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3,583 results for “elevations”
Data from: Different roles of elevational and local environmental factors on abundance-based beta diversity of the soil Enchytraeidae on the Changbai Mountain
The elevational alpha biodiversity gradient in mountain regions is one of the well-known ecological patterns, but its beta diversity pattern remains poorly-known. Examining the beta diversity and its components could enhance the understanding of community assembly mechanism. We studied the beta diversity pattern of the soil enchytraeids along a distinct elevational gradient (705—2280 m) on the Changbai Mountain, the best-preserved mountain in northeastern China. The overall abundance-based community dissimilarity was relatively high (ca. 0.70), largely due to the balanced-variation component (85%). The overall dissimilarity and its balanced-variation (substitution) component were both related to local environmental heterogeneity and elevational distance, with the environmental relationships being stronger. In contrast, the abundance-gradient (subsets) component was not related to the two gradients. The same important spatial and environmental variables were detected in structuring overall dissimilarity and substitution component, different from that in subsets component. Variation partitioning analysis showed that environmental control played a more important role than spatial (vertical and horizontal) factors in structuring the patterns of overall beta diversity and its two components. The predictive power of multivariate analysis was higher for the substitution component (nearly 50%) and overall dissimilarity (35%), but much lower for subsets components (< 4%). These findings implied that abundance-based beta diversity patterns of the soil enchytraeids were the results of different ecological processes (e.g. environmental sorting and dispersal limitation), operating in the two antithetic components. Our study showed the substitution and loss of individuals reflecting different ecological processes and highlights the importance of partitioning beta diversity in assessing biodiversity patterns and their causes.
Data from: Dauer life stage of Caenorhabditis elegans induces elevated levels of defense against the parasite Serratia marcescens
Host-parasite research often focuses on a single host life stage, yet different life stages may exhibit different defenses. The nematode Caenorhabditis elegans has an alternate dispersal life stage, dauer. Despite dauer's importance in nature, we know little of how it responds to parasites. Previous research indicates that non-dauer C. elegans prefer to consume the virulent bacterial parasite, Serratia marcescens, when given a choice between the parasite and benign Escherichia coli. Here, we compared the preferences of dauer individuals from six strains of C. elegans to the preferences of other life stages. We found that dauer individuals exhibited reduced preference for S. marcescens, and dauers from some strains preferred E. coli to S. marcescens. In addition to testing food preference, a mechanism of parasite avoidance, we also measured host mortality rates after direct parasite exposure to determine if life stage also altered host survival. Overall, dauer individuals exhibited reduced mortality rates. However, dauer versus non-dauer larvae mortality rates also varied significantly by host strain. Collectively, we found evidence of dauer-induced parasite avoidance and reduced mortality in the presence of a parasite, but these effects were strain-specific. These results demonstrate the importance of host life stage and genotype when assessing infection dynamics.
Ecological limits as the driver of bird species richness patterns along the east Himalayan elevational gradient
<p>Variation in species richness across environmental gradients results from a combination of historical non-equilibrium processes (time, speciation, extinction) and present-day differences in environmental carrying capacities (i.e., ecological limits, affected by species interactions and the abundance and diversity of resources). In a study of bird richness along the sub-tropical east Himalayan elevational gradient, we test the prediction that species richness patterns are consistent with ecological limits using data on morphology, phylogeny, elevational distribution, and arthropod resources. Species richness peaks at mid-elevations. Occupied morphological volume is roughly constant from low to mid-elevations, implying more species are packed into the same space at mid-elevations compared with low elevations. However, variance in beak length, and differences in beak length between close relatives decline with elevation, a consequence of the addition of many small insectivores at mid-elevations. These patterns are predicted from resource distributions: arthropod size diversity declines from low to mid elevations, largely because many more small insects are present at mid-elevations. Weak correlations of species mean morphological traits with elevation also match predictions based on resources and habitats. Elevational transects in the tropical Andes, New Guinea and Tanzania similarly show declines in mean arthropod size and mean beak length, and in these cases likely contribute to declining numbers of insectivorous bird species richness along these gradients. The results imply conditions for ecological limits are met, although historical non-equilibrium processes are likely to also contribute to the pattern of species richness.</p>
Data from: Diversity increases with elevation: empidine dance flies (Diptera, Empididae) challenge a predominant pattern
Tropical mountain forests are important reservoirs of biodiversity. They are usually species rich and often support endemic species making them prime targets for conservation effort. The aim of this study is to investigate elevational patterns of species diversity and phenology in order to provide a meaningful understanding of insects' spatio-temporal distributions along a tropical gradient of elevation. Our study focuses on the Empidinae communities (Diptera, Empididae) from Doi Inthanon (north Thailand, gradient 400–2556 m.a.s.l), sampled during two entire years (2006–2007, 2014). This group of insects is more diverse in temperate localities than in the tropics and we found that (1) increase in altitude and latitude has a similar effect, so that the diversity of our model increases with elevation, (2) the phenology is strongly influenced by seasonality with a peak of diversity occurring during the transition between the dry and rainy seasons, (3) there is no phenological shift in the diversity peak with elevations, (4) the species composition changes along the altitudinal gradient and through the year (high beta diversity). The increase of diversity with increasing elevation and the peak of diversity occuring at the transitional period both strongly coincide with abiotic factors, the decreasing temperature and the arrival of the monsoon, respectively.
Data from: Elevational filtering and the evolution of planthoppers (Hemiptera, Fulgoromorpha) in Papua New Guinea
Along elevational gradients, phylogenetic relatedness patterns constitute a considerable source of information, and may shed light on ecological processes that structure communities. This study focuses on community phylogenetic structure of planthoppers, specifically the species-rich and abundant Fulgoromorpha families (Hemiptera, Auchenorrhyncha), Cixiidae and Derbidae+Achilidae, along an elevational gradient on Mount Wilhelm (Papua New Guinea). In order to assess the factors driving planthoppers community composition, we recorded abundance data for planthoppers species at each elevation and we generated a molecular phylogeny of the local species, using Bayesian Inference. We analyzed 168 individuals representing 59 local morphospecies. Using a fully resolved and well-supported phylogeny, we then investigated the phylogenetic structure of the communities by performing a Spatial Analysis of Community Diversity. We show that Cixiidae are phylogenetically clustered along the elevational gradient, whereas Derbidae+Achilidae harbour a random structure, suggesting that local adaptation to elevation shapes community structure of Cixiidae, but not that of Derbidae+Achilidae. Our findings highlight the importance of phylogenies in the study of tropical elevational gradients.
Data from: Elevated atmospheric carbon dioxide concentrations promote ant tending of aphids
1. Animal mutualisms, which involve beneficial interactions between individuals of different species, are common in nature. Insect-insect mutualism, for example, is widely regarded as a keystone ecological interaction. Some mutualisms are anticipated to be modified by climate change, but the focus has largely been on plant-microbe and plant-animal mutualisms rather than those between animals. 2. Ant-aphid mutualisms, whereby ants tend aphids to harvest their honeydew excretions and, in return, provide protection for the aphids are widespread. The mutualism is heavily influenced by the quality and quantity of honeydew produced by aphids, which is directly affected by host plant quality. Since predicted increases in concentrations of atmospheric carbon dioxide (eCO2) are widely reported to affect plant nutritional chemistry, this may also alter honeydew quality and hence the nature of ant-aphid mutualisms. 3. Using glasshouse chambers and field-based open top chambers we determined the effect of eCO2 on the growth and nutritional quality (foliar amino acids) of lucerne (Medicago sativa). We determined how cowpea aphid (Aphis craccivora) populations and honeydew production were impacted when feeding on such plants and how this affected the tending behaviour of ants (Iridomyrmex spp.). 4. eCO2 stimulated plant growth but decreased concentrations of foliar amino acids by 29% and 14% on aphid-infested plants and aphid-free plants, respectively. Despite the deterioration in host plant quality under eCO2, aphids maintained performance and populations were unchanged by eCO2. Aphids induced higher concentrations of amino acids (glutamine, asparagine, glutamic acid and aspartic acid) important for endosymbiont-mediated synthesis of essential amino acids. Aphids feeding under eCO2 also produced over three times more honeydew than aphids feeding under ambient CO2., suggesting they were imbibing more phloem sap at eCO2. The frequency of ant tending of aphids more than doubled in response to eCO2. 5. To our knowledge, this is the first study to demonstrate the effects of atmospheric change on an ant-aphid mutualism. In particular, these results highlight how impending changes to concentrations of atmospheric CO2 may alter mutualistic behaviour between animals. These could include positive impacts, as reported here, shifts from mutualism to antagonism, partner switches and mutualism abandonment.
Data from: Cardiac plasticity influences aerobic performance and thermal tolerance in a tropical, freshwater fish at elevated temperatures
Fishes faced with novel thermal conditions often modify physiological functioning to compensate for elevated temperatures. This physiological plasticity (thermal acclimation) has been shown to improve metabolic performance and extend thermal limits in many species. Adjustments in cardiorespiratory function are often invoked as mechanisms underlying thermal plasticity because limitations in oxygen supply have been predicted to define thermal optima in fishes, however few studies have explicitly linked cardiorespiratory plasticity to metabolic compensation. Here we quantify thermal acclimation capacity in the commercially harvested Nile perch (Lates niloticus) of East Africa, and investigate mechanisms underlying observed changes. We reared juvenile Nile perch for 3 months under two temperature regimes, and then measured a series of metabolic traits (e.g., aerobic scope, AS) and critical thermal maximum (CTmax) upon acute exposure to a range of experimental temperatures. We also measured morphological traits of heart ventricles, gills, and brains to identify potential mechanisms for compensation. We found that long-term (3-months) exposure to elevated temperature induced compensation in upper thermal tolerance (CTmax) and metabolic performance (SMR, MMR and AS), and induced cardiac remodeling in Nile perch. Furthermore, variation in heart morphology influenced variations in metabolic function and thermal tolerance. These results indicate that plastic changes enacted over longer exposures lead to differences in metabolic flexibility when acutely exposed to temperature variation. Furthermore, we established functional links between cardiac plasticity, metabolic performance, and thermal tolerance, providing evidence that plasticity in cardiac capacity may be one mechanism for coping with climate change.
Data from: High-speed displays encoding motor skill trigger elevated territorial aggression in downy woodpeckers
1) Many species perform social displays that incorporate complex body movements. However, the reason why such exaggerated behavioral signals evolve in the first place is unclear. 2) Recent work posits that physical displays arise in part because they showcase an animal's motor skill—that is, the ability to produce challenging motor acts with great coordination, precision, and/or speed. Support for this idea is largely correlational, with few studies attempting to manipulate metrics of motor skill to assess their effect on physical display efficacy. 3) Here, we address this issue in the downy woodpecker (Dryobates pubescens). Individuals of this species compete for territories through the performance of drums, which are complex displays produced by rapidly hammering the bill against a resonate surface at rates of 16 hits sec-1. This display is a whole-body endeavor, and its production relies on the ability to swiftly oscillate the head forward and backward at fraction-of-a-second periods. 4) Using a series of playback studies, we expose resident birds to experimentally engineered drums that reflect putative fine-scale differences in the motor command of the head and neck. We show that resident individuals respond more aggressively to drums characterized by a cadence with a 9-msec faster beat speed. These residents even modulate their own drum speed to resemble this high-performance stimulus, although they often fail to reach it. Residents also appear to appraise drum acceleration by listening to the time intervals between successive beats in a single drum, while tracking how these time intervals change as the signal progresses. 5) Our data support a connection between motor skill and the effectiveness of a physical display produced through elaborate body movement. We therefore suspect that motor skill is adaptive and evolves in response to selection by competition for effective drum displays.
Elevational niche-shift migration: Why the degree of elevational change matters for the ecology, evolution, and physiology of migratory birds to ornithology
<p>Elevational migration can be defined as roundtrip seasonal movement that involves upward and downward shifts in elevation. These shifts incur physiological challenges that are proportional to the degree of elevational change. Larger shifts in elevation correspond to larger shifts in partial pressure of oxygen, air density, temperature, and UV exposure. Although most avian examples of elevational migration involve subtle shifts that would have minimal impacts on physiology, shifts of <i>any magnitude</i> have previously been considered under the broad umbrella of 'elevational migration'. Here, we consider extreme seasonal elevational movements (≥2000 m), sufficient to shift the elevational dimension of the eco-climatic niche. Migratory bird populations typically maintain inter-seasonal stability in the temperature, precipitation, and elevational aspects of their climatic niches, a tendency that likely reflects genetic physiological specialization on environmental conditions such as atmospheric pressure. A shift of ≥2000 m involves a ≥20% change in air density and oxygen partial pressure, sufficient to incur functionally impactful declines in arterial blood-oxygen saturation and require compensatory shifts in respiratory physiology. We refer to this phenomenon as elevational niche-shift migration (ENSM). In this review, we analyzed >4 million occurrence records to identify 105 populations, representing 92 bird species, that undergo complete or partial ENSM. We identified key ecological and evolutionary questions regarding causes and consequences of ENSM. Our synthesis reveals that ENSM has evolved independently in at least 29 avian families spanning 10 orders. Nonetheless, ENSM is rare relative to other forms of seasonal migration, consistent with the general tendency of seasonal niche conservatism by migratory species and evolutionarily conserved elevational range limits. For many migratory species and populations, within-species patterns of migratory connectivity are not sufficiently understood to determine ENSM status. ENSM is distinguished by its scale within the broader phenomenon of elevational migration. Critical examination of ENSM illustrates fundamental constraints on the ecology and evolution of migration systems, topographical influences on geographic patterns of migratory connectivity, and the remarkable metabolic flexibility of certain bird species that allows them to occupy disparate elevations across different seasons.</p>
Data from: A metabolic syndrome in terrestrial ectotherms with different elevational and distribution patterns
The metabolic performance of ectotherms is expected to be driven by the environment in which they live. Ecologically similar species with contrasting elevation distributions occurring in sympatry at mid-elevations, provide good models for studying how physiological responses to temperature vary as a function of adaptation to different elevations.. Under sympatry, at middle elevations, where divergent species ranges overlap, sympatric populations are expected to have similar thermal responses, suggesting similar local acclimation or adaptation, while observed differences would suggest adaptation to each species' core range. We analysed the metabolic traits of sympatric species pairs from three ectotherm groups: reptiles (Reptilia: Lacertidae), amphibians (Amphibia: Salamandridae) and beetles (Coleoptera: Carabidae), living at different elevations, in order to test how adaptation to different elevations affects metabolic responses to temperature. We experimentally tested the thermal response of respiration rate (RR) and estimated potential metabolic activity (PMA) at three temperature regimes surrounding the groups' optimal activity body temperatures. RR was relatively similar among groups and showed a positive response to increasing temperature, which was more pronounced in the high-elevation species of reptiles and beetles. Relative to RR, PMA displayed a stronger and more consistent positive response to increased temperature in all three groups. For all three groups, the average biochemical capacity for metabolism (PMA) was higher in the range-restricted, high-elevation species, and this difference increased at higher temperatures in a consistent manner. These results, indicating consistent pattern in three independently evolved animal groups, suggest a ubiquitous adaptive syndrome and represent a novel understanding of the mechanisms shaping spatial biodiversity patterns. Our results also highlight the importance of geographic patterns for the mechanistic understanding of adaptations in physiological traits, including species' potential to respond/adapt to global climate changes.
Data from: Herbivory and pollen limitation at the upper elevational range limit of two forest understory plants of eastern North America
Studies of species' range limits focus most often on abiotic factors, although the strength of biotic interactions might also vary along environmental gradients and have strong demographic effects. For example, pollinator abundance might decrease at range limits due to harsh environmental conditions, and reduced plant density can reduce attractiveness to pollinators and increase or decrease herbivory. We tested for variation in the strength of pollen limitation and herbivory by ungulates along a gradient leading to the upper elevational range limits of Trillium erectum (Melanthiaceae) and Erythronium americanum (Liliaceae) in Mont-Mégantic National Park, Québec, Canada. In T. erectum, pollen limitation was higher at the range limit, but seed set decreased only slightly with elevation and only in one of two years. In contrast, herbivory of T. erectum increased from <10% at low elevations to >60% at the upper elevational range limit. In E. americanum, we found no evidence of pollen limitation despite a significant decrease in seed set with elevation, and herbivory was low across the entire gradient. Overall, our results demonstrate the potential for relatively strong negative interactions (herbivory) and weak positive interactions (pollination) at plant range edges, although this was clearly species-specific. To the extent that these interactions have important demographic consequences – highly likely for herbivory on Trillium, based on previous studies – such interactions might play a role in determining plant species' range limits along putatively climatic gradients.
Data from: The simultaneous inducibility of phytochemicals related to plant direct and indirect defences against herbivores is stronger at low elevation
Ecological theory indicates that warmer and more stable climates should result in stronger biotic interactions. Therefore, plant species growing at lower elevations and experiencing greater herbivore pressure, should invest in higher levels of defences than those at higher elevations. Nonetheless, there are a number of studies that have found no effect of elevational gradients on plant defensive traits. Several factors might explain the lack of consistency for the altitude-defence relationships; including 1) the reduction of all defensive traits into one measure of resistance; 2) not considering plant defence as the simultaneous expression of several defensive traits; and 3) not considering the relative influence of biotic (e.g. herbivory) and abiotic (e.g. climate and soil conditions) factors associated with the ecological gradient. Here, we present a comprehensive test of the effects of elevation and its associated biotic and abiotic factors on the individual and simultaneous expression of constitutive direct and indirect defences and their inducibility (i.e. expression of defences after herbivore attack). Specifically, we estimated climatic and soil variables and measured herbivore damage and constitutive and jasmonic acid-induced glucosinolate levels in the leaves as a proxy for direct defences, and volatile emission as a proxy for indirect defences in 16 Cardamine species naturally growing along the steep elevational gradient of the Alps. Within a phylogenetic comparative framework, we found that species growing at lower elevations invested more in the simultaneous inducibility of both direct and indirect defences, whereas species growing at higher elevations invested more in constitutive direct defences. Although we found strong elevation gradients in herbivory and climatic and soil variables, these biotic and abiotic factors only partially explained elevational patterns in plant defences. Synthesis - These results highlight that the complex regulation of multiple defence traits strongly vary across elevational gradients and build towards a better understanding of the multiple mechanisms underlying trait evolution and species interactions along ecological gradients.
Data from: Urbanization and elevated cholesterol in American crows
Although urban areas can be sources of abundant food for wildlife, anthropogenic foods may be lower in quality than natural food sources. Overall, the consequences of anthropogenic food consumption for wildlife are poorly understood. Here, we examined how urbanization and anthropogenic food were linked to cholesterol, condition, and survival of American crows (Corvus brachyrhynchos). We collected cholesterol and landscape data from 140 crow nestlings along an urban to rural gradient in Davis, CA, USA, and we ran a supplementation experiment with high-cholesterol fast food (McDonald's cheeseburgers) on 86 nestlings in a rural population in Clinton, NY, USA. We used these data to evaluate links between cholesterol level, urbanization, condition, and crow survival. We found that plasma cholesterol increased with percentage of impervious surface along the urban to rural gradient. Cholesterol levels were sensitive to anthropogenic foods: crows supplemented with fastfood cheeseburgers had higher cholesterol levels than unsupplemented crows. Elevated cholesterol levels had no detectable effects on survival and were associated with higher indices of body condition, although urbanization itself was linked to lower survival. Elevated cholesterol levels could indicate access to high-calorie, high-fat anthropogenic foods, which might, in some contexts, improve body condition, potentially offsetting other negative effects of urbanization. Observations over a longer time-scale, assessing additional indices of health and fitness, are needed to evaluate long-term costs or benefits of elevated cholesterol for urban crows.
Data from: Heterogeneous distributional responses to climate warming: evidence from rodents along a subtropical elevational gradient
Background: Understanding whether species' elevational range is shifting in response to directional changes in climate and whether there is a predictable pattern in that response is one of the major challenges in ecology. However, so far very little is known about the distributional responses of subtropical species to climate change, especially for small mammals. In this study, we examined the elevational range shifts at three range points (upper and lower range limits and abundance-weighted range centre) of rodents over a 30-year period (1986 to 2014-2015), in a subtropical forest of Southwest China. We also examined the influences of four ecological traits (body mass, habitat breadth, diet and daily activity pattern) on the upslope shifts in species' abundance-weighted range centres. Results: Despite the warming trend between 1986 and 2015, the eleven rodent species in analysis displayed heterogeneous dynamics at each of the three range points. Species which have larger body sizes and narrower habitat breadths, show both diurnal and nocturnal activities and more specialized dietary requirements, are more likely to exhibit upslope shifts in abundance-weighted range centres. Conclusions: Species' distributional responses can be heterogeneous even though there are directional changes in climate. Our study indicates that climate-induced alleviation of competition and lag in response may potentially drive species' range shift, which may not conform to the expectation from climate change. Difference in traits can lead to different range dynamics. Our study also illustrates the merit of multi-faceted assessment in studying elevational range shifts.
Data from: Comparative landscape genetics of two river frog species occurring at different elevations on Mount Kilimanjaro
Estimating population connectivity and species' abilities to disperse across the landscape is crucial for understanding the long-term persistence of species in changing environments. Surprisingly, few landscape genetics studies focused on tropical regions despite the alarming extinction rates within these ecosystems. Here, we compared the influence of landscape features on the distribution of genetic variation of an Afromontane frog, Amietia wittei, with that of its more broadly distributed lowland congener, A. angolensis, on Mt. Kilimanjaro, Tanzania. We predicted high gene flow in the montane species with movements enhanced through terrestrial habitats of the continuous rainforest. In contrast, dispersal might be restricted to aquatic corridors and reduced by anthropogenic disturbance in the lowland species. We found high gene flow in A. wittei relative to other montane amphibians. Nonetheless, gene flow was lower than in the lowland species which showed little population structure. Least-cost path analysis suggested that dispersal is facilitated by stream networks in both species, but different landscape features were identified to influence connectivity among populations. Contrary to a previous study, gene flow in the lowland species was negatively correlated with the presence of human settlements. Also, genetic subdivision in A. wittei did not coincide with specific physical barriers as in other landscape genetics studies, suggesting that factors other than topography may contribute to population divergence. Overall these results highlight the importance of a comparative landscape genetics approach for assessing the influence of the landscape matrix on population connectivity, particularly because non-intuitive results can alter the course of conservation and management.
Data from: The response of mixed-species bird flocks to anthropogenic disturbance and elevational variation in southwest China
Avian mixed-species flocks (MSFs) are an important example of species interactions threatened by the biodiversity crisis. They are found throughout the world in forested habitats, but are generally reduced in size or frequency by human disturbance. In southern China, a unique MSF system has been described that is led by fulvettas (Alcippe morrisonia, A. hueti and A. davidi). Our objective was to understand how this system is distributed across elevational gradients, especially moving west into the Hengduan Mountains, and how it responds to human disturbance. We sampled leadership and composition of 375 MSFs over 2 years in and surrounding 5 nature reserves in Guangxi Zhuang Autonomous Region and Yunnan Province, with transects placed in different land use types – protected forest, buffer areas, or agriculture – and ranging from 400 to 3200 m. We also sampled birds outside of MSFs. We found MSFs led by fulvettas (A. fratercula and A. davidi) in forests across the region up to 2900 m. Elevation was not a significant influence on MSF size or prevalence in models that also included land use. We found that MSFs were encountered at only 1/3 of the frequency in agriculture as in forest, and had strongly different composition and leadership. Although MSFs in buffer areas more similar to those in forest, birds in buffer had lower flocking propensity with different flock leaders and less complex social networks. In particular, buffer transects that were seeded pine had low numbers of fulvetta-led MSFs and forest specialists. In the future, it is important to understand which vegetational characteristics allow MSFs, particularly fulvetta-led MSFs, to persist in buffer habitats.
Data from: Recent speciation and elevated Z-chromosome differentiation between sexually monochromatic and dichromatic species of Australian teals
Sex chromosomes potentially have an important role in speciation and often have elevated differentiation between closely related species. In birds, traits associated with male plumage, female mate preference, and hybrid fitness have been linked to the Z-chromosome (females are heterogametic, ZW). We tested for elevated Z-differentiation between two recently diverged species of Australian ducks, the sexually monochromatic grey teal Anas gracilis and the dichromatic chestnut teal A. castanea. Despite prominent morphological differences, these two species are genetically indistinguishable at both mitochondrial DNA (mean ΦST < 0.0001) and 17 autosomal loci (mean ΦST = 0.0056). However, we detected elevated Z-differentiation (mean ΦST = 0.281) and tentative evidence of an island of differentiation on the Z-chromosome. This elevated differentiation was explained by a high frequency of derived alleles in chestnut teal that were absent in grey teal, which parallels independent evidence for a gain in dichromatism from a monochromatic ancestor. Coalescent estimates of demographic history and simulations indicated that the elevated Z-differentiation was unlikely to be explained by neutral processes, but instead supported a role of divergent selection. We discuss evidence for models of speciation with gene flow versus adaptive divergence in the absence of gene flow and find that both hypotheses are plausible explanations of the data. Overall, these teal have the weakest background differentiation documented to date for a species showing a large Z-effect, and they are an excellent model species for studying speciation genomics and the evolution of sexual dichromatism.
Data from: Variation in thermal biology of three closely related lizard species across an elevation gradient
The critical thermal limits of organisms and the thermal sensitivity of their performance tends to vary predictably across latitudinal gradients. There has been comparatively less investigation into variation in thermal limits biology with altitude, despite similar gradients in environmental temperatures with elevation. To redress this, we examined species critical thermal limits (CTmin and CTmax); thermal sensitivity of locomotor performance, and shelter site attributes, in three lizard species that replace one another along a contiguous elevation gradient in south eastern Australia. The species examined consisted of a highland specialist, Liopholis guthega, mid elevation species L. montana, and lowland L. whitii. We found similar habitat attributes between the species, but L. guthega predominantly occurred in open habitat which may reflect a strategy for maximising exposure to insolation. We found intraspecific variation in lizard thermal traits, most notably in cold tolerance of L. guthega and in both heat and cold tolerance of L. whitii, suggesting population specific variables acting on thermal physiology rather than a species distribution maintained by distinct thermal tolerances. This study represents one of the few examinations of thermal trait variability within and between species with elevation in a temperate system, and provides evidence for thermal physiology driven by localised adaptation and/or physiological plasticity to local conditions.
Data from: Extrapair paternity rates vary with latitude and elevation in Emberizid sparrows
Mating systems can vary among species and populations and thus influence evolutionary trajectories, ecological traits, and population demography. The siring of offspring by an extrapair male, or extrapair paternity (EPP), is a widespread and varied phenomenon in all vertebrate classes. However, we do not understand all of the factors associated with variation in EPP rates. The breeding synchrony hypothesis suggests that EPP rates should increase with latitude and elevation, whereas the paternal care hypothesis predicts that EPP rates should decrease with elevation. To address these hypotheses, we investigated how population EPP rates vary over elevation and latitude in emberizid sparrows. In comparative analyses including the effects of phylogeny, the relationship between EPP rates and elevation depended on latitude. EPP rates were greater in higher-latitude populations. But within higher-latitude populations, EPP rates decreased with increasing elevation. These findings provide support for both the breeding synchrony and paternal care hypotheses, suggesting that in lower-latitude, higher-elevation populations, the need for male parental care does not outweigh the benefits of seeking extrapair fertilizations in populations with relatively synchronous breeding. In contrast, at higher-latitude, higher-elevation sites, the need for male parental care is greater and might drive lower rates of extrapair mating despite highly synchronous breeding.
Data from: Complementary responses of morphology and physiology enhance the stand-scale production of a model invasive species under elevated CO2 and nitrogen
1. Elevated atmospheric carbon dioxide (eCO2) concentrations and nitrogen (N) enrichment are known to enhance plant productivity and invasion. However, the implications of their interactive effects for plant productivity are not well understood, especially at the stand scale, presumably because morphological and physiological responses to these global change factors are rarely studied together in the field or assessed at the stand-level. 2. We first determined how leaf-level morphological and physiological traits responded to factorial combinations of ambient and elevated CO2 and N. We collected trait data from the model invasive species Phragmites australis (common reed) that were measured over three years in a long-term global change field experiment. We then combined the trait data and additional descriptions of P. australis canopies in a simulation model of carbon assimilation to determine how morphology and physiology contribute to P. australis' stand scale productivity. 3. At the leaf level, we found that light-saturated rates of photosynthesis were strongly stimulated by eCO2 (37%) and that this effect was enhanced by increasing salinity. N had a smaller effect (17% stimulation) on physiological responses than eCO2, but leaf morphological traits responded primarily to N; plant height increased by 27% and leaf area increased by 47%. 4. Stand scale simulations demonstrated that that morphological and physiological adjustments induced approximately additive responses when P. australis experienced both eCO2 and N enrichment. The simulations also indicated that morphological changes (which were primarily associated with canopy size) influenced stand scale carbon assimilation more than physiological changes. Moreover, 97% of the N response was due to changes in morphology, whereas 62% of the eCO2 response was caused by physiological shifts. 5. Our analysis indicates that morphological and physiological trait responses to elevated CO2 and nitrogen are likely to enhance the productivity of P. australis in complementary ways, potentially accelerating its invasion in North America. Furthermore, our data suggest that changes in morphological traits may have a greater influence on carbon gain than leaf-level physiology under near-future environmental conditions. Our study also highlights the importance of accounting for both morphological and physiological responses when attempting to infer global change responses from leaf-level data.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.