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.
75
datasets available to search
ShareScore release 0.7.1
Dataset results
75 results for “intraspecific competition”
Data from: Nonlinear effects of intraspecific competition alter landscape-wide scaling up of ecosystem function
A major focus of ecology is to understand and predict ecosystem function across scales. Many ecosystem functions are only measured at local scales, while their effects occur at a landscape level. Here, we investigate how landscape-scale predictions of ecosystem function depend on intraspecific competition, a fine-scale process, by manipulating intraspecific density of shredding macroinvertebrates and examining effects on leaf litter decomposition, a key function in freshwater ecosystems. For two species, we found that per-capita leaf processing rates declined with increasing density following power functions with negative exponents, likely due to interference competition. To demonstrate consequences of this nonlinearity, we scaled up estimates of leaf litter processing from shredder abundance surveys in 10 replicated headwater streams. In accordance with Jensen's inequality, applying density-dependent consumption rates reduced estimates of catchment-scale leaf consumption by an order of magnitude relative to density-independent rates. Density-dependent consumption estimates aligned closely with metabolic requirements in catchments with large, but not small, shredder populations. Importantly, shredder abundance was not limited by leaf litter availability and catchment-level leaf litter supply was much higher than estimated consumption. Thus leaf litter processing was not limited by resource supply. Our work highlights the need for scaling-up which accounts for intraspecific interactions.
Intraspecific competition drives dispersal of an endangered ibis data
<p>Although dispersal drives population dynamics and species distribution, we still know little about how it affects the dynamic of endangered and restricted-range species. After 1981, when the last seven wild individuals of Crested Ibis were discovered in China, the species remained confined to a single location ('original nesting area') until 2000 (< 24 breeding pairs). Then, the breeding population began a significant spatial and numerical expansion (toward the 'secondary nesting area'). Our analyses of long-term (1993–2017) individual-based data (<i>n</i> = 193) show that: (i) natal, but not breeding dispersal, was common (≈77% and ≈2.1%); (ii) as predicted by the intraspecific competition hypothesis, the probability of natal dispersal from the original nesting area increased with increasing and decreasing density at the birthplace and the first breeding site, respectively; nonetheless, (iii) in the secondary nesting area, birth dispersal was density-independent, but (iv) from here they were more likely to disperse, pointing to weak competition at these breeding areas and, since they were all born to dispersing parents, to a role for individual personality; (v) the Weibull distribution provided the best fit to the observed dispersal distances, indicating the presence of long-distance dispersers. We expect the Crested Ibis to continue to spread throughout the region if the protection programs cover a wide range to allow long-distance dispersal. Overall, our study suggests that intraspecific competition can cause dispersal in a population of few individuals confined to a small area and, therefore, be critical for the recovery and expansion of an endangered species.</p>
Data from: Trait plasticity and tradeoffs shape intraspecific variation in competitive response in a foundation tree species
<ul> <li>The ability to tolerate neighboring plants (i.e., degree of competitive response) is a key determinant of plant success in high-competition environments. Plant genotypes adjust their functional trait expression under high levels of competition, which may help explain intraspecific variation in competitive response. However, the relationships between traits and competitive response are not well understood, especially in trees. In this study, we investigated among-genotype associations between tree trait plasticity and competitive response. </li> <li>We manipulated competition intensity in experimental stands of trembling aspen (<i>Populus tremuloides</i>) to address the covariance between competition-induced changes in functional trait expression and aspects of competitive ability at the genotype level. </li> <li>Genotypic variation in the direction and magnitude of functional trait responses, especially those of crown foliar mass, phytochemistry, and leaf physiology, was associated with genotypic variation in competitive response. Traits exhibited distinct plastic responses to competition, with varying degrees of genotypic variation and covariance with other trait responses. </li> <li>The combination of genotypic diversity and covariance among functional traits led to tree responses to competition that were coordinated among traits yet variable among genotypes. Such relationships between tree traits and competitive success have the potential to shape stand-level trait distributions over space and time. </li> </ul>
Data from: Consumer interaction strength may limit the diversifying effect of intraspecific competition: a test in alewife (Alosa pseudoharengus).
Intraspecific competition is considered a principal driver of dietary variation, however, empirical studies provide mixed support for this mechanism. Here we link comparative and experimental work testing the effects of competition and resource availability on the dietary variation of alewife (Alosa pseudoharengus). Alewife, a consumer with extreme effects on its resources, are specifically utilized to additionally test the idea that that the strength of the interaction between a consumer and its resources may diminish the diversifying effect of competition. First, we compared the short- and long-term diet measures of from wild populations across a range of densities. Second, in a series of large-scale field mesocosm experiments we explored the influence of competition and interaction strength on alewife dietary variation. Results from the whole lake comparison and field experiments indicated that increasing competition was negatively correlated with population dietary variation. Further, altering the strength of the interaction between alewife and their prey via prey supplementation eliminated this negative relationship. Collectively, our results suggest that competitive interactions may not drive dietary diversification in highly effective consumers. Our results also suggest that further consideration of the strength of species interactions (and the consumer traits that underlie them) would improve our understanding of the link between intraspecific competition and variation
Where to spend the winter? The role of intraspecific competition and climate in determining the selection of wintering areas by migratory caribou
<p>Depicted as predictable movements, migrations can, however, show important interannual variations, making the conservation of migratory species particularly challenging. Plasticity in migratory behaviour allows individuals to adjust their migratory tactics to maximize their fitness. Destination of migration, and therefore migration patterns, may vary according to climatic and environmental conditions encountered during migration or at the arrival site but also according to competition. In Northern-Québec and Labrador, Canada, fall migration patterns of caribou from the Rivière-George (RGH) and the Rivière-aux-Feuilles (RFH) herds have varied greatly during the last decades. Meanwhile, both herds have shown large fluctuations in abundance. We assessed the influence of environmental factors and changes in population size on wintering area selection. Based on 649 fall migrations of 284 females equipped with ARGOS collars, we used a machine-learning algorithm, the random forests, to assess how climate, resources and population size affected the selection of four different wintering areas. Individuals followed over several years switched to a different wintering area 45% of the time between consecutive years, and this probability increased at high population size. The main determinant of wintering area selection was the population size for both herds, suggesting intra- and inter-herd competition for wintering areas. The long migrations of RGH toward the western wintering areas, also used by RFH, were favoured when the herd was abundant and when the availability of resources was low at the departure. The migrations of RFH toward the south-western area increased as RGH declined, possibly because the past presence of RGH in this area reduced access for caribou from RFH. These results highlight the flexibility in the migratory behaviour of caribou in response to variation in competition. Our study is the first to suggest that wintering area selection can be determined by competition between populations of the same ungulate species.</p>
Data from: Experimental evidence for an eco-evolutionary coupling between local adaptation and intraspecific competition
Determining how adaptive evolution can be coupled to ecological processes is key for developing a more integrative understanding of the demographic factors that regulate populations. Intraspecific competition is an especially important ecological process because it generates negative density dependence in demographic rates. Although ecological factors are most often investigated to determine the strength of density dependence, evolutionary processes such as local adaptation could also feed back to shape variation in the strength of density dependence among populations. Using an experimental approach with damselflies, a predaceous aquatic insect, we find evidence that both density-dependent intraspecific competition and local adaptation can reduce per capita growth rates. In some cases, the effects of local adaptation on reducing per capita growth rates exceeded the ecological competitive effects of a doubling of density. However, we also found that these ecological and evolutionary properties of populations are coupled, and we offer two interpretations of the causes underlying this pattern: (1) the strength of density-dependent competition depends on the extent of local adaptation, or (2) the extent of local adaptation is shaped by the strength of density-dependent competition. Regardless of the underlying causal pathway, these results show how eco-evolutionary dynamics can affect a key demographic process regulating populations.
Data from: Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators
Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the large-scale latitudinal variation of population- and individual-level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within- and between-individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within-individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large-scale spatial variation in ecological opportunity, suggesting species-specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem.
Data from: Intraspecific adaptive radiation: competition, ecological opportunity, and phenotypic diversification within species
Intraspecific variation in resource-use traits can have profound ecological and evolutionary implications. Among the most striking examples are resource polymorphisms, where alternative morphs that utilize different resources evolve within a population. An underappreciated aspect of their evolution is that the same conditions that favor resource polymorphism—competition and ecological opportunity—might foster additional rounds of diversification within already existing morphs. We examined these issues in spadefoot toad tadpoles that develop into either a generalist 'omnivore' or a specialist 'carnivore' morph. Specifically, we assessed the morphological diversity of tadpoles from natural ponds and experimentally induced carnivores reared on alternative diets. We also surveyed natural ponds to determine if the strength of intramorph competition and the diversity and abundance of dietary resources (measures of ecological opportunity) influenced the diversity of within-morph variation. We found that five omnivore and four carnivore types were present in natural ponds; alternative diets led to shape differences, some of which mirrored variation in the wild; and both competition and ecological opportunity were associated with enhanced morphological diversity in natural ponds. Such fine-scale intraspecific variation might represent an underappreciated form of biodiversity and might constitute a crucible of evolutionary innovation and diversification.
Data from: The reciprocal relationship between competition and intraspecific trait variation
Trait differences among plants are expected to influence the outcome of competition; competition should be strongest between similar species (or individuals) under limiting similarity, and between dissimilar species within competitive hierarchies. These hypotheses are often used to infer competitive dynamics from trait patterns within communities. However, plant traits are frequently plastic in response to competition. This variation is poorly accounted for in trait-based studies of competition and community assembly. To explore the relationship between trait responses and competitive outcomes, we grew 15 species alone, in monoculture and in mixture. We measured traits relating to leaf and root tissue morphology as well as biomass allocation and related competition-induced changes in these traits to intra- and interspecific competition using multi-model inference. Additionally, we tested how traits from different competitive environments influenced potential community assembly inferences. The competitive environment had large effects on species' traits, although many effects were species specific. Differences among species in how competition affected trait expression were linked to both intra- and interspecific competition, frequently affecting competitive hierarchies. Intraspecific competition was lower for species that limited competition-induced increases in root allocation and had less variability in this trait overall. Interspecific competition was lower for species with larger leaves and lower specific leaf area than their neighbours. Switching to more stress-tolerant strategies by increasing root diameter and leaf tissue density also reduced competition. However, dissimilarity in root tissue density also minimized competition, consistent with limiting similarity affecting competitive outcomes. Moreover, changes in these traits were linked to changes in functional diversity, suggesting that competition affects functional diversity by affecting trait expression. Synthesis. Both trait hierarchies and trait dissimilarity affect the outcome of competition by acting on different traits, although competition-induced changes in trait expression can alter competitive outcomes. Moreover, the magnitude of these trait changes suggests that the source environment where plant traits are collected can affect the inferences drawn from trait patterns within communities. Combined, our results suggest that considering the effect of competition on trait expression is critical to understanding the relationship between traits and community assembly.
Data from: Intraspecific competition, not predation, drives lizard tail loss on islands
Tail autotomy is mainly considered an antipredator mechanism. Theory suggests that predation pressure relaxes on islands, subsequently reducing autotomy rates. Intraspecific aggression, which may also cause tail loss, probably intensifies on islands due to the higher abundance. We studied whether tail autotomy is mostly affected by predation pressure or by intraspecific competition. We further studied whether predator abundance or predator richness is more important in this context. To test our predictions, we examined multiple populations of two gecko species: Kotschy's gecko (Mediodactylus kotschyi; mainland and 41 islands) and the Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundance together with five indices of predation. In both species, autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M. kotschyi, tail-loss rates are higher on predator and viper-free islands, but increase with viper abundance. We suggest that autotomy is not simply, or maybe even mainly, an antipredatory mechanism. Rather, such defence mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail autotomy in insular populations, chiefly to intraspecific aggression.
Data from: Field manipulations of resources mediate the transition from intraspecific competition to facilitation
1. Population density affects individual performance, though its effects are often mixed. For sessile species, increases in population density typically reduce performance. Still, cases of positive density dependence do occur in these systems and demand explanation. The stress gradient hypothesis (SGH) predicts that under stressful conditions, positive effects of facilitation may outweigh the negative effects of competition. 2. While some elements of the SGH are well studied, its potential to explain intraspecific facilitation has received little attention. Further, there have been questions regarding whether the SGH holds if the stressor is a resource. Most studies of interactions between the environment and intraspecific facilitation have relied on natural environmental gradients; manipulative studies are much rarer. 3. To test the effects of intraspecific density and resources, we manipulated resource availability over natural population densities for the marine bryozoan Watersipora subtorquata. 4. We found negative effects of density on colony performance in low resource environments, but mainly positive density-dependence in high resource environments. By adding resources, competition effects were reduced and the positive effects of facilitation were revealed. 5. Our results suggest that resource availability mediates the relative strength of competition and facilitation in our system. We also suggest that intraspecific facilitation is more common than may be appreciated and that environmental variation may act as mediators to the balance between negative and positive density-dependence.
The effect of inter-and intraspecific competition on individual and population niche widths – a four-decade study on two interacting salmonids
<p>Competition is assumed to shape niche widths, affecting species survival and coexistence. Expectedly, high interspecific competition will reduce population niche widths, whereas high intraspecific competition will do the opposite. Here we test in situ how intra- and interspecific competition affects trophic resource use and the individual and population niche widths of two lacustrine fish species, Arctic charr and brown trout, covering a 40 year study period with highly contrasting competitive impacts prior to and following a large-scale fish culling experiment. Initially, an overcrowded Arctic charr population dominated the study system, with brown trout being nearly absent. The culling experiment reduced the littoral Arctic charr density by 80%, whereupon brown trout gradually increased its density in the system. Thus, over the study period, the Arctic charr population went from high to low intraspecific competition, followed by increasing interspecific competition with brown trout. As hypothesized, the relaxed intraspecific competition following the experimental culling reduced individual diet specialization and compressed population niche width of Arctic charr. During the initial increase of the brown trout population, there was a large dietary overlap between the two species. Over the subsequent intensified interspecific competition from the population build-up of brown trout, their trophic niche overlap chiefly declined due to a dietary shift of Arctic charr towards enhanced zooplankton consumption. Contrary to theoretical expectations, the individual and population niche widths of Arctic charr increased with intensified interspecific competition. In contrast, the diet and niche width of brown trout remained stable over time, confirming its competitive superiority. The large-scale culling experiment and associated long-term research revealed pronounced temporal dynamics in trophic niche and resource use of the inferior competitor, substantiating that intra- and interspecific competition have large and contrasting impacts on individual and population niches.</p>
Intraspecific competition and temperature drive habitat-based resource polymorphism in brook charr
<p><span>Intra- and interspecific competition, two density-dependent processes, are the two main driving forces suggested to promote habitat-based resource polymorphism, but very few studies have provided empirical support for this hypothesis. Furthermore, </span><span>external drivers like temperature, an important environmental constraint in ectotherms, are often omitted when studying density-dependent habitat selection. Specifically, ambient temperature may have important effects on habitat-based resource polymorphism in ectotherms. Using mixed-effects modelling and isodar analyses, we quantified the effects of water temperature as well as intra- and interspecific competition on abundance and density-dependent habitat selection of brook charr (<em>Salvelinus</em> <em>fontinalis</em>) between littoral and pelagic habitats in 27 Canadian Shield lakes. We found that interspecific competition with white sucker (<em>Catostomus</em> <em>commersonii</em>) reduced brook charr abundances in both habitats but did not affect their </span><span>density-dependent habitat selection. </span><span>In contrast, the isodar analysis </span><span>showed density-dependent habitat selection, confirming that intraspecific competition is a driver of brook charr habitat use in this system. </span><span>Furthermore, brook charr preferred the littoral habitat at water temperatures below 20.8°C, but preferred the pelagic habitat above this threshold and no longer used the littoral habitat when its temperature was above ~22.2°C. By incorporating an external driver in the density-dependent habitat selection model, we show how the littoral temperature can shape brook charr distribution patterns between the littoral and pelagic habitats by acting as a thermal barrier and thus limiting the willingness of fish to use resources in the littoral habitat. </span><span>This result suggests that global warming could constrain the diversifying effect of intraspecific competition</span><span> and prevent resource polymorphism, a phenomenon that promotes adaptive radiation and speciation</span><span>.</span></p>
From individuals to populations: How intraspecific competition shapes thermal reaction norms
1. Most ectotherms follow the temperature-size rule (TSR): in cold environments individuals grow slowly but reach a large asymptotic length. Intraspecific competition can induce plastic changes of growth rate and asymptotic length and competition may itself be modulated by temperature. 2. Our aim is to disentangle the joint effects of temperature and intraspecific competition on growth rate and asymptotic length. 3. We used two distinct clonal lineages of the Collembola Folsomia candida, to describe thermal reaction norms of growth rate, asymptotic length and reproduction over 6 temperatures between 6°C and 29°C. In parallel, we measured the long-term size-structure and dynamics of populations reared under the same temperatures to measure growth rates and asymptotic lengths in populations and to quantify the joint effects of competition and temperature on these traits. 4. We show that intraspecific competition modulates the temperature-size rule. In dense populations there is a direct negative effect of temperature on asymptotic length, but there is no temperature dependence of the growth rate, the dominant factor regulating growth being competition. The two lineages responded differently to the joint effects of temperature and competition on growth and asymptotic size and these genetic differences have marked effects on population structure along our temperature gradient. 5. Our results reinforce the idea that the TSR response of ectotherms can be modulated by biotic and abiotic stressors when studied in non-optimal laboratory experiments. Untangling complex interactions between environment and demography will help to understand how size will respond to environmental change and how climate change may influence population size structure.
Data from: A rapid and cost-effective quantitative microsatellite genotyping protocol to estimate intraspecific competition in protist microcosm experiments
High levels of intra-specific variation are commonly observed in natural microbial populations, yet the consequences of this variation for ecological and evolutionary processes remains poorly understood. Protists are excellent experimental models for investigating fundamental and applied questions in ecology and evolution, but studying intra-specific variation remains a challenge due to a lack of molecular resources to aid in quantifying and distinguishing strains during experiments. Here we present a molecular method, quantitative microsatellite genotyping, to accurately quantify strain specific frequencies from microcosm experiments of the marine flagellate Oxyrrhis marina, both between many pairs of strains and between strains in a multi-strain mixture. We find that for pairs of strains the method is effective for relative frequencies as low as 0.02 and with around 99% accuracy. The method is able to quantify four strains reasonably well, though less accurately than for pairs (range 92%-97% accuracy). This makes accessible a cheap and easy to implement method for quantifying strain (or allele) frequencies, and is suitable for use in a broad range of single celled eukaryotes (Protists) where copy number should correlate well with number of individuals (i.e. cells). This opens up the possibility of examining the role of intra-specific variation using experimental protist microcosms.
Sex-specific responses to intraspecific competition in the mosquitofish Gambusia holbrooki
<p>Intraspecific competition constitutes an important source of selection that can influence the development, expression and evolution of phenotypic traits. Although often neglected in studies of intraspecific competition, the sex of competitors can alter the nature and intensity of competition between individuals, and in turn can influence the development of resource-dependent traits. We examine here how the sex of focal and of competitor individuals interact to affect developmental responses to competition in the Eastern mosquitofish <i>Gambusia holbrooki</i>. We raised individuals of both sexes either alone or in the presence of a male or female competitor, and measured their juvenile growth rate, time to maturity and size at maturity; for males we also measured their gonopodium length, sperm quantity, and sperm velocity. We found that plastic phenotypic responses to competition were dependent on the sex of the focal individual, the sex of their competitor and sometimes an interaction between the two. When there was a competitor present, regardless of its sex, males had slower growth rates and took longer to mature, but eventually matured at the same size. Like males, females also showed slower growth rates in the presence of a competitor, but in contrast to males, reached maturity sooner and at a smaller size than when there was no competitor present. Presence of a competitor influenced male sexual traits, however there was little evidence that these effects were mediated by the sex of the competitor. Males that were reared with competitors had longer gonopodia for their body size, as well as fewer and faster sperm. Overall our results suggest that the effects of competition on resource-dependent traits are different for males and females, potentially due to sex differences in adult life history strategies. Further, for males, both life history traits and sexual traits were influenced by competition. For life history traits this effect appears to result from decreased resources and/or increased energy expenditure, but for sexual traits, effects appear to be mediated, at least in part, by the social environment, which also differs in the presence of competitors.</p>
Sex-specific responses to intraspecific competition in the mosquitofish Gambusia holbrooki
Open the record for dataset details and reuse information.
Data from: Intraspecific competition, not predation, drives lizard tail loss on islands
Open the record for dataset details and reuse information.
Data from: Nonlinear effects of intraspecific competition alter landscape-wide scaling up of ecosystem function
Open the record for dataset details and reuse information.
Intraspecific competition and temperature drive habitat-based resource polymorphism in brook charr
Open the record for dataset details and reuse information.
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.