Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
13,587
datasets available to search
ShareScore release 0.9.0
Dataset results
13,587 results for “specification”
Data from: Traits underlying community consequences of plant intra-specific diversity
A plant's performance and interactions with other trophic levels are recorgnized to be contingent upon plant diversity and underlying associational dynamics, but far less is known about the plant traits driving such phenomena. We manipulated diversity in plant traits using pairs of plant and a substitutive design to elucidate the mechanisms underlying diversity effects operating at a fine spatial scale. Specifically, we measured the effects of diversity in sex (sexual monocultures vs. male and female genotypes together) and growth rate (growth rate monocultures vs. fast- and slow-growing genotypes together) on growth of the shrub Baccharis salicifolia and on above- and belowground consumers associated with this plant. We compared effects on associate abundance (# associates per plant) vs. density (# associates per kg plant biomass) to elucidate the mechanisms underlying diversity effects; effects on abundance but not density suggest diversity effects are mediated by resource abundance (i.e. plant biomass) alone, whereas effects on density suggest diversity effects are mediated by plant-based heterogeneity or quality. Sexual diversity increased root growth but reduced the density (but not abundance) of the dietary generalist aphid Aphis gossypii and its associated aphid-tending ants, suggesting sex mixtures were of lower quality to this herbivore (e.g. via reduced plant quality), and that this effect indirectly influenced ants. Sexual diversity had no effect on the abundance or density of parasitoids attacking A. gossypii, the dietary specialist aphid Uroleucon macolai, or mycorrhizae. In contrast, growth rate diversity did not influence plant growth or any associates except for the dietary specialist aphid U. macolai, which increased in both abundance and density at high diversity, suggesting growth rate mixtures were of higher quality to this herbivore. These results highlight that plant associational and diversity effects on consumers are contingent upon the source of plant trait variation, and that the nature of such dynamics may vary both within and among trophic levels.
Data from: Sex-specific effects of outbreeding on offspring quality in pike (Esox lucius)
Intraspecific genetic admixture occurs when previously separated populations within a species start interbreeding, and it can have either positive, negative or netural effects on reproductive performance. There is currently little knowledge regarding what determines the outcome of admixture. We tested for effects of admixture on offspring quality in three subpopulations of pike (Esox lucius). Gametes were collected in the field, and eggs from each female were experimentally fertilized with milt from a male from each population (one 'pure' and two 'admixed' treatments). Three offspring quality measures (hatching success, fry survival, and fry length) were determined and compared between (i) pure and admixed population combinations, and (ii) the sex-specific treatments within each admixed population combination (based on the origin of the male and female respectively). The results revealed that although there were no overall effects of admixture on offspring quality, the consequences for a given population combination could be sex-specific and thus differ depending on which of the parents originated from one or the other population. All offspring quality traits were influenced by both maternal ID and paternal ID. Sex- and individual-specific effects can have implications for dispersal behavior and gene flow between natural populations, and are important to consider in conservation efforts.
Data from: Next-generation freshwater bioassessment: eDNA metabarcoding with a conserved metazoan primer reveals species-rich and reservoir-specific communities
Freshwater habitats are of high conservation value and provide a wide range of ecosystem services. Effective management requires regular monitoring. However, conventional methods based on direct observation or specimen collection are so invasive, expensive and labour-intensive that frequent monitoring is uncommon. Here, we test whether the evaluation of environmental DNA (eDNA) from water based on a simple protocol can be used for assessing biodiversity. We use universal metazoan primers for characterizing water eDNA across horizontal and vertical spatial dimensions in two reservoirs with known species diversity for two key taxa. eDNA obtained directly from 42 samples × 15 ml water (total = 630 ml) per reservoir yielded DNA signatures for more than 500 metazoan species, of which 105 could be identified to species/genus based on DNA barcodes. We show that eDNA can be used to assign each water sample to its reservoir of origin, and that eDNA outperforms conventional survey methods in single-sample richness comparisons, while revealing evidence for hundreds of unknown species that are undetected by conventional bioassessment methods. eDNA also confirms the presence of a recently discovered invasive snail species and provides evidence for the continued survival of a rare native species of goby not sighted in that habitat since 2007. eDNA thus promises to be a useful addition to the bioassessment toolbox for freshwater systems.
Data from: Rapid sex-specific evolution of age at maturity is shaped by genetic architecture in Atlantic salmon
Understanding the mechanisms by which populations adapt to their environments is a fundamental aim in biology. However, it remains challenging to identify the genetic basis of traits, provide evidence of genetic changes and quantify phenotypic responses. Age at maturity in Atlantic salmon represents an ideal trait to study contemporary adaptive evolution as it has been associated with a single locus in the vgll3 region, and has also strongly changed in recent decades. Here, we provide an empirical example of contemporary adaptive evolution of a large effect locus driving contrasting sex-specific evolutionary responses at the phenotypic level. We identified an 18% decrease in the vgll3 allele associated with late maturity (L) in a large and diverse salmon population over 36 years, induced by sex-specific selection during the sea migration. Those genetic changes resulted in a significant evolutionary response in males only, due to sex-specific dominance patterns and vgll3 allelic effects. The vgll3 allelic and dominance effects differed greatly in a second population and were likely to generate different selection and evolutionary patterns. Our study highlights the importance of knowledge of genetic architecture to better understand fitness trait evolution and phenotypic diversity. It also emphasizes the potential role of adaptive evolution in the trend toward earlier maturation observed in numerous Atlantic salmon populations worldwide.
Data from: Exposure to dairy manure leads to greater antibiotic resistance and increased mass-specific respiration in soil microbial communities
Intensifying livestock production to meet the demands of a growing global population coincides with increases in both the administration of veterinary antibiotics and manure inputs to soils. These trends have the potential to increase antibiotic resistance in soil microbial communities. The effect of maintaining increased antibiotic resistance on soil microbial communities and the ecosystem processes they regulate is unknown. We compare soil microbial communities from paired reference and dairy manure-exposed sites across the USA. Given that manure exposure has been shown to elicit increased antibiotic resistance in soil microbial communities, we expect that manure-exposed sites will exhibit (i) compositionally different soil microbial communities, with shifts toward taxa known to exhibit resistance; (ii) greater abundance of antibiotic resistance genes; and (iii) corresponding maintenance of antibiotic resistance would lead to decreased microbial efficiency. We found that bacterial and fungal communities differed between reference and manure-exposed sites. Additionally, the β-lactam resistance gene ampC was 5.2-fold greater under manure exposure, potentially due to the use of cephalosporin antibiotics in dairy herds. Finally, ampC abundance was positively correlated with indicators of microbial stress, and microbial mass-specific respiration, which increased 2.1-fold under manure exposure. These findings demonstrate that the maintenance of antibiotic resistance associated with manure inputs alters soil microbial communities and ecosystem function.
Data from: Sex-specific and individual preferences for hunting strategies in white sharks
Fine-scale predator movements may be driven by many factors including sex, habitat, and distribution of resources. There may also be individual preferences for certain movement strategies within a population which can be hard to quantify. Within top predators, movements are also going to be directly related to the mode of hunting; for example sit-and-wait or actively searching for prey. Although there is mounting evidence that different hunting modes can cause opposing trophic cascades, there has been little focus on the modes used by top predators, especially those in the marine environment. Adult white sharks (Carcharhodon carcharias) are well known to forage on marine mammal prey, particularly pinnipeds. Sharks primarily ambush pinnipeds on the surface but there has been less focus on the strategies they use to encounter prey. We applied mixed hidden Markov models to acoustic tracking data of white sharks in a coastal aggregation area in order to quantify changing movement states (Area Restricted Searching (ARS) vs. patrolling) and the factors that influenced them. Individuals were re-tracked over multiple days throughout a month to see if state-switching dynamics varied or if individuals preferred certain movement strategies. Sharks were more likely to use ARS movements in the morning and during periods of chumming by ecotourism operators. Furthermore, the proportion of time individuals spent in the two different states and the state-switching frequency, differed between the sexes and between individuals. Predation attempts/success on pinnipeds were observed for sharks in both ARS and patrolling movement states and within all random effects groupings. Therefore white sharks can use both a 'sit-and-wait' (ARS) and 'active searching' (patrolling) movements to ambush pinniped prey on the surface. White sharks demonstrate individual preferences for fine scale movement patterns which may be related to their use of different hunting modes. Marine top predators are generally assumed to use only one type of hunting mode, but we show that there is likely a mix within populations. As such, individual variability should be considered when modelling behavioural effects of predators on prey species.
Data from: Sex-specific arrival times on the breeding grounds: hybridizing migratory skuas provide empirical support for the role of sex ratios
In migratory animals, protandry (earlier arrival of males on the breeding grounds) prevails over protogyny (females preceding males). In theory, sex differences in timing of arrival should be driven by the operational sex ratio, shifting toward protogyny in female-biased populations. However, empirical support for this hypothesis is, to date, lacking. To test this hypothesis, we analyzed arrival data from three populations of the long-distance migratory south polar skua (Catharacta maccormicki). These populations differed in their operational sex ratio caused by the unidirectional hybridization of male south polar skuas with female brown skuas (Catharacta antarctica lonnbergi). We found that arrival times were protandrous in allopatry, shifting toward protogyny in female-biased populations when breeding in sympatry. This unique observation is consistent with theoretical predictions that sex-specific arrival times should be influenced by sex ratio and that protogyny should be observed in populations with female-biased operational sex ratio.
The implications of lineage-specific rates for divergence time estimation
<p>Rate variation adds considerable complexity to divergence time estimation in molecular phylogenies. Here, we evaluate the impact of lineage-specific rates—which we define as among-branch-rate-variation that acts consistently across the entire genome. We compare its impact to residual rates—defined as among-branch-rate-variation that shows a different pattern of rate variation at each sampled locus, and gene-specific rates—defined as variation in the average rate across all branches at each sampled locus. We show that lineage-specific rates lead to erroneous divergence time estimates, regardless of how many loci are sampled. Further, we show that stronger lineage-specific rates lead to increasing error. This contrasts to residual rates and gene-specific rates, where sampling more loci significantly reduces error. If divergence times are inferred in a Bayesian framework, we highlight that error caused by lineage-specific rates significantly reduces the probability that the 95% highest posterior density includes the correct value, and leads to sensitivity to the prior. Use of a more complex rate prior—which has recently been proposed to model rate variation more accurately—does not affect these conclusions. Finally, we show that the scale of lineage-specific rates used in our simulation experiments is comparable to that of an empirical data set for the angiosperm genus Ipomoea. Taken together, our findings demonstrate that lineage-specific rates cause error in divergence time estimates, and that this error is not overcome by analyzing genomic scale multilocus data sets.</p>
Data from: Parting ways: Parasite release in nature leads to sex-specific evolution of defense
We evaluate the extent to which males and females evolve along similar or different trajectories in response to the same environmental shift. Specifically, we use replicate experimental introductions in nature to consider how release from a key parasite (Gyrodactylus) generates similar or different defense evolution in male versus female guppies (Poecilia reticulata). After 8-12 generations of evolution, guppies were collected from the ancestral (parasite still present) and derived (parasite now absent) populations and bred for two generations in the laboratory to control for non-genetic effects. These F2 guppies were then individually infected with Gyrodactylus and infection dynamics were monitored on each fish. We found that parasite release in nature led to sex-specific evolutionary responses: males did not show much evolution of resistance, whereas females showed the evolution of increased resistance. Given that male guppies in the ancestral population had greater resistance to Gyrodactylus than did females, evolution in the derived populations led to reduction of sexual dimorphism in resistance. We argue that previous selection for high resistance in males constrained (relative to females) further evolution of the trait. We advocate more experiments considering sex-specific evolutionary responses to environmental change.
Data from: A framework for developing ecosystem-specific nutrient criteria: integrating biological thresholds with predictive modeling
We present a novel ecosystem-specific framework for developing nutrient criteria from biological thresholds and predictive modeling (BTPM) and an application of this framework to lakes in Michigan, U.S. The four main components for the BTPM framework are: (1) to predict each ecosystem s expected nutrient concentration in the absence of human effects using a predictive model, (2) to identify important biological thresholds along a nutrient gradient (i.e., biological [BIO] benchmarks), (3) to determine each ecosystem s current nutrient concentration, and (4) to use the above information to derive a nutrient criterion for each ecosystem using the BTPM algorithm. The BTPM framework is extremely flexible in that it can be applied to any aquatic ecosystem type or nutrient and the four components can be implemented in a variety of ways. Our BTPM framework has two additional features: it recognizes that prior to human disturbance, ecosystems varied in their natural nutrient concentrations, and it incorporates risk into the decision-making process. In the simplest scheme, a nutrient criterion is set at a BIO benchmark greater than the expected nutrient concentration. However, to protect ecosystems more conservatively, a criterion is set at current lake nutrient concentrations if current is less than the BIO benchmark. In our application of the BTPM framework, we developed total phosphorus (TP) criteria for a diverse set of 374 lakes in MI. The expected lake TP concentrations in the absence of human effects ranged from 3 µg L-1 to 24 µg L-1, suggesting that a single criterion approach would not be appropriate.We found two predominant benchmarks in the biological data along the TP gradient, one for zooplankton metrics at 8 µg L-1, and one for phytoplankton metrics at 18 µg L-1. We present the sequence of analyses and decisions that could be used to apply this approach in a management context using Michigan lakes as an example.
Data from: Stage-specific genotype-by-environment interactions for cold and heat hardiness in Drosophila melanogaster.
Environments often vary across a life cycle, imposing fluctuating natural selection across development. Such fluctuating selection can drive evolutionary responses specific to distinct life-history stages. However, selection and genetic variation, phenotypic plasticity, and their interaction (GxE), as well as genetic correlation across development dictate stage-specific evolution. Thus, quantifying genetic covariance of fitness-related traits and plasticity across development is vital to determine whether stage-specific adaptation occurs in nature. Additionally, the interaction of genetic variation and environmental plasticity (GxE) may be stage-specific, leading to a 3-way interaction between genotype, environment, and development or GxDxE. To test for these patterns in a natural system, we exposed larvae and adults of Drosophila melanogaster isogenic lines derived from a natural population to extreme heat and cold after developmental acclimation to cool (18°C) and warm (25°C) conditions and measured genetic variance for thermal hardiness. We detected significant GxE that was specific to larvae and adults for cold and heat hardiness (GxDxE), but no significant genetic correlation across development for either trait at either acclimation temperature. However, cross-development phenotypic correlations for acclimation responses suggest that plasticity itself may be developmentally constrained, though rigorously testing this hypothesis requires more experimentation. In general, we find evidence for thermal niche adaptation across development as larvae are more heat-hardy while adults are more cold-hardy. These results illustrate the potential for stage-specific adaptation within a complex life cycle and highlight the importance of measuring traits at appropriate developmental stages and environmental conditions when predicting evolutionary responses to changing climates.
Data from: Melanin-specific life-history strategies
The maintenance of genetic variation is a long-standing issue because the adaptive value of life-history strategies associated with each genetic variant is usually unknown. However, evidence for the coexistence of alternative evolutionary fixed strategies at the population level remains scarce. Because in the tawny owl (Strix aluco) heritable melanin-based coloration shows different physiological and behavioral norms of reaction, we investigated whether coloration is associated with investment in maintenance and reproduction. Light melanic owls had lower adult survival compared to dark melanic conspecifics, and color variation was related to the trade-off between offspring number and quality. When we experimentally enlarged brood size, light melanic males produced more fledglings but in poorer condition, and they were less often recruited in the local breeding population than those of darker melanic conspecifics. Our results also suggest that dark melanic males allocate a constant effort to raise their brood independently of environmental conditions, whereas lighter melanic males finely adjust reproductive effort in relation to changes in environmental conditions. Color traits can therefore be associated with life-history strategies, and stochastic environmental perturbation can temporarily favor one phenotype over others. The existence of fixed strategies implies that some phenotypes can sometimes display a "maladapted" strategy. Long-term population monitoring is therefore vital for a full understanding of how different genotypes deal with trade-offs.
Data from: Prominent intra-specific genetic divergence within Anopheles gambiae sibling species triggered by habitat discontinuities across a riverine landscape
The Anopheles gambiae complex of mosquitoes includes malaria vectors at different stages of speciation, whose study enables a better understanding of how adaptation to divergent environmental conditions leads to evolution of reproductive isolation. We investigated the population genetic structure of closely-related sympatric taxa that have recently been proposed as separate species (An. coluzzii and An. gambiae), sampled from diverse habitats along the Gambia River in West Africa. We characterised putatively neutral microsatellite loci as well as chromosomal inversion polymorphisms known to be associated with ecological adaptation. The results revealed strong ecologically-associated population subdivisions within both species. Microsatellite loci at chromosome-3L revealed a clear differentiation between coastal and inland populations, which in An. coluzzii is reinforced by a peculiar inversion polymorphism pattern, supporting the hypothesis of genetic divergence driven by adaptation to the coastal habitat. Striking genetic differences, compatible with a strong reduction of gene-flow, were observed between An. gambiae populations west and east of an extensively rice-cultivated region exclusively occupied by An. coluzzii. Notably, this 'intra-specific' differentiation was higher than that observed between the two species and involved also the centromeric region of chromosome-X which has previously been considered a marker of speciation within this complex, suggesting that the two populations may be at an advanced stage of reproductive isolation triggered by human-made habitat fragmentation. These results confirm ongoing ecological speciation within these most important Afro-tropical malaria vectors and raise new questions on the possible effect of this process in malaria transmission.
Data from: Radial changes in wood specific gravity of tropical trees: inter- and intra-specific variation during secondary succession
Variation in wood specific gravity (WSG) within and across species of tropical trees is poorly studied in relation to vegetation change during tropical forest succession. We investigated WSG of 91 species in eight long-term plots along a successional chronosequence in northeastern Costa Rica. Radial changes in WSG were described by the rate of change (slope) along the stem radius. Significant radial changes were found in 42 of 74 species, with 37 species exhibiting increases from inner to outer wood, and 5 exhibiting decreases. Radial increases were commonly observed in species with inner WSG below 0.5, whereas radial decreases were observed in species with inner WSG above 0.7. Wood specific gravity weighted by cross-sectional area (wWSG) varied four-fold among species. Species classified as second-growth specialists had lower wWSG, lower inner and outer WSG, and higher slopes than old-growth specialists; successional generalists showed intermediate trait values. Among 18 species sampled in both second- and old-growth forests, 4 species (22%) showed significant variation in wWSG between forest types. Of 33 widely sampled species, seven species (21%) showed a significant effect of stem diameter on wWSG. Second-growth plots had lower stand-level wWSG and more pronounced radial increases than old-growth plots. Individual tree biomass for species with radial increases and low WSG was substantially underestimated when based on unweighted WSG compared to wWSG. Wood specific gravity varied with successional stage at multiple levels: within species, among successional specialist groups, and across plots of varying ages. Radial increases in WSG are common among trees in early and intermediate stages of tropical forest succession. This trait may confer growth advantages early in succession and increased resistance to physical or biotic damage during later successional stages.
Data from: Accelerometers can measure total and activity-specific energy expenditure in free-ranging marine mammals only if linked to time-activity budgets
Energy expenditure is an important component of foraging ecology, but is extremely difficult to estimate in free-ranging animals and depends on how animals partition their time between different activities during foraging. Acceleration data have emerged as a new way to determine energy expenditure at a fine scale but this needs to be tested and validated in wild animals. This study investigated whether vectorial dynamic body acceleration (VeDBA) could accurately predict the energy expended by marine predators during a full foraging trip. We also aimed to determine whether the accuracy of predictions of energy expenditure derived from acceleration increased when partitioned by different types of at-sea activities (i.e. diving, transiting, resting and surface activities). To do so, we equipped 20 lactating northern (Callorhinus ursinus) and 20 lactating Antarctic fur seals (Arctocephalus gazella) with GPS, time-depth recorders and tri-axial accelerometers and obtained estimates of field metabolic rates using the doubly labelled water (DLW) method. VeDBA was derived from tri-axial acceleration, and at-sea activities (diving, transiting, resting and surface activities) were determined using dive depth, tri-axial acceleration and travelling speed. We found that VeDBA did not accurately predict the total energy expended by fur seals during their full foraging trips (R2 = 0·36). However, the accuracy of VeDBA as a predictor of total energy expenditure increased significantly when foraging trips were partitioned by activity and when activity-specific VeDBA was paired with time-activity budgets (R2 = 0·70). Activity-specific VeDBA also accurately predicted the energy expenditures of each activity independent of each other (R2 > 0·85). Our study confirms that acceleration is a promising way to estimate energy expenditures of free-ranging marine mammals at a fine scale never attained before. However, it shows that it needs to be based on the time-activity budgets that make up foraging trips rather than being derived as a single measure of VeDBA applied to entire foraging trips. Our activity-based method provides a cost-effective means to accurately calculate energy expenditures of fur seals using acceleration and time-activity budgets, that can be transfered to studies on other species.
Data from: Specificity in diversity: single origin of a widespread ciliate-bacteria symbiosis
Symbioses between eukaryotes and sulfur-oxidizing (thiotrophic) bacteria have convergently evolved multiple times. Although well described in at least eight classes of metazoan animals, almost nothing is known about the evolution of thiotrophic symbioses in microbial eukaryotes (protists). In this study, we characterized the symbioses between mouthless marine ciliates of the genus Kentrophoros, and their thiotrophic bacteria, using comparative sequence analysis and fluorescence in situ hybridization. Ciliate small-subunit rRNA sequences were obtained from 17 morphospecies collected in the Mediterranean and Caribbean, and symbiont sequences from 13 of these morphospecies. We discovered a new Kentrophoros morphotype where the symbiont-bearing surface is folded into pouch-like compartments, illustrating the variability of the basic body plan. Phylogenetic analyses revealed that all investigated Kentrophoros belonged to a single clade, despite the remarkable morphological diversity of these hosts. The symbionts were also monophyletic and belonged to a new clade within the Gammaproteobacteria, with no known cultured representatives. Each host morphospecies had a distinct symbiont phylotype, and statistical analyses revealed significant support for host–symbiont codiversification. Given that these symbioses were collected from two widely separated oceans, our results indicate that symbiotic associations in unicellular hosts can be highly specific and stable over long periods of evolutionary time.
Data from: Low host specificity among arctic root-assosiated fungi
In High Arctic ecosystems, plant growth and reproduction are limited by low soil moisture and nutrient availability, low soil and air temperatures, and a short growing season. Mycorrhizal associations facilitate plant nutrient acquisition and water uptake and may therefore be particularly ecologically important in nutrition-poor and dry environments, such as parts of the Arctic. Similarly, endophytic root associates are thought to play a protective role, increasing plants' stress tolerance, and likely have an important ecosystem function. Despite the importance of these root-associated fungi, little is known about their host specificity in the Arctic. We investigated the host specificity of root-associated fungi in the common, widely distributed arctic plant species Bistorta vivipara, Salix polaris and Dryas octopetala in the High Arctic archipelago Svalbard. High-throughput sequencing of the internal transcribed spacer 1 (ITS1) amplified from whole root systems generated no evidence of host specificity and no spatial autocorrelation within two 3 m × 3 m sample plots. The lack of spatial structure at small spatial scales indicates that Common Mycelial Networks (CMNs) are rare in marginal arctic environments. Moreover, no significant differences in fungal OTU richness were observed across the three plant species, although their root system characteristics (size, biomass) differed considerably. Reasons for lack of host specificity could be that association with generalist fungi may allow arctic plants to more rapidly and easily colonize newly available habitats, and it may be favourable to establish symbiotic relationships with fungi possessing different physiological attributes.
Data from: Specificity of fungal associations of Pyroleae and Monotropa hypopitys during germination and seedling development
Mycoheterotrophic plants obtain organic carbon from associated mycorrhizal fungi, fully or partially. Angiosperms with this form of nutrition possess exceptionally small 'dust seeds' which after germination develop 'seedlings' that remain subterranean for several years, fully dependent on fungi for supply of carbon. Mycoheterotrophs which as adults have photosynthesis thus develop from full to partial mycoheterotrophy, or autotrophy, during ontogeny. Mycoheterotrophic plants may represent a gradient of variation in a parasitism-mutualism continuum, both among and within species. Previous studies on plant-fungal associations in mycoheterotrophs have focused on either germination or the adult life stages of the plant. Much less is known about the fungal associations during development of the subterranean seedlings. We investigated germination and seedling development and the diversity of fungi associated with germinating seeds and subterranean seedlings (juveniles) in five Monotropoideae (Ericaceae) species, the full mycoheterotroph Monotropa hypopitys and the putatively partial mycoheterotrophs Pyrola chlorantha, P. rotundifolia, Moneses uniflora and Chimaphila umbellata. Seedlings retrieved from seed sowing experiments in the field were used to examine diversity of fungal associates, using pyrosequencing analysis of ITS2 region for fungal identification. The investigated species varied with regard to germination, seedling development and diversity of associated fungi during juvenile ontogeny. Results suggest that fungal host specificity increases during juvenile ontogeny, most pronounced in the fully mycoheterotrophic species, but a narrowing of fungal associates was found also in two partially mycoheterotrophic species. We suggest that variation in specificity of associated fungi during seedling ontogeny in mycoheterotrophs represents ongoing evolution along a parasitism-mutualism continuum.
Data from: Intra-specific variability of hindlimb length in the palmate newt: an indicator of population isolation induced by habitat fragmentation?
Habitat fragmentation is one of the main drivers of global amphibian decline. Anthropogenic landscape elements can act as barriers, hindering the dispersal that is essential for maintaining gene flow between populations. Dispersal ability can be influenced by locomotor performance, which in turn can depend on morphological traits, such as hindlimb length (HLL) in amphibians. Here, we tested relationships between HLL and environmental variables—road types, forests and agricultural lands—among 35 sub-populations of palmate newts (Lissotriton helveticus) in southwestern France. We expected roads to select for short-legged newts due to a higher mortality of more mobile individuals (long-legged newts) when crossing roads. Accordingly, short-legged newts were found in the vicinity of roads, whereas long-legged newts were found closer to forests and in ponds close geographically to another water body. HLL in newts was hence influenced by habitat types in a heterogeneous landscape, and could therefore be used as an indicator of population isolation in a meta-population system.
Data from: Tissue-specific carbon concentration, carbon stock, and distribution in Cunninghamia lanceolata (Lamb.) Hookplantations at various developmental stages in subtropical China
Key message Carbon (C) concentrations in Cunninghamia lanceolata (Lamb.) Hook plantations differed significantly among tissue types and were greater for aboveground than belowground tissues. Plantation C stock increased with developmental stage from young to mature to overmature, but at all stages the majority occurred as soil organic carbon (SOC) and was more influenced by belowground fine roots than by aboveground litterfall. Context Failing to account for tissue-specific variation in the C concentration can result in inaccurate forest C stock estimates. Aims We aimed to quantify the relative magnitudes of C stock for Chinese fir plantations at different developmental stages. Specifically, we focused on assessing tissue-specific C concentrations and C dynamics return of above- and belowground litterfall. Methods Carbon traits (C concentration, C flux, C stock and distribution at tree and ecosystem scales) were quantified in a chronosequence of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) monoculture plantation stands at young (10), mature (22), and overmature (34 years old) developmental stages. Results Carbon concentrations differed significantly among tissue types, with mean values of 48.5 ± 0.1% and 42.5 ± 0.2% for above- and belowground biomass, respectively. The aboveground tissue C concentration, tree- and plantation-scale C stock, and SOC stock depended on developmental stage. Carbon return in litterfall, tree C stock, and SOC increased from the young to the overmature stage. SOC stock accounted for the majority of plantation C stock at all developmental stages (78.3, 59.6 and 55.7% in the young, mature and overmature stages, respectively) and was more highly influenced by belowground fine roots than aboveground litterfall. Carbon stocks in Chinese fir plantations were 86, 129, and 153 t ha-2 at the young, mature, and overmature stages. Conclusion Prolonging Chinese fir rotation increases C sequestration potential and should be the focus of forest management strategies. The tissue-specific C concentrations provide detailed information for more accurate biomass C stock estimates for Chinese fir plantations and other subtropical coniferous forest. They indicate that current guidelines result in an overestimation of belowground biomass C stocks. Using the standard 0.47 biomass to C conversion factor, the belowground C stock would have been overestimated by 7.6-13.0% for the Chinese fir developmental stages investigated, while tree C stock would be underestimated by 0.08-3.24%. Therefore, developing species- and tissue-specific conversion factors are required for supporting C plantation and forest C accounting strategies.
ScienceDex guides
Understand access before you commit
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.