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The Chinese alligator (Alligator sinensis) is an endemic and rare species in China, and is considered to be one of the most endangered vertebrates in the world. It is known to hibernate, an energy-saving strategy against cold temperatures and food deprivation. Changes in gene expression during hibernation remain largely unknown. To understand these complex seasonal adaptive mechanisms, we performed a comprehensive survey of differential gene expression in heart, skeletal muscle, and kidney of hibernating and active Chinese alligators using RNA-Sequencing. In total, we identified 4780 genes differentially expressed between the active and hibernating periods. GO and KEGG pathway analysis indicated the likely role of these differentially expressed genes (DEGs). The upregulated DEGs in the active Chinese alligator, CSRP3, MYG and PCKGC, may maintain heart and skeletal muscle contraction, transport and storage of oxygen, and enhance the body’s metabolism, respectively. The upregulated DEGs in the dormant Chinese alligator, ADIPO, CIRBP and TMM27, may improve insulin sensitivity and glucose/lipid metabolism, protect cells against harmful effects of cold temperature and hypoxia, regulate amino acid transport and uptake, and stimulate the proliferation of islet cells and the secretion of insulin. These results provide a foundation for understanding the molecular mechanisms of the seasonal adaptation required for hibernation in Chinese alligators, as well as effective information for other non-model organisms research.
The range of the greater glider (Petauroides volans) is predicted to contract with climate change. Following indications of a decline in the Blue Mountains, we collated records and undertook surveys in 2015–16 to assess whether a decline has occurred and whether the decline is associated with climate change or other factors. We were unable to relocate greater gliders at 35% of our study sites, even though all were in known former locations. The species is now rare at lower elevations but remains relatively common at higher elevations: about seven times more abundant above 500 m than below. Historical data suggest that in 1986–96 it occurred in similar abundance across all elevations, 80–1060 m. Nine habitat variables accounted for 84% of the variation in greater glider density between our study sites, with significant independent contributions from elevation (37%) and time since fire (23%). We found no evidence that greater gliders have been impacted by increasing numbers of owls or cockatoos or that either the fire regime or rainfall has changed in the last 20 years. The most likely cause of the decline is the direct and indirect effects of a marked increase in temperature in the Blue Mountains. Similar declines are likely throughout the distribution of the species with increasing climate change.
Australia was once thought to be a biodiversity desert when considering the subterranean world; however, recent work has revealed a fascinating collection of cave creatures, many with surprising biogeographic histories. This has especially been so in the karstic regions of north-western Australia (Cape Range peninsula, Barrow Island, Pilbara), which is home not only to a diverse collection of subterranean invertebrates, but also to the continent’s only known underworld-adapted vertebrates, which includes the cave fish in the genus Milyeringa. These cave gudgeons have recently been in a state of taxonomic flux, with species being both split and lumped, but this was done with limited data (incomplete geographic sampling and no nuclear DNA sequence data). Therefore, we have revisited the systematic status of Milyeringa in a total-evidence molecular approach by integrating all existing data (mitochondrial, allozymes) with new DNA sequences from nuclear and mitochondrial loci and new multilocus allozyme data. Our conclusion, that there are two species, matches the most recent taxonomic treatment, with Milyeringa veritas present on both the eastern and western sides of the Cape Range peninsula, and Milyeringa justitia on Barrow Island. This has implications for future research in the linked fields of biogeography and conservation.
Stranded marine fauna have been identified as a potentially significant food resource for terrestrial carnivores, but how such subsidisation influences terrestrial species ecology is not well understood. We describe the dietary and behavioural responses of dingoes (Canis familiaris) to the occurrence of large-animal marine strandings (e.g. dead cetaceans, marine turtles and pinnipeds) between 2006 and 2016 on K’gari (Fraser Island), Australia, to better understand the trophic links between marine and terrestrial systems. A total of 309 strandings were recorded during this period (∼3.1 strandings per month), yielding an annual average of 30.3 tons of available carrion to the 100–200 dingoes present on the island. Carcass monitoring with camera traps showed that dingoes used carcasses almost daily after a short period of decomposition. Whole packs of up to seven dingoes of all age classes at a time were observed visiting carcasses for multiple successive days. These data demonstrate that large-animal marine subsidies can be a common, substantial and important food source for dingoes, and that the estimated daily dietary needs of roughly 5–10% of the island’s dingo population were supported by this food source. Our data suggest that marine subsidisation can influence terrestrial carnivore diet, behaviour and abundance, which may produce cascading indirect effects for terrestrial ecosystems in contexts where subsidised carnivores interact strongly with other species.
Knowledge of the habitat requirements of nocturnal birds is vital for the development of effective conservation strategies. This study is the first intensive systematic survey of the occurrence of the threatened Tasmanian masked owl (Tyto novaehollandiae castanops), the Tasmanian boobook (Ninox leucopsis) and the Australian owlet-nightjar (Aegotheles cristatus) in Tasmania using call playback, spotlighting and listening techniques. Occupancy models were created that explain the spatial distribution of the three species. Temperature and wind influenced the detectability of all species. Detectability of the Tasmanian boobook was also associated with nightlight. The Tasmanian masked owl was most often found in low-elevation mature dry eucalypt forest. This may be related to a combination of availability of nesting sites, food availability and accessibility, and physiological factors. The Australian owlet-nightjar also showed a broad preference for dry eucalypt forest and avoided open country. In contrast, the Tasmanian boobook was most often found in wet eucalypt forest with higher temperatures and fewer roads. We conclude that mature dry and wet forest types at low elevations need to be carefully managed to maintain populations of Tasmania’s nocturnal birds, particularly the threatened Tasmanian masked owl. Consideration should be given to retention of a network of contiguous areas of undisturbed mature forest across forested landscapes.
North Queensland harbours many microendemic species. These species are of conservation concern due to their small and fragmented populations, coupled with threats such as fire and climate change. We aimed to resolve the distribution and population genetic structure in two localised Phyllurus leaf-tailed geckos: P. gulbaru and P. amnicola. We conducted field surveys to better resolve distributions, used Species Distribution Models (SDMs) to assess the potential distribution, and then used the SDMs to target further surveys. We also sequenced all populations for a mitochondrial gene to assess population genetic structure. Our surveys found additional small, isolated populations of both species, including significant range extensions. SDMs revealed the climatic and non-climatic variables that best predict the distribution of these species. Targeted surveys based on the SDMs found P. gulbaru at an additional two sites but failed to find either species at other sites, suggesting that we have broadly resolved their distributions. Genetic analysis revealed population genetic structuring in both species, including deeply divergent mitochondrial lineages. Current and potential threats are overlain on these results to determine conservation listings and identify management actions. More broadly, this study highlights how targeted surveys, SDMs, and genetic data can rapidly increase our knowledge of microendemic species, and direct management.
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