Predation on tent tortoise and leopard tortoise hatchlings by the pale chanting goshawk in the Little Karoo

Predation by the pale chanting goshawk Melierax canorus on Psammobates tentorius and Geochelone pardalis hatchlings correlates with the habitat preference of these tortoise species as well as with the breeding pattern of P. tentorius. It is not known why the particularly abundant Chersìna angolata was not preyed upon

Predation on the angulate tortoise Chersina angulata by the kelp gull Larus dominicanus on Dassen Island, Western Cape

The kelp gull (Larus dominicanus) is an important predator on the angulate tortoise (Chersina angulata) on Dassen Island, Western Cape, South Africa. Tortoise shell fragments (n= 142) were collected and measured. Using regression curves based on 184 live tortoises measured on the island, the size class of tortoises eaten by kelp gulls was determined to include tortoises from 38-124 mm (mean 84 mm) total length (mass 25-350 g; mean 130 g). It is probable that very small tortoises were also eaten, but totally consumed. It is suggested that predation on tortoises occurs during the autumn-winter by the small population of resident gulls (approximately 50 individuals)

The tortoises (Testudinidae) and terrapins (Pelomedusidae) of southern Africa: their diversity, distribution and conservation

Southern Africa has the richest diversity of land tortoises in the world, as well as an important radiation of pelomedusid terrapins. Total species richness has two epicentres, including the Transvaal lowveld and adjacent KwaZulu/Natal (owing to the prevalence of pelomedusid terrapins) and the Eastern and south-western Cape (owing to small testudinids). The area encompassing Lesotho, Transkei and adjacent regions, lacks testudinids for unknown reasons. Archaeological data indicates that this gap is natural, and not the result of man-induced extinctions. Endemic species are clustered in the Cape, whilst the few threatened species are more widely distributed. The majority of species is well protected in existing reserves. The small number of chelonian species in southern Africa and their relatively well-known distributions, test the efficacy of an iterative reserve selection algorithm. The presence of many allopatric (or nearly so) congeneric species leads to the selection of iterative reserves that protect peripheral populations. To avoid this, marginal records and isolated, peripheral populations should be excluded from the analysis

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

Diet and feeding in the Cape Cobra, Naja nivea

It is widely reported that African cobras (genus Naja) are generalist predators, but examination of formal literature yields relatively little evidence of this for most species. Here, we review the diet of cape cobras (Naja nivea) based on examination of museum specimens, an extensive literature review, and social media reported natural history observations. We quantify dietary niche breadth and test the hypothesis that cape cobras are generalist predators. Additionally, we test the hypotheses that diet varies significantly (1) across biomes, and (2) across winter, summer and year-round rainfall regions. We gathered 101 feeding records for cape cobras and based on family-level prey frequencies calculated Levins’ measure of niche breadth as B = 6.57, which we standardised to BA = 0.29. We found no association between prey classes and biomes or rainfall region. Our data indicate that cape cobras consume a wide range of vertebrate prey from all four tetrapod classes, including a large number and diversity of snakes. Our findings suggest that cape cobras may be involved in several important ecological processes. Moreover, our study demonstrates the utility and value of collating natural history observations reported on social media platforms

Marine pelagic ecosystems: the West Antarctic Peninsula

The marine ecosystem of the West Antarctic Peninsula (WAP) extends from the Bellingshausen Sea to the northern tip of the peninsula and from the mostly glaciated coast across the continental shelf to the shelf break in the west. The glacially sculpted coastline along the peninsula is highly convoluted and characterized by deep embayments that are often interconnected by channels that facilitate transport of heat and nutrients into the shelf domain. The ecosystem is divided into three subregions, the continental slope, shelf and coastal regions, each with unique ocean dynamics, water mass and biological distributions. The WAP shelf lies within the Antarctic Sea Ice Zone (SIZ) and like other SIZs, the WAP system is very productive, supporting large stocks of marine mammals, birds and the Antarctic krill, Euphausia superba. Ecosystem dynamics is dominated by the seasonal and interannual variation in sea ice extent and retreat. The Antarctic Peninsula is one among the most rapidly warming regions on Earth, having experienced a 28C increase in the annual mean temperature and a 68C rise in the mean winter temperature since 1950. Delivery of heat from the Antarctic Circumpolar Current has increased significantly in the past decade, sufficient to drive to a 0.68C warming of the upper 300 m of shelf water. In the past 50 years and continuing in the twenty-first century, the warm, moist maritime climate of the northern WAP has been migrating south, displacing the once dominant cold, dry continental Antarctic climate and causing multi-level responses in the marine ecosystem. Ecosystem responses to the regional warming include increased heat transport, decreased sea ice extent and duration, local declines in icedependent Ade´lie penguins, increase in ice-tolerant gentoo and chinstrap penguins, alterations in phytoplankton and zooplankton community composition and changes in krill recruitment, abundance and availability to predators. The climate/ecological gradients extending along theWAPand the presence of monitoring systems, field stations and long-term research programmes make the region an invaluable observatory of climate change and marine ecosystem response

Chromosome morphology of the Madagascar tree boa Sanzinia madagascariensis

The karyotype of Sanzinia madagascariensis (2n = 34, NF = 50) was obtained from peripheral lymphocytes. A survey of chromosome morphology in the Boidae reveals that the karyotype of S. madagascariensis is unique, and not easily derivable from that of other pythons and boas. The significance of this in relation to the Zoogeographie anomaly presented by the endemic Madagascar boas Sanzinia and Acrantophis is discussed

Introduced Reptiles in the Addo Elephant National Park

Natural History Note

Another reptile translocation to a national park

On 4 May 1988 a sub-adult (50 mm snout-vent length, 42 mm tail) Jones' girdled lizard Cordylus tropidosternum jonesi was collected in a pile of wood being off-loaded at the new restcamp in the Karoo National Park, Beaufort West. The wood had been transported by lorry from the Kruger National Park. The specimen is deposited in the herpetological collection of the Port Elizabeth Museum (PEM R 4584). Jones' girdled lizard is a small, arboreal cordylid that shelters under tree bark and in hollow logs. It is common and widely-distributed in the Kruger National Park (Pienaar, Haacke & Jacobsen 1983, The Reptiles of the Kruger National Park, 3rd edition. Pretoria: National Parks Board) and adjacent lowveld, being replaced in northern Zimbabwe and East Africa by the nominate race. Hewitt & Power (1913, Transactions of the Royal Society of South Africa 3: 147-176, 1913) reported a similar translocation of the species to Kimberley in association with timber brought to the diamond mining camps. One of us noted recently the ease and danger of the unwitting spread of commensal reptile species into conservation areas (Branch 1978, Koedoe 30: 165), and this is confirmed by this additional example. We recommend that should similar shipments of wood be considered essential, then they be fumigated to prevent the translocation of other alien organisms that may potentially have more dangerous consequences