The «Empty Forest Syndrome» and the Herpetofaunal Communities in Laos (South-Eastern Asia)

Nowadays, Laos remains one of the scientifically least known countries of Asia in terms of herpetological knowledge. Here, we evaluate composition of species in freshwater ecosystems (main river courses) and terrestrial ecosystems (forests) in two distinct regions using Visual Encounter Surveys along designed transects, examination of fishers’ catches and standardized interviews. In Northern Laos, we recorded only 18 reptile individuals (2 turtle and 1 snake species). Interview surveys demonstrated that in Nam Xam River, fishers are more likely to hunt turtles and we identified one potential site where the world’s rarest turtle, Rafetus swinhoei, could be still present in the wild. In Nam Et Phou Louey National Park, we found 19 reptile species (8 lizard, 10 snake, 1 turtle species) in the different study sites, demonstrating a low species density in all different surveyed habitats. In Central/Southern Laos, we observed 30 species of reptiles (14 snake, 16 lizard, 35 amphibian species). Our study offers preliminary insights into the composition of amphibians and reptiles in Laos. The great majority of the species were non-threatened or not evaluated, and a few were threatened, suggesting that more research is needed to proper understand the conservation status of Laos’ herpetofauna. We highlighted, indirectly by interviews with local fishers, the possible presence of the turtle Rafetus swinhoei, thus providing a new hope for avoiding the extinction of this species. Finally, we observed a relatively low number of species in each habitat type, which is remarkably lower than in tropical forests of other continents or of nearby south-east Asian countries, indicating that the herpetofauna communities in Laos are depleted, reflecting an ‘empty forest syndrome’.

Evidence for Host Selectivity and Specialization by Epizoic Chelonibia Barnacles Between Hawksbill and Green Sea Turtles

Epibionts are organisms that utilize the exterior of other organisms as a living substratum. Many affiliate opportunistically with hosts of different species, but others specialize on particular hosts as obligate associates. We investigated a case of apparent host specificity between two barnacles that are epizoites of sea turtles and illuminate some ecological considerations that may shape their host relationships. The barnacles Chelonibia testudinaria and Chelonibia caretta, though roughly similar in appearance, are separable by distinctions in morphology, genotype, and lifestyle. However, though each is known to colonize both green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) sea turtles, C. testudinaria is >5 times more common on greens, while C. caretta is >300 times more common on hawksbills. Two competing explanations for this asymmetry in barnacle incidence are either that the species’ larvae are spatially segregated in mutually exclusive host-encounter zones or their distributions overlap and the larvae behaviorally select their hosts from a common pool. We indirectly tested the latter by documenting the occurrence of adults of both barnacle species in two locations (SE Florida and Nose Be, Madagascar) where both turtle species co-mingle. For green and hawksbill turtles in both locations (Florida: n = 32 and n = 275, respectively; Madagascar: n = 32 and n = 125, respectively), we found that C. testudinaria occurred on green turtles only (percent occurrence – FL: 38.1%; MD: 6.3%), whereas the barnacle C. caretta was exclusively found on hawksbill turtles (FL: 82.2%; MD: 27.5%). These results support the hypothesis that the larvae of these barnacles differentially select host species from a shared supply. Physio-biochemical differences in host shell material, conspecific chemical cues, external microbial biofilms, and other surface signals may be salient factors in larval selectivity. Alternatively, barnacle presence may vary by host micro-environment. Dissimilarities in scute structure and shell growth between hawksbill and green turtles may promote critical differences in attachment modes observed between these barnacles. In understanding the co-evolution of barnacles and hosts it is key to consider the ecologies of both hosts and epibionts in interpreting associations of chance, choice, and dependence. Further studies are necessary to investigate the population status and settlement spectrum of barnacles inhabiting sea turtles.

Ecological Vulnerability of Adult Female Marine Turtles as Indicators of Opportunities for Regional Socioecosystem Management in the Southern Gulf of Mexico

Planning for marine ecosystems management demands spatially explicit information about structural and functional components, in a tradeoff between including the most taxa and keeping it functional. Sentinel, umbrella, and surrogate taxa are strategic for developing indexes that account for other associated species and contribute to a sustainable administration of our seas. Marine turtles feature the former species descriptions, and the knowledge on their ecology contributes to design conservation and restoration strategies in regions they occupy, such as the Gulf of Mexico. Several administrative tools exist to govern marine territories for biodiversity conservation, and assessing how these tools interact with the ecological vulnerability of endangered species is crucial for improving public policies. We assessed the spatial interactions among ecological sensitivity, vulnerability, and the potential impacts on four marine turtle species in the southern Gulf of Mexico and northwestern Caribbean Sea with territorial management tools (natural protected areas, marine priority sites, and ecoregions). A small percentage of the most vulnerable areas is inside natural protected areas, while marine priority sites include a higher percentage. We identified spatial covering gaps that need to be addressed to ensure the conservation and recovery of these endangered species in the Gulf of Mexico and proposed key regions for maximizing territorial conservation.

Muscles in Winter: The Epigenetics of Metabolic Arrest

The winter months are challenging for many animal species, which often enter a state of dormancy or hypometabolism to “wait out” the cold weather, food scarcity, reduced daylight, and restricted mobility that can characterize the season. To survive, many species use metabolic rate depression (MRD) to suppress nonessential metabolic processes, conserving energy and limiting tissue atrophy particularly of skeletal and cardiac muscles. Mammalian hibernation is the best recognized example of winter MRD, but some turtle species spend the winter unable to breathe air and use MRD to survive with little or no oxygen (hypoxia/anoxia), and various frogs endure the freezing of about two-thirds of their total body water as extracellular ice. These winter survival strategies are highly effective, but create physiological and metabolic challenges that require specific biochemical adaptive strategies. Gene-related processes as well as epigenetic processes can lower the risk of atrophy during prolonged inactivity and limited nutrient stores, and DNA modifications, mRNA storage, and microRNA action are enacted to maintain and preserve muscle. This review article focuses on epigenetic controls on muscle metabolism that regulate MRD to avoid muscle atrophy and support winter survival in model species of hibernating mammals, anoxia-tolerant turtles and freeze-tolerant frogs. Such research may lead to human applications including muscle-wasting disorders such as sarcopenia, or other conditions of limited mobility.

Disseminated Candidiasis and Candidemia Caused by Candida palmioleophila in a Green Sea Turtle (Chelonia mydas)

A sub-adult green sea turtle (Chelonia mydas) was rescued and treated for carapace and plastron shell fractures. The turtle was kept dry-docked for the first 2 months with a placement of a long-term jugular central venous catheter (CVC). Pain management, aggressive antibiotic and anthelmintic therapy, fluid therapy, force feeding, and wound debridement were provided to manage the shell fractures and control bacteremia. Human albumin was administered to treat severe hypoalbuminemia. On day 59, small budding yeasts were noted on the blood smears. Candidemia was confirmed by blood culture, as the yeasts were identified as Candida palmioleophila by the molecular multi-locus identification method. The CVC was removed, and the patient was treated with itraconazole. Although the carapace and plastron wounds had epithelized by 5.5 months after the rescue, the turtle died unexpectedly by 7.5 months. The postmortem examination revealed numerous necrogranulomas with intralesional yeasts, morphologically compatible with Candida spp., in joints, bones, brain, and lungs, suggestive of disseminated candidiasis. We describe a rare case of candidemia in the veterinary field. To our knowledge, this is the first report of candidiasis caused by C. palmioleophila in a reptile. The present results should improve veterinary medical care and, therefore, enhance the conservation of endangered sea turtle species.

Olive ridley (Lepidochelys olivacea) laying eggs habitat mapping in Penimbangan Beach, Bali Island

Penimbangan beach is one of the tourist destinations located in Buleleng Regency, Bali Province, Indonesia. This beach is also a nesting place for one of the sea turtle species in Indonesia, which is olive ridley (Lepidochelys olivacea). The problem that exists on the island of Bali today is most of the land in coastal areas were experienced land degradation. This land degradation occurs due to human activities or natural factors, it harms the turtle nesting habitat around the coastal area of Bali Island. Conservation of nesting turtle habitat is needed through spatial analysis using Geographic Information Systems (GIS). This study uses the parameters of sand particle, beach slope, width beach, humidity, and temperature parameter to determine the suitability of the turtle nesting habitat. Penimbangan beach area which is very suitable for turtle nesting locations has an area of 163,45 m2, suitable for laying eggs 4.886,44 m2, and not suitable for laying eggs 10.201,64 m2. The map of the suitability for laying turtle eggs is dominated by areas that are not suitable because the width of the beach is not too long and the humidity is still relatively high.

Occurrence and diet analysis of sea turtles in Korean shore

Background Sea turtles, which are globally endangered species, have been stranded and found as bycatch on the Korean shore recently. More studies on sea turtles in Korea are necessary to aid their conservation. To investigate the spatio-temporal occurrence patterns of sea turtles on the Korean shore, we recorded sampling locations and dates, identified species and sexes and measured sizes (maximum curved carapace length; CCL) of collected sea turtles from the year 2014 to 2020. For an analysis of diets through stomach contents, we identified the morphology of the remaining food and extracted DNA, followed by amplification, cloning, and sequencing. Results A total of 62 stranded or bycaught sea turtle samples were collected from the Korean shores during the study period. There were 36 loggerhead turtles, which were the dominant species, followed by 19 green turtles, three hawksbill turtles, two olive ridley turtles, and two leatherback turtles. The highest numbers were collected in the year 2017 and during summer among the seasons. In terms of locations, most sea turtles were collected from the East Sea, especially from Pohang. Comparing the sizes of collected sea turtles according to species, the average CCL of loggerhead turtles was 79.8 cm, of green turtles was 73.5 cm, and of the relatively large leatherback turtle species was 126.2 cm. In most species, the proportion of females was higher than that of males and juveniles, and was more than 70% across all the species. Food remains were morphologically identified from 19 stomachs, mainly at class level. Seaweeds were abundant in stomachs of green turtles, and Bivalvia was the most detected food item in loggerhead turtles. Based on DNA analysis, food items from a total of 26 stomachs were identified to the species or genus level. The gulfweed, Sargassum thunbergii, and the kelp species, Saccharina japonica, were frequently detected from the stomachs of green turtles and the jellyfish, Cyanea nozakii, the swimming crab, Portunus trituberculatus, and kelps had high frequencies of occurrences in loggerhead turtles. Conclusions Our findings support those of previous studies suggesting that sea turtles are steadily appearing in the Korean sea. In addition, we verified that fish and seaweed, which inhabit the Korean sea, are frequently detected in the stomach of sea turtles. Accordingly, there is a possibility that sea turtles use the Korean sea as feeding grounds and habitats. These results can serve as basic data for the conservation of globally endangered sea turtles.