RESUMO
Global warming impacts biodiversity worldwide, leading to species' adaptation, migration, or extinction. The population's persistence depends on the maintenance of essential activities, which is notably driven by phenotypic adaptation to local environments. Metabolic rate - that increases with temperature in ectotherms - is a key physiological proxy for the energy available to fuel individuals' activities. Cold-adapted ectotherms can exhibit a higher resting metabolism than warm-adapted ones to maintain functionality at higher elevations or latitudes, known as the metabolic cold-adaptation hypothesis. How climate change will affect metabolism in species inhabiting contrasting climates (cold or warm) is still a debate. Therefore, it is of high interest to assess the pace of metabolic responses to global warming among populations adapted to highly different baseline climatic conditions. Here, we conducted a physiological experiment in the endemic Pyrenean brook newt (Calotriton asper). We measured a proxy of standard metabolic rate (SMR) along a temperature gradient in individuals sampled among 6 populations located from 550 to 2189 m a.s.l. We demonstrated that SMR increased with temperature, but significantly diverged depending on populations' origins. The baseline and the slope of the relationship between SMR and temperature were both higher for high-elevation populations than for low-elevation populations. We discussed the stronger metabolic response observed in high-elevation populations suggesting a drop of performance in essential life activities for these individuals under current climate change. With the increase of metabolism as the climate warms, the metabolic-cold adaptation strategy selected in the past could compromise the sustainability of cold-adapted populations if short-term evolutionary responses do not allow to offset this evolutionary legacy.
Assuntos
Altitude , Regulação da Temperatura Corporal , Salamandridae/fisiologia , Aclimatação , Animais , Temperatura Corporal , Feminino , Aquecimento Global , Masculino , Oxigênio/metabolismo , Salamandridae/metabolismoRESUMO
Habitat fragmentation is one of the main drivers of global amphibian decline. Anthropogenic landscape elements can act as barriers, hindering the dispersal that is essential for maintaining gene flow between populations. Dispersal ability can be influenced by locomotor performance, which in turn can depend on morphological traits, such as hindlimb length (HLL) in amphibians. Here, we tested relationships between HLL and environmental variables--road types, forests and agricultural lands--among 35 sub-populations of palmate newts (Lissotriton helveticus) in southwestern France. We expected roads to select for short-legged newts due to a higher mortality of more mobile individuals (long-legged newts) when crossing roads. Accordingly, short-legged newts were found in the vicinity of roads, whereas long-legged newts were found closer to forests and in ponds close geographically to another water body. HLL in newts was hence influenced by habitat types in a heterogeneous landscape, and could therefore be used as an indicator of population isolation in a meta-population system.
Assuntos
Ecossistema , Membro Posterior/anatomia & histologia , Salamandridae/anatomia & histologia , Animais , Feminino , Florestas , França , Locomoção , Masculino , Lagoas , Salamandridae/genética , Seleção GenéticaRESUMO
In the Rhône Valley's Middle Neolithic gathering site of Saint-Paul-Trois-Châteaux (France), the positioning of two females within a structure aligned with the solstices is atypical. Their placement (back and prone) under the overhang of a silo in front of a third in a central position suggests a ritualized form of homicidal ligature strangulation. The first occurrence dates back to the Mesolithic, and it is from the Early Neolithic of Central Europe that the practice expands, becoming a sacrificial rite associated with an agricultural context in the Middle Neolithic. Examining 20 cases from 14 sites spanning nearly two millennia from Eastern Europe to Catalonia reveals the evolution of this ritual murder practice.
Assuntos
Agricultura , Comportamento Ritualístico , Europa (Continente) , França , DNA MitocondrialRESUMO
Zellweger et al (Reports, 15 May 2020, p. 772) claimed that forest plant communities' response to global warming is primarily controlled by microclimate dynamics. We show that community thermophilization is poorly explained by the underlying components of microclimate, and that global warming primarily controls the climatic lag of plant communities. Deconstructing the underlying components of microclimate provides insights for managers.
Assuntos
Florestas , Microclima , Aquecimento Global , PlantasRESUMO
BACKGROUND: Inter-patch movements may lead to genetic mixing, decreasing both inbreeding and population extinction risks, and is hence a crucial aspect of amphibian meta-population dynamics. Traveling through heterogeneous landscapes might be particularly risky for amphibians. Understanding how these species perceive their environment and how they move in heterogeneous habitats is an essential step in explaining metapopulation dynamics and can be important for predicting species' responses to climate change and for conservation policy and management. METHODS: Using an experimental approach, the present study focused on the movement behavior (crossing speed and number of stops) on different substrates mimicking landscape components (human-made and natural substrates) in two amphibian species contrasting in locomotion mode: the common toad (Bufo bufo), a hopping and burrowing anuran and the marbled newt (Triturus marmoratus), a walking salamander. We tested the hypothesis that species reaction to substrate is dependent on specific ecological requirements or locomotion modes because of morphological and behavioral differences. RESULTS: In both species, substrate type influenced individual crossing speed, with individuals moving faster on soil than on concrete substrate. We also demonstrated that long-legged individuals moved faster than individuals with short legs. In both species, the number of stops was higher in females than in males. In common toads, the number of stops did not vary between substrates tested, whereas in marbled newts the number of stops was higher on concrete than on soil substrate. DISCUSSION: We highlighted that concrete substrate (mimicking roads) negatively affect the crossing speed of both studied species, with an effect potentially higher in marbled newts. Our findings corroborate negative effects of such heterogeneous landscapes on movement behavior of two amphibian species, which may have implications for the dynamics of metapopulations.
RESUMO
This study is part of an ongoing project aiming at determining the ethnogenesis of an eastern Siberian ethnic group, the Yakuts, on the basis of archaeological excavations carried out over a period of 10 years in three regions of Yakutia: Central Yakutia, the Vilyuy River basin and the Verkhoyansk area. In this study, genetic analyses were carried out on skeletal remains from 130 individuals of unknown ancestry dated mainly from the fifteenth to the nineteenth century AD. Kinship studies were conducted using sets of commercially available autosomal and Y-chromosomal short tandem repeats (STRs) along with hypervariable region I sequences of the mitochondrial DNA. An unexpected and intriguing finding of this work was that the uniparental marker systems did not always corroborate results from autosomal DNA analyses; in some cases, false-positive relationships were observed. These discrepancies revealed that 15 autosomal STR loci are not sufficient to discriminate between first degree relatives and more distantly related individuals in our ancient Yakut sample. The Y-STR analyses led to similar conclusions, because the current Y-STR panels provided the limited resolution of the paternal lineages.
Assuntos
Cromossomos Humanos Y/genética , DNA Mitocondrial/genética , Etnicidade/genética , Etnicidade/história , Fósseis , Sequência de Bases , Osso e Ossos/química , DNA Mitocondrial/história , Genética Populacional , Haplótipos/genética , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , História do Século XIX , Humanos , Funções Verossimilhança , Masculino , Repetições de Microssatélites/genética , Dados de Sequência Molecular , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA , SibériaRESUMO
The pattern of genetic differentiation of the endemic alpine salamander, Salamandra atra, has been studied using amplified fragment length polymorphism (AFLP) from 11 populations throughout the range of the two currently recognized subspecies, atra and aurorae. Five different primer combinations produced 706 bands and were analyzed by constructing a phylogenetic tree using NJ and principal component analysis. Significant genetic variation was revealed by AFLP between and within populations but, our results show a lack of genetic structure. AFLP markers seems to be unsuitable to investigate complex and recent diversification.