[Status and perspective of soil fauna eco-geography in China]. / ä¸­å›½åœŸå£¤åŠ¨ç‰©ç”Ÿæ€åœ°ç†å­¦ç ”ç©¶çŽ°çŠ¶ä¸Žå±•æœ›.

As regulators of the surface land processes, soil fauna communities are the vital foundations for healthy terrestrial ecosystems. Soil fauna have been studied in China for more than 70 years. Great progresses have been achieved in exploring soil fauna species composition and geographical distribution patterns. Soil fauna eco-geography, as a bridge between soil fauna geographic patterns and ecosystem services, has a new development opportunity with the deep recognition of soil fauna ecological functions. Soil fauna eco-geography research could be partitioned into four dimensions including the spatio-temporal patterns of: 1) the apparent characteristics of soil fauna community, such as species composition, richness and abundance; 2) the intrinsic characteristics of soil fauna community, such as dietary and habits; 3) soil fauna-related biotic and abiotic interactions especially those indicating drivers of soil fauna community structure or shaping the roles of soil fauna in ecosystems; and 4) soil fauna-related or -regulated key ecological processes. Current studies focus solely on soil fauna themselves and their geographical distributions. To link soil fauna geography more closely with ecosystem services, we suggested that: 1) converting the pure biogeography studies to those of revealing the spatio-temporal patterns of the soil fauna-related or regulated key relationships and ecological processes;2) expanding the temporal and spatial scales in soil fauna geographical research;3) exploring the integrated analysis approach for soil fauna-related data with multi-scales, multi-factors, and multi-processes;and 4) establishing standard reference systems for soil fauna eco-geographical researches. Hence, the change patterns of ecological niche of soil fauna communities could be illustrated, and precision mani-pulations of soil fauna communities and their ecological functions would become implementable, which finally contributes to ecosystem health and human well-being.

Survival analysis of freezing stress in the North American native perennial flax, Linum lewisii.

Abstract. The expansive range of Lewis flax (Linum lewisii), an herbaceous perennial, exposes the species to a diversity of climatic conditions. As interest in the domestication and adoption of perennial crop alternatives grows and interest in this species for natural area restoration continues, the assurance of a commercial plant variety's ability to endure the full range of possible climatic extremes is paramount. This study examines the freezing tolerance of a geographically representative sampling of 44 Lewis flax accessions at winter temperature extremes experienced in the northern Great Plains of the USA. Survival analysis models were adapted to include temperature exposure, in replacement of ordinal time typically used in such models, to produce statistics evaluating reactions to extreme temperatures that Lewis flax would encounter in our field environments. Our results revealed Lewis flax is more freezing tolerant than previously reported, and revealed four accessions with significantly superior genetic freezing tolerance than the released 'Maple Grove' cultivar. Furthermore, regrowth analyses indicate variation among accessions not associated with survival, which could lead to improving regrowth rate and survival simultaneously. These findings and their methodology expand the understanding of Lewis flax adaptation for winter hardiness and offer an efficient, new model that can be used to evaluate freezing tolerance at ordinal temperatures without requiring extensive prior physiological knowledge for a species.

Mean reef fish body size decreases towards warmer waters.

Aquatic ectotherms often attain smaller body sizes at higher temperatures. By analysing ~15,000 coastal-reef fish surveys across a 15°C spatial sea surface temperature (SST) gradient, we found that the mean length of fish in communities decreased by ~5% for each 1°C temperature increase across space, or 50% decrease in mean length from 14 to 29°C mean annual SST. Community mean body size change was driven by differential temperature responses within trophic groups and temperature-driven change in their relative abundance. Herbivores, invertivores and planktivores became smaller on average in warmer temperatures, but no trend was found in piscivores. Nearly 25% of the temperature-related community mean size trend was attributable to trophic composition at the warmest sites, but at colder temperatures, this was <1% due to trophic groups being similarly sized. Our findings suggest that small changes in temperature are associated with large changes in fish community composition and body sizes, with important ecological implications.

A practical guide to collections-based research on ecogeographic rules.

Ecogeographic research into how species' forms vary across space, time, and climate has taken on new urgency due to contemporary global climate change. Research using museum specimens and other records to study biological rules like Bergmann's, Allen's, and Gloger's Rules has a long history and continues to generate publications and robust scientific debates. Despite the prevalence and history of the field, however, no simple guide on how to carry out such work has ever been published. To lower the barriers of entry for new researchers, this review was created as a practical guide on how to perform ecogeographic research. The guide consolidates disparately published methodologies into a single, convenient document that reviews the history and present of the field of ecogeographic rule research, and describes how to generate appropriate hypotheses, design experiments, gather, and analyze biotic and geographic data, and interpret the results in an ecologically meaningful manner. The result is a semi-standardized guide that enables scientists at all levels from any institution to carry out an investigation from start to finish on any biological rule, taxon, and location of their choice.

Increasing Body Sizes in Anomala expansa expansa (Coleoptera: Scarabaeidae) Populations in Response to Rising Temperatures Over Time.

Many insects have been studied over wide geographical areas to determine whether they follow Bergmann's Rule, which predicts that animal clades or populations should have smaller body sizes in warmer climates. While this ecogeographic rule is well supported in mammals and birds, insect latitudinal sizes can show Bergmann, converse Bergmann, or no size clines at all. Museum collections are typical sources of data for insect clines, and long-term collections should reflect rising global temperatures and shifting climates, possibly producing temporal size clines along with any geographical clines. We hypothesize that insects with Bergmann clines geographically will show Bergmann-like clines temporally as well, and that the converse and inverse of this rule are also true. By looking at museum samples going back a century, we tested whether Anomala expansa expansa (Bates, 1866), a species of Scarabaeidae beetle common in lowland Taiwan, was experiencing long-term changes in body size in response to rising temperatures. We found that overall, the size of these beetles increased over time. Within Taipei populations, this increase was correlated with rising average yearly temperatures. The impact of this pest species' rising size with time will need to be monitored, and temporal size clines in other pests need to be investigated.

The genetic structure of flax illustrates environmental and anthropogenic selections that gave rise to its eco-geographical adaptation.

Flax, one of the eight founder crops of agriculture, has been cultivated for its oil and/or fiber for millennia. Understanding genetic divergence and geographic origins of germplasm in line with their cultivation history and ecological adaptation are essential for conservation and breeding. Here we performed a genome-wide assessment based on more than 51,000 single nucleotide polymorphic sites defining 383 flax accessions from a core collection representing 37 flax growing countries. Population structure analysis resulted in a total of 12 populations that were pooled into four major groups: Temperate, South Asian, Abyssinian and Mediterranean. The vast majority (n = 335) belonged to the Temperate group that comprised eight populations including one dominated by fiber flax. Genetic variation between fiber and oil morphotypes was less pronounced than variation within morphotypes. The genetic variation among groups and populations was attributed in part to eco-geographic and anthropogenic factors. Genetic signatures indicated loci under strong selection by environmental factors such as day length. A high concentration of private haplotypes were observed in the South Asian, Mediterranean and Abyssinian populations despite their low genotype representation, hinting at the long history of the crop in these regions. The addition of genotypes from these three regions would enrich the core collection by capturing a wider genetic breadth for breeding and conservation.

Ecogeographic patterns in fetal limb proportions.

OBJECTIVES: Humans generally comply with the ecological rule of Allen (1877), with populations from tropical environments exhibiting body proportions in which limb segments are long relative to trunk height compared to temperate groups. This study tests whether ecogeographic differences in intralimb proportions are identifiable among two modern fetal samples of differing ancestry. MATERIALS AND METHODS: Data are derived from radiographic measurements of long bone diaphyseal length and crown-heel length (CHL) of contemporary, spontaneously aborted fetuses of African Americans ("black") of assumed African (tropical) ancestry and European Americans ("white") of assumed European (temperate) ancestry (n = 184). Population individual limb elements, brachial, and crural indices are compared via analyses of covariance (ANCOVA). Potential patterns of divergent allometric growth are quantified through principal components analysis (PCA). RESULTS: African ancestral distal limb elements were consistently, albeit slightly, longer than those of European ancestry, relative to CHL. None of the ANCOVA interactions with ancestry are statistically significant for limb indices. The radius was the only single element that displayed a statistically significant ancestry effect (p = 0.0435) equating to a 1 mm difference. PCA highlights that upper limbs demonstrate negative allometry and lower limbs demonstrate positive allometry with sample-specific multivariate growth patterns being nearly identical. Differences in growth allometry late in gestation make little contribution to observed differences in adult limb proportions. DISCUSSION: No statistically significant ecogeographic patterns were appreciated among intralimb proportions between these groups during the fetal period. This study contributes to a greater appreciation of phenotypic plasticity, ecogeographic variation in ontogeny, and the evolution of modern human diversity.

Overwintering adaptations and extreme freeze tolerance in a subarctic population of the wood frog, Rana sylvatica.

The terrestrially hibernating wood frog (Rana sylvatica) is well-known for its iconic freeze tolerance, an overwintering adaptation that has received considerable investigation over the past 35 years. Virtually, all of this research has concerned frogs indigenous to the temperate regions of its broad range within North America. However, recent investigations have shown that frogs of subarctic populations are extremely cold hardy, being capable of surviving freezing for longer periods and at much lower temperatures as compared to conspecifics from temperate regions. Their exceptional freeze tolerance is partly supported by an enhanced cryoprotectant system that uses very high levels of urea and glucose to limit ice formation, regulate metabolism, and protect macromolecules and cellular structures from freezing/thawing stresses. In the weeks before they begin hibernating, northern frogs undertake radical physiological transitions, such as depletion of fat stores and catabolism of muscle protein, that prime the cryoprotectant system by accruing urea and stockpiling glycogen from which glucose is mobilized during freezing. Concentrations of cryoprotectants ultimately achieved in Alaskan frogs when freezing occurs vary among tissues but generally are higher than those of frogs inhabiting milder climates. This review summarizes the molecular, biochemical, and physiological adaptations permitting this northern phenotype to survive the long and harsh winters of the region.

Composición taxonómica y abundancia espacio-temporal de la ictiofauna del Río Presidio, Sinaloa, México / Taxonomic composition and spatio-temporal abundance of the ichthyofauna in Presidio River, Sinaloa, Mexico

Resumen El Río Presidio, ubicado en el sur de Sinaloa, México, pertenece a la zona de transición zoogeográfica NeárticoNeotropical, donde su fauna de peces podría manifestar cambios en la abundancia y distribución de las especies durante los períodos de lluvias y de secas. El objetivo principal de este estudio fue describir la composición taxonómica y la abundancia espacial y temporal de la fauna de peces de la parte baja y media del Río Presidio, mediante muestreos bimestrales de abril 2008 a febrero 2009. Cuarenta especies (39 nativas y 1 exótica) pertenecientes a 32 géneros y 19 familias fueron registradas, siendo las familias Gerreidae y Poeciliidae las más diversas con cinco y cuatro especies, respectivamente. Seis especies: Lile stolifera, Oreochromis aureus, Awaous banana, Gobiomorus maculatus, Anchoa analis y Atherinella crystallina, en ese orden de importancia contribuyeron con casi el 49 % de la abundancia íctica total. La riqueza de especies y la salinidad demostraron una relación directa y ambas tuvieron una relación inversa con la altitud. Con base en la disimilitud de especies entre sitios, dos tipos de ensambles de peces fueron distinguidos a través de un gradiente de salinidad y turbidez en el río, el primero representado por especies de derivación marina (periféricas) en la parte baja, y el segundo por especies dulceacuícolas secundarias en la parte media. La mayor similitud de especies se dio en agosto y septiembre y estuvo asociada a condiciones de altos flujos del periodo de lluvias. Veintisiete especies tienen afinidad a la Región del Pacífico oriental, seis a la Región Neotropical, dos a la Región Neártica (Dorosoma smithi e Ictalurus cf. pricei), una Anfiatlántica (Mugil curema), una Circumtropical (M. cephalus), dos Anfiamericanas (Agonostomus monticola y Gerres cinereus) y una exótica (O. aureus).

Abstract The Rio Presidio in the southern Sinaloa, Mexico belongs to Nearctic-Neotropical zoogeographical transition zone, where its fish fauna could manifest changes in the abundance and distribution of the species during rainy and dry periods. The main objective of this study was to describe the taxonomic composition and spatial and temporal abundance of the fish fauna from the lower and middle Rio Presidio, by means of bimonthly samplings from April 2008 to February 2009. Forty fish species (39 native and 1 exotic) belonging to 32 genera and 19 families were registered. Two families (Gerreidae and Poeciliidae) contained the highest numbers of species (five and four, respectively). Six species (Lile stolifera, Oreochromis aureus, Awaous banana, Anchoa analis, Gobiomorus maculatus and Atherinella crystallina) in this order of importance contributed with almost 49 % of the total fish abundance. Species richness and salinity showed a direct relationship and an inverse relationship with the altitude. Based on the coefficient of similarity of species among sites two fish assemblages were identified. The first assemblage formed by species from marine derivation (peripheral) occurring in the lower part of the river, and the second assemblage by secondary freshwater species in the middle part. The higher fish species similarity observed in August and September was under the influence of the highest flows of the rainy period. Twenty-seven 27 species showed affinity to the Tropical Eastern Pacific Region, six species to the Neotropical region and two to the Nearctic region (Dorosoma smithi and Ictalurus cf. pricei ); one species has an Amphiatlantic distribution (Mugil curema), another is circumtropical (Mugil cephalus), two species have Amphiamerican distribution (A. monticola and G. cinereus), and one is exotic (O. aureus). Rev. Biol. Trop. 66(2): 848-862. Epub 2018 June 01.

Femoral neck-shaft angle and climate-induced body proportions.

OBJECTIVES: Declination in femoral neck-shaft angle (NSA) is commonly linked to an increased level of physical activity during life. More recently, however, research suggests that lower NSA might also be explained, in part, as the mechanical consequence of differences in ecogeographic body proportions. This study tests the proposed link between NSA and climatic-induced body proportions, using relative body mass (RBM), throughout the course of development. MATERIALS AND METHODS: NSA and RBM were collected for 445 immature remains from five geographic locations. NSA and RBM were standardized for age-effects. ANOVA was used to examine when population differences emerged in both NSA and RBM. Regression analyses were used to examine the pattern of relationship between NSA and RBM. RESULTS: Populations differ significantly in NSA and RBM before skeletal maturity, and these differences occur early in life. While both NSA and RBM change over the course of development, no significant relationship was found between NSA and RBM for any sample, or any age category (p = .244). DISCUSSION: Individuals who have relatively greater relative body mass do not necessarily have lower NSA. Population differences in NSA were found to be variable, while differences in RBM remained consistent across the developmental span. Taken together, these results suggest that regardless of body proportions, the degree of declination of NSA is presumed to be similar among individuals with similar gait and ambulatory behaviors. Conversely, populations differ in RBM from birth, and these differences are consistent throughout development. These two measures likely are responsive to diffing stimuli, and any potential relationship is likely complex and multifactorial.

Exploring Jordan's rule in Pacific three-spined stickleback Gasterosteus aculeatus.

Coastal marine Gasterosteus aculeatus were captured from seven locations along the Pacific coast of North America, ranging across 21·8° latitude to test Jordan's rule, i.e. that vertebral number should increase with increasing latitude for related populations of fish. Vertebral number significantly increased with increasing latitude for both total and caudal vertebral number. Increasing length with latitude (sensu Bergmann's rule) was also supported, but the predictions for Jordan's rule held when controlling for standard length. Pleomerism was weakly evidenced. Gasterosteus aculeatus exhibited sexual dimorphism for Jordan's rule, with both sexes having more vertebrae at higher latitudes, but only males showing a positive association between latitude and the ratio of caudal to abdominal vertebrae. The number of dorsal- and anal-fin rays and basals increased with increasing latitude, while pectoral-fin ray number decreased. This study reinforces the association between phenotypic variation and environmental variation in marine populations of G. aculeatus.

Ecogeographic variability and genetic diversity associated with seed albumins, globulins and prolamins patterns in Vicia taxa from Algeria.

Genetic variability was studied in 78 populations of locally collected Vicia L. taxa for seed albumins, globulins and prolamins patterns by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) along with an ecogeographic characterization of sites investigated. 131, 119 and 98 bands were respectively used for albumin, globulin and prolamin cluster analysis. Dendrograms based on the Jaccard index and the UPGMA method were generated and the degree of genetic diversity between and within taxa was evaluated. Five clusters were generated from albumins, six from globulins and four from prolamins patterns. The results reflect the great diversity of storage proteins and a high correlation was obtained between the three studied fractions. Several accessions present specific bands which could be used as a discriminatory marker both on intra and interspecific levels. No clear relationships were seen between the groups according to their geographical origin. Data obtained from ecogeographic investigation can be used for future collecting missions.

Morphological variation in Homo erectus and the origins of developmental plasticity.

Homo erectus was the first hominin to exhibit extensive range expansion. This extraordinary departure from Africa, especially into more temperate climates of Eurasia, has been variously related to technological, energetic and foraging shifts. The temporal and regional anatomical variation in H. erectus suggests that a high level of developmental plasticity, a key factor in the ability of H. sapiens to occupy a variety of habitats, may also have been present in H. erectus. Developmental plasticity, the ability to modify development in response to environmental conditions, results in differences in size, shape and dimorphism across populations that relate in part to levels of resource sufficiency and extrinsic mortality. These differences predict not only regional variations but also overall smaller adult sizes and lower levels of dimorphism in instances of resource scarcity and high predator load. We consider the metric variation in 35 human and non-human primate 'populations' from known environmental contexts and 14 time- and space-restricted paleodemes of H. erectus and other fossil Homo Human and non-human primates exhibit more similar patterns of variation than expected, with plasticity evident, but in differing patterns by sex across populations. The fossil samples show less evidence of variation than expected, although H. erectus varies more than Neandertals.This article is part of the themed issue 'Major transitions in human evolution'.

Intra- and interspecific variation in macaque molar enamel thickness.

Enamel thickness has played an important role in studies of primate taxonomy, phylogeny, and functional morphology, although its variation among hominins is poorly understood. Macaques parallel hominins in their widespread geographic distribution, relative range of body sizes, and radiation during the last five million years. To explore enamel thickness variation, we quantified average and relative enamel thickness (AET and RET) in Macaca arctoides, Macaca fascicularis, Macaca fuscata, Macaca mulatta, Macaca nemestrina, and Macaca sylvanus. Enamel area, dentine area, and enamel-dentine junction length were measured from mesial sections of 386 molars scanned with micro-computed tomography, yielding AET and RET indices. Intraspecific sex differences were not found in AET or RET. Macaca fuscata had the highest AET and RET, M. fascicularis showed the lowest AET, and M. arctoides had the lowest RET. The latitudinal distribution of macaque species was associated with AET for these six species. Temperate macaques had thicker molar enamel than did tropical macaques, suggesting that thick enamel may be adaptive in seasonal environments. Additional research is needed to determine if thick enamel in temperate macaques is a response to intensified hard-object feeding, increased abrasion, and/or a broader diet with a greater range of food material properties. The extreme ecological flexibility of macaques may prohibit identification of consistent trends between specific diets and enamel thickness conditions. Such complications of interpretation of ecological variability, dietary diversity, and enamel thickness may similarly apply for fossil Homo species.

Cloning, characterization, and expression of glucose transporter 2 in the freeze-tolerant wood frog, Rana sylvatica.

BACKGROUND: The essential role of glucose transporter 2 (GLUT2) in glucose homeostasis has been extensively studied in mammals; however, little is known about this important protein in lower vertebrates. The freeze-tolerant wood frog (Rana sylvatica), which copiously mobilizes glucose in response to freezing, represents an excellent system for the study of glucose transport in amphibians. METHODS: GLUT2 was sequenced from northern and southern phenotypes of R. sylvatica, as well as the freeze-intolerant Rana pipiens. These proteins were expressed and functionally characterized in Xenopus oocytes. Abundance of GLUT2 in tissues was analyzed using immunoblotting techniques. RESULTS: GLUT2s cloned from these anurans encoded proteins with high sequence homologies to known vertebrate GLUT2s and had similar transport properties, although, notably, transport of the glucose analog 3-O-methyl-d-glucose (3-OMG) was strongly inhibited by 150mM urea. Proteins from all study subjects had similar affinity constants (~12mM) and other kinetic properties; however, GLUT2 abundance in liver was 3.5-fold greater in northern R. sylvatica than in the southern conspecific and R. pipiens. CONCLUSION: Our results indicate that amphibian GLUT2s are structurally and functionally similar to their homologs in other vertebrates, attesting to the conserved nature of this transport protein. The greater abundance of this protein in the northern phenotype of R. sylvatica suggests that these transporters contribute importantly to freezing survival. GENERAL SIGNIFICANCE: This study provides the first functional characterization of any GLUT isoform from an anuran amphibian and novel insights into the role of these proteins in glucose homeostasis and cryoprotectant mobilization in freeze-tolerant vertebrates.

Hibernation physiology, freezing adaptation and extreme freeze tolerance in a northern population of the wood frog.

We investigated hibernation physiology and freeze tolerance in a population of the wood frog, Rana sylvatica, indigenous to Interior Alaska, USA, near the northernmost limit of the species' range. Winter acclimatization responses included a 233% increase in the hepatic glycogen depot that was subsidized by fat body and skeletal muscle catabolism, and a rise in plasma osmolality that reflected accrual of urea (to 106±10 µmol ml(-1)) and an unidentified solute (to ~73 µmol ml(-1)). In contrast, frogs from a cool-temperate population (southern Ohio, USA) amassed much less glycogen, had a lower uremia (28±5 µmol ml(-1)) and apparently lacked the unidentified solute. Alaskan frogs survived freezing at temperatures as low as -16°C, some 10-13°C below those tolerated by southern conspecifics, and endured a 2-month bout of freezing at -4°C. The profound freeze tolerance is presumably due to their high levels of organic osmolytes and bound water, which limits ice formation. Adaptive responses to freezing (-2.5°C for 48 h) and subsequent thawing (4°C) included synthesis of the cryoprotectants urea and glucose, and dehydration of certain tissues. Alaskan frogs differed from Ohioan frogs in retaining a substantial reserve capacity for glucose synthesis, accumulating high levels of cryoprotectants in brain tissue, and remaining hyperglycemic long after thawing. The northern phenotype also incurred less stress during freezing/thawing, as indicated by limited cryohemolysis and lactate accumulation. Post-glacial colonization of high latitudes by R. sylvatica required a substantial increase in freeze tolerance that was at least partly achieved by enhancing their cryoprotectant system.