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1,551 results for “Availability”
Cloud-hosted DBMS Performance, Scalability and Availability Evaluation Data
<p>These data sets contain evaluation data for the evaluation objectives performance, scalability and availability of different cloud-hosted, distributed DBMS. </p> <p>The data sets contain the raw performance metrics, monitoring data and evaluation metadata. For the higher-level evaluation objectives scalability and availability, supportive plots are provided.</p> <p><br> The performance and scalability evaluations have been carried out with the <a href="https://dl.acm.org/doi/10.1145/3297663.3310303">Mowgli framework</a> and the availability evaluation have been carried out with the <a href="https://dl.acm.org/doi/abs/10.1145/3341105.3373968">King Louie framework</a>.</p>
Data from: Local soil legacy effects in a multi-species grassland community are underlain by root foraging and soil nutrient availability
<p>1. Plant soil legacies consisting of species-specific microbial communities are hypothesized to play a critical, structuring role in plant species co-existence processes. Plant species are thought to perform worse on soil conditioned by the same species compared to soil of other species, which serves as a self-limitation mechanism and averts mono-dominance of strong competitors. Here we test in a multi-species community setting, whether root colonisation and resource utilisation of soil patches with distinct soil legacies, are consistent with this hypothesis. 2. We grew eight grassland species together in an outdoor mesocosm setup in unconditioned soil and created soil patches in these communities conditioned by one of four plant species, or a soil mixture of all four. During two subsequent growing seasons, we tested the effect of these conditioned soil patches on belowground root colonisation into the patches of each surrounding plant species using a novel sequencing based approach. In addition, we tested the effect of soil conditioning on local root functioning by injecting tracers into the soil patches and measuring the recovery in aboveground biomass. 3. Against expectations, plant species did not place less roots in own soil patches compared to foreign soil patches, nor did species take up less tracer from own compared to foreign soil patches. Using structural equation modelling, we found that tracer uptake of the plant species was to a varying degree explained by root densities in the various soil patches and by differing soil nutrient availability of the soil patches. We conclude that soil legacy effects are inextricably connected to soil nutrient availability, which needs to be taken into account in plant-soil feedback research to understand the processes that shape plant communities. 4. Synthesis. We found that soil legacy effects in complex, multi-species semi-field conditions did not match expectations based on theory and experiments in controlled conditions. Among the many complicating factors that may modify or even overrule soil legacy effects in semi-field settings, we identified soil nutrient availability as a critical force that may, together with soil biota, shape plant species co-existence processes.</p>
Demographic analysis of invasible habitat fraction identifies context-dependent roles of resource availability and biotic resistance in determining invasion success
<p>Theories of plant invasions predict that plant communities should be more easily invaded when resources increase and/or competition decreases. We tested this with an experimentally introduced plant population by manipulating precipitation and resident community biomass. We used a spatially-explicit demographic approach to develop a new population-level metric of invasibility that quantifies the invasible habitat fraction (IHF) across the landscape.</p> <p>The existing community was essentially uninvasible (median IHF ≈ 0%), but experimental manipulations greatly increased the range of outcomes, with maximum observed IHF values over 50%. However, changes in invasibility were often context-dependent, resulting in some outcomes that aligned with existing theory, and others that were not readily predicted. Moreover, variation in invasibility was often driven by specific sets of invader demographic vital rates.</p> <p>Removing competitors revealed the capacity for strong biotic resistance, but this interacted with precipitation such that little biotic resistance was detected under drought conditions. Adding precipitation typically had little positive effect on invasibility, and moderate drought relief led to relatively high invasibility. However, the latter was driven to a large extent by interactions with mammal herbivory that otherwise inhibited invasion in one year.</p> <p><i>Synthesis</i>. Our findings show that interactions between abiotic and biotic factors, as well as legacy effects, can strongly mediate invasibility. This study also highlights the importance of incorporating spatial heterogeneity into population-level assessments of invasion, as initial population declines do not necessarily indicate resistance to invasion.</p>
Data from: Geographic location and food availability offer differing levels of influence on the bacterial communities associated with larval sea urchins
Determining the factors underlying the assembly, structure, and diversity of symbiont communities remains a focal point of animal-microbiome research. Much of these efforts focus on taxonomic variation of microbiota within or between animal populations, but rarely test the proportional impacts of ecological components that may affect animal-associated microbiota. Using larvae from the sea urchin Strongylocentrotus droebachiensis from the Atlantic and Pacific Oceans, we test the hypothesis that, under natural conditions, inter-population differences in the composition of larval-associated bacterial communities are larger than intra-population variation due to a heterogeneous feeding environment. Despite significant differences in bacterial community structure within each S. droebachiensis larval population based on food availability, development, phenotype, and time, variation in OTU membership and community composition correlated more strongly with geographic location. Moreover, 20-30% of OTUs associated with larvae were specific to a single location while less than 10% were shared. Taken together, these results suggest that inter-populational variation in symbiont communities may be more pronounced than intra-populational variation, and that this difference may suggest that broad scale ecological variables (e.g., across ocean basins) may mask smaller scale ecological variables (e.g., food availability).
Status quo in data availability and predictive models of nano-mixture toxicity
<p>Supplementary materials for manuscript: Status quo in data availability and predictive models of nano-mixture toxicity.</p> <p>This table contains the list of 183 curated literature used in this study.</p>
Hornbill abundance and breeding incidence in relation to habitat modification and fig fruit availability
<p>Asian hornbills are known to forage and breed in fragmented rainforests and agroforestry plantations in human‐modified landscapes adjoining contiguous protected forests. However, the factors influencing year‐round hornbill abundance, demography and tracking of key food resources such as wild fig <em>Ficus</em> fruits in modified habitats and protected forests remain poorly understood. We carried out monthly surveys of two species of high conservation concern, the Vulnerable Great Hornbill (GH, <em>Buceros bicornis</em>) and the endemic Malabar Grey Hornbill (MGH, <em>Ocyceros griseus</em>) for 15 months and monitored ripe fig fruit availability for 12 months along 11 line transects (total length 24 km) in shade‐coffee plantations and adjoining continuous rainforests in a protected area (PA) in the Anamalai Hills, Western Ghats, India. Both hornbill species used plantations and the PA year‐round but distance sampling density estimates were higher in the PA in both nesting (GH by 57%; MGH by 50%) and non‐nesting (GH by 53%; MGH by 144%) seasons. Relative to estimates from 2004 to 2005, mean GH density appeared stable or increasing, whereas MGH had declined by 39% in the PA and by 56% in plantations. Monthly encounter rate of both hornbills tended to be higher in the PA and that of MGH was also positively related to the density of fig trees with ripe fruit. Sex ratios of observed adult birds in the non‐nesting season were relatively even (GH) or slightly female‐biased (MGH), but became male‐biased in both species during the nesting season when females were confined in tree‐cavity nests. We used change in the adult sex ratio of observed birds from the non‐nesting to nesting season to estimate an index of the proportion of adult pairs breeding at any point within the season, providing the first such estimates for any hornbill species. The proportion of breeding pairs was higher in the PA (GH – 56%, MGH – 64%) than in the plantations (GH – 33%, MGH – 30%). Although hornbills use shade‐coffee plantations year‐round, partly due to fig fruit availability, differences in hornbill density and breeding incidence, as assessed from the sex ratios of observed adult birds, indicate that plantations are a sub‐optimal habitat for both species.</p>
Changes in arthropod community but not plant quality benefit a specialist herbivore on plants under reduced water availability
<p>Plants growing under reduced water availability can affect insect herbivores differently, in some instances benefitting them. However, the forces mediating these positive impacts remain mostly unclear. To identify how water availability impacts plant quality and multitrophic interactions, we conducted manipulative field studies with two populations of the specialist herbivore <i>Pieris rapae</i>, and its host plant, <i>Rorippa indica</i>. We found that <i>P. rapae </i>larvae experienced higher survival on <i>R. indica</i> growing under low water availability compared with plants grown under high water availability. Higher survival of eggs and larvae was related to the reduced abundance of other herbivores and natural enemies. Water availability had differential impacts on other members of the herbivore community by altering plant quality. Low water availability decreased the quality of <i>R. indica</i> to most herbivores, as indicated by reduced abundance in the field and decreased relative growth rate in laboratory feeding assays. In contrast, <i>P. rapae </i>larval performance was not affected by sympatric <i>R. indica </i>grown under different water availability. These results indicate that local <i>P. rapae</i> populations possess physiological adaptations to overcome fluctuations in host quality. Our findings illustrate that reduced water availability is beneficial to a specialist herbivore but detrimental to most other herbivores. Our work highlights the complex effects of the arthropod communities associated with plants in determining the impacts of water availability on insect herbivores.</p>
Rwenzori colobus core unit SNA data - association scans between units, simple association index per dyad, male dispersal events, rainfall and food availability
<p>1. Multi-level societies are complex, nested social systems where basic social groups (i.e., core units) associate in a hierarchical manner, allowing animals to adjust their group sizes in response to variables such as food availability, predation, or conspecific threat. These pressures fluctuate over time and examining the extent to which this variation affects the clustering of core units into different tiers may be instrumental in understanding the evolution of multi-level societies.</p> <p>2. The goal of our study was to determine the degree of temporal variability in inter-unit associations in a multi-level society of Rwenzori Angolan colobus monkey (<i>Colobus angolensis ruwenzorii</i>), and to determine the social and ecological factors that underlie association patterns. The <i>C. a. ruwenzorii</i> multi-level society consists of at least three tiers, with core units clustering into clans that share a home range in a band tier.</p> <p>3. We performed social network analyses on 21 months of association data from 13 core units (totaling 139 identifiable individuals) at Lake Nabugabo, Uganda. We described the patterns of variation in core-unit associations over time and investigated how changes in rainfall, food availability, and inter-unit dispersals were correlated with these associations over the short-term (month to month) and long-term (year to year).</p> <p>4. Although clans were relatively stable, larger-scale changes in association patterns included the formation of an all-male unit and the transfer of one core unit between clans (within the band tier). Seasonally, core units associated significantly more when fruit, their preferred food source, was abundant (i.e., social networks were denser and more clustered) and there was no direct effect of rainfall seasonality or young leaf availability. Male dispersals also occurred more during periods of high fruit availability, suggesting that greater band cohesion allowed males to prospect and transfer between core units. Once males transferred, their previous and new units associated significantly more with one another than with other core units for 1-2 months post-dispersal. The dispersal of five males from one core unit to another in a different clan co-occurred with this core unit switching its clan affiliation.</p> <p>5. By examining temporal shifts in social network structure among core units, this study shows the inter-connected roles that food availability and dispersal have in shaping the <i>C. a. ruwenzorii</i> multi-level social system. Our findings highlight how ecological conditions can drive association patterns, impact interunit relationships, and influence social organization.</p>
Overyielding in young tree communities does not support the stress-gradient hypothesis and is favoured by functional diversity and higher water availability
<p class="CxSpFirst"><strong>Summary:</strong></p> <ol> <li class="CxSpMiddle">Biodiversity effects on productivity and other ecosystem functions are strongly dependent on climate and resource availability. Based on the stress-gradient hypothesis, under conditions of greater abiotic stress, diversity effects on plant performance are intensified due to the increased relative importance of positive plant interactions. However, whether this hypothesis is consistently applicable in forest systems remains unclear. A field trial was established to test the stress-gradient hypothesis and examine diversity effects on aboveground biomass production of young trees in mixtures exposed to different water availability.</li> <li class="CxSpMiddle">Six native tree species of northern temperate forests (<i>Acer saccharum</i>,<i> Betula papyrifera</i>,<i> Larix laricina</i>,<i> Picea glauca, Pinus strobus</i>,<i> and Quercus rubra</i>) were planted as monocultures and as mixtures of two, four, and six species. For five growing seasons, four replicates of each community were exposed to conditions of either low- or high-water availability created by rainfall exclusion and weekly irrigation, respectively. Growth-years 4 and 5 were significantly different when the climatic water balance of the growing seasons were compared. We tested the effects of functional diversity on: (1) total growth of mixtures under low- and high-water availability, and (2) annual growth in years 4 (higher water availability, 2017) and 5 (lower water availability, 2018).</li> <li class="CxSpMiddle">Annual growth of most species in both years was greater under high- vs. low-water availability. Functional diversity had a significant positive effect on total biomass production and annual growth, and this effect was more strongly expressed under high-water availability. Functional diversity effects on annual growth did not differ between years 4 and 5 regardless of their climatic water balance. Functional and species identity were key to understanding productivity responses to mixture and treatment effects.</li> <li class="CxSpMiddle"> <i>Synthesis</i>: Contrary to the stress-gradient hypothesis, the positive effects of functional diversity on productivity were enhanced by high-water availability and were independent of seasonal water balance.</li> </ol>
Code and Data Availability of the manuscript: Mapping tree diversity in the tropical forest region of Chocó-Colombia
<p><strong>Code and Data Availability of the manuscript: Mapping tree diversity in the tropical forest region of Chocó-Colombia</strong></p> <p>In revision at Environmental Research letters.</p> <p> </p> <p>J. Camilo Fagua<sup>1</sup>*, Patrick Jantz<sup>1</sup>, Patrick Burns<sup>1</sup>, Richard Massey<sup>1</sup><sub>,</sub> Jeiner Y. Buitrago<sup>2</sup>, Sassan Saatchi<sup>3</sup></p> <p>and Scott J. Goetz<sup>1 </sup></p> <p> </p> <p><sup>1</sup><em> Global Earth Observation & Dynamics of Ecosystems Lab (GEODE), School of Informatics, Computing, and Cyber Systems (SICCS), Northern Arizona University, Flagstaff, Arizona, US<em>.</em></em></p> <p> </p> <p><em><sup>2</sup></em><em> Department of Agronomy, Faculty of Agricultural Sciences, Universidad Nacional de Colombia. Bogota (Colombia).</em></p> <p> </p> <p><em><sup>3</sup></em><em> Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA</em></p> <p> </p> <p>*Corresponding author: J. Camilo Fagua, School of Informatics, Computing, and Cyber Systems (Building #90) 1295 S. Knoles Dr. Flagstaff, AZ 86011. Email: <a href="mailto:Camilo.Fagua@nau.edu">Camilo.Fagua@nau.edu</a></p> <p> </p> <p><strong>1) The files “0_Forest_Structure_maps_in_tif” and “1_Forest_Structure_maps_in_tif” contain seven maps of forest structural metrics for the Chocó region of Colombia in the raster format .tif</strong></p> <p>(a) Canopy height (CH) map: CHOCO_MAP_CH</p> <p>(b) 50th percentile of heights (z_50) map: CHOCO_MAP_z_50</p> <p>(c) Vertical Canopy Heterogeneity (VCH) map: CHOCO_MAP_VCH</p> <p>(d) Standard deviation of normalized heights (z_SD) map: CHOCO_MAP_z_SD</p> <p>(e) Horizontal standard deviation of canopy height (CH_ SD): CHOCO_MAP_CH_SD</p> <p>(f) Horizontal heterogeneity of canopy height (CH_H): CHOCO_MAP_CH_H</p> <p>(g) Rumple Index of canopy height (R_INDEX): CHOCO_MAP_R_INDEX</p> <p> </p> <p><strong>2) The file “2_Diversity_maps_in_tif” contains five maps of forest structural metrics for the Chocó region of Colombia in the raster format .tif</strong></p> <p>(a) Species richness (Richness): MAPS_MEAN_Richness</p> <p>(b) Shannon’s entropy index (ENS-Shannon): MAPS_MEAN_ENS_shannon</p> <p>(c) Simpson’s concentration index (ENS-Simpson): MAPS_MEAN_ENS_Simpson</p> <p>(d) Shannon diversity index (H): MAPS_MEAN_Shannon</p> <p>(e) Simpson diversity index (D): MAPS_MEAN_Simpson</p> <p> </p> <p><strong>3) The file “3_LiDAR_processing” contents data and R codes to estimate forest structural metrics from ALS-LiDAR data (.las) in an Amazon moist forest.</strong></p>
Data from: Forest fragmentation and loss reduce richness, availability, and specialization in tropical hummingbird communities
Hummingbirds are important pollinators of many native Neotropical plants but their abundance and diversity in landscapes dominated by intensive human uses such as agriculture have rarely been examined, despite such land-uses prevailing in the tropics. We examined how tropical deforestation affects hummingbird community structure in premontane forest patches embedded in a tropical countryside of Coto Brus Canton, Costa Rica. We captured hummingbirds in fourteen landscapes representing a gradient in patch size and forest amount, and tested for the effects of these variables on (1) hummingbird captures at flowers (pollinator availability); (2) species richness; and (3) filtering of functional traits. After accounting for sampling effects, both hummingbird availability and species richness declined by 40% and 50%, respectively, across the gradient in deforestation that we observed (9–66% forest within 1000 m). Focal patch size was the strongest predictor, even after statistically accounting for the amount of forest and matrix composition of landscapes. These reductions in availability and richness were well predicted by functional traits; morphologically specialized species with the capacity to transport long-distance outcrossed pollen and low functional redundancy within the pollinator network showed the greatest sensitivity to landscape change. We hypothesize that declines in hummingbird availability, diversity, and functional traits are important mechanisms driving the observed pollen limitation of ornithophilous flowers in fragmented tropical landscapes. Efforts to conserve large forest patches and enhance matrix permeability are critical for maintaining forest hummingbird communities and pollination services under current and predicted deforestation regimes.
Data from: Tooth fracture frequency in gray wolves reflects prey availability
Exceptionally high rates of tooth fracture in large Pleistocene carnivorans imply intensified interspecific competition, given that tooth fracture rises with increased bone consumption, a behavior that likely occurs when prey are difficult to acquire. To assess the link between prey availability and dental attrition, we documented dental fracture rates over decades among three well-studied populations of extant gray wolves that differed in prey:predator ratio and levels of carcass utilization. When prey:predator ratios declined, kills were more fully consumed, and rates of tooth fracture more than doubled. This supports tooth fracture frequency as a relative measure of the difficulty of acquiring prey, and reveals a rapid response to diminished food levels in large carnivores despite risks of infection and reduced fitness due to dental injuries. More broadly, large carnivore tooth fracture frequency likely reflects energetic stress, an aspect of predator success that is challenging to quantify in wild populations.
Data from: Mate availability determines use of alternative reproductive phenotypes in hermaphrodites
<p>In many species individuals can employ alternative reproductive phenotypes, with profound consequences for individual fitness and population dynamics. This is particularly relevant for self-compatible hermaphrodites, which have exceptionally many reproductive options. Here we investigated the occurrence of reproductive phenotypes in the simultaneously hermaphroditic freshwater snail <i>Radix balthica</i> under experimentally simulated conditions of low vs. moderate population density. We captured all mating behavior on camera and measured individual female lifetime reproductive success. We found every possible reproductive phenotype: (1) both male and female (i.e. truly hermaphroditic) reproduction, (2) purely female and (3) purely male reproduction, (4) male reproduction combined with self-fertilization and (5) female mating activity, (6) pure self‑fertilization without mating and (7-8) two types of reproductive failure. Variation in alternative reproductive phenotypes was explained by mate availability (10.8%) and individual condition, approximated by a snail's mean daily growth rate (17.5%). Increased mate availability resulted in a lower diversity of reproductive phenotypes, in particular increasing the frequency of true hermaphrodites. However, it lowered phenotype-specific fecundities and hence reduced the population growth rate. Snails in better condition were more likely to reproduce as true hermaphrodites or pure females, while low-condition snails tended to suffer reproductive failure. Overall, we show substantial variation in alternative reproductive phenotypes in a hermaphrodite, which is possibly in part maintained by fluctuations in population density and thus mate availability, and by variation in individual condition. We also provide evidence of an almost two-fold increase in clutch size that can be ascribed specifically to mating as a female.</p>
Data from: Feeding strategies of brown howler monkeys in response to variations in food availability
Primates display varying degrees of behavioral flexibility that allow them to adjust their diet to temporal changes in food availability. This trait might be critical for the survival of folivorous-frugivorous species inhabiting small forest fragments, where the availability of food resources tends to be lower than in large fragments and continuous forests. However, the scarcity of studies addressing this issue hampers our understanding of the adaptive behaviors that favor the survival of these primates in low-quality habitats. We conducted a 36-mo study testing the hypothesis that brown howler monkeys (Alouatta guariba clamitans) are able to adjust their diet in response to local and seasonal changes in resource availability. We compared the diet of six free-ranging groups inhabiting three small (<10 ha) and three large (>90 ha) Atlantic forest fragments in southern Brazil and estimated the temporal availability of their top food species (i.e., those species that together contribute ≥80% of total feeding records). We found that brown howlers exploited similarly rich diets in small (45, 54, and 57 plant species) and large (48, 51, and 56 species) fragments. However, intermonth diet similarity was higher for groups in small fragments, where howlers also fed on plant items from nine alien species. Fruits and leaves were the most consumed plant items in both small (42% and 49% of feeding records, respectively) and large (51% and 41%, respectively) fragments. The consumption of young leaves was higher in small than in large fragments, whereas the consumption of other plant items did not show a pattern related to fragment size. Regarding the contribution of growth forms as food sources, only the exploitation of palms showed a pattern related to fragment size. Palms contributed more to the diet of groups inhabiting large fragments. The availability of seasonal food items–ripe fruits and young leaves–influenced their consumption in both habitat types. Therefore, brown howlers cope with local and seasonal fluctuations in food availability by opportunistically exploiting resources. We believe that this feeding flexibility is a key component of the phenotypic plasticity that enables howlers to thrive in disturbed habitat patches, where periods of scarcity of preferred foods shall be more common.
Data from: Acceleration or deceleration of litter decomposition by herbivory depends on nutrient availability through intraspecific differences in induced plant resistance traits
1. Herbivores often induce changes in plant defensive chemistry or nutrient content that may respectively inhibit or promote microbial decomposition of senesced litter. Often the directional impact of herbivores on decomposition is considered to be a property of a species or ecosystem. While rarely explored, intraspecific plasticity in the induction of defensive strategies across environmental gradients may also result in divergent impacts of herbivores on decomposition (deceleration vs. acceleration). 2. Here, we examined how soil nutrient conditions determine after-life effects of herbivory, using nine goldenrod (Solidago altissima) genotypes grown across four levels of nutrient supply and with or without grasshopper herbivory. In this species, herbivory induces defensive traits in genotypes grown in high soil nutrient conditions but induces tolerance (compensatory growth) in low nutrient conditions. We combined senesced litter from each treatment with a common soil inoculum in experimental microcosms and measured soil respiration and litter mass loss over 100 days as estimates of decomposition. 3. Plant genotype, nutrient environment, and herbivory all had significant effects on decomposition. The legacy effect of herbivory overwhelmed the positive effects of high soil nutrient supply on decomposition. This significant herbivory nutrient environment interaction meant that herbivore-induced plants grown in high nutrient environments produced litter that was more resistant to microbial breakdown than litter from the same genotype not exposed to herbivory. But the opposite occurred at low nutrient levels where litter from herbivore-induced plants was most readily decomposed. Further we mechanistically tie nutrient and herbivory legacy treatments to decomposition rates through predictable changes in leaf trait expression. Lastly, we demonstrate a significant correlation among herbivore growth rates on the living tissue and decomposition efficiencies by the microbial community of the senesced tissue, suggesting that herbivores and microbes perceive the "quality" of the induced substrate similarly. 4. Synthesis: Herbivore-induced changes in leaf palatability and trait expression due to defense induction or compensatory growth can cascade through to either promote or inhibit the decomposability of leaf litter within a single species. These findings offer mechanistic understanding of how spatial heterogeneity in ecosystem process rates can be generated by spatial variation in herbivory and nutrient availability.
Community composition and photosynthetic physiology of phytoplankton in the western subarctic Pacific near the Kuril Islands with special reference to iron availability
<p class="Abstract">The western subarctic Pacific (WSP) is known as one of the most productive regions among the world's oceans in spring. However, its oceanic waters are also known as a High Nutrient, Low Chlorophyll (HNLC) region during summer due to low iron (Fe) availability in seawater. Indeed, recent studies have demonstrated that the distribution of Fe in the WSP is complex and heterogeneous. This study thus investigated the effects of Fe availability on the community composition and photophysiology of surface phytoplankton from coastal to offshore waters in the WSP in the summer of 2014. Although relatively high concentrations (>2 mg m<sup>–3</sup>) of chlorophyll (chl) <i>a</i> were found in the Sea of Okhotsk and some coastal waters, low chl <i>a</i> concentrations (<1 mg m<sup>–3</sup>) were commonly observed. Based on dissolved Fe and macronutrient concentrations, we deduced that low Fe availability limited phytoplankton growth in offshore waters, whereas low silicate and/or nitrate levels limited growth in the shelf areas. Scanning electron microscopy also revealed that the centric diatom <i>Chaetoceros</i> exclusively dominated the diatom assemblages in the shelf<i> </i>and coexisted with pennate diatoms in offshore waters, respectively<i>.</i> Primary productivity in surface waters was negatively correlated with the bottom of the euphotic layer or the light saturation index of the photosynthesis–irradiance curve, which indicates that the phytoplankton assemblages were well acclimated to <i>in situ</i> light conditions regardless of the water masses.</p>
Data from: Selection for seed size: the unexpected effects of water availability and density
1. Seed size is a functional trait with important fitness consequences that potentially extend throughout the life cycle of plants. Dithyrea californica experiences selection for larger seeds in post‐germination stages but it is still uncertain how environmental factors mediate the strength and the direction of natural selection on seed size. 2. D. californica represents a unique opportunity to investigate selection on seed size in natural conditions due to a persistent seed ring that stays attached to the root throughout the plant's life. This makes it possible to unearth plants at any stage and measure the size of the seed from which they originated. 3. We conducted a factorial experiment manipulating water availability and intraspecific competition using plants that naturally germinated in the wild. 4. Selection on seed size via survivorship was nil because all individuals survived to reproduce. The strength and the direction of selection on seed size via fecundity depended on water availability and conspecific density. 5. Contrary to our predictions, increasing conspecific density relaxed directional selection favoring larger seeds, but only in the wettest conditions and an increase in water availability strengthened it, but only at low density. A possible explanation of these counter‐intuitive results relies on the observed absence of survival selection and increased plant growth rates under high water and low density. 6. Larger seeds require more resources to construct and when this cost is taken into account; there is no overall fitness increase with seed size. This nicely follows the life history theory predictions for optimal seed size. At the evolutionary equilibrium, if seeds could be larger, per seed fitness would still increase, which is what we observed. But cost corrected fitness should be flat. Maternal fitness equals per seed fitness times seed number, so any increase to per seed fitness of making a bigger seed is balanced by the resulting cost to seed number. Our results indicate flat cost corrected fitness of seed size as theory predicts.
Data from: Livestock overgrazing disrupts the positive associations between soil biodiversity and nitrogen availability
Livestock overgrazing influences both microbial communities and nutrient cycling in terrestrial ecosystems. However, the role of overgrazing in regulating the relationship between soil biodiversity and nitrogen availability remains largely unexplored. We performed long-term grazing exclusion experiments across eight sites along precipitation gradient covering three major types of grassland in northern China to compare the linkage between soil microbial diversity and N availability in overgrazed versus non-grazed conditions. We found a positive association between fungal diversity and soil available N in non-grazed grasslands. However, the positive association was absent in overgrazed environments. Bacterial diversity is not related to soil available N in either non-grazed or overgrazed grasslands. Moreover, in bacterial community, we found a positive link between the relative abundance of Actinobacteria with soil available N in non-grazed, but not overgrazed, grasslands. Instead we found the links between relative abundance of Bacteroidetes and Acidobacteria with soil available N in overgrazed grasslands, but not non-grazed, grasslands. Our work provides evidence that the relationships between microbial diversity and ecosystem functions are context-dependent, and so microbial community diversity is likely not the major driver of soil N mineralization in overgrazed grasslands. Our study suggests that high intensity anthropogenic activities in grasslands restrains the capacity of diverse soil microbial communities to sustain ecosystem function, and more broadly the capacity of entire ecosystems to maintain important ecosystem processes such as plant production. Our study also indicates that the fundamental microbial communities associated with N availability change with differing land management strategies (e.g. livestock grazing).
Barn Swallow (Hirundo rustica) fledglings use crop habitat more frequently in relation to its availability than pasture and other habitat types
Populations of birds that forage on aerial insects have been declining across North America for several decades, but the main causes of and reasons for geographical variation in these declines remains unclear. We examined the habitat use and survival of post-fledging Barn Swallows (Hirundo rustica), near Vancouver, BC, Canada using VHF radio telemetry. We predicted that fledgling Barn Swallows hatched in higher quality natal habitat (pasture) would fledge at higher quality, stay closest to the nest, disproportionately use higher-quality habitat during the post-fledge stage and have higher survival rates in the region. Contrary to our predictions, we found that natal habitat (crop, pasture or non-agriculture) had no effect on fledgling quality or movement distance. Barn Swallow fledglings used crop habitat more frequently in relation to its availability than other habitat types, including pasture. Barn Swallows had low post-fledging survival rates (0.44; 95% CI: 0.35-0.57), which could negatively influence the population trend of the species in this region. While natal habitat had only minor effects, crop habitat appears to be important for fledgling Barn Swallows and therefore a decline in this habitat type could have further negative implications for an already declining species.
Data from: Contrasting leaf trait responses of conifer and broadleaved seedlings to altered resource availability are linked to resource strategies
<p>(1) Understanding tree seedling responses to water, nutrient and light availability is crucial to precisely predict potential shifts in composition and structure of forest communities under future climatic conditions.</p> <p>(2) We exposed seedlings of widespread central European tree species with contrasting leaf habit, deciduous broadleaves (DB) and evergreen conifers (EC), to factorial combinations of manipulated precipitation (100% and 50% of ambient), shade (40% and 60% of full sunlight) and nutrient availability (low and high NPK), and measured specific leaf area, C/N ratio, soluble sugars, starch and non-structural carbohydrate concentration, and δ<sup>13</sup>C of the leaves.</p> <p>(3) We found contrasting effects of water and nutrient availability on foliar traits of the two species groups: EC exhibited higher tolerance to low resource availability but also less plasticity in foliar traits, which is congruent with a "slow" resource strategy. In contrast, foliage of DB reacted particularly to altered nutrient availability, corresponding to a "fast" resource strategy with high foliar plasticity and rapid adjustments to resource fluctuations, commonly adopted by species with high growth rates.</p> <p>(4) We conclude that DB will respond to environmental change with foliar acclimation, while EC will either tolerate, to some extent, or shift their distribution range in response to environmental change.</p>
ScienceDex guides
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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
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.