Life-history traits such as rates of growth, survival and reproduction can vary though time within a single population, or through space among populations, due to abiotically-driven changes in resource availability. In terrestrial reptiles, parameters such as temperature and rainfall generate variation in life-histories – but other parameters likely are more important in marine systems. We studied three populations of sea snakes (Emydocephalus annulatus) in adjacent bays in the IndoPacific archipelago of New Caledonia. The extreme...
For sea snakes as for many types of animals, long-term studies on population biology are rare and hence, we do not understand the degree to which annual variation in population sizes is driven by density-dependent regulation versus by stochastic abiotic factors. We monitored three populations of turtle-headed sea snakes (Emydocephalus annulatus) in New Caledonia over an 18-year period. Annual recruitment (% change in numbers) showed negative density-dependence: that is, recruitment increased when population densities were...
Evolutionary theory suggests that polymorphic traits can be maintained within a single population only under specific conditions, such as negative frequency-dependent selection or heterozygote advantage. Non-venomous turtle-headed sea snakes (Emydocephalus annulatus) living in shallow bays near Noumea in New Caledonia exhibit three colour morphs: black, black-and-white banded, and an intermediate (grey-banded) morph that darkens with age. We recorded morph frequencies during 18 consecutive years of surveys, and found that the numbers of recruits (neonates plus...
The evolution of bright “warning” colours in nontoxic animals often is attributed to mimicry of toxic species, but empirical tests of that hypothesis are elusive. Populations of a harmless sea snake species (Emydocephalus annulatus) in New Caledonia exhibit colour polymorphism, with around 20% of individuals banded rather than melanic. Stability in that proportion over 20 years has been attributed to Batesian mimicry of deadly snake species by banded morphs of the harmless taxon. This hypothesis...
Data from: Distribution patterns of microbial communities in ultramafic landscape: a metagenetic approach highlights the strong relationships between diversity and environmental traitsLaurent Bordez, Philippe Jourand, Marc Ducousso, Fabian Carriconde, Yvon Cavaloc, Sébastien Santini, Jean M. Claverie, Laurent Wantiez, Antoine Leveau & Hamid Amir
Microbial species richness and assemblages across ultramafic ecosystems were investigated to assess the relationship between their distributional patterns and environmental traits. The structure of microorganism communities in the Koniambo massif, New Caledonia, was investigated using a metagenetic approach correlated with edaphic and floristic factors. Vegetation cover and soil properties significantly shaped the large phylogenetic distribution of operational taxonomic unit within microbial populations, with a mean per habitat of 3.477 (±317) for bacteria and 712 (±43)...
In snakes, divergence in head size between the sexes has been interpreted as an adaptation to intersexual niche divergence. By overcoming gape-limitation, a larger head enables snakes of one sex to ingest larger prey items. Under this hypothesis, we do not expect a species that consumes only tiny prey items to exhibit sex differences in relative head size, or to show empirical links between relative head size and fitness-relevant traits such as growth and fecundity....
Niche partitioning within a population of seasnakes is constrained by ambient thermal homogeneity and small prey sizeRichard Shine, Claire Goiran & Gregory Brown
In many populations of terrestrial snakes, an individual’s phenotype (e.g. body size, sex, colour) affects its habitat use. One cause for that link is gape-limitation, which can result in larger snakes eating prey that are found in different habitats. A second factor involves thermoregulatory opportunities, whereby individuals select habitats based upon thermal conditions. These ideas predict minimal intraspecific variation in habitat use in a species that eats small prey and lives in a thermally uniform...
Data from: Isolation and no-entry marine reserves mitigate anthropogenic impacts on grey reef shark behaviorJean-Baptiste Juhel, Laurent Vigliola, Laurent Wantiez, Tom B. Letessier, Jessica J. Meeuwig & David Mouillot
Reef sharks are vulnerable predators experiencing severe population declines mainly due to overexploitation. However, beyond direct exploitation, human activities can produce indirect or sub-lethal effects such as behavioral alterations. Such alterations are well known for terrestrial fauna but poorly documented for marine species. Using an extensive sampling of 367 stereo baited underwater videos systems, we show modifications in grey reef shark (Carcharhinus amblyrhynchos) occurrence and feeding behavior along a marked gradient of isolation from humans...
1. Reef sharks are declining worldwide under ever increasing fishing pressure with potential consequences on ecosystem functioning. Marine protected areas (MPAs) are currently one of the management tools to counteract the pervasive impacts of fishing. However, MPAs in which reef sharks are abundant tend to be located in remote and underexploited areas preventing a fair assessment of management effectiveness beyond remoteness from human activities. 2. Here we determine the conditions under which MPAs can effectively...
University of New Caledonia9
Zoological Society of London2
University of Western Australia2
Institut de Recherche pour le Développement1
Surfers Against Sewage1
French National Centre for Scientific Research1
University of Perpignan1
James Cook University1