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171 results for “density-dependent”
Data from: Density-dependent changes in neophobia and stress-coping styles in the world's oldest farmed fish
Farmed fish are typically reared at densities much higher than those observed in the wild, but to what extent crowding results in abnormal behaviours that can impact welfare and stress coping styles is subject to debate. Neophobia (i.e. fear of the 'new') is thought to be adaptive under natural conditions by limiting risks, but it is potentially maladapted in captivity, where there are no predators or novel foods. We reared juvenile Nile tilapia (Oreochromis niloticus) for six weeks at either high (50g/L) or low density (14g/L), assessed the extent of skin and eye darkening (two proxies of chronic stress), and exposed them to a novel object in an open-test arena, with and without cover, to assess the effects of density on neophobia and stress coping styles. Fish reared at high density were darker, more neophobic, less aggressive, less mobile and less likely to take risks than those reared at low density, and these effects were exacerbated when no cover was available. Thus, the reactive coping style shown by fish at high density was very different from the proactive coping style shown by fish at low density. Our findings provide novel insights into the plasticity of fish behaviour and the effects of aquaculture intensification on one of the world's oldest farmed and most invasive fish, and highlight the importance of considering context. Crowding could have a positive effect on the welfare of tilapia by reducing aggressive behaviour, but it can also make fish chronically stressed and more fearful, which could make them less invasive.
Data from: Density-dependent diel activity in stream-dwelling Arctic charr Salvelinus alpinus
Intraspecific competition plays a significant role in shaping how animals use and share habitats in space and time. However, the way individuals may modify their diel activity in response to increased competition has received limited attention. We used juvenile (age 1+) Arctic charr Salvelinus alpinus to test the prediction that individuals at high population density are more active and distribute their foraging activity over a greater portion of the 24-h cycle than individuals at low population density. Individually tagged fish were stocked in seminatural stream enclosures at low (2 fish/m2) and high (6 fish/m2) density. During each of two 2-week experimental rounds, activity of all fish within each enclosure was recorded every 3 h over seven 24-h cycles. At high density, fish were more active and distributed their activity over a greater portion of the 24-h cycle, with increased activity particularly at crepuscular times. Fluctuations in ecological conditions (e.g., water temperature and light intensity) also affected activity. Fish at high density grew as fast as fish at low density. This study demonstrates that individuals exhibit a degree of behavioral flexibility in their response to changes in ecological conditions and suggests that intraspecific competition can cause animals to modify temporal aspects of their activity to gain access to resources and maintain growth.
Data from: Contemporary evolution of sea urchin gamete-recognition proteins: experimental evidence of density-dependent gamete performance predicts shifts in allele frequencies over time
Species whose reproductive strategies evolved at one density regime might be poorly adapted to other regimes. Field and laboratory experiments on the sea urchin Strongylocentrotus franciscanus examined the influences of the two most common sperm bindin alleles, which differ at two amino acid sites, on fertilization success. In the field experiment, the Arginine/Glycine (RG) genotype performed best at low densities and the Glycine/Arginine (GR) genotype at high densities. In the lab experiment, the RG genotype had a higher affinity with available eggs, whereas the GR genotype was less likely to induce polyspermy. These sea urchins can reach 200 years of age. The RG allele dominates in old sea urchins, whereas younger sea urchins have near equal RG and GR allele frequencies. A latitudinal cline in RG and GR genotypes is consistent with longer survival of sea urchins in the north and with predominance of RG genotypes in older individuals. The oldest sea urchins were likely conceived at low densities, before sea-urchin predators, like sea otters, were overharvested and sea urchin densities exploded off the west coast. Contemporary evolution of gamete-recognition proteins might allow species to adapt to shifts in abundances and reduces the risk of reproductive failure in altered populations.
Data from: The sensitivity of seabird populations to density-dependence, environmental stochasticity and anthropogenic mortality
1.The balance between economic growth and wildlife conservation is a priority for many governments. Enhancing realism in assessment of population‐level impacts of anthropogenic mortality can help achieve this balance. Population Viability Analysis (PVA) is commonly applied to investigate population vulnerability, but outcomes of PVA are sensitive to formulations of density‐dependence, environmental stochasticity and life‐history. Current practice in marine assessments is to use precautionary models that assume no compensation from density‐dependence or rescue‐effects via "re‐seeding" from other colonies. However, if we could empirically quantify regulatory population processes, the responses of populations to additional anthropogenic mortality may be assessed with more realism in PVA. 2. Using Bayesian state‐space models fitted to population time‐series from three sympatric seabird populations, selected for varied life histories, we inferred the extent to which their dynamics are driven by environmental stochasticity and density‐dependence. 3. Based on these inferences, we conducted an exhaustive PVA across credible parameterisations for intrinsic and extrinsic population regulation, simulated as a closed and re‐seeded system. Scenarios of anthropogenic mortality, along a sliding scale of precaution, were applied both proportionally and as a fixed quota using Potential Biological Removal (PBR). 4. Baseline results from fitting revealed clear environmental regulation in two of our three species. Crucially, we found that for our empirically derived, realistic model parameterisations there are risks of decline to real populations even under very precautionary mortality scenarios. We find that PBR is dubious in application as a sustainable tool for population assessment when we account for regulation. Closed versus re‐seeded models showed a large divergence in outcomes, with sharper declines in closed simulations. Fixed‐quota mortality typically induced greater population declines comparative to proportional mortality, subject to regulation and re‐seeding. 5. Synthesis and applications: Practitioners using arbitrary formulations of population regulation risk over‐precaution (economic constraint) or under‐precaution (endangering populations). The demands of increased economic development and preservation of wildlife require that methodologies apply techniques that confer reality and rigour to assessment. The current practice of employing models lacking density‐dependence and empirical environmental information imposes limitations in the efficacy of estimating impacts. Here, we provide a method to quantify the conditions that predominantly regulate a population and exacerbate the risk of decline from anthropogenic mortality. It is in the interests of both developers and conservationists to apply methods in population impact assessments that capture realism in the processes driving population dynamics.
Data from: Density-dependent intraspecific aggression regulates survival in northern Yellowstone wolves (Canis lupus)
1. Understanding the population dynamics of top predators is essential to assess their impact on ecosystems and to guide their management. Key to this understanding is identifying the mechanisms regulating vital rates. 2. Determining the influence of density on survival is necessary to understand the extent to which human-caused mortality is compensatory or additive. In wolves (Canis lupus), empirical evidence for density-dependent survival is lacking. Dispersal is considered the principal way in which wolves adjust their numbers to prey supply or compensate for human exploitation. However, studies to date have primarily focused on exploited wolf populations, in which density-dependent mechanisms are likely weak due to artificially low wolf densities. 3. Using 13 years of data on 280 collared wolves in Yellowstone National Park, we assessed the effect of wolf density, prey abundance and population structure, as well as winter severity, on age-specific survival in two areas (prey-rich vs. prey-poor) of the national park. We further analysed cause-specific mortality and explored the factors driving intraspecific aggression in the prey-rich northern area of the park. 4. Overall, survival rates decreased during the study. In northern Yellowstone, density-dependence regulated adult survival through an increase in intraspecific aggression, independent of prey availability. In the interior of the park, adult survival was less variable and density-independent, despite reduced prey availability. There was no effect of prey population structure in northern Yellowstone, nor of winter severity in either area. Survival was similar among yearlings and adults, but lower for adults older than 6 years. 5. Our results indicate that density-dependent intraspecific aggression is a major driver of adult wolf survival in northern Yellowstone, suggesting intrinsic density-dependent mechanisms have the potential to regulate wolf populations at high ungulate densities. When low prey availability or high removal rates maintain wolves at lower densities, limited inter-pack interactions may prevent density-dependent survival, consistent with our findings in the interior of the park.
Data from: Density-dependent habitat selection of spawning Chinook salmon: broad scale evidence and implications
1. An extensive body of theory suggests that density-dependent habitat selection drives many fundamental ecological processes. The ideal free distribution and the ideal despotic distribution make contrasting predictions about the effect of total population size on relative abundances among habitats. Empirical assessment of these habitat selection models is uncommon because data must be collected over large temporal and spatial scales. 2. I ask whether fluctuation in Chinook salmon (Oncorhynchus tshawytscha) spawner population size through time leads to different relative densities over space. 3. Twenty six years of monitoring data on spawning Chinook salmon across the entire coast of Oregon, USA, were used to evaluate models that make contrasting statements about the interactions of a latent population abundance parameter with physical habitat characteristics. 4. There is strong information-theoretic support for models that include terms that allow the spatial variation in density to change as population size changes through time. Analysis of the best model reveals nonlinear isodars, which suggests a "despotic" or "preemptive" distribution of individuals across habitats, indicating that dominant or early arriving individuals exclude others from breeding sites. 5. This finding has implications for genetic dynamics, population dynamics, and conservation metrics of these highly valued fish. The novel application of modeling techniques used here to assess mechanisms of habitat selection from observational data can be used in the emerging field of eco-evolutionary dynamics.
Data from: Density-dependent effects of a widespread invasive herbivore on tree survival and biomass during reforestation
Reforestation has been widely adopted as a solution to multiple global change issues. However, the role of herbivory by invasive species in the restoration of grassland to forest has received little attention. We conducted a field experiment to investigate the impacts of a widespread invasive mammalian herbivore, the European rabbit (Oryctolagus cuniculus), on trees planted in a landscape-scale reforestation program in south-eastern Australia. Three native tree species were planted inside and outside rabbit-proof exclosures within 10 experimental units, and a random half of the units were subjected to intensive and sustained rabbit control for the remainder of the experiment. Quarterly survival of trees, and total aboveground biomass at the conclusion of the experiment, were estimated using hierarchical Bayesian models. Control substantially reduced rabbit densities on the five treatment units relative to the five non-treatment units. Survival of trees planted outside exclosures was highest at lowest rabbit density and declined non-linearly with increasing rabbit density for all three tree species, but even very low rabbit densities had strong negative effects on the survival of trees outside exclosures. There was a three-way interaction between tree height, being outside an exclosure, and rabbit density. Smaller trees planted outside exclosures always had substantially lower overall survival than trees of the same height planted inside exclosures, and the magnitude of the difference increased with increasing rabbit density. Increasing rabbit densities reduced the overall survival of increasingly taller trees of all three species planted outside exclosures. The aboveground biomass of trees surviving outside exclosures was significantly greater in treatment units compared with non-treatment units for all three species. The combined effects of differential survival and accumulation of aboveground biomass led to higher biomasses inside exclosures relative to outside exclosures just 21 months after planting. The aboveground biomass of trees planted outside exclosures declined with increasing rabbit density, and was effectively zero when rabbit densities exceeded 100 active warren entrances/ha. These results demonstrate that invasive herbivores can rapidly arrest the conversion of grassland to forest. Invasive herbivores such as the European rabbit may need to be completely excluded in order to maximize the benefits of reforestation.
Data from: Spatio-temporal dynamics of density-dependent dispersal during a population colonisation
Predicting population colonisations requires understanding how spatio-temporal changes in density affect dispersal. Density can inform on fitness prospects, acting as a cue for either habitat quality, or competition over resources. However, when escaping competition, high local density should only increase emigration if lower-density patches are available elsewhere. Few empirical studies on dispersal have considered the effects of density at the local and landscape scale simultaneously. To explore this, we analyze 5 years of individual-based data from an experimental introduction of wild guppies Poecilia reticulata. Natal dispersal showed a decrease in local density dependence as density at the landscape level increased. Landscape density did not affect dispersal among adults, but local density-dependent dispersal switched from negative (conspecific attraction) to positive (conspecific avoidance), as the colonisation progressed. This study demonstrates that densities at various scales interact to determine dispersal, and suggests that dispersal trade-offs differ across life stages.
Data from: Separating sources of density-dependent and density-independent establishment limitation in invading species
Successful colonization by invasive species depends on both the ability to disperse seeds to a site and an ability to establish once seeds have arrived. While seed and establishment limitation are known to jointly influence colonization, decomposing establishment limitation into density-dependent and density-independent components has remained challenging. Here, we couple theoretical models of recruitment with a multispecies invasion experiment conducted within a natural gradient of soil moisture and productivity to assess how variation in establishment limitation shapes outcomes for invasion. Recruitment was affected by both density-dependent and density-independent sources of establishment limitation in three of four species. Soil moisture stress and productivity both increased density-independent mortality in one species, whereas density-dependent mortality increased in locations with favourable soil moisture. Synthesis. Successful establishment of invading species can be limited by both density-dependent and density-independent mechanisms. In particular, the strength of density-independent limitation may depend on natural gradients in abiotic factors. The varying strengths of establishment limitation suggest that patterns of invasion are likely to be uneven both in space and in time. Understanding how intraspecific competitive constraints and density-independent limitation vary with abiotic gradients can assist with predicting when invasions are likely to occur, information that can be harnessed in the development of better methods for control.
Data from: Density-dependent fitness effects stabilize parasitic hitchhiking within a mutualism
1. Mutualisms are often subject to perturbations by parasitism arising from third-party interactions. How third-party perturbations are dampened is a fundamental question pertaining to mutualism stability. Phoretic organisms that turn parasitic within a mutualism may destabilise it. If the fitness cost of such phoresy is high, then density-dependent effects could be one mechanism to stabilize these interactions. 2. We experimentally examined the fitness effects of a phoretic nematode community on a brood-site pollination mutualism involving a pollinating fig wasp (the vehicle) and its associated fig species (the host for wasp and nematode development). 3. We comprehensively investigated fitness impacts of phoresy on wasp lifespan, lifetime reproductive success, dispersal ability and predation risk as well as on host brood-site volume and seed number. We employed a range of hitchhiker densities that encompassed natural and overloading levels for two nematode taxa (one plant- and one animal-parasitic type). 4. None of the plant host and vehicle fitness parameters were affected by wasps with low nematode transportation loads for either type of nematode. Furthermore, wasps arriving at their destinations carried lower densities of both animal- and plant-parasitic nematodes compared to dispersing wasps suggesting that there is selection on hitchhiker numbers during the dispersal process, and that wasps loaded with a greater density of nematodes do not successfully disperse. Overloaded wasps had shorter flight durations, suggesting limited dispersal ability; on arrival at their destination they suffered greater predation risk. Such overloaded wasps delivered impaired pollination services and produced fewer offspring resulting in lower lifetime fitness. Therefore, the direct and indirect effects of nematodes on their vehicles are strong. These effects also translated into impacts on host plant fitness, with the overloaded pollinators promoting the development of smaller brood-sites with fewer seeds, thus reducing fig tree reproductive success. The effects of the animal parasites were greater than that of the plant parasite in this study. 5. The third-party interaction is therefore self-limited and exhibits density dependence. The strong negative effects of overloading likely explain the low number of nematodes found in nature on dispersing and arriving fig wasps. Consequently, parasitic hitchhikers do not destabilise the mutualism.
Data from: Direct evidence that density-dependent regulation underpins the temporal stability of abundant species in a diverse animal community
To understand how ecosystems are structured and stabilized, and to identify when communities are at risk of damage or collapse, we need to know how the abundances of the taxa in the entire assemblage vary over ecologically meaningful timescales. Here, we present an analysis of species temporal variability within a single large vertebrate community. Using an exceptionally complete 33-year monthly time series following the dynamics of 81 species of fishes, we show that the most abundant species are least variable in terms of temporal biomass, because they are under density-dependent (negative feedback) regulation. At the other extreme, a relatively large number of low abundance transient species exhibit the greatest population variability. The high stability of the consistently common high abundance species—a result of density-dependence—is reflected in the observation that they consistently represent over 98% of total fish biomass. This leads to steady ecosystem nutrient and energy flux irrespective of the changes in species number and abundance among the large number of low abundance transient species. While the density-dependence of the core species ensures stability under the existing environmental regime, the pool of transient species may support long-term stability by replacing core species should environmental conditions change.
Data from: Population variation in density-dependent growth, mortality and their trade-off in a stream fish
<ol> <li>Important variation in the shape and strength of density-dependent growth and mortality is observed across animal populations. Understanding this population variation is critical for predicting density-dependent relationships in natural populations, but comparisons among studies are challenging as studies differ in methodologies and in local environmental conditions.</li> <li>Consequently, it is unclear whether: (1) the shape and strength of density-dependent growth and mortality are population-specific; (2) the potential trade-off between density-dependent growth and mortality differs among populations; and (3) environmental characteristics can be related to population differences in density-dependent relationships.</li> <li>To elucidate these uncertainties, we manipulated the density (0.3-7 fish/m<sup>2</sup>) of young-of-the-year brook trout (<i>Salvelinus fontinalis</i>) simultaneously in three neighboring populations in a field experiment in Newfoundland, Canada. Within each population, our experiment included both spatial (three sites per stream) and temporal (three consecutive summers) replication.</li> <li>We detected temporally consistent population variation in the shape of density-dependent growth (negative linear and negative logarithmic), but not for mortality (positive logarithmic). The strength of density-dependent growth across populations was reduced in sections with a high percentage of boulder substrate, whereas density-dependent mortality increased with increasing flow, water temperature, and more acidic pH. Neighbouring populations exhibited different mortality-growth trade-offs: the ratio of mortality-to-growth increased linearly with increasing density at different rates across populations (up to 4-fold differences), but also increased with increasing temperature.</li> <li>Our results are some of the first to demonstrate temporally consistent, population-specific density-dependent relationships and trade-offs at small spatial scales that match the magnitude of interspecific variation observed across the globe. Furthermore, key environmental characteristics explain some of these differences in predictable ways. Such population differences merit further attention in models of density-dependence and in science-based management of animal populations.</li> </ol>
Density-dependent effects of parasitism on the activity of a benthic engineer species: potential impact on ecosystem functioning
<p>While parasitism is a common lifestyle on Earth, its importance for the functioning of marine ecosystems has been overlooked for a long time. In particular, parasites have significant potential to influence central ecological processes through their impacts on hosts that serve as ecosystem engineers. Using an ex-situ experimental approach, we explored the effects of trematode parasites on the engineering bioturbation activity of a common and abundant bivalve along European Atlantic soft-bottom coastlines, the peppery furrow shell <em>Scrobicularia</em> <em>plana</em>, as well as knock-on effects for nutrient exchanges at the sediment-water interface. Trematodes negatively impacted the host's ability to transport sediment particles and solutes in a density-dependent way with parasite burden explaining 22–31% of the inter-individual variability. This could be explained by parasitism impairing the bivalve physiological state and ability to burrow as we observed a decrease in the condition index and the burrowing depth of the bivalves with an increase in the number of parasites they host. In contrast, the influence of <em>S. plana</em> on benthic biogeochemical fluxes did not vary significantly according to parasitic burden over a short time scale. Here, we focused on the effects of trematode parasites on the sole behaviour of <em>S. plana</em> and thus excluded other macrofaunal organisms. We should next test whether trematodes modulate the structure and functioning of benthic communities dominated by <em>S. plana</em> to better understand and quantify the engineering role of parasites in soft-bottom coastal environments.</p>
Data from: Harvest and density-dependent predation drive long-term population decline in a northern ungulate
<p><span>The relative effect of top-down versus bottom-up forces in regulating and limiting wildlife populations is an important theme in ecology. Untangling these effects is critical for a basic understanding of trophic dynamics and effective management. We examined the drivers of moose (<em>Alces alces</em>) population growth by integrating two independent sources of observations within a hierarchical Bayesian population model. This analysis used one of the largest existing spatiotemporal datasets on ungulate population dynamics globally. We documented a 20% population decline over the period examined. Moose population growth was negatively density-dependent. Although the mechanisms producing density-dependent suppression of population growth could not be determined, the relatively low densities at which moose populations were documented suggests it could be due primarily to density-dependent predation. Predation </span>primarily limited population growth, except at low density, where it was regulating. <span>Harvest appeared to be largely </span>additive<span> and contributed to population declines.</span> Our results, highlight how <span>population dynamics are context dependent and vary strongly across gradients in climate, forest type, and predator abundance. These results help clarify long-standing questions in population ecology and highlight the complex relationships between natural and human-caused mortality in driving ungulate population dynamics. </span></p>
Prey and predator density-dependent interactions under different water volumes
<p>Predation is a critical ecological process that directly and indirectly mediates population stabilities, as well as ecosystem structure and function. The strength of interactions between predators and prey may be mediated by multiple density-dependences concerning numbers of predators and prey. In temporary wetland ecosystems in particular, fluctuating water volumes may alter predation rates through differing search space and prey encounters rates. Using a functional response approach, we examined the influence of predator and prey densities on interaction strengths of the temporary pond specialist copepod <i>Lovenula raynerae </i>preying on cladoceran prey, <i>Daphnia pulex</i>, under contrasting water volumes. Further, using a population dynamic modelling approach, we quantified multiple predator effects across differences in prey density and water volume. Predators exhibited Type II functional responses under both water volumes, with significant antagonistic multiple predator effects (i.e. antagonisms) exhibited overall. The strengths of antagonistic interactions were, however, enhanced under reduced water volumes and at intermediate prey densities. These findings indicate important biotic and abiotic contexts that mediate predator-prey dynamics, whereby multiple predator effects are contingent on both prey density and search area characteristics. In particular, reduced search areas (i.e., water volumes) under intermediate prey densities could enhance antagonisms by heightening predator-predator interference effects.</p>
Data from: Density-dependent unidirectional hybridization between the Japanese pond turtle, Mauremys japonica and the exotic Reeves' pond turtle, Mauremys reevesii in Japan, inferred from molecular and morphological analyses
<p>Hybridisation between the indigenous Japanese pond turtle, <em>Mauremys japonica</em>, and the exotic Reeves' pond turtle, <em>Mauremys reevesii</em>, is widespread in Japan. In this study, we examined this hybridisation using an analysis of mtDNA and 11 microsatellite markers (MS) combined with morphometry. In a Bayesian clustering analysis of MS, the admixture of two clusters equivalent to the two species was detected in the Seto Inland Sea and Ise Bay regions. While mtDNA showed reciprocal hybridisation between the two species, their hybrids tended to possess the mtDNA of the rarer species at each locality. Contrary to preceding studies, F2/later generations outnumbered F1 generations. In addition, the admixture of two mtDNA lineages (Chinese and Korean) of <em>M. reevesii</em> was widely observed in all regions, together with the range expansion of the recently introduced Chinese lineage. A significant correlation was observed between plastron morph and assignment probability of MS, showing that plastron morphology reflects the degree of introgression by <em>M. reevesii</em> in <em>M. japonica</em>. This finding means that the reproductive interference of the dominant species on a rarer species is a major factor driving the hybridisation of the two Mauremys species. In addition, the range expansion of the Chinese lineage of M. reevesii appears to enhance the introgression by <em>M. reevesii</em> in <em>M. japonica</em>.</p>
The dataset for the manuscript entitled "SUPHRE: A reactive transport model with unsaturated and density-dependent flow"
<p>This is the dataset for the manuscript entitled "SUPHRE: A reactive transport model with unsaturated and density-dependent flow".</p>
FIG. 2 in Density-Dependent Fitness Attributes and Carry-Over Effects in Crawfish Frogs (Rana areolata), a Species of Conservation Concern
FIG. 2. Field data showing effects of juvenile density on juvenile body size (A, C) and time to metamorphosis (E), and breeding adult size (B, D) and survivorship (F). Lines reflect regression calculations. While suggestive, none of these trends is significant except for the adult SVL data shown in B.
Data from: Density-dependent sex-biased development of macroptery in a water strider
<p>In wing-polymorphic insects, wing morphs differ not only in dispersal capability but also in life history traits because of trade-offs between flight capability and reproduction. When the fitness benefits and costs of producing wings differ between males and females, sex-specific trade-offs can result in sex differences in the frequency of long-winged individuals. Furthermore, the social environment during development affects sex differences in wing development, but few empirical tests of this phenomenon have been performed to date. Here, I used the wing-dimorphic water strider <i>Tenagogerris euphrosyne</i> to test how rearing density and sex ratio affect the sex-specific development of long-winged dispersing morphs (i.e., sex-specific macroptery). I also used a full-sib, split-family breeding design to assess genetic effects on density-dependent, sex-specific macroptery. I reared water strider nymphs at either high or low densities and measured their wing development. I found that long-winged morphs developed more frequently in males than in females when individuals were reared in a high-density environment. However, the frequency of long-winged morphs was not biased according to sex when individuals were reared in a low-density environment. In addition, full-sib males and females showed similar macroptery incidence rates at low nymphal density, whereas the macroptery incidence rates differed between full-sib males and females at high nymphal density. Thus complex gene-by-environment-by-sex interactions may explain the density-specific levels of sex bias in macroptery, although this interpretation should be treated with some caution. Overall, my study provides empirical evidence for density-specific, sex-biased wing development. My findings suggest that social factors as well as abiotic factors can be important in determining sex-biased wing development in insects.</p>
Interactions with soil fungi alter density-dependence and neighborhood effects in a locally abundant dipterocarp species
<p>Seedling recruitment can be strongly affected by the composition of nearby plant species. At the neighborhood scale (on the order of tens of meters), adult conspecifics can modify soil chemistry and presence of host microbes (pathogens and mutualists) across their combined canopy area or rooting zones. At local or small spatial scales (on the order of one to few meters), conspecific seed or seedling density can influence the strength of intraspecific light and resource competition and also modify the density-dependent spread of natural enemies such as pathogens or invertebrate predators. Intrinsic correlation between proximity to adult conspecifics (i.e. recruitment neighborhood) and local seedling density, arising from dispersal, make it difficult to separate the independent and interactive factors that contribute to recruitment success. </p> <p>Here, we present a field experiment in which we manipulated both the recruitment neighborhood and seedling density to explore how they interact to influence the growth and survival of Dryobalanops aromatica, a dominant ectomycorrhizal tree species in a Bornean tropical rainforest. First, we found that both local seedling density and recruitment neighborhood had effects on performance of D. aromatica seedlings, though the nature of these impacts varied between growth and survival. Second, we did not find strong evidence that the effect of density on seedling survival is dependent on the presence of conspecific adult trees. However, accumulation of mutualistic fungi beneath conspecifics adults does facilitate establishment of D. aromatica seedlings. In total, our results suggest that recruitment near adult conspecifics was not associated with a performance cost and may have weakly benefitted recruiting seedlings. Positive effects of conspecifics may be a factor facilitating the regional hyperabundance of this species. </p> <p>Synthesis: Our results provide support for the idea that dominant species in diverse forests may escape the localized recruitment suppression that limits abundance in rarer species.</p>
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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.