Find research datasets worth reusing

opencc-by-4.0Oct 2022View details →

High-resolution digital elevation models and orthomosaics generated from historical aerial photographs (since the 1960s) of the Bale Mountains in Ethiopia

This dataset contains the inputs used for Structure from Motion Multiview Stereo photogrammetry processing for the year 1967 and 1984 i.e Unprocessed scanned historical aerial Photographs, camera position coordinates, flight index and Ground Control Points. All the scanned historical aerial photographs data are in TIFF format except four photographs in JPEG format under a zipped folder ("1967_Scanned_HAPs_Part1.7z and 1967_Scanned_HAPs_Part2.7z" for the 1967 Historical Aerial Photographs and "1984_Scanned_HAPs_Part1.7z and 1984_Scanned_HAPs_Part2.7z" for the 1984  Historical Aerial Photographs). The "Flight_Index.Zip" contains shapefiles of the camera position and polygon of consecutive aerial photograph index; "GCP.Zip" contains text file of the GCPs used for the 1967 and 1984; and "Camera_Position.Zip" contains the file of the camera position (Label, Easting, Northing and Altitude) of each historical aerial photographs.  The results of the above dataset could be accessible on Zenodo repository "10.5281/zenodo.7269999". Anyone can reuse the presented dataset to produce DEMs and Orthomosaics; and use for the following application  areas: 1. watershed management 2. analyses of historical landscape change 3. detailed mapping and analyses of geological and archaeological features, as well as natural resources 4. analyses of geomorphological processes 5. socioecological patterns and dynamics 6. modelling and planning for telecommunications  7. biodiversity research.

Changing patterns of nest predation and predator communities along a tropical elevation gradient

Tropical montane communities host the world's highest beta diversity of birds, a phenomenon usually attributed to community turnover caused by changes in biotic and abiotic factors along elevation gradients. Yet, empirical data on most biotic factors are lacking. Nest predation is thought to be especially important because it appears to be common and can change selective pressures underlying life history traits, which can alter competitive interactions. We monitored 2,538 nests, 338 of which had known nest predators, to evaluate if nest predation changes along a tropical elevational gradient. We found that nest predation decreased with elevation, reflecting the loss of lowland predators that do not tolerate colder climates. We found different "super" nest predators at each elevation that accounted for a high percentage of events, suggesting that selection pressures exerted by nest predator communities may be less diffuse than has been hypothesized, at least for birds nesting in the understory.

Soil microbial relative resource limitation exhibited contrasting seasonal patterns along an elevational gradient in Yulong snow mountain

1. Microbial relative resource limitations represented by enzyme stoichiometry reflect the relationship between microbial nutrient requirements and nutrient status in soil, but the issue on whether alterations in environments along elevational gradients affect the magnitude of microbial relative resource limitations remains unresolved. 2. Here, we examined seasonal patterns in microbial relative carbon (C) and phosphorus (P) limitations indicated by vector lengths and angles using relative proportional enzymatic activities and key controlling factors along an elevational gradient in the Yulong Snow Mountain. We also analyzed the relationships between microbial metabolic processes and microclimates (i.e., soil moisture and temperature), soil properties (i.e., pH and soil texture), and microbial attributes (i.e., microbial biomass and fungal: bacterial ratio). 3. We found that soil microbial relative C limitation decreased with increasing elevations, with lower levels observed in the dry season than in the wet season. In contrast, soil microbial relative P limitation varied significantly with elevations, with linearly increasing trends in wet seasons but unimodal trends in dry seasons. Meanwhile, we found higher relative C limitation in the coniferous forest but higher relative P limitation in the broad-leaved forest. Notably, soil microbial relative C limitation was primarily affected by the soil microenvironment (i.e., soil temperature) and substrate quantity (i.e., the ratio of soil dissolved organic C to available P), whereas soil microbial relative P limitation could be alleviated by increasing microbial relative C limitation combined with increasing soil pH. Additionally, the significant linear pattern of the C use efficacy with elevations was only observed in the wet seasons, which was directly influenced by soil microclimates and microbial relative C limitation. 4. Overall, our results provided important information for better understanding the essential role of microbial processes in the regulation of C and P cycling in vulnerable subtropical mountain ecosystems.

Increasing species richness along elevational gradients is associated with niche packing in bat assemblages

1. The change in species richness along elevational gradients is a well-known pattern in nature. Niche theory predicts that increasing species richness in assemblages can either lead to denser packing of niche space ('niche packing') or an expansion into its novel regions ('niche expansion'). Traditionally, these scenarios have been studied using functional traits, but stable isotopes provide advantages such as identifying the degree of resource specialisation or niche partitioning among functionally similar species. 2. In this study, we evaluate the relevance of niche packing vs. niche expansion by investigating stable carbon and nitrogen isotopic niche width and overlap among 23 bat species from six functional groups across a 1500 m elevational gradient in the Himalaya. 3. Our results suggest that an increase in species richness in the low elevation is accompanied by small niche width with high overlap, whereas the high elevation assemblage shows large niche width with low overlap among functional group members. At the functional group level, edge-space foraging, trawling, and active gleaning bats have the highest niche width while passive-gleaning bats that are only found in high elevations are isotopic specialists showing low overlap with other groups. Edge and open-space foraging bats showed idiosyncratic changes in niche width across elevations. We also find that the niches of rhinolophid bats overlap with edge-space and open-space foraging bats despite their unique functional traits. 4. These results support the idea that, at low elevations, high species richness is associated with niche packing while at high elevations, strong niche partitioning prevails in dynamic and resource-poor environments. We conclude that although high-elevation animal assemblages are often 'functionally underdispersed', i.e. show homogenous functional traits, our approach based on stable isotopes demonstrates niche partitioning among such functionally similar species.

Preparation and tribological properties of multi-layer graphene/silicon dioxide composites-based solid lubricant coatings at elevated temperatures

The solid lubricating coatings have an important role in hot metal forming. However, traditional lubricants can't be applied to the harsh working conditions. In this investigation, the novel solid lubricant coatings including multi-layer graphene (MLG)/silicon dioxide (SiO2) composites and sodium metaphosphate phosphate were prepared. The high-temperature tribological properties of the solid lubricant coatings were investigated by friction and wear tester. The experimental results showed that SiO2 nanoparticles were evenly grafted by sol–gel method on the surface of MLG, forming MLG/SiO2 composites. MLG/SiO2 composites were presented excellent thermal stability at 800°C. In the range of 400–800°C, the average coefficient of frictions (COFs) were decreased from 0.3936 to 0.3663, and then increased from 0.3663 to 0.4226. Based on the analysis of wear scar, the lubrication mechanisms of the solid lubricating coatings were proposed. The low interlayer shear of MLG and the ball bearing of SiO2 nanoparticles are the main reason for the reduction of COFs. In addition, the tribo-chemical reaction film formed on the frictional interface could protect the contact surfaces from severe damages. The findings would be beneficial for developing novel lubricants for hot metal forming process.

Data for: Liverworts show a globally consistent mid-elevation richness peak

The study of elevational gradients allows to draw conclusions on factors and mechanisms determining patterns in species richness distribution. Several earlier studies investigated liverwort diversity on single or few elevational transects. However, a comprehensive survey on elevational distribution patterns of liverwort richness and their underlying factors is lacking so far. This study's purpose was to fill this gap by compiling an extensive dataset of liverwort elevational patterns encompassing a broad diversity of mountains and mountain ranges around the world. Using polynomial regression analyses, we found a prevalence of hump-shaped richness patterns (19 of 25 gradients), where liverwort species richness peaked at mid-elevation and decreased towards both ends of the gradient. Against our expectation and unlike in other plant groups, in liverworts, this pattern also applies to elevational gradients at mid-latitudes in temperate climates. Indeed, relative elevation, calculated as the percentage of the elevational range potentially inhabited by liverworts, was the most powerful predictor for the distribution of liverwort species richness. We conclude from these results that admixture of low- and high-elevation liverwort floras, in combination with steep ecological gradients, leads to a floristic turnover shaping elevational distribution patterns of liverwort diversity. Our analyses further detected significant effects of climatic variables (temperature of the warmest month, potential evapotranspiration, and precipitation of the warmest month) in explaining elevational liverwort richness patterns. This indicates that montane liverwort diversity is restricted by high temperatures and subsequent low water availability, especially towards lower elevations, which presumably will lead to serious effects by temperature shifts associated with global warming.

Data for: Species richness and assemblages of bats along a forest elevational transect in Papua New Guinea

Over the past decades, elevational gradients have become a powerful tool with which to understand the underlying cause(s) of biodiversity. The Mt. Wilhelm elevational transect is one such example, having been used to study the birds, insects, and plants of Papua New Guinea (PNG). However, a survey of mammals from this forest elevational transect was lacking. We thus aimed to investigate patterns in the community structure and species richness of bats (Chiroptera) along the transect, link the species to available regional data, and explain the observed patterns by including environmental characteristics. Bat assemblages were surveyed between 200 m and a timberline at 3,700 m a.s.l. at eight study sites separated by 500 m in elevation. We conducted mist-netting and acoustic surveys to detect and identify species at each site. Regional data were compiled to compare local with regional diversity. Finally, biotic (i.e., food availability, habitat features) and abiotic (i.e., mean daily temperature) factors were included in our analyses to disentangle the ecological drivers underlying bat diversity. Results revealed that species richness decreases with ascending elevation and was best explained by a corresponding decrease in temperature. We observed both turnover and nestedness of the species composition at regional scale whereas turnover was dominant at local scale. Extensions and shifts of bat elevational ranges were also found in Mt. Wilhelm. Consequently, despite that the study was restricted to one mountain in PNG, it demonstrates how basic inventory surveys can be used to address ecological questions in other similar and undisturbed tropical mountains.

opencc-by-4.0Feb 2023View details →

Generated data for "Limited ventilation of the central Baltic Sea due to elevated oxygen consumption" paper

This data are essential for reproducing the figures from Naumov et al. "Limited ventilation of the central Baltic Sea due to elevated oxygen consumption" paper. Each archive is named after one of the ten figures and includes the data necessary for that specific figure. Some data are used in more than one figure. In some cases, performing a particular type of analysis with the given data (linear regression, for instance) is necessary to fully reproduce the figure.

Microhabitat data of bryophyte occurrences in and near Sequoia National Park at varying elevations

On the western slope of California's Sierra Nevada, bryophytes were studied from the foothills (summers dry; winters mild) to the alpine zone (summers short; winters with snow cover). Plots of 25 m2 were chosen from 380 to 3,578 meters above sea level. Within each of the 253 plots, bryophyte species and their abundance were recorded along with microsite wetness, shadiness, incline, and the type of substrate. Data was used to assess changes in species richness and abundance across elevations and microhabitat characteristics.

Distinct responses and range shifts of lizards populations across an elevational gradient under climate change

Ongoing climate change has profoundly affected global biodiversity, but its impacts on populations across elevations remain understudied. Using a mechanistic niche model incorporating species traits, we predicted ecophysiological responses (activity times, oxygen consumption and evaporative water loss) for lizard populations at high-elevation (< 3600 m asl) and extra-high-elevation (> 3600 m asl) under recent (1970–2000) and future (2081–2100) climates. Compared with their high-elevation counterparts, lizards from extra-high-elevations are predicted to experience a greater increase in activity time and oxygen consumption but a similar increase in evaporative water loss. By integrating these ecophysiological traits into a hybrid species distribution model (HSDM), we were able to make the following predictions under two warming scenarios (SSP1-2.6, SSP5-8.5). By 2081–2100, we predict that lizards at both high- and extra-high-elevations will shift upslope; lizards at extra-high-elevations will gain more and lose less habitat than will their high-elevation congeners. We therefore advocate the conservation of high-elevation species in the context of climate change, especially for those populations living close to their lower elevational range limits. In addition, by comparing the results from HSDM and traditional species distribution models, we highlight the importance of considering intraspecific variation and local adaptation in physiological traits along elevational gradients when forecasting species' future distributions under climate change.

opencc-zeroMar 2023View details →

Small mammal granivory as a biotic filter for tree establishment beyond elevation range boundaries

Trees often experience migration lags in their response to rapidly changing climate. Preferential granivory by nocturnal small mammals has the potential to create lags by reducing germination success beyond range edges. To determine how granivory may limit establishment of trees beyond their range margins, we conducted a seed choice experiment which offered seeds of five regionally dominant tree species to small mammals within distinct forest communities across a 400m elevational gradient on four mountains in the northeastern United States. Multinomial logistic mixed effects models were used to (a) quantify seed preference of each species across the elevational gradient and (b) assess relationships between seed preference and abiotic variables. A separate seed dispersal experiment was used to compare the probability of seed consumption versus seed caching. The low-elevation temperate tree species Fagus grandifolia and Acer saccharum had an equally high probability of granivory within and beyond their range margins (~40% and ~20%, respectively). Generally, seed preference was positively correlated with seed mass and nutrient content regardless of elevation. Our seed dispersal experiment revealed that seeds were 3× more likely to be consumed than cached, suggesting that small mammals can potentially decrease germination success. Overall, temperate tree species with either high seed mass or nutritional value may experience substantial granivory beyond their range margin, partially explaining the observed lag between tree dispersal and climate change. Thus, granivory is vital to consider when modeling future tree species distributions under various climate change scenarios.

opencc-zeroMar 2023View details →

Experimental warming increases the vulnerability of high-elevation plant populations to a specialist herbivore

<ol> <li>Ongoing climate change may impact alpine plant populations via both direct effects of increased temperature and climate-driven changes in interactions between plants and other organisms, such as insect herbivores. Rates of herbivory in high-elevation environments are predicted to increase with warmer temperatures, which may also lead to changes in morphological and physiological traits that influence plant resistance. Yet, we currently know little about how temperature-mediated changes in traits will impact alpine plant vulnerability to herbivores, as well as the extent to which populations from high-elevation environments might need to rapidly adapt to increasing herbivore pressure with rising temperatures.</li> <li>We assessed the effect of experimental warming on the relative vulnerability of populations of the alpine plant Arabis alpina from different elevations to a specialist herbivore. Herbivore performance was measured on plants from nine populations grown in climate chambers at two temperatures, representing low (warm) and high (cold) elevations. We also measured changes in putative drivers of performance: plant phenological, chemical and defence traits. Assuming populations would be adapted to local climates and levels of herbivory, we predicted that low-elevation populations would be more resistant to herbivores under warmer temperatures than high-elevation populations.</li> <li>We found reduced performance of a specialist herbivore on A. alpina grown under warm rather than cold conditions, though this effect varied with elevation. Larvae grew faster on high-elevation populations than low-elevation populations when grown under warm temperatures, whereas similar growth rates were observed for plants grown under colder temperatures, consistent with plant adaptation to the lower existing herbivore pressure in cold, high-elevation environments. Regression analyses suggested that polar metabolite variation explained more variance in larval performance than changes in defensive glucosinolates or morphological traits.</li> <li>Our results suggest that although physiological responses to warming may increase the resistance of cold-adapted plants to herbivory, populations from different elevations may differ in their interactions with herbivores under climate warming. Without genetic adaptation, existing physiological responses of high-elevation populations to warmer temperatures may leave these populations vulnerable to the increases in herbivore pressure predicted under climate change.</li> </ol>

opencc-zeroMar 2023View details →

Elevation and phylogeny shape herbaceous seed dormancy in a biodiversity hotspot of southwest China

Seed dormancy contributes greatly to successful establishment and community stability and shows large variation over a continuous status scale in mountain ecosystems. Although empirical studies have shown that seed dormancy status (SDS) is shaped by elevation and phylogenetic history in mountain ecosystems, few studies have quantified their combined effects on SDS. Here, we collected mature seeds from 51 populations of 11 Impatiens species (Balsaminaceae) along an elevational gradient in the Gaoligong Mountains of southwest China and estimated SDS using mean dormancy percentage of fresh seeds germinated at three constant temperatures (15, 20, and 25 °C). We downloaded 19 bioclimatic variables from WorldClim v.2.1 for each Impatiens population and used internal transcribed spacer (ITS), atpB-rbcL, and trnL-F molecular sequences from the GenBank nucleotide database to construct a phylogenetic tree of the 11 species of Impatiens. Logistic regression model analysis was performed to quantify the effects of phylogeny and environment on SDS. Results identified a significant phylogenetic SDS signal in the Impatiens species. Furthermore, elevation and phylogeny accounted for 63.629% of the total variation in SDS among the Impatiens populations. The best logistic model indicated that temperature was the main factor influencing variation in SDS among the Impatiens species, and model residuals were significantly correlated with phylogeny, but not with elevation. Our results indicated that seed dormancy is phylogenetically conserved, and climate drives elevational patterns of SDS variation in mountain ecosystems. This study provides new insights into the response of seed plant diversity to climate change.

opencc-zeroApr 2023View details →

Elevated atmospheric CO2 suppresses silicon accumulation and exacerbates endophyte reductions in plant phosphorus

Many temperate grasses are both hyper-accumulators of silicon (Si) and hosts of Epichloë fungal endophytes; functional traits which may alleviate environmental stresses such as herbivore attack. Si accumulation and endophyte infection may operate synergistically, but this has not been tested in a field setting, nor in the context of changing environmental conditions. Predicted increases in atmospheric CO2 concentrations can affect both Si accumulation and endophyte function, but these have not been studied in combination. We investigated how elevated atmospheric CO2 (eCO2), Si supplementation, endophyte-presence and insect herbivory impacted plant growth, stoichiometry (C, N, P and Si), leaf gas exchange (rates of photosynthesis, stomatal conductance, transpiration rates) and endophyte production of anti-herbivore defences (alkaloids) of an important pasture grass (tall fescue; Lolium arundinaceum) in the field. eCO2 and Si supplementation increased shoot biomass (+52% and +31%, respectively), whereas herbivory reduced shoot biomass by at least 35% and induced Si accumulation by 24%. Shoot Si concentrations, in contrast, decreased by 17–21% under eCO2. Si supplementation and herbivory reduced shoot C concentrations. eCO2 reduced shoot N concentrations which led to increased shoot C:N ratios. Overall, shoot P concentrations were 26% lower in endophytic plants compared to non-endophytic plants, potentially due to decreased mass flow (i.e. observed reductions in stomatal conductance and transpiration). Alkaloid production was not discernibly affected by any experimental treatment. The negative impacts of endophytes on P uptake were particularly strong under eCO2. We show that eCO2 and insect herbivory reduce and promote Si accumulation, respectively, incorporating some field conditions for the first time. This indicates that these drivers operate in a more realistic ecological context than previously demonstrated. Reduced uptake of P in endophytic plants may adversely affect plant productivity in the future, particularly if increased demand for P due to improved plant growth under eCO2 cannot be met.

opencc-zeroDec 2022View details →

Data from: Network structure of avian mixed-species flocks decays with elevation and latitude across the Andes

Birds in mixed-species flocks benefit from greater foraging efficiency and reduced predation but also face costs related to competition and activity matching. Because this cost-benefit trade-off is context-dependent (e.g., abiotic conditions, habitat quality), the structure of flocks is expected to vary along elevational, latitudinal, and disturbance gradients. Specifically, we predicted that the connectivity and cohesion of flocking networks would (1) decline towards tropical latitudes and lower elevations, where competition and activity matching costs are higher, and (2) increase with lower forest cover and greater human disturbance. We analysed the structure of 84 flock networks across the Andes and assessed the effect of elevation, latitude, forest cover and human disturbance on network characteristics. We found that Andean flocks are overall open-membership systems (unstructured), though the extent of network structure varied across gradients. Elevation was the main predictor of structure, with more connected and less modular flocks upslope. As expected, flocks in areas with higher forest cover were less cohesive, with better-defined flock subtypes. Flocks also varied across latitude and disturbance gradients as predicted, but effect sizes were small. Our findings indicate that the unstructured nature of Andean flocks might arise as a strategy to cope with harsh environmental conditions.

opencc-by-4.0May 2023View details →

Experimental data of "Elevated concentrations cause upright alpha-synuclein conformation at lipid interfaces" (NatComm)

The experimental data in this dataset is the basis of the article entitled "Elevated concentrations cause upright alpha-synuclein conformation at lipid interfaces", which will hopefully be published in NatComm soon. We will add a DOI then. It contains the vibrational sum-frequency generation (VSFG), atomic-force microscopy (AFM) and surface-pressure datasets of alpha-synuclein interacting with 1,2-Dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) monolayers, at various alpha-synuclein concentrations.

opencc-zeroMay 2023View details →

Data for: Relatively large wings facilitate life at higher elevations in Nearctic dragonflies

<ol> <li>Determining which traits allow species to live at higher elevations is essential to understanding the forces shaping montane biodiversity.</li> <li>For the many animals that rely on flight for locomotion, a long-standing hypothesis is that species with relatively large wings should better persist in high-elevation environments because wings that are large relative to the body generate more lift and decrease the aerobic costs of remaining aloft. Although these biomechanical and physiological predictions have received some support in birds, other flying taxa often possess smaller wings at high elevations or no wings at all.</li> <li>To test if predictions about the requirements for relative wing size at high elevations are generalizable beyond birds, we conducted macroecological analyses on the altitudinal characteristics of 302 Nearctic dragonfly species.</li> <li>Consistent with the biomechanical and aerobic hypotheses, species with relatively larger wings live at higher elevations and have wider elevation breadths—even after controlling for a species' body size, mean thermal conditions, and range size. Moreover, a species' relative wing size had nearly as large of an impact on its maximum elevation as being adapted to the cold. </li> <li>Relatively large wings may be essential to high-elevation life in species that completely depend on flight for locomotion, like dragonflies or birds. With climate change forcing taxa to disperse upslope, our findings further suggest that relatively large wings may be a requirement for completely volant taxa to persist in montane habitats. </li> </ol>

opencc-zeroMay 2023View details →

Ultraconserved elements support the elevation of a new avian family, Eurocephalidae, the white-crowned shrikes

In this study, we infer genus-level relationships within shrikes (Laniidae), crows (Corvidae), and their allies using ultraconserved elements (UCEs). We confirm previous results of the Crested Shrikejay (Platylophus galericulatus) as comprising its own taxonomic family and find strong support for its sister relationship to laniid shrikes. We also find strong support that the African-endemic genus Eurocephalus, which comprises two allopatric species (E. ruppelli and E. anguitimens), are not shrikes. We propose elevating the white-crowned shrikes to their own family, Eurocephalidae.

opencc-zeroMay 2023View details →

Data for: Coupled anaerobic methane oxidation and metal reduction in soil under elevated CO2

Continued current emissions of carbon dioxide (CO2) and methane (CH4) by human activities will increase global atmospheric CO2 and CH4 concentrations and surface temperature significantly. Fields of paddy rice, the most important form of anthropogenic wetlands, account for about 9% of anthropogenic sources of CH4. Elevated atmospheric CO2 may enhance CH4 production in rice paddies, potentially reinforcing the increase in atmospheric CH4. However, what is not known is whether and how elevated CO2 influences CH4 consumption under anoxic soil conditions in rice paddies, as the net emission of CH4 is a balance of methanogenesis and methanotrophy. In this study, we used a long-term free-air CO2 enrichment experiment to examine the impact of elevated CO2 on the transformation of CH4 in a paddy rice agroecosystem. We demonstrate that elevated CO2 substantially increased anaerobic oxidation of methane (AOM) coupled to manganese and/or iron oxides reduction in the calcareous paddy soil. We further show that elevated CO2 may stimulate the growth and metabolism of Candidatus Methanoperedens nitroreducens, which is actively involved in catalyzing AOM when coupled to metal reduction, mainly through enhancing the availability of soil CH4. These findings suggest that a thorough evaluation of climate-carbon cycle feedbacks may need to consider the coupling of methane and metal cycles in natural and agricultural wetlands under future climate change scenarios.