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opencc-by-4.0Feb 2022View details →

Complementary observations aid identification of the mountain rain-snow transition elevation

If data have a time stamp, all data are in UTC Includes: <ul> <li>precipitation gauge [meters] data from California Data Exchange (CDEC)</li> <li>SNOTEL data (soil moisture [%], snow water equivalent [meters])</li> <li>snow depth [meters] data from snow pillow sites from CDEC</li> <li>snow water equivalent [meters] from snow pillow sites from CDEC</li> <li>temperature [degrees C] data from snow pillow sites from CDEC</li> <li>FMCW radar freezing level [km above the surface] data from NOAA</li> <li>MODSCAG remote sensing data [rgb, grain size, snow covered area, zenith angle] from JPL</li> </ul>

opencc-zeroFeb 2022View details →

Exotic herbivores dominate Australian high‐elevation grasslands

Invasive species are major drivers of ecosystem degradation globally. How invasive herbivore impacts differ from native herbivore impacts remains understudied. We examined the relationships between herbivore sign and vegetation height, foliage density, cover of forbs, weeds, bare ground, and soil compaction across environmental and herbivore activity gradients in the mainland Australian Alps. We detected native and exotic herbivore sign at 32.8% and 94.0% of sites, respectively. Total herbivore activity was primarily attributed to exotic herbivores and was associated with elevation and grassland type. Greater horse (exotic) activity was associated with lower vegetation height, lower foliage density, higher forb cover, and higher soil compaction. Greater rabbit and hare (exotic) activity was associated with lower vegetation height, lower foliage density, and a higher cover of bare ground. Greater total herbivore activity was associated with greater weed cover. Neither deer (exotic) nor kangaroo and wallaby (native) activity was related to response variables. We demonstrate that exotic herbivores dominate mammalian herbivory in these grasslands, which evolved without analogous hooved species. Given the restricted distribution and high endemism of these ecosystems, and associations between exotic herbivores and characteristics of degraded grasslands, we recommend landscape-scale exotic herbivore management, focusing on maintaining ground cover and vegetation structure.

opencc-zeroMar 2022View details →

Predicted alteration of vertebrate communities in response to climate-induced elevational shifts

Aim Climate change is driving species to migrate to novel areas as current environments become unsuitable. As a result, species distributions have shifted uphill in montane ecosystems globally, leading to projections of severe impacts on upland specialist species. Heterogenous dispersal rate among shifting species could result in complex changes to community assemblages. For example, interspecific differences in dispersal ability could lead to the disruption, or creation, of species interactions and processes within communities, likely amplifying the impact of climate change on ecosystems. Here, we provide a comprehensive assessment of the impacts of climate change on communities and ecosystems by developing a novel spatially explicit approach focussing on changes in local populations. Location The Australian Wet Tropics. Method We used a spatially explicit approach to simulate the elevational shift of 7,613 community assemblages (defined at the patch level) along the elevational gradient, using empirical information about the distribution of 202 vertebrate species. We analysed changes in community structures and species co-occurrence derived from the elevational shift as a proxy for potential changes in species interactions. Results Our results showed a consistent pattern of increasing temporal β-dissimilarity between community assemblages along the elevational gradient resulting from local species extinctions. The local extinction rate was especially remarkable at high elevations, suggesting potential mass local extinctions of upland species unable to shift to the isolated mountaintops. Furthermore, the increasing local extinction rate with elevation resulted in a marked decline in species co-occurrence towards mountaintops. Main conclusions Our study highlights the escalating impact of climate change on community assemblages in response to climate-induced elevational shifts in species' ranges, providing a classic example of the "escalator to extinction". Future predictions of the impacts of climate change on ecosystems will benefit from improvements in understanding species interactions and species potential to adapt to a changing environment.

opencc-zeroMar 2022View details →

Elevational and local climate variability predicts thermal breadth of mountain tropical tadpoles

The climate variability hypothesis posits that increased environmental thermal variation should promote species with broader thermal tolerance breadths, while stable environments should promote thermal specialists. This hypothesis has been tested on large spatial scales, such as latitude and elevation, but less so on smaller scales which reflect the experienced microclimate. Here, we estimated thermal tolerance limits of 75 species of amphibian tadpoles from an aseasonal tropical mountain range of the Ecuadorian Andes, distributed along a 3500 m elevational range, to test the climatic variability hypothesis at a large (elevation) and a small (microhabitat) scales. We show how species from less variable thermal habitats, such as lowlands and those restricted to streams, exhibit narrower thermal tolerance breadths than highland and pond-dwelling species respectively. Interestingly, while broader thermal tolerance breadths at large scales are driven by higher cold tolerance variation (heat-invariant hypothesis), at local scales they are driven by higher heat tolerance variation. This contrasting pattern may result from divergent selection on both thermal limits to face environmental thermal extremes at different scales. Specifically, within the same elevational window, exposure to extreme maximum temperatures could be avoided through habitat shifts from temporary ponds to permanent ponds or streams, while minimum peak temperatures remained invariable between habitats but steadily decreased with elevation. Therefore addressing the effects of habitat conversion is crucial for future research on resilience to climate change.

opencc-by-4.0Mar 2022View details →

Elevated temperature and carbon dioxide levels alter growth rates and shell composition in the fluted giant clam, Tridacna squamosa

We investigated the effects of 60-d exposure to end-of-the-century projections for seawater temperature (+3 °C) and pCO2 (+500 µatm) on growth, mineralogy, and organic content of shells and scutes in juvenile Tridacna squamosa clams. The provided excel file contains tables supplying the following raw datasets: (1) Concentrations of trace minerals (Data_Minerals) in shells and scutes <blockquote> IndividualID - unique ID for each juvenile Tridacna squamosa clam Type - type of skeletal material sampled (New: newly-formed, Old: older-growth, Shell: shell, Scute: scute). Exposure - experimental treatments (Ambient: ambient seawater conditions, High Temp: elevated temperature alone, High pCO2: elevated pCO2 alone, Multistressor: elevated temperature and pCO2 in combination). SampleMass_mg - mass (in mg) of powdered skeletal material analyzed. X_ppb - concentration (in parts per billion) of element X (Mg: Magnesium,  Si: Silica, P: Phosphorus, K: Potassium, Mn: Manganese, As: Arsenic, Sr: Strontium, Ba: Barium, Ca: Calcium) in the sample. X_mmol_kg-1 - concentration (in mmol kg-1) of element X in the sample. XCaRatio_mmol_mol-1 - ratio of the concentrations of element X (in mmol) and calcium (in mol). BaCaRatio_µmol_mol-1 - ratio of the concentrations of barium (in µmol) and calcium (in mol). </blockquote> (2) Morphometric characteristics (Data_Morphometry) of shells/scutes <blockquote> IndividualID - unique ID for each juvenile Tridacna squamosa clam Exposure - experimental treatments (Ambient: ambient seawater conditions, High Temp: elevated temperature alone, High pCO2: elevated pCO2 alone, Multistressor: elevated temperature and pCO2 in combination). X_pre_mm - measurement value (in millimeters) prior to exposure to experimental treatments (APM: anterior-posterior margin or shell length, DVM: dorsal-ventral margin or shell height, OrnamentationMaxWidth: maximum width of the shell across the scutes, Width: shell width). X_pre_g - measurement value (in grams) prior to exposure to experimental treatments (WetMass: whole animal wet mass). X_post_mm - measurement value (in millimeters) after 60-d exposure to experimental treatments. X_post_g - measurement value (in grams) after 60-d  exposure to experimental treatments. X_gain_mm - change in measurment value (in millimeters) over the course of the 60-d experiment. X_gain_%change - change in measurment value over the course of the 60-d experiment as a percentage of the initial, pre-exposure value (i.e., % change). </blockquote> (3) Organic content (Data_Organics) of shells <blockquote> IndividualID - unique ID for each juvenile Tridacna squamosa clam Exposure - experimental treatments (Ambient: ambient seawater conditions, High Temp: elevated temperature alone, High pCO2: elevated pCO2 alone, Multistressor: elevated temperature and pCO2 in combination). X-newgrowth_weight% - concentration of element X (Nitrogen, Carbon, or Hydrogen) as a percentage of the weight of sample analyzed in newly-formed shell. X-oldgrowth_weight% - concentration of element X as a percentage of the weight of sample analyzed in older-growth shell. </blockquote>

opencc-zeroApr 2022View details →

Lepidagathis mahakassapae sp. nov. (Acanthaceae: Barlerieae) from the high elevated Lateritic Plateau of Northern Western Ghats of Maharashtra, India

Lepidagathis mahakassapae. sp. nov., monocarpic and endemic species is described from Western Maharashtra, India. The new species is allied to L. sabui from Konkan, Maharashtra. Stems of L. mahakassapae grows up to 250 cm in length which is remarkably long while few prostrate species attains this much length. Illustration and colour photographs are provided for ease of identification

opencc-zeroApr 2022View details →

Root traits along a subarctic tundra elevational gradient

While root trait research has received increasing attention over the past two decades, the relationship between root traits and environmental factors remains elusive. At the same time, knowledge about these relationships is necessary if we are to understand plant community responses to environmental change. Here, we assessed the relationships between elevation (i.e., temperature) and fine root traits of plant species and communities. We focused on the sub-arctic tundra where plant communities are expected to experience extreme environmental change by the end of the century.

Dataset for: Aboveground carbon stocks, woody and litter productivity along an elevational gradient in the Rwenzori Mountains, Uganda

Montane forests are characterized by high biodiversity, endemism and strong elevational environmental gradients. The latter attribute makes them also suitable as a 'natural laboratory' for studying the effects of environmental parameters on ecosystem functions. To provide better insight into the carbon cycle of Afromontane ecosystems, we used an elevational gradient approach to quantify carbon stocks, woody and litter productivity, and their constraining factors. Twenty plots were established, covering five elevations from Kibale Forest at 1250 m to 3000 m in the Rwenzori Mountains. Results revealed aboveground carbon stocks of between 185.4 ± 48.9 Mg C ha-1 and 70.8 ±18.6 Mg C ha-1 at 1250-1300 m and 2700-3000 m respectively. Aboveground carbon tended to decrease with elevation, but this trend was not significant. This was due to similarities in stem diameter combined with different effects of tree height and stem density. Similarly, woody productivity did not change with elevation, ranging from 8.3 ± 4.1 Mg C ha-1 year-1 to 3.4 ± 1.5 Mg C ha-1 year-1 at 2500-2600 m and 2700-3000 m respectively. However, litter productivity decreased linearly by 0.14 ± 0.04 Mg C ha-1 year-1 per 100 m of elevation increase, ranging from 4.0 ± 0.7 Mg C ha-1 year-1 at 1750-1850 m to 1.2 Mg C ha-1 year-1 at 2700-3000 m. Topsoil physicochemical properties varied with elevation, but showed no significant relationship with carbon stocks and woody productivity. However, litter productivity increased with mean soil temperature, whereas it decreased with soil total nitrogen.

Anna's hummingbird (Calypte anna) physiological response to novel thermal and hypoxic conditions at high elevations

Many species have not tracked their thermal niches upslope as predicted by climate change, potentially because higher elevations are associated with abiotic challenges beyond temperature. To better predict if organisms can continue to move upslope with rising temperatures, we need to understand their physiological performance when subjected to novel high elevation conditions. Here, we captured Anna's hummingbirds – a species expanding their elevational distribution in concordance with rising temperatures – from across their current elevational distribution and tested their physiological response to novel abiotic conditions. First, at a central aviary within their current elevational range, we measured hovering metabolic rate to assess their response to oxygen conditions and torpor use to assess their response to thermal conditions. Second, we transported the hummingbirds to a location 1200 meters above their current elevational range limit to test an acute response to novel oxygen and thermal conditions. Hummingbirds exhibited lower hovering metabolic rates above their current elevational range limit, suggesting lower oxygen availability may reduce performance after an acute exposure. Alternatively, hummingbirds showed a facultative response to thermal conditions by using torpor more frequently and longer. Finally, post-experimental dissection found that hummingbirds originating from higher elevations within their range had larger hearts, a potential plastic response to hypoxic environments. Overall, our results suggest lower oxygen availability and low air pressure may be difficult challenges to overcome for hummingbirds shifting upslope due to rising temperatures, especially if there is little to no long-term acclimatization. Future studies should investigate how chronic exposure and acclimatization to novel conditions, as opposed to acute experiments, may result in alternative outcomes that help organisms better respond to abiotic challenges associated climate-induced range shifts.

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

Accurate biodiversity and population monitoring is a requirement for effective conservation decision-making. Survey method bias is therefore a concern, particularly when research programs face logistical and cost limitations. We employed point counts (PCs) and autonomous recording units (ARUs) to survey avian biodiversity within comparable, high elevation, temperate mountain habitats at opposite ends of the Americas: 9 mountains in British Columbia (BC), Canada and 10 in southern Chile. We compared detected species richness against multi-year species inventories and examined method-specific detection probability by family. By incorporating time costs, we assessed the performance and efficiency of single vs. combined methods. Species accumulation curves indicate ARUs can capture ~93% of species present in BC but only ~58% in Chile, despite Chilean mountain communities being less diverse. The avian community, rather than landscape composition, appears to drive this dramatic difference. Chilean communities contain less-vocal species, which ARUs missed. Further, 6/13 families in BC were better detected by ARUs while 11/11 families in Chile were better detected by PCs. Where survey conditions differentially impacted method performance, PCs mostly varied over the morning and with canopy cover in BC, while ARUs mostly varied seasonally in Chile. Within a single year of monitoring, neither method alone was predicted to capture the full avian community, with the exception of ARUs in the alpine and subalpine of BC. PCs contributed little to detected diversity in BC, but including this method resulted in negligible increases in total time costs. Combining PCs with ARUs in Chile significantly increased species detections, again, for little cost. Combined methods were among the most efficient and accurate approaches to capturing diversity. We recommend conducting point counts while ARUs are being deployed and retrieved in order to capture additional diversity with minimal additional effort and to flag methodological biases using a comparative framework.

opencc-zeroAug 2022View details →

Data from: Metabolic changes associated with two endocrine abnormalities in dogs: elevated fructosamine and low thyroxine

Metabolomics studies in canine endocrine abnormalities are sparse and basic information on these abnormalities must be generated. This dataset includes the 1H NMR metabolic profiling results of 151 dog serum samples. The samples have been collected in an ethical way, being leftovers of clinical diagnostic samples. The sample set includes 25 control samples based on unremarkable routine clinical chemistry and hematology, 79 samples exhibiting high fructosamine which reflects poor glycemic control, and 47 samples with low thyroxine, a metabolically important thyroid hormone. The metabolite data and metadata were utilized in the study: Ottka et al. Metabolic changes associated with two endocrine abnormalities in dogs: elevated fructosamine and low thyroxine. The control group results were utilized also in: Ottka et al. Serum NMR metabolomics uncovers multiple metabolic changes in phenobarbital-treated dogs.

Genomic and phenotypic divergence‐with‐gene‐flow across an ecological and elevational gradient in a neotropical bird

Aim: Along with environmental gradients, some species show significant differences in morphological, ecological-related traits. Those differences are commonly related to past events of allopatry but, alternatively, could be caused by natural selection in the presence of gene flow. We aimed to explore the prevalence of the divergence-with-gene-flow model across the Chaco-Andes dry forest belt, testing competing models of evolution in a Neotropical bird. Location: Central Andes Mountain range and Chaco region of Argentina and Bolivia. Taxon: Phytotoma rutila (Aves, Cotingidae). Methods: We studied ddRADseq loci (4,893 SNPs) of 21 tissue samples and body size variation of 146 specimens. We evaluated population genetic structure and tested the effects of altitude and distance on genomic divergence. To evaluate allopatry and divergence-with-gene-flow, we compared the divergence on phenotypic traits (bill, tarsus, and wing measurements) versus neutral genomic variation, conducted coalescent analyses to estimate gene flow and divergence time among populations, and calculated relative (FST) versus absolute (DXY) genomic divergence. Results: a) there is a genomic and phenotypic differentiation in P. rutila matched the highland-lowland axis, where the altitude variation explains genomic variation; b) A larger phenotypic than neutral genomic variation was found. c) there is an asymmetric gene flow between populations; d) a pattern of relative and absolute genomic differentiation compatible with divergence-with-gene-flow. Main conclusions: The mechanism behind the morphological and genomic diversification along the Chaco-Andes dry forest belt in P. rutila is divergence‐with‐gene‐flow. Far more complex than we traditionally thought, diversification in South America implicates gene flow between populations and also natural selection along with the environmental gradients, as well as vicariance, contrasting with the idea of tropical speciation primarily based on allopatric models.

opencc-by-4.0May 2022View details →

Elevational patterns in tropical bryophyte diversity differ among substrates: a case study on Baru volcano, Panama

Questions. Bryophytes attain their highest diversity in tropical mountain forests. Although distribution patterns have been described, little emphasis has been placed on comparing patterns among substrates (e.g., terrestrial, epiphytic). Understanding these patterns is important, because they determine not only the pool of genetic resources, but also the functioning of these forest ecosystems. Therefore, we studied how bryophyte species diversity changes with elevation, how elevational patterns differ between substrate types, and how elevational trends relate to environmental drivers. Location. Baru Volcano, Panama. Methods. At each of eight elevations, between 1900 and 3300 m, bryophytes were collected in 600-cm2 plots from six substrate types with four replicates. Species cover was registered as a measure of relative abundance. Species richness and community structure were determined and related to elevation, substrate types, and environmental drivers at three scales (plots, sets of four replicate plots per substrate per elevation, and all plots at each elevation). Results. Bryophyte species richness decreased towards higher elevations, at all three scales and on all substrates except bryophytes on soil, for which, at the plot scale, richness peaked at higher elevations than on the other substrates. Relative humidity explained richness slightly better than elevation. Communities at the lowest elevations had the most uneven compositions, due to the presence of many small species with low abundance. Conclusions. In studies on the spatial distribution of bryophyte diversity, it is essential to consider different substrates and spatial scales separately. If substrates differ in their elevational species-richness patterns, climate and land-use change may affect bryophyte diversity patterns not only directly, but also indirectly via changes in substrate availability. Therefore, a better understanding of the spatial variation in bryophyte diversity in mountains is essential to elucidate the effects of environmental change on this important group of plants and their implications for ecosystem functioning. FILE: Main data base_JVC.xlsx Sheet=TaxonomicInformation Our database contains taxonomic information on bryophyte species collected along an elevation gradient on the Baru volcano, Panama. Sheet=data The relative abundance of each species or morpho-species is included per 600-cm2 plot in each of the six considered substrates (soil = terricolous, rock = saxicolous, decomposing downed log (i.e. lying on the ground) = lignicolous, tree base = epiphytic on tree base, tree trunk = epiphytic on tree trunk, and understorey branch = epiphytic on branch). Sheet: climatic info In addition, we present the information on the climate recorded between April and December 2017. Acronyms: elev: elevation, tempmean: mean temperature over the measurement period (°C), tempmin: minimum temperature over the measurement period (°C), tempmax: maximum temperature over the measurement period (°C), rhmean: mean relative humidity over the measurement period (%), rhmin: minimum relative humidity over the measurement period (%), rhmax: maximum relative humidity over the measurement period (%), cancov: canopy-cover (%), heican: height of the canopy ( m).

Elevated O3 inhibited isoprene emission of a diploid and a triploid genotype of Populus tomentosa by different mechanisms

Ozone (O3) pollution affects plant growth and isoprene (ISO) emission. However, the response mechanism of isoprene emission rate (ISOrate) to elevated O3 (EO3) remains poorly understood. ISOrate was investigated in two genotypes (diploid and triploid) of Chinese white poplar (Populus tomentosa Carr.) exposed to EO3 in an open top chamber (OTC) system. The triploid genotype had higher photosynthesis rate (A) and stomatal conductance (gs) than the diploid one. EO3 significantly decreased A, gs, and ISOrate of middle and lower leaf positions in both genotypes. In the diploid genotype, the reduction of ISOrate was caused by a systematic decrease related to ISO synthesis capacity, as indicated by decreased contents of isoprene precursor dimethylallyl diphosphate (DMADP) and isoprene synthase (ISPS) protein and activity of ISPS. On the other hand, the negative effect of O3 on ISOrate of the triploid genotype did not result from inhibited ISO synthesis capacity, but from increased ISO oxidative loss within the leaf. Our findings will be useful for breeding poplar genotypes with high-yield and lower ISOrate, depending on local atmospheric VOC/NOx ratio, to cope with both the rising O3 concentrations and increasing biomass demand. They can also enlighten the incorporation of O3 effects into process-based models of isoprene emission.

WorldClim, elevation and distribution data for all palms from: The ecology of palm genomes: Repeat-associated genome size expansion is constrained by aridity

Genome size varies 2,400-fold across plants, influencing their evolution through changes in cell size and cell division rates which impact plants' environmental stress tolerance. Repetitive element expansion explains much genome size diversity, and the processes structuring repeat 'communities' are analogous to those structuring ecological communities. However, which environmental stressors influence repeat community dynamics has not yet been examined from an ecological perspective. We measured genome size and leveraged climatic data for 91% of genera within the ecologically diverse palm family (Arecaceae). We then generated genomic repeat profiles for 141 palm species, and analysed repeats using phylogenetically-informed linear models to explore relationships between repeat dynamics and environmental factors. We show that palm genome size and repeat 'community' composition are best explained by aridity. Specifically, Ty3-gypsy and TIR elements were more abundant in palm species from wetter environments, which generally had larger genomes, suggesting amplification. In contrast, Ty1-copia and LINE elements were more abundant in drier environments. Our results suggest that water stress inhibits repeat expansion through selection on upper genome size limits. However, elements which may associate with stress-response genes (e.g., Ty1-copia) have amplified in arid-adapted palm species. Overall, we provide novel evidence of climate influencing the assembly of repeat 'communities'.

Data for: Elevated inbreeding in Heliconia tortuosa is determined by tropical forest stand age, isolation, and loss of hummingbird functional diversity

Forest conversion and habitat loss are major threats to biological diversity. Forest regeneration can mitigate the negative effects of old growth forest loss on species diversity, but less is known about the extent to which forest loss reduces genetic diversity in remnant populations and whether secondary forests play a role in the maintenance of genetic diversity. We quantified genetic diversity in a tropical hummingbird-pollinated understory herb, Heliconia tortuosa, across a landscape mosaic of primary and secondary forest regrowth. Using microsatellite genotypes from >850 adult and juvenile plants within 33 forest patches and extensive bird surveys, we examined the effect of contemporary and historical landscape features including forest age (primary vs. secondary forest), stand isolation, and pollinator assemblages on genetic diversity and levels of inbreeding in H. tortuosa. We found that inbreeding was up to 3x higher in secondary forest, and this effect was amplified with reductions in primary forest in the surrounding landscape through reduced observed heterozygosity in isolated fragments. Inbreeding in forest patches was negatively correlated with the local frequency of specialist long-distance foraging traplining hummingbirds. Traplining hummingbirds therefore appear to facilitate mating among unrelated plants - an inference we tested using empirically parameterized simulations. Higher levels of inbreeding in H. tortuosa are therefore associated with reduced functional diversity of hummingbirds in secondary forests and forest patches isolated from primary forests. Our findings suggest a cryptic consequence of primary forest loss and secondary forest regeneration through the disruption of mutualistic interactions resulting in the erosion of genetic diversity in a common understory plant.

Effects of social organisation and elevation on spatial genetic structure in a montane ant

Studying patterns of population structure across the landscape sheds light on dispersal and demographic processes, which helps to inform conservation decisions. Here, we study how social organisation and landscape factors affect spatial patterns of genetic differentiation in an ant species living in mountainous regions. Using genome-wide SNP markers, we assess population structure in the Alpine silver ant, Formica selysi. This species has two social forms controlled by a supergene. The monogyne form has one queen per colony, while the polygyne form has multiple queens per colony. The two social forms co-occur in the same populations. For both social forms, we found a strong pattern of isolation-by-distance across the Alps. Within regions, genetic differentiation between populations was weaker for the monogyne form than for the polygyne form. We suggest that this pattern is due to higher dispersal and effective population sizes in the monogyne form. In addition, we found stronger isolation-by-distance and lower genetic diversity in high elevation populations, compared to lowland populations, suggesting that gene flow between F. selysi populations in the Alps occurs mostly through riparian corridors along lowland valleys. Overall, this survey highlights the need to consider intraspecific polymorphisms when assessing population connectivity and calls for special attention to the conservation of lowland habitats in mountain regions.

Elevational shifts in foliar-soil δ15N in the Hengduan Mountains and different potential mechanisms

The natural abundance of stable nitrogen isotopes (δ15N) provides insights into the N dynamics of terrestrial ecosystems, the determination of which is considered an effective approach for gaining a better understanding ecosystem N cycling. However, there is currently little information available regarding the patterns and mechanisms underlying the variation in foliar-soil δ15N among mountain ecosystems. In this study, we examined the determinants of foliar-soil δ15N in association with N transportation rates along an elevational gradient in the Hengduan Mountains. Despite the relatively high levels of available N produced from high N fixation and mineralization, we detected the lowest levels of foliar δ15N at 3500 m a.s.l., reflecting the stronger vegetation N limitation at medium high elevations. The enhanced vegetation N limitation was driven by the combined effects of higher microbial immobilization and inherent plant dynamic (the shifts of δ15N in vegetation preference, including vegetation community) with changing climate along the elevational gradient. Unexpectedly, we established that soil δ15N was characterized by an undulating rise and uncoupled correlation with foliar δ15N with increasing elevation, thereby indicating that litter input might not be a prominent driver of soil δ15N. Conversely, soil nitrification and denitrification were found to make a more pronounced contribution to the pattern of soil δ15N along the elevational gradient. Collectively, our results serve to highlight the importance of microbial immobilization in soil N dynamics and provide novel insights that will contribute to enhancing our understanding of N cycling as indicated by foliar-soil δ15N along elevational gradients.

opencc-by-4.0Jun 2022View details →

Digital elevation model of differences of two debris flow event in Chutou gully

We release two datasets that reflected the height alteration of channel deposits during the debris flow events, which occurred on 20 August 2019 and 17 August 2020 in Chutou gully, Miansi Town, Wenchuan County, Sichuan Province, Southwestern China. The first dataset indicates the height alteration during the 2019 debris flow, whereas the second indicates the 2020 debris flow. The datasets can be used to analyse the deposit evolution during the debris flow events. The datasets can be viewed or edited through the ArcGIS software

Data from: Trading water for carbon in the future: effects of elevated CO2 and warming on leaf hydraulic traits in a semiarid grassland

<a name="_Hlk96844723"></a>The effects of climate change on plants and ecosystems are mediated by plant hydraulic traits, including interspecific and intraspecific variability of trait phenotypes. Yet, integrative and realistic studies of hydraulic traits and climate change are rare. In a semiarid grassland, we assessed the response of several plant hydraulic traits to elevated CO2 (+200 ppm) and warming (+1.5 to 3℃; day to night). For leaves of five dominant species (three graminoids, two forbs), and in replicated plots exposed to seven years of elevated CO2, warming, or ambient climate, we measured: stomatal density and size, xylem vessel size, turgor loss point, and water potential (pre-dawn). Interspecific differences in hydraulic traits were larger than intraspecific shifts induced by elevated CO2 and/or warming. Effects of elevated CO2 were greater than effects of warming, and interactions between treatments were weak or not detected. The forbs showed little phenotypic plasticity. The graminoids had leaf water potentials and turgor loss points that were 10 to 50% less negative under elevated CO2; thus, climate change might cause these species to adjust their drought resistance strategy away from tolerance and toward avoidance. The C4 grass also reduced allocation of leaf area to stomata under elevated CO2, which helps explain observations of higher soil moisture. The shifts in hydraulic traits under elevated CO2 were not, however, simply due to higher soil moisture. Integration of our results with others' indicates that common species in this grassland are more likely to adjust stomatal aperture in response to near-term climate change, rather than anatomical traits; this contrasts with apparent effects of changing CO2 on plant anatomy over evolutionary time. Future studies should assess how plant responses to drought may be constrained by the apparent shift from tolerance (via low turgor loss point) to avoidance (via stomatal regulation and/or access to deeper soil moisture).