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3,583 results for “elevations”
Data from: Spatial patterns along an elevation gradient in high altitude grasslands, Brazil
The Brazilian high altitude grasslands are important biodiversity centers that contribute to human well being far outside their boundaries. They host many vulnerable species that may go locally extinct as a result of small changes in the environment. Performing studies on local species distribution is important to achieve biodiversity conservation in these areas. This study intended to characterize a high altitude grassland plant community along an elevation gradient in Southeastern Brazil. Simple logistic regression, chi-squared tests and indicator species analysis were performed to investigate respectively whether: (i) the occurrence of botanical families was related to the altitude; (ii) the richness and abundance of life forms varied along the gradient and (iii) there were populations associated with specific altitudinal belts. Rubiaceae and Polygalaceae had higher occurrence probability in higher altitudes. Hemicryptophytes and chamaephytes seem to be the most favored life forms under local extreme conditions such as low temperatures and drought. Vegetation spectra varied significantly along the gradient, highlighting the major role of the turnover of habitats in a local scale in underlying patterns of species distribution. Upper elevations encompassed a high number of indicator species, and further identification of high altitude grasslands' indicator species will provide clues about adaptability of local species, which is important to be considered in ecosystem management and conservation.
Data from: Elevated oxidative stress in pied flycatcher nestlings of eumelanic foster fathers under low rearing temperatures
Striking variation in melanin coloration within natural populations is likely due to the different fitness outcomes of alternative phenotypes in varying environmental conditions. There are two types of melanins. Eumelanins yield blackish hues, while pheomelanins yield reddish hues. The production of eumelanins requires low levels of glutathione (GSH), which is the most important intracellular antioxidant, while the production of pheomelanins requires high levels of GSH. We investigated the oxidative status of male pied flycatchers (Ficedula hypoleuca) with different degrees of melanin coloration under different temperatures during the nestling period. Moreover, we assessed the oxidative status of offspring in relation to their biological or foster father's melanin coloration and ambient temperature. To separate offspring genotype effects and paternal effects in different temperatures, we used a partial cross-foster design. The temperature differently affected the oxidative status of differently colored male pied flycatchers and their foster offspring. When the weather was relatively cold, black males had higher glutathione S-transferase levels compared to brown males, indicating enhanced stress in black males. Foster offspring of black males had lower ratio between reduced and oxidized GSH followed by higher total amount of GSH than foster offspring of brown males. Thus, foster offspring of black males seem to suffer from oxidative stress under relatively cold weather compared to those of brown males, and vice versa under relatively warm weather. While differently colored males experienced changes in their oxidative status under different temperatures, the link between father melanin coloration and offspring oxidative stress appears to be environmentally induced.
Data from: Intensifying drought eliminates the expected benefits of elevated carbon dioxide for soybean
Stimulation of C3 crop yield by rising concentrations of atmospheric carbon dioxide ([CO2]) is widely expected to counteract crop losses that are due to greater drought this century. But these expectations come from sparse field trials that have been biased towards mesic growth conditions. This eight-year study used precipitation manipulation and year-to-year variation in weather conditions at a unique open-air field facility to show that the stimulation of soybean yield by elevated [CO2] diminished to zero as drought intensified. Contrary to the prevalent expectation in the literature, rising [CO2] did not counteract the effect of strong drought on photosynthesis and yield because elevated [CO2] interacted with drought to modify stomatal function and canopy energy balance. This new insight from field experimentation under hot and dry conditions, which will become increasingly prevalent in the coming decades, highlights the likelihood of negative impacts from interacting global change factors on a key global commodity crop in its primary region of production.
Data from: Traits that allow bats of tropical lowland origin to conquer mountains: bat assemblages along elevational gradients in the South American Atlantic Forest
Aim: This study aims to contribute to the identification of ecological determinants of tropical moist forest montane biodiversity, analyzing changes in the structure of bat assemblages along an elevational gradient and testing the role of species traits shaping those assemblages. Location: Mountain ranges in the Brazilian Atlantic Forest. Methods: We compiled a dataset with the composition of phyllostomid bat assemblages at 32 forested sites, ranging from 60m to 1960m a.s.l. We quantified how abundance and diversity changed along this elevational gradient, and assessed the capacity of each species to be present and abundant at each elevation, identifying traits that may influence that capacity. Results: Abundance and species diversity declined markedly with increasing elevation. Tolerance to low temperatures, low habitat specialization, and cave roosting facilitated success at higher elevations. Owing to trait filtering, and to changes in resource availability with elevation, assemblages were progressively dominated by a smaller number of mostly generalist species as elevation increased. Higher elevations harbor only a subset of the species that are present in the lowland forest, with no mountain specialized species. Main conclusions: High mountains harbor phyllostomid assemblages that are impoverished subsets of those at lower elevations. Phyllostomids have a tropical origin and may thus have a low potential to adapt to montane forest environments, which possibly explains the observed climatic trait filtering. Habitat filtering is also important, keeping forest specialists mostly at lowest elevations. Protected areas in the Atlantic Forest are mostly limited to mountains. While these areas are clearly important to protect biodiversity, including phyllostomid assemblages, it is now critical to protect and restore the few remnants of lower elevation Atlantic Forest where higher productivity and resource levels, increased complexity of vertical structure, and fewer climatic constraints favor the success of a wider range of phyllostomid bat species of tropical origin.
Data from: Contrasting forms of competition set elevational range limits of species
How abiotic and biotic factors constrain distribution limits at the harsh and benign edges of species ranges is hotly debated, partly because macroecological experiments testing the proximate causes of distribution limits are scarce. It has long been recognized—at least since Darwin's On the Origin of Species—that a harsh climate strengthens competition and thus sets species range limits. Using thorough field manipulations along a large elevation gradient, we show the mechanisms by which temperature determines competition type, resulting in a transition from interference to exploitative competition from the lower to the upper elevation limits in burying beetles (Nicrophorus nepalensis). This transition is an example of Darwin's classic hypothesis that benign climates favor direct competition for highly accessible resources while harsh climates result in competition through resources of high rivalry. We propose that identifying the properties of these key resources will provide a more predictive framework to understand the interplay between biotic and abiotic factors in determining geographic range limits.
Data from: Elevated mitochondrial genome variation after 50 generations of radiation exposure in a wild rodent
Currently, the effects of chronic, continuous low dose environmental irradiation on the mitochondrial genome of resident small mammals are unknown. Using the bank vole (Myodes glareolus) as a model system, we tested the hypothesis that approximately 50 generations of exposure to the Chernobyl environment has significantly altered genetic diversity of the mitochondrial genome. Using deep sequencing, we compared mitochondrial genomes from 131 individuals from reference sites with radioactive contamination comparable to that present in Northern Ukraine before the April 26, 1986 meltdown, to populations where substantial fallout was deposited following the nuclear accident. Population genetic variables revealed significant differences among populations from contaminated and uncontaminated localities. Therefore, we rejected the null hypothesis of no significant genetic effect from 50 generations of exposure to the environment created by the Chernobyl meltdown. Samples from contaminated localities exhibited significantly higher numbers of haplotypes and polymorphic loci, elevated genetic diversity, and a significantly higher average number of substitutions-per-site across mitochondrial gene regions. Observed genetic variation was dominated by synonymous mutations, which may indicate a history of purify selection against nonsynonymous or insertion/deletion mutations. These significant differences were not attributable to sample size artifacts. The observed increase in mitochondrial genomic diversity in voles from radioactive sites is consistent with the possibility that chronic, continuous irradiation resulting from the Chernobyl disaster has produced an accelerated mutation rate in this species over the last 25 years. Our results, being the first to demonstrate this phenomenon in a wild mammalian species, are important for understanding genetic consequences of exposure to low-dose radiation sources.
Data from: Variation in growth and defence traits among plant populations at different elevations: implications for adaptation to climate change
Alpine plants occurring at high elevation are vulnerable to ongoing climate change, yet relatively little is known about the potential for high‐elevation species to adapt to changing environmental conditions. In particular, the extent to which high‐elevation plants will be able to resist predicted increases in the intensity of biotic interactions, such as herbivory, remains unclear. Species distributed across broad elevational ranges provide an opportunity to investigate evolutionary mechanisms and traits involved in adaptation to varying abiotic and biotic environments. This study focused on the perennial alpine plant Arabis alpina and combined field surveys and climate‐chamber experiments to test for intraspecific genetic divergence in traits related to growth and defence against herbivores. We screened multiple populations from low, intermediate and high elevations across a broad geographic area, characterising differences in growth form, leaf structural traits, palatability for herbivores and defensive chemistry. We then quantified the proportion of variation explained by elevation and population‐level effects. Our results document within‐species genetic divergence in multiple traits relevant for adaptation to the different abiotic and biotic pressures experienced at low and high elevations. Rates of herbivore damage declined with increasing elevation in the field, but plants from high‐ and intermediate‐elevation populations were generally more palatable for specialist herbivores than those from low‐elevation populations in feeding assays. Elevational clines were also observed in several glucosinolate defence compounds, and leaf herbivory more strongly induced glucosinolates in plants from high‐elevation populations than in those from low‐elevation populations. Leaf trichome density and growth form also diverged among populations contributing to growth‐defence phenotypes associated with different elevations. However, populations from similar elevations often differed significantly in both growth and defence‐related traits, with trait variation often better explained by population‐level effects than by elevation alone. Synthesis: Arabis alpina exhibits patterns of genetic variation in growth and defence traits consistent with adaptation to different elevations. However, populations from similar elevations also diverged in many of these ecologically relevant traits. Together, the extent of the observed trait variation suggests that this alpine species has considerable potential to adapt to a changing biotic environment.
Data from: A taxonomic, functional and phylogenetic perspective on the community assembly of passerine birds along an elevational gradient in southwest China
Integrating multiple-facets of biodiversity to describe spatial and temporal distribution patterns is one way of revealing the mechanisms driving community assembly. We assessed the species, functional and phylogenetic composition and structure of passerine bird communities along an elevational gradient both in wintering and breeding seasons in the Ailao Mountains, southwest China, in order to identify the dominant ecological processes structuring the communities and how these processes change with elevation and season. Our research confirms that the highest taxonomic diversity, and distinct community composition, was found in the moist evergreen broadleaf forest at high elevation in both seasons. Environmental filtering was the dominant force at high elevations with relatively cold and wet climatic conditions, while the observed value of mean pairwise functional and phylogenetic distances of low elevation were constantly higher than expectation in two seasons, suggested interspecific competition could played the key role at low elevations, perhaps because of relative rich resource result from complex vegetation structure and human-induced disturbance. Across all elevations, there was a trend of decreasing intensity of environmental filtering whereas increasing interspecific competition from wintering season to breeding season. This was likely due to the increased resource availability but reproduction-associated competition in the summer months. In general, there is a clear justification for conservation efforts to protect entire elevational gradients in the Ailao Mountains, given the distinct taxonomic, functional and phylogenetic compositions and also elevational migration pattern in passerine bird communities.
Data from: Hindered and constrained: limited potential for thermal adaptation in post-metamorphic and adult Rana temporaria along elevational gradients
Adaptation to warming climates could counteract the effects of global warming. Thus, understanding how species cope with contrasting climates may inform us about their potential for thermal adaptation and which processes may hamper that ability (e.g. evolutionary trade-offs, phenology, or behavioural thermoregulation). In addition to temperature, time constraints may also exert important selective pressures. Here we compare the thermal sensitivity of locomotion of metamorphic and adult European common frogs (Rana temporaria) originating from populations along an elevational gradient. We employed the template mode of variation (TMV) analysis to decompose the thermal sensitivity of locomotion and explore the existence of trade-offs ('hotter is better' and 'specialist-generalist') and the degree of local adaptation. To that end, we studied the relationship between TMV parameters and local environmental conditions. Further, we compared preferred temperatures to assess whether behavioral thermoregulation could dampen the effects of thermal variation, reducing the intensity of selection and limiting thermal adaptation (i.e. 'Bogert effect'). We suggest that behavioral thermoregulation has promoted the conservatism of thermal sensitivity in R. temporaria. Yet, we observed a trend towards narrower thermal niches shifted towards warmer temperature in populations with severe temporal constraints, conforming to the 'generalist-specialist' trade-off. Apparently, this enables time-constrained populations – especially in the case of metamorphs – to effectively exploit resources during the warmest periods. The limited potential of R. temporaria for thermal adaptation suggests that forecasts of global warming should incorporate thermoregulation and explore its potential to buffer species from rising temperatures.
Data from: Trait patterns of epiphytes compared to other plant life forms along a tropical elevation gradient
Compared to other plant life forms, epiphytes remain understudied. Understanding the responses of epiphytes to changing environmental conditions is necessary to predict changes in ecosystem functioning especially in subtropical and tropical regions. We investigated the functional traits of epiphytes along a large elevation gradient on Mount Kilimanjaro, Tanzania. We measured traits of co-occurring trees and terrestrial non-tree life forms, and compared changes in community-weighted means of traits (CWM) and trait spread, the range of observed trait values. We chose traits linked to growth and persistence: leaf area, specific leaf area, leaf dry matter content, stem specific density, plant height, leaf carbon, leaf nitrogen, and leaf phosphorus. For most traits, differences in community-weighted means between life forms exceeded differences within life forms along the elevation gradient. Many CWM showed linear changes with elevation, but no response and unimodal patterns were also frequent. This was best explained by temperature, or a combination of temperature with precipitation or humidity, indicating effects of these factors on the distribution of epiphytic and non-epiphytic species. Trait spread did not change with elevation in nearly half of the traits, but hump-shaped patterns were also common, probably a result of weaker environmental filtering in the gradient center. The magnitude of trait spread, i.e. the variability between species of the same life form within communities, was highest for terrestrial non-trees. Excluding ferns from the analyses lead to marked differences in trait patterns for epiphytes, as ferns made up 59 % of the epiphytic species, while playing a minor role in the other groups. The observed differences can be explained by a dichotomy in epiphytic life strategies, with tough-leaved xero-tolerant species on one side and succulent soft-leaved species on the other. However, the influence of phylogeny was lower than expected from the taxonomic composition of the three life form groups. Our results emphasize that environmental constraints act upon functional traits of epiphytes, trees and terrestrial non-trees. The differences in trait expressions, arguably adaptations of the different life forms, need to be taken into account in conservation contexts as well as when modeling the effects of global change on ecosystems.
Data from: Manipulating saltmarsh microtopography modulates the effects of elevation on sediment redox potential and halophyte distribution
1. Halophyte distributions on saltmarshes are strongly related to elevation in the tidal frame. However, collinearity between elevation, the consequent inundation regime, and sediment waterlogging/redox potential obscures the proximate causes of distribution patterns. We sought to distinguish the effects of elevation per se from those of waterlogging by manipulating microtopography. 2. We experimentally manipulated elevation by ±15 cm at locations that spanned the elevation ranges of three saltmarshes recently reactivated by managed coastal realignment. Experimental plots were initially cleared of any vegetation. Elevation and sediment redox potential were determined for each plot. We planted five perennial species (Armeria maritima, Atriplex portulacoides, Limonium vulgare, Plantago maritima and Triglochin maritima) in half of the plots, recording survival over four years, and monitored natural colonisation of the other plots. 3. Overall, redox potential increased with elevation. Sediments were more oxidising in raised plots and more reducing in lowered plots. Redox reductions in lowered plots were in line with those that would be predicted from the overall redox/elevation relationship, but increases in raised plots were greater than predicted from elevation alone. 4. Plant colonisation and survival was poorer in lowered plots and, for most species, improved in raised plots. This can, in part, be attributed to the concomitant alterations in redox potential and elevation in the tidal frame, but microtopographic manipulation also had substantial independent effects on plant performance, including on the survival of all planted species and the colonisation of Puccinellia maritima, Salicornia europaea agg. and Tripolium pannonicum. 5. Synthesis: Microtopography can have effects on sediment chemistry and plant performance similar in magnitude to those of overall tidal elevation. Understanding how its effects modulate the relationship between tidal elevation, redox and other environmental conditions helps clarify the abiotic factors that fundamentally determine halophyte colonisation and survival. These results support the use of topographic manipulation to enhance the diversity of created saltmarshes.
Data from: Elevated CO2 and temperature increase soil C losses from a soybean-maize ecosystem
Warming temperatures and increasing CO2 are likely to have large effects on the amount of carbon stored in soil, but predictions of these effects are poorly constrained. We elevated temperature (canopy: +2.8 °C; soil growing season: +1.8 °C; soil fallow: +2.3 °C) for 3 years within the 9th–11th years of an elevated CO2 (+200 ppm) experiment on a maize–soybean agroecosystem, measured respiration by roots and soil microbes, and then used a process-based ecosystem model (DayCent) to simulate the decadal effects of warming and CO2 enrichment on soil C. Both heating and elevated CO2 increased respiration from soil microbes by ~20%, but heating reduced respiration from roots and rhizosphere by ~25%. The effects were additive, with no heat × CO2 interactions. Particulate organic matter and total soil C declined over time in all treatments and were lower in elevated CO2 plots than in ambient plots, but did not differ between heat treatments. We speculate that these declines indicate a priming effect, with increased C inputs under elevated CO2 fueling a loss of old soil carbon. Model simulations of heated plots agreed with our observations and predicted loss of ~15% of soil organic C after 100 years of heating, but simulations of elevated CO2 failed to predict the observed C losses and instead predicted a ~4% gain in soil organic C under any heating conditions. Despite model uncertainty, our empirical results suggest that combined, elevated CO2 and temperature will lead to long-term declines in the amount of carbon stored in agricultural soils.
Data from: Beta diversity and specialization in plant-pollinator networks along an elevational gradient
Aim: To assess whether the reduced nutritional resources available for pollinators due to plant community simplification along an elevational plant-diversity gradient changes pollinator niche breadth and richness. Additionally, we evaluated how body size and proboscis length of pollinators shifted along the gradient, and whether these changes were related to pollinator niche breadth. Location: An elevational gradient (2,350-3,520 m a.s.l.) on the oceanic high-mountain strato-volcano of El Teide (Tenerife, Canary Islands). Taxon: Flowering plant and pollinator species. Methods: We compared quantitative plant–pollinator networks along the plant-diversity gradient. We calculated a set of niche-based topological metrics that capture the degree of specialization, niche breadth and niche overlap. Furthermore, we obtained β-diversity measures and the proportion of replacement and richness components. Results: There was an overall decline in species richness of pollinators with increasing elevation. This decline was mainly driven by the loss of species along the elevational gradient, which conformed a nested subset pattern. The whole network showed less specialization, greater connectance and lower modularity towards the summit. At high elevations, pollinators were more generalized and less selective in their flower choice, showing a greater trophic niche breadth compared to pollinators at lower elevations. Mean body size of pollinators increased with elevation, and species body size and proboscis length were positively associated with the number of plant species visited. Main conclusions. Overall, results indicated that the elevational gradient filters pollinator species, probably according to their thermal tolerance and ability to exploit a wide range of trophic resources. The finding that pollinators become more generalized and opportunistic at higher elevations is a novel result, which may have implications for new research into how ecological networks vary over environmental gradients. From an applied perspective, our results highlight the importance of considering the spatial variation of species assemblages when aiming to construct functionally reliable interaction networks along environmental gradients.
Data from: Facilitation consequences for reproduction of the benefactor cushion plant Laretia acaulis along an elevational gradient: costs or benefits?
Environmental stress may favour facilitative interactions among plants but whether these interactions are positive for the benefactor and how this depends on stress factors, remains to be determined. We studied the effect of beneficiary cover and biomass on reproduction of the benefactor cushion plant Laretia acaulis (Apiaceae) in the central Chilean Andes during three years. Study sites were situated along an elevational gradient at 2600, 2800, 3000 and 3150 m a.s.l. This range comprises a cold- and a drought-stress gradient, with moisture increasing and temperature decreasing with elevation. We studied the effect of natural gradients in beneficiary cover and of experimental cover removal on cushion flower and fruit production. Beneficiary cover had a negative effect on flower production but not on infructescence and fruit densities or fruit weights. A positive effect of beneficiaries on the fraction of flowers converted into fruits was detected for hermaphrodite cushions. The effect of beneficiary cover on flowering was independent of elevation or cushion gender, although these latter factors explained most of the variation. Removing the aboveground parts of the beneficiaries positively affected flowering at 2800 m a.s.l. but not at the other elevations. Our results suggest negative effects of facilitation on L. acaulis flowering, but these are neutralized in fruit production. Surprisingly, this conclusion holds along the entire elevational or stress gradient. This suggests that this system of facilitation is evolutionarily stable and not very sensitive to environmental change. It remains to be tested, however, whether facilitation affects fitness via growth and long-term survival in these slow-growing alpine cushions.
Data from: High-elevation range limit of an annual herb is neither caused nor reinforced by declining pollinator service
1. Pollination failure has been proposed to be an important determinant of plant species' range limits, if pollinator activity declines along an environmental gradient, directly limiting plant populations, or if plant populations decline along an environmental gradient and subsequently fail to attract sufficient visitation. Both mechanisms predict reduced pollinator visitation, increased pollen limitation, and decreased seed production towards range limits, and the first additionally predicts declining pollinator abundance independent of any particular plant species. However, many self-compatible species have some capacity for autonomous self-fertilization, which may buffer reproductive success from declining pollinator visitation if inbreeding depression is mild. Thus pollinator-mediated limits may also predict selection for reduced reliance on pollinators towards range limits. 2. We tested these predictions towards the high-elevation limit of the self-compatible, bumble bee (Bombus) pollinated Rhinanthus minor, along two elevation transects in the Rocky Mountains of Alberta, Canada. 3. Bombus abundance was highest at mid- (range-centre) and high-elevation (range limit) sites, so declining pollinator abundance is unlikely to impose high-elevation limits for bumble bee pollinated species in this area. 4. Flowers per plant and per m2 declined at upper range limits, potentially rendering edge populations less attractive. However, visitation rate did not decline towards the range limit at either transect. Stigmatic pollen receipt declined with increasing elevation, but seed set did not, nor did outcross pollen supplementation increase seed set at any site. 5. Investment in floral attractiveness (corolla area/ovary area) increased towards range limits, but capacity for high-quality autonomous seed set and adult inbreeding coefficients inferred from genetic markers were uniformly high, suggesting frequent self-fertilization and weak inbreeding depression throughout the range. 6. Synthesis We found no evidence for pollination failure towards the upper range limit of R. minor. Moreover, unlike some species with a capacity for autogamy, autonomous selfing makes a major contribution to R. minor's mating system and demography, and likely buffers reproductive success from stochasticity in pollination. Continued investment in floral attractiveness despite high autonomous selfing suggests some evolutionary benefit to pollinator-mediated outcrossing, rather than ecological benefits via increasing seed quantity or quality. Given that >50% of angiosperms are self-compatible, the reproductive assurance provided by selfing may reduce the importance of pollination in limiting plant distributions compared to other biotic interactions.
Data from: Is black plumage an adaptation to high elevations in a cosmopolitan bird genus?
Black plumage is expected to absorb and retain more heat and provide better protection against UV radiation compared with lighter plumages. Black plumage is common in species of the genera Turdus and Platycichla that inhabit highlands across different regions of the world. Considering this geographical recurrent pattern we tested the hypothesis that black plumage in these two genera has evolved as a co-adaptive response to inhabiting highlands, reconstructing ancestral character states for plumage and altitudinal distribution using maximum-likelihood methods, and a Pagel's multistate discrete method. For these analyses, we used a phylogeny based on mitochondrial and nuclear DNA regions that included 60 of the 66 recognized species in the genera Turdus and Platycichla. We found that black-plumage coloration evolved independently on eight occasions within these two genera, and species with black plumage occur more often at highlands. Our results support the hypothesis that black-plumage is adaptative in highlands; but, studies in other bird groups with black-plumage inhabiting at the same elevations will provide evidence for this adaptive hypothesis or if the evolution of black-plumage in other groups is explained by other evolutionary forces.
Data from: Aircraft sound exposure leads to song frequency decline and elevated aggression in wild chiffchaffs
Abstract: 1. The ubiquitous anthropogenic low-frequency noise impedes communication by masking animal signals. To overcome this communication barrier, animals may increase the frequency, amplitude and delivery rate of their acoustic signals, making them more easily heard. However, a direct impact of intermittent, high-level aircraft noise on birds' behaviour living close to a runway has not been studies in detail. 2. We recorded common chiffchaffs Phylloscopus collybita songs near two airports and nearby control areas, and we measured sound levels in their territories at Manchester airport. The song recordings were made in between aircraft movements, when ambient sound levels were similar between airport and control populations. We also conducted playback experiments at the airport and a control population to test the salience of airport, and control population specific songs. 3. In contrast to the general pattern of increased song frequency in noisy areas, we show that common chiffchaffs at airports show a negative relationship between noise exposure level and song frequency. 4. Experimental data show that chiffchaffs living near airports also respond more aggressively to song playback. 5. Since the decrease in song frequency results in increased overlap with aircraft noise, these findings cannot be explained as an adaptation to improve communication. The increased levels of aggression suggests that chiffchaffs, like humans, might be affected behaviourally by extreme noise pollution. These findings should influence environmental impact assessments for airport expansions globally.
The role of non-glandular emergences in Croton floribundus (Euphorbiaceae) upon elevated ozone exposures
<p>The role of non-glandular emergences in avoiding ozone (O<sub>3</sub>) damages by preventing its entrance into leaf tissues was previously suggested to the O<sub>3</sub>-tolerant species <i>Croton floribundus </i>(Euphorbiaceae). However, this function against O<sub>3</sub> damage has been underestimated due to the covering wax layer mostly composed of saturated hydrocarbon with low reactivity to this gas. To evaluate the role of these structures in conferring tolerance to O<sub>3</sub>, we mechanically removed the non-glandular emergences from leaf blades of <i>C. floribundus</i>, submitted the plants to acute O<sub>3</sub> fumigation, and assessed the morphological and microscopic alterations. Plants with intact leaves showed the same phenotype of control samples but showed microscopic markers of accelerated senescence. These alterations indicated a whole-plant response to O<sub>3</sub>. Plants bearing leaves with emergences removed exhibited specific morphological symptoms and microscopic markers of O<sub>3</sub>. The leaf emergences encompass a barrier for volatiles contention, preventing O<sub>3</sub> damage to leaf tissues of <i>C. floribundus</i>. The absence of these structures possibly disperses defense volatiles quickly and allows this species to become vulnerable to O<sub>3</sub> effects. This study highlights the relevance of surface structures in confer resistance of plants against O<sub>3</sub> damages over biochemical defenses alone.</p>
Data from: Bergmann's Rule rules body size in an ectotherm: heat conservation in a lizard along a 2200-meter elevational gradient
Bergmann's Rule predicts larger body sizes in colder habitats, increasing organisms' ability to conserve heat. Originally formulated for endotherms, it is controversial whether Bergmann's Rule may be applicable to ectotherms, given that larger ectotherms show diminished capacity for heating up. We predict that Bergmann's Rule will be applicable to ectotherms when the benefits of a higher conservation of heat due to a larger body size overcompensate for decreased capacity to heating up. We test this hypothesis in the lizard Psammodromus algirus, which shows increased body size with elevation in Sierra Nevada (SE Spain). We measured heating and cooling rates of lizards from different elevations (from 300 to 2500 meters above sea level) under controlled conditions. We found no significant differences in the heating rate along an elevational gradient. However, the cooling rate diminished with elevation and body size: highland lizards, with larger masses, have a higher thermal inertia for cooling, which allows them to maintain heat for more time and keep a high body temperature despite the lower thermal availability. Consequently, the net gaining of heat increased with elevation and body size. This study highlights that the heat conservation mechanism for explaining Bergmann's Rule works and is applicable to ectotherms, depending on the thermal benefits and costs associated with larger body sizes.
Data from: The effect of elevated CO2 on growth and competition in experimental phytoplankton communities
We report an experiment designed to identify the effect of elevated CO2 on species of phytoplankton in a simple laboratory system. Major taxa of phytoplankton differ in their ability to take up CO2, which might lead to predictable changes in the growth rate of species and thereby shifts in the composition of phytoplankton communities in response to rising CO2. Six species of phytoplankton belonging to three major taxa (cyanobacteria, diatoms and chlorophytes) were cultured in atmospheres whose CO2 concentration was gradually increased from ambient levels to 1000 parts per million over about 100 generations and then maintained for a further 200 generations at elevated CO2. The experimental design allowed us to trace a predictive sequence, from physiological features to the growth response of species to elevated CO2 in pure culture, from the growth response in pure culture to competitive ability in pairwise mixtures and from pairwise competitive ability to shifts in the relative abundance of species in the full community of all six species. CO2 altered the dynamics of growth in a fashion consistent with known differences among major taxa in their ability to take up and use CO2. This pure-culture response was partly successful in predicting the outcome of competition in pairwise mixtures, especially the enhanced competitive ability of chlorophytes relative to cyanobacteria, although generally statistical support was weak. The competitive response in pairwise mixtures was a good predictor of changes in competitive ability in the full community. Hence, there is a potential for forging a logical chain of inferences for predicting how phytoplankton communities will respond to elevated CO2. Clearly further extensive experiments will be required to validate this approach in the greater complexity found in diverse communities and environments of natural systems.
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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.