≤7°C annually). Our results suggest that directional selection imposed by climate warming at a regional scale may be amplified by forest loss and suppressed by forest persistence, with a mediating effect of land use that varies geographically. Our work highlights how the complex interaction of selection pressures imposed by different components of global change may lead to divergent evolutionary trajectories among populations

Colección José Arencibia [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Reproduction of endangered Big-headed Turtle, Platysternon megacephalum (Reptilia: Testudines: Platysternidae)

The big-headed turtle (Platysternon megacephalum) is heavily harvested to support tremendous demands from food and pet markets, and thus its ecology remains poorly understood. The presence of self-sustaining populations in Hong Kong (22°09’-22°37’N, 113°50’-114°30’E) provides important opportunities to advance our understanding of this species. We employed mark-recapture surveying, radio-tracking of two gravid females, and directed streamside searches to document the reproductive ecology of the species between September 2009 and June 2011 in Hong Kong. We found seven gravid females between 20-27 June 2010 and 2011, and which subsequently oviposited on average three eggs (range 2-8), with mean length and width of 36 mm and 21 mm, in early July. There was positive correlation between the size of females and clutch sizes. We found one clutch in leaf litter 1.6 m away from the stream, which hatched between 14 to 18 October. The incubation period was estimated to be between 103 and 110 days. The results of this study provide important information to formulate conservation plan for this endangered species