Temperate Habitats Research Articles

Heat shock proteins: a history of study in Russia

This review describes a brief history of the discovery and studies in Russia and associated countries of the main stress protein (Hsp70) that plays important roles both in the normal function of the cell and body as well as under various stressful stimuli. Research on this protein at the Institute of Molecular Biology (Moscow) began with the elucidation of its adaptive functions at the cellular level and at the level of the whole organism. These studies examined the function of Hsp70 under normal and extreme conditions using a wide range of model and non-model animal species, from Leishmania and Drosophila to camels and humans. These analyses made it possible to elucidate the primary regulations in the evolution and function of heat shock (HS) genes in the studied organisms. Next, we studied the structure and characteristic features of heat shock genes and proteins in species with contrasting habitat temperatures. The systems of Hsp70 expression and isolation we developed using various research objects allowed us to proceed to study the protective properties of human recombinant Hsp70 in normal-aging animal models as well as animal models experiencing sepsis, Alzheimer's disease, and stroke. The results obtained open the prospects of using recombinant Hsp70 for the treatment of various neuropathologies in humans. This review describes the logic and history of investigation of Hsp70 performed by one group of scientists from Engelhardt Institute of Molecular Biology, Russian Academy of Sciences. It was not the goal of this paper to give a comprehensive general picture of other similar studies carried out in Russia during this period.

Insights into the Cultured Bacterial Fraction of Corals.

ABSTRACTBacteria associated with coral hosts are diverse and abundant, with recent studies suggesting involvement of these symbionts in host resilience to anthropogenic stress. Despite their putative importance, the work dedicated to culturing coral-associated bacteria has received little attention. Combining published and unpublished data, here we report a comprehensive overview of the diversity and function of culturable bacteria isolated from corals originating from tropical, temperate, and cold-water habitats. A total of 3,055 isolates from 52 studies were considered by our metasurvey. Of these, 1,045 had full-length 16S rRNA gene sequences, spanning 138 formally described and 12 putatively novel bacterial genera across the Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria phyla. We performed comparative genomic analysis using the available genomes of 74 strains and identified potential signatures of beneficial bacterium-coral symbioses among the strains. Our analysis revealed >400 biosynthetic gene clusters that underlie the biosynthesis of antioxidant, antimicrobial, cytotoxic, and other secondary metabolites. Moreover, we uncovered genomic features—not previously described for coral-bacterium symbioses—potentially involved in host colonization and host-symbiont recognition, antiviral defense mechanisms, and/or integrated metabolic interactions, which we suggest as novel targets for the screening of coral probiotics. Our results highlight the importance of bacterial cultures to elucidate coral holobiont functioning and guide the selection of probiotic candidates to promote coral resilience and improve holistic and customized reef restoration and rehabilitation efforts.IMPORTANCE Our paper is the first study to synthesize currently available but decentralized data of cultured microbes associated with corals. We were able to collate 3,055 isolates across a number of published studies and unpublished collections from various laboratories and researchers around the world. This equated to 1,045 individual isolates which had full-length 16S rRNA gene sequences, after filtering of the original 3,055. We also explored which of these had genomes available. Originally, only 36 were available, and as part of this study, we added a further 38—equating to 74 in total. From this, we investigated potential genetic signatures that may facilitate a host-associated lifestyle. Further, such a resource is an important step in the selection of probiotic candidates, which are being investigated for promoting coral resilience and potentially applied as a novel strategy in reef restoration and rehabilitation efforts. In the spirit of open access, we have ensured this collection is available to the wider research community through the web site http://isolates.reefgenomics.org/ with the hope many scientists across the globe will ask for access to these cultures for future studies.

Analysis of long-term changes in inundation characteristics of near-natural temperate riparian habitats in the Lower Basin of the Biebrza Valley, Poland

Study regionNortheast Poland, Biebrza Basin. Study focusStudying reference ecosystems and their specific features provides information to be used as background principles for ecosystem management. In the case of riparian wetlands, these are hydrological indicators (such as average water levels, flooding extents and flood duration) that are either used as criteria for ecosystem conservation or remain easy-to-measure targets for habitat restoration. We focused on revealing whether any trends in flood extents and durations of inundation exist within near-natural temperate floodplains persisting under the natural lowland river flow regime. We analysed whether the fraction of inundation time in a year (FIT) changed over time. River discharge data from 1951 to 2011 applied as boundary conditions in a 1D hydrodynamic model were used to generate flood extents and durations in the Lower Basin of the Biebrza Valley. New hydrological insights for the regionWe found no substantial trends in flood extents and flood durations in both time-dependent mean and standard deviation. We revealed that the average, long-term values of the FIT, influencing the persistence of Caricetum approprinquatae, Caricetum gracilis, Glycerietum maximae and Phragmitetum communis, reached, respectively, 0.33, 0.43, 0.49 and 0.53 and did not present trends. Variability of the FIT within particular plant communities was high. The main challenges in conservation of temperate riparian wetlands are likely related to appropriate management addressing nonlinear climatic pressures.

Combining point counts and autonomous recording units improves avian survey efficacy across elevational gradients on two continents.

Accurate biodiversity and population monitoring is a requirement for effective conservation decision making. Survey method bias is therefore a concern, particularly when research programs face logistical and cost limitations.We employed point counts (PCs) and autonomous recording units (ARUs) to survey avian biodiversity within comparable, high elevation, temperate mountain habitats at opposite ends of the Americas: nine mountains in British Columbia (BC), Canada, and 10 in southern Chile. We compared detected species richness against multiyear species inventories and examined method‐specific detection probability by family. By incorporating time costs, we assessed the performance and efficiency of single versus combined methods.Species accumulation curves indicate ARUs can capture ~93% of species present in BC but only ~58% in Chile, despite Chilean mountain communities being less diverse. The avian community, rather than landscape composition, appears to drive this dramatic difference. Chilean communities contain less‐vocal species, which ARUs missed. Further, 6/13 families in BC were better detected by ARUs, while 11/11 families in Chile were better detected by PCs. Where survey conditions differentially impacted method performance, PCs mostly varied over the morning and with canopy cover in BC, while ARUs mostly varied seasonally in Chile. Within a single year of monitoring, neither method alone was predicted to capture the full avian community, with the exception of ARUs in the alpine and subalpine of BC. PCs contributed little to detected diversity in BC, but including this method resulted in negligible increases in total time costs. Combining PCs with ARUs in Chile significantly increased species detections, again, for little cost.Combined methods were among the most efficient and accurate approaches to capturing diversity. We recommend conducting point counts, while ARUs are being deployed and retrieved in order to capture additional diversity with minimal additional effort and to flag methodological biases using a comparative framework.

Spatiotemporal assembly patterns of macroinvertebrate metacommunity structure in subtropical wetlands with different hydroperiods

AbstractUnderstanding seasonal patterns of assembly mechanisms are key to comprehending the metacommunity dynamics of organisms inhabiting temporary habitats such as wetland macroinvertebrates. However, tests of the seasonal variation in assembly mechanisms of macroinvertebrates in wetlands with differing hydroperiods are rare, especially in the Neotropical region. We tested for seasonal patterns in the metacommunity assembly mechanisms of macroinvertebrates in small subtropical highland wetlands of southern Brazil with different hydroperiods. We also tested whether patterns varied between macroinvertebrate taxa with different dispersal modes. Macroinvertebrates were sampled in 12 wetlands classified into “short,” “medium,” and “long” hydroperiods (N = 4 in each category) in three seasons (fall, winter, and spring) over two full hydrological cycles (from 2012 to 2014). We assessed the role of spatial and environmental variables to metacommunity structure using distance‐based redundancy analysis and variation partitioning. Environmental and spatial variables explained macroinvertebrate metacommunity structure, although their relative influence markedly changed among seasons and hydroperiods. Environmental variables were important in fall and winter, whereas spatial variables predominated in spring. Different environmental variables influenced the metacommunity structure in each hydroperiod. Environmental variables influenced active‐dispersing macroinvertebrates, whereas the influence of environmental and spatial variables on passive‐dispersing taxa changed among seasons. We showed that the assembly mechanisms of macroinvertebrate metacommunities show a distinct temporal dynamic among wetlands with different hydroperiods. Our findings contribute to a more complete understanding of the metacommunity structure in temporary ecosystems.

Digging deep: a revised phylogeny of Australian burrowing cockroaches (Blaberidae: Panesthiinae, Geoscapheinae) confirms extensive nonmonophyly and provides insights into biogeography and evolution of burrowing

ABSTRACTSoil‐burrowing cockroaches (Blaberidae: Geoscapheinae) are large insects endemic to Australia. Originally thought to represent a monophyletic group, these enigmatic species have in fact evolved burrowing behaviour, associated fossorial morphological modifications, and dietary transitions to dry leaf litter feeding multiple times from the wood‐feeding Panesthiinae in a striking example of parallel evolution. However, various relationships within these two subfamilies remain unresolved or poorly understood, notably the apparent paraphyly of Panesthiinae with respect to Geoscapheinae, the position and diversification of certain species within major clades, and several aspects of the overall group's biogeography and morphological evolution. Here, we investigate the phylogeny of Australian members of these two subfamilies using whole mitochondrial genomes paired with nuclear ribosomal markers and highly conserved genes from the bacterial endosymbiont Blattabacterium. Using the resulting robust, fossil‐calibrated phylogeny from these three sources we confirm the nonmonophyly of both subfamilies and recover Geoscapheinae as polyphyletic within a paraphyletic Panesthiinae. The nonmonophyly of natural groups, at all levels from subfamily to species, has been driven by repeated, independent acquisitions of burrowing forms in Geoscapheinae from panesthiine ancestors that colonized the continent on two separate occasions during the Miocene. We additionally find morphological variation within Geoscapheinae itself is correlated with species distributions. Older soil‐burrowing clades living in comparatively arid environments have additional morphological reductions beyond obvious fossorial adaptations compared to those in younger burrowing clades from more temperate habitats. Ultimately, the results presented here demonstrate connections among phylogeny, biogeography and morphology throughout Australian representatives of these two subfamilies, factors that could not be previously consolidated using existing phylogenetic frameworks. Given the discordance between molecular data implemented here and the existing taxonomic classification, we find no support for retaining Geoscapheinae as a discrete taxonomic grouping. In closing, we discuss the taxonomic implications of these results and present a roadmap for future research on Geoscapheinae and their panesthiine relatives.

Habitat heterogeneity, temperature, and primary productivity drive elevational gradients in avian species diversity.

AimAnticipating and mitigating the impacts of climate change on species diversity in montane ecosystems requires a mechanistic understanding of drivers of current patterns of diversity. We documented the shape of elevational gradients in avian species richness in North America and tested a suite of a priori predictions for each of five mechanistic hypotheses to explain those patterns.LocationUnited StatesMethodsWe used predicted occupancy maps generated from species distribution models for each of 646 breeding birds to document elevational patterns in avian species richness across the six largest U.S. mountain ranges. We used spatially explicit biotic and abiotic data to test five mechanistic hypotheses proposed to explain geographic variation in species richness.ResultsElevational gradients in avian species richness followed a consistent pattern of low elevation plateau‐mid‐elevation peak (as per McCain, 2009). We found support for three of the five hypotheses to explain the underlying cause of this pattern: the habitat heterogeneity, temperature, and primary productivity hypotheses.Main ConclusionsSpecies richness typically decreases with elevation, but the primary cause and precise shape of the relationship remain topics of debate. We used a novel approach to study the richness‐elevation relationship and our results are unique in that they show a consistent relationship between species richness and elevation among 6 mountain ranges, and universal support for three hypotheses proposed to explain the underlying cause of the observed relationship. Taken together, these results suggest that elevational variation in food availability may be the ecological process that best explains elevational gradients in avian species richness in North America. Although much attention has focused on the role of abiotic factors, particularly temperature, in limiting species’ ranges, our results offer compelling evidence that other processes also influence (and may better explain) elevational gradients in species richness.

Filling the Gap: Entirely Beige/Brite Adipose Tissues in One of the Smallest Mammals, Suncus etruscus

Mammalian brown adipose tissue provides a means of non-shivering thermogenesis to defend normothermia in the cold by uncoupling protein 1 (UCP1) mediated uncoupling of mitochondrial respiration from ATP production. Apart from brown adipose tissue, thermogenic beige/brite adipocytes reside interspersed within white adipose tissue depots. In rodents, the number of beige/brite adipocytes is highly variable and adapts to thermogenic requirements. We here studied adipose tissue composition of the Etruscan shrew S. etruscus, an insectivore and one of the smallest known mammals with a consequently extreme thermogenic demand in its temperate habitat with cold winters. By dissection, phase contrast computer tomography, histology and mitochondrial enzyme activity assays, we mapped the distribution of adipose tissue depots in shrews from a research colony kept at room temperature. In similar anatomical locations as typically found in rodents, an especially large amount of brown adipose tissue concentrated to the interscapular and subscapular region, while white adipose tissue with a very high content of multilocular cells formed the inguinal and gluteal depots. Uniquely, shrews featured a large, interrenal adipose tissue that by visual inspection, mitochondrial density, fat content, UCP1 transcript abundance, histological analysis and mitochondrial enzyme activity appeared to be an intermediate between classical brown and very beige/brite adipose tissue. This unusual, centrally located depot expansively sheathed both the Vena cava inferior and the Aorta abdominalis, the two largest blood vessels, and must be assumed to provide considerable thermogenic capacity. In conclusion, we identified a novel adipose tissue depot with unique properties placing it in between very beige/brite and brown adipose tissue. Importantly, this finding fills in a conceptual gap within our understanding of adipose tissue plasticity previously thought to include a range from white to beige/brite on the one end, and brown on the other. Etruscan shrew fat depots, however, demonstrate the existence of a gapless continuum of white-to-brown characteristics. Functionally, the transitional, interrenal depot appears strategically placed to deliver heat into circulation via the penetrating, large blood vessels in an animal with extreme thermogenic demand.

Construction of Ecological Network Based on Multi-Scale Conversion and Nesting

Ecological protection and the restoration of full-array ecosystems is an important part of ecological civilization construction, which is a powerful measure to implement the concept of green development and help bridge the gap between the respective inevitable requirements of the current ecological environment and economic development. To solve this problem, a multi-scale index system was constructed to identify ecological sources comprehensively. The minimum-cost path method, the circuit theory, and the cyclic window search method were adopted to quantitatively identify the important ecological sources and corridors in scale nesting and pinch points and barrier points that affect multi-level connectivity. Furthermore, the specific optimization layout strategy of the ecological network structure of the Hefei metropolitan area was proposed. According to the results, if ecological sources and corridors at two scales are overlaid, the coincident area of ecological sources at two scales is 1719.95 km2. As important ecological sources, Chaohu Lake Basin, Niuwangzhai, and Wuding Mountain, which are important areas to maintain the ecological network, need to be protected. Ten overlapping ecological corridors, which are mainly distributed in Changfeng County, are easily damaged long term. As a result, ecological nodes should be set up as temporary habitats for species transfer. In addition, based on the circuit theory and the cyclic window search method, calculating areas of pinch points at two scales yields 1637.75 km2 and 434.22 km2, respectively, and for areas of barrier points yields 2182.75 km2 and 126.97 km2, respectively. The ecological pinch points at two overlapping scales among them are important areas for future protection. Due to the small and fragmented spatial distribution in the urban area, pinch points with an average size of 0.58 km2 are easy to be restored and will greatly improve the connectivity of the ecological network after restoration. Furthermore, through the quantitative identification of ecological network elements of two scales, the paper puts forward an optimization strategy for an ecological network in the Hefei metropolitan area from three aspects of “point-line-polygon.” The research results can reference decision-making concerning the delineation of urban growth boundary, regional ecological security pattern, land space renovation, and ecosystem restoration.

Sturnira hondurensis(Chiroptera: Phyllostomidae)

AbstractThe Honduran yellow-shouldered bat (Sturnira hondurensis Goodwin, 1940) is a medium-sized Stenodermatinae with a vestigial uropatagium and no tail; it typically has reddish or yellowish patches on the shoulders. It is found in temperate habitats from Mexico to northern Nicaragua, and it is one of 24 described species of the genus Sturnira. S. hondurensis is considered a common species and is listed as “Least Concern” (LC) by the International Union for Conservation of Nature and Natural Resources. Nevertheless, it primarily depends on the preservation of native and continuous forest, so maintaining the connectivity of vegetation patches and the availability of food in modified landscapes are strategies for the preservation of S. hondurensis and the ecosystem services that it provides.

A Bayesian network with fuzzy mathematics for species habitat suitability analysis: A case with limited Angelica sinensis (Oliv.) Diels data

There are many different types of species distribution models (SDMs) that are widely used in the field of ecology. In this research, we explored a new advanced mechanism for predicting the distribution of species based on fuzzy membership function, principle of maximum entropy, fuzzy mathematics comprehensive evaluation, and the framework of Bayesian networks. We use fuzzy mathematics and Bayesian network model (FBM) to simulate relationships between species’ habitats and environmental variables, and the relationship may be difficult to quantify effectively. FBM, which combines species data, environmental data, expert experience, and machine learning, could reduce the data and system error. In the case of medicinal plant, Angelica sinensis (Oliv.) Diels, many approaches have been applied, including nine learning sequence of sampling sites, three FBM models, two types of information classification by fuzzy mathematical classification (FMC) and equal interval classification (EIC), and the evaluation of AIC and log-likelihood. Through the comparison of reasoning results between FBM and fuzzy matter element model (FME) in testing sites, the result shows that the combination of objective data and empirical model structure makes FBM have better result output. Besides, FBM sensitivity analysis helps researchers explore in detail the impact of environmental factors on each level of species habitat suitability. The temperature factor has an important influence on the highly suitable, moderately suitable, and lowly suitable habitats of A. sinensis. Through FMC and sensitivity analysis, annual mean temperature (Bio1) in 5.92 °C-9.05 °C and mean temperature of warmest quarter (Bio10) in 14.80 °C-18.60 °C are the highly suitable habitat temperature range of A. sinensis.

Comparative thermal performance among four young-of-the-year temperate reef fish species

Abstract Identifying the role of temperature on species-specific performance is critical for predicting how species will respond to temperature increases expected under climate change. We compared the thermal performance of two sympatric Pacific rockfish species complexes (controls for relatedness and geographic location) that vary in larval life-history traits associated with different oceanographic regimes including temperature during early life-history stages: the BY complex (Black: Sebastes melanops, Yellowtail: S. flavidus) and the CQ complex (Copper: S. caurinus, Quillback: S. maliger). By using controlled experiments, we evaluated foraging activity, growth, and survival of young-of-the-year rockfish recruits under current and future habitat temperatures over a 14-day time period indicative of marine heatwave events expected with climate change. BY rockfish displayed a heat-intolerant behaviour by only foraging at temperatures within current habitat temperatures, whereas the CQ rockfish displayed a heat-tolerant behaviour by actively foraging at temperatures above current and future predicted temperatures for a limited time. Although growth and survival in each species significantly declined with temperature, the magnitude of the effect did not vary between species. Taken together, our results show that rockfish are capable of using different behavioural strategies to cope with warming and may be differentially impacted by future climate conditions.

Cytochrome Oxidase 2 (COX2), β-Tubulin (TUB) and Chitin Synthase Subunit 2 (CHS2) Expression in Pythium insidiosum Thai Strains

This study aimed to investigate the real-time fluctuation of temperature-sensitive gene expression in a Pythium insidiosum growing at human body temperature (37 ºC) when it can cause life-threatening disease, whereas its natural habitat is in agricultural water sources with lower temperature. Genes encoding cytochrome oxidase 2 (COX2), β-tubulin (TUB), and chitin synthase subunit 2 (CHS2) were tested for their expression at the infection temperature (37 ºC) and natural habitat temperature (27 ºC) using real-time RT-PCR. Sixteen strains of P. insidiosum, representing 3 phylogeographic preferences, were analyzed. The subculturing process at 27 ºC was repeated at least 2 - 3 cycles. The results showed that at 37 ºC, the COX2 was expressed 2.5-fold higher than that of 27 ºC (p = 0.0347) while the level of TUB and CHS2 mRNA disclosed indistinguishable profiles. These results suggested that these genes were suitable to be used as housekeeping genes for temperature-susceptible gene expression studies. This work was likely to be the 1st study examining the gene expression levels of the Thai strain of P. insidiosum under thermal stress conditions. Follow-up studies for the COX2 genes may useful to provide valuable insight into the pathogenesis, diagnostic, or therapeutic targets for further investigation.

Population density dynamics of Pachymelania byronensis (Wood, 1828) (Gastropoda: Thiaridae) in the Cross River, Nigeria

The ecology of an exploited population of the commercially important molluscan species, Pachymelania byronensis (Wood, 1828) was studied (January-December, 2018) in the lower Cross River, Nigeria, using density [number per hectare (N. ha-1)] as measure of stock abundance. The results revealed that the river supports a considerable stock of the gastropod (density range: Drange = 508000 – 12510000 N. ha-1; mean: Dmean = 4849833N.ha-1). The density decreased by 12002N. ha-1 (i.e. 10001667N. ha-1 mo-1) between January and December, a reflection of the increasing human exploitation as the year progressed. However, the monthly density changes scored low stochasticity (randomness), a product of the resilience of the population to human exploitation. The monthly densities were significantly correlated with river limnological parameters, including surface temperature, discharge, water level, transparency, dissolved oxygen concentration and hydrogen ion concentration. The coefficients of determination showed the decreasing order of theimportance of these parameters as: transparency (67.8%), water level (57.0%), surface temperature (43.5%), pH (40.5%), dissolved oxygen concentration (36.1%) and discharge (34.3%). The monthly values of biotic potential (rmax) were used to show trends in the population dynamics. Major density decreases were noted in February (rmax = -5.456) and December (rmax = -2.931) whereas notable density increases were recorded in January (rmax = + 3.204) and November (rmax = + 3.052). The value of the annual mean biotic potential (mean: rmax(mean) = -0.191) portrayed the general effect of heavy human exploitation on the mollusc. Hence, the gastropod total mortality rate was high (Z = -3.204 yr-1) The river carrying capacity of the gastropod was estimated at 12510000N ha-1. The monthly biotic potential correlated significantly with habitat temperature and dissolved oxygen concentration, two important life support parameters.
 Keywords: Pachymelania byronensis; density; biotic potential; exploitation; Cross River; Nigeria.

Species composition, spatio-temporal variation and habitat characterization of Anopheline larvae in Bure district, northwestern Ethiopia

In Ethiopia, mosquito larva control interventions are given less emphasis due to a number of factors including lack of precise information on potential breeding habitats and complicated vector biology. Hence, the objective of this study was to assess the spatio-temporal variation and habitat characterization of Anopheline larvae in Bure district, Northwestern Ethiopia. Longitudinal larval sampling was done in 3 villages (Bukta, Workimdr and Shnebekuma) for a year (July 2015 - June, 2016). Sampling was done one time per month. Documentation of habitat type and environmental characteristics were done in each round of sampling. A total of 3490 Anophelines larvae were collected in a year. Seven larval species were identified morphologically: Anopheles gambiae s.l, An. funestus s.l, An. pharoensis. An. demeilloni, An. coustani, An. squamosus, An. cinereus. Of these, An. demeilloni (1.97 ± 0.03) and An. gambiae s. l (1.79 ± 0.06) were the predominant larvae, whereas An. pharoensis (0.18 ± 0.04) was the least representative (p < 0.01). Anophelines larvae were found in various breading habitats, but the mean density of Anophelines larvae in dam- edge (0.45 ± 0. 19) was relatively smaller than other habitats (p < 0.01). The large densities of An. gambiae s.l and An. funestus s.l larvae were sampled from natural, permanent and temporary aquatic habitats that had clean and standing water, without mats of algae, vegetation’s and plants. Multiple linear regression analysis showed that only standing water was found to be the main predictor of the density of An. gambiae s.l density (R2 = 0.457; p < 0.016). In conclusion, the larvae of the two most important malaria vectors of Ethiopia, An. gambiae and An. funestus s.l, were collected through the year.

Investigating links between thermal tolerance and oxygen supply capacity in shark neonates from a hyperoxic tropical environment

Temperature and oxygen limit the distribution of marine ectotherms. Haematological traits underlying blood-oxygen carrying capacity are thought to be correlated with thermal tolerance in certain fishes, and this relationship is hypothesised to be explained by oxygen supply capacity. We tested this hypothesis using reef shark neonates as experimental models because they live near their upper thermal limits and are physiologically sensitive to low oxygen conditions. We first described in situ associations between temperature and oxygen at the study site (Moorea, French Polynesia) and found that the habitats for reef shark neonates (Carcharhinus melanopterus and Negaprion acutidens) were hyperoxic at the maximum recorded temperatures. Next, we tested for in situ associations between thermal habitat characteristics and haematological traits of neonates. Contrary to predictions, we only demonstrated a negative association between haemoglobin concentration and maximum habitat temperatures in C. melanopterus. Next, we tested for ex situ associations between critical thermal maximum (CTMax) and haematological traits, but only demonstrated a negative association between haematocrit and CTMax in C. melanopterus. Finally, we measured critical oxygen tension (pcrit) ex situ and estimated its temperature sensitivity to predict oxygen-dependent values of CTMax. Estimated temperature sensitivity of pcrit was similar to reported values for sharks and skates, and predicted values for CTMax equalled maximum habitat temperatures. These data demonstrate unique associations between haematological traits and thermal tolerance in a reef shark that are likely not explained by oxygen supply capacity. However, a relationship between oxygen supply capacity and thermal tolerance remains to be demonstrated empirically.

Heat hardening in a pair of Anolis lizards: constraints, dynamics and ecological consequences.

Heat tolerance plasticity is predicted to be an important buffer against global warming. Nonetheless, basal heat tolerance often correlates negatively with tolerance plasticity ('trade-off hypothesis'), a constraint that could limit plasticity benefits. We tested the trade-off hypothesis at the individual level with respect to heat hardening in two lizard species, Anolis carolinensis and Anolis sagrei. Heat hardening is a rapid increase in heat tolerance after heat shock that is rarely measured in reptiles but is generally considered to be a first line of physiological defense against heat. We also employed a biophysical model of operative habitat temperatures to estimate the performance consequences of hardening under ecologically relevant conditions. Anolis carolinensis hardened by 2h post-heat shock and maintained hardening for several hours. However, A. sagrei did not harden. Biophysical models showed that hardening in A. carolinensis reduces their overheating risk in the field. Therefore, while not all lizards heat harden, hardening has benefits for species that can. We initially found a negative relationship between basal tolerance and hardening within both species, consistent with the trade-off hypothesis. However, permutation analyses showed that the apparent trade-offs could not be differentiated from statistical artifact. We found the same result when we re-analyzed published data supporting the trade-off hypothesis in another lizard species. Our results show that false positives may be common when testing the trade-off hypothesis. Statistical approaches that account for this are critical to ensure that the hypothesis, which has broad implications for thermal adaptation and responses to warming, is assessed appropriately.

Relative Efficiency of Pitfall vs. Bait Trapping for Capturing Taxonomic and Functional Diversities of Ant Assemblages in Temperate Heathlands.

Simple SummaryAnts, due to their high ecological diversity, are challenging to properly sample. This issue has been addressed by many authors devising multiple sampling techniques. Depending on the habitats sampled, the effectiveness and complementarity of the sampling techniques may vary. Only little work has been done in open temperate habitats. This study aimed to assess the relative efficiency of two common sampling methods: pitfall and bait trapping. The comparison was performed using both a taxonomic (species count) and a functional (i.e., acknowledging of ecological characteristics of species to describe an assemblage of species) approach. Pitfall traps captured more species and a wider set of functional traits than did bait traps, and all species caught by bait traps were also caught by pitfall traps. It therefore appears that in the particular context of open temperate habitats, using bait traps on top of pitfall traps will cost time without information gained and that pitfalls should thus be favored in this context.Whereas bait and pitfall trappings are two of the most commonly used techniques for sampling ant assemblages, they have not been properly compared in temperate open habitats. In this study, taking advantage of a large-scale project of heathland restoration (three sites along the French Atlantic Coast forming a north-south gradient), we evaluated the relative efficiency of these two methods for assessing both taxonomic and functional diversities of ants. Ants were collected and identified to species level, and six traits related to morphology, behavior (diet, dispersal and maximum foraging distance), and social life (colony size and dominance type) were attributed to all 23 species. Both observed and estimated species richness were significantly higher in pitfalls compared to spatially pair-matched bait traps. Functional richness followed the same pattern, with consistent results for both community weighted mean (CWM) and Rao’s quadratic entropy. Taxonomic and functional diversities from pitfall assemblages increased from north to south locations, following a pattern frequently reported at larger spatial scales. Bait trapping can hardly be considered a complementary method to pitfall trapping for sampling ants in open temperate habitats, as it appears basically redundant with the latter sampling method, at least in coastal heathlands of the East-Atlantic coast.

Does the invasive macro-algae Sargassum muticum (Yendo) Fensholt, 1955 offer an appropriate temporary habitat for mobile fauna including non indigenous species?

The fauna inhabiting the brown seaweed Sargassum muticum was studied on a spatial scale along the Normandy coast from the Normand-Breton Gulf to the Bay of Seine (English Channel) in both shallow sandy and rocky tidal pools during the springs 2018 and 2019. In this paper, we test the following hypothesis: do the areas with dense populations of S. muticum represent an appropriate habitat for dense motile fauna including other Non-Indigenous Species (NIS)? The ALEX (ALien biotic indEX) is used to ascertain whether or not S. muticum favours the establishment of other NIS in this new habitat. Results show that the epifaunal assemblage associated with S. muticum differs between the five sampling sites. However, the fauna at all five sites is dominated by arthropoda, especially the amphipods and isopods. In addition, five non indigenous species are observed inhabiting the brown seaweed (four amphipods: Aoroides longimerus, Aoroides semicurvatus, Monocorophium acherusicum, Monocorophium sextonae and one decapod: Hemigrapsus sanguineus). In spite of the presence of Non-Indigenous Species (NIS) associated with the invasive Sargassum, the ALEX yields a high Ecological Quality Status for all the sites. Nevertheless, the results suggest that S. muticum is a suitable habitat for many invertebrates especially amphipods and isopods, while also representing a potential source of food for several local fish and cephalopod species.

Identification of putative key genes for thermal adaptation in the Japanese mantis shrimp (Oratosquilla oratoria) through population genomic analysis

Little is known about the mechanisms underlying the relationship between genetic variation and the adaptation of Oratosquilla oratoria populations to different habitat temperature. Here, the genome-wide genetic information of three O. oratoria populations were obtained by IIB restriction site-associated DNA (2b-RAD) sequencing and 2403 single-nucleotide polymorphisms (SNPs) were identified. Based on the 2403 SNPs, we found a remarkable genetic differentiation between the Yellow Sea and the East China Sea groups of O. oratoria. Furthermore, 63 SNPs are thought to be associated with different sea temperatures. Based on the 63 SNPs, it is hypothesised that the long-term temperature differences may contribute to the variation of genes associated with multiple biological functions, such as material metabolism, cytoskeleton, cellular processes, inflammatory response and hormonal regulation. This study provides new information for elucidating the molecular mechanisms underlying the relationship between genetic variation and the adaptation of Oratosquilla oratoria populations to different temperature.