Population ecology of Psammobates oculifer in a semi-arid environment

We studied the ecology of Psammobates oculifer over 13 months near Kimberley, South Africa, to ascertain if the population’s life history traits conform to chelonian patterns in arid environments. Capture rates were highest in spring and lowest in winter when environmental conditions were respectively most and least favourable for tortoise activity. Body condition did not change from autumn to spring, but reached lower values during the summer drought. Capture effort averaged 5 hours/tortoise, which corresponds closely to that of species with low population densities in arid regions. Population size structure was skewed towards adults, indicative of low recruitment and/or low juvenile survivorship. Females were larger and heavier than males, confirming sexual dimorphism in this species. Body size of cohorts scaled to annuli counts, indicating a close correspondence between body size and age. Telemetered adults deposited one or no growth ring in the year of study; consequently, annuli counts could underestimate adult age. Regression analyses showed that male and female growth rates did not differ, but males matured at a smaller size and younger age than females. The smallest male showing reproductive behaviour had 12 annuli and a shell volume of 157 cm3, while similar measures for females were 14 annuli and 185 cm3. The sex ratio of the population did not differ from 1:1 but the bias towards males in spring, and towards females in autumn, indicates that studies limited to particular seasons can misrepresent life history traits of populations. We concluded that the life history of P. oculifer conforms to chelonian patterns in arid regions.Web of Scienc

Terrestrial habitat requirements of nesting freshwater turtles

Because particular life history traits affect species vulnerability to development pressures, cross-species summaries of life history traits are useful for generating management guidelines. Conservation of aquatic turtles, many members of which are regionally or globally imperiled, requires knowing the extent of upland habitat used for nesting. Therefore, we compiled distances that nests and gravid females had been observed from wetlands. Based on records of \u3e 8000 nests and gravid female records compiled for 31 species in the United States and Canada, the distances that encompass 95% of nests vary dramatically among genera and populations, from just 8 m for Malaclemys to nearly 1400 m for Trachemys. Widths of core areas to encompass varying fractions of nesting populations (based on mean maxima across all genera) were estimated as: 50% coverage = 93 m, 75% = 154 m, 90% = 198 m, 95% = 232 m, 100% = 942 m. Approximately 6–98 m is required to encompass each consecutive 10% segment of a nesting population up to 90% coverage; thereafter, ca. 424 m is required to encompass the remaining 10%. Many genera require modest terrestrial areas (\u3c200 m zones) for 95% nest coverage (Actinemys, Apalone, Chelydra, Chrysemys, Clemmys, Glyptemys, Graptemys, Macrochelys, Malaclemys, Pseudemys, Sternotherus), whereas other genera require larger zones (Deirochelys, Emydoidea, Kinosternon, Trachemys). Our results represent planning targets for conserving sufficient areas of uplands around wetlands to ensure protection of turtle nesting sites, migrating adult female turtles, and dispersing turtle hatchlings

Community Characteristics of Sympatric Freshwater Turtles from Savannah Waterbodies in Ghana

Despite increasing pressures on freshwater resources worldwide, and the threatened status of most freshwater turtles, there is still limited knowledge of habitat use and niche partitioning in Afrotropical freshwater turtle communities. In this study, we describe habitat associations, community diversity, and temporal patterns of occurrence of freshwater turtle species in the Dahomey Gap ecoregion of Ghana (West Africa). We gathered data from 13 sites in central Ghana and along the Sene Arm of Lake Volta in the Digya National Park (Bono East Region). We employed opportunistic short-term surveys (at seven sites) together with longer-term (six-months duration) standardized evaluations of turtle presence and numbers in different habitats (at six sites). Overall, a total of 210 turtle individuals of four species (Trionyx triunguis, Cyclanorbis senegalensis, Pelomedusa sp. and Pelusios castaneus) were recorded; precise capture sites and habitat type were recorded for 139 individuals, but the 71 individuals observed in marketplaces were not considered in our analyses. At a local scale, we observed three sympatric species in various study sites. In each of these sites, the dominant species was either C. senegalensis or Pelomedusa sp., with the latter species being more abundant in temporary waterbodies and C. senegalensis more numerous in permanent ones. A Multiple Correspondence Analysis suggested that, in permanent waterbodies all species were associated with similar physical habitat variables. In a Canonical Correspondence Analysis, we showed that the density of herbaceous emergent vegetation was more important for P. castaneus than for C. senegalensis. Comparisons of diversity metrics between our study sites and previous studies revealed that turtle community composition was similar across savannah sites

Проектирование и разработка сайта кафедры (на примере сайта кафедры технологий программирования)

Проектирование и разработка сайта кафедры (на примере сайта кафедры технологий программирования): аннотация к дипломной работе / Глеб Владимирович Бондарчук; БГУ, Факультет прикладной математики и информатики, Кафедра технологий программирования; науч. рук. Войтешенко И. С

Highway mortality of turtles and other herpetofauna at Lake Jackson, Florida, USA, and the efficacy of a temporary fence/culvert system to reduce roadkills

I investigated highway mortality and the attempted crossings of turtles and other herpetofauna from 2000-2003 on a 1.2-km-section of a four-lane highway crossing Lake Jackson, Florida. U.S. Highway 27 was built directly through the northwest arm of Lake Jackson, separating a 21-ha portion of the lake to the west (now known as “Little Lake Jackson”). U.S. Highway 27 is a virtually impassable barrier to wildlife (21,500 vehicles per day) and prevents normal movements, dispersal, and migration of most species both during non-drought periods and periodic natural drydowns (on average every 12 yrs). During periods of drought, Little Lake Jackson maintains water and is the destination for large numbers of migrating turtles and other wildlife that leave the drying lake until it refi lls. The objectives of this study were to: (1) determine the level of road mortality and attempted crossings of turtles and other herpetofauna, (2) examine the potential effects of road mortality on turtle demography including sex ratios and female population size, and (3) design and evaluate the effectiveness of a temporary drift fence-culvert system to both reduce road mortality and facilitate migration. Two drift fences (885 and 600m) were constructed to divert animals away from the north and southbound lanes and direct them into an existing 3.5-m-diameter culvert. Monitoring of road kills and attempted crossings consisted of multiple daily surveys for 43 months (5558 h) including a pre-fence (40 d) and post-fence (1274 d) survey during a drought migration and non-drought conditions. A total of 10,180 reptiles and amphibians of 44 species were found either road killed or alive behind drift fences: 8,833 turtles, 825 frogs, 344 snakes, 145 lizards, 31 alligators, and 2 salamanders. Diversity among taxonomic groups included 10 species of turtles, 15 species of snakes, 10 species of anurans, 6 species of lizards, 2 salamander species, and 1 crocodilian. Drift fences combined with intensive monitoring greatly reduced turtle road kills and facilitated the use of an under-highway culvert. Pre-fence turtle mortality (9.7/km/day) was signifi cantly greater than post-fence mortality (0.08/km/day), and only 84 of 8,466 turtles climbed or penetrated the temporary fences. Pre-fence data provided strong evidence that turtles cannot successfully cross all four lanes of U.S. Highway 27, with 95 percent of 343 turtles killed as they fi rst entered the highway adjacent to the shoulder and the remaining fi ve percent killed in the fi rst two traffi c lanes. I used the equation, Pkilled = 1 - e -Na/v, to estimate the probability of being struck in one attempted crossing of U.S. Highway 27, where N is traffi c rate in vehicles/lane/sec during 80 percent of daily volume, a = width of the kill zone (2 tire widths per lane plus 2 times weighted average shell length of 5 species), and v = turtle velocity (m/sec). Solving this equation results in a 98 percent probability of a turtle being killed in one attempted crossing, closely matching my direct observations. Using this model and historic traffi c data, the probability of a turtle successfully crossing U.S. Highway 27 decreased from 32 percent in 1977 to only two percent in 2001. Therefore, at least 98 percent of turtles diverted by the fences would have been killed on U.S. Highway 27 during this study if fences were not in place, and the road kill rate is estimated at 1,294/km/yr. Based on a literature survey, this is the highest attempted crossing rate ever documented for turtles. Sex ratios (M:F) of Pseudemys fl oridana (4:1), Trachemys scripta (3:1), and Sternotherus odoratus (2:1) were signifi cantly male-biased and low numbers of mature females are likely due to 5-10 percent annual road mortality during attempted nesting forays. Because of demographic and life history constraints, turtle populations cannot compensate for the combined effects of annual road mortality (5-10%) and periodic mass road mortality (95-99%) during lake dry-downs

Comparative study on the growth of juvenile Galapagos giant tortoises (Geochelone nigra) at the Charles Darwin Research Station (Galapagos Islands, Ecuador) and Zoo Zurich (Zurich, Switzerland)

In this study, the growth rates of a group of Galapagos giant tortoises raised in their natural habitat at the Charles Darwin Research Station (CDRS; Galapagos Islands, Ecuador) and a group of captive-bred specimens (Zoo Zurich, Zurich, Switzerland) were compared for the first time. A great discrepancy in growth rates was observed after the first year. When the animals were 4 years old, the carapace in the Zurich specimens was approximately twice as long as that in the CDRS tortoises, and the Zurich animals weighed approximately 10 times more than the CDRS animals. The zoo diet was modified by a reduction in nutrients and an increase in fiber to produce a more natural growth rate

United States Bureau of Mines Bulletin 516

From Forward: "This bulletin is the first of a new series, which includes analyses of only tipple and delivered coal. It covers samples collected throughout the United States from July 1, 1947 to June 30, 1950 (fiscal years 1948-50). It is planned that future publications of this series will cover a period of one fiscal year only and be issued as soon as possible after June 30 of each year.

Analyses of tipple and delivered samples of coal : collected during fiscal year 1967 /

Includes index.Chiefly tables.Mode of access: Internet