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141 results for “species density”
Do food distribution and competitor density affect agonistic behaviour within and between clans in a high fission-fusion species?
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Data from: Density-dependent species interactions modulate alpine treeline shifts
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Data from: Density-dependence produces spurious relationships among demographic parameters in a harvested species
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Data from: The arboreal ants of a Neotropical rainforest show high species density and comprise one third of the ant fauna
<p>In tropical rainforests, the ant community can be divided into ground and arboreal faunas. Here we report a thorough sampling of the arboreal ant fauna of La Selva Biological Station, a Neotropical rainforest site. Forty-five canopy fogging samples were centered around large trees. Individual samples harbored an average of 35 ant species, with up to 55 species in a single sample. The fogging samples yielded 163 observed species total, out of a statistically estimated 199 species. We found no relationship between within-sample ant richness and focal tree species, nor were the ant faunas of nearby trees more similar to each other than the faunas of widely spaced trees. Species density was high and beta diversity was low: a single column of vegetation typically harbors at least a fifth of the entire arboreal ant fauna. Considering the entire fauna, based on 23,326 species occurrence records using a wide variety of collecting methods, 182 of 539 observed species (196 of 605, estimated statistically) were entirely arboreal. The arboreal ant fauna is thus about a third of the total La Selva ant fauna, a robust result because inventory completeness was similar for ground and arboreal ants. The taxonomic history of discovery of the species that make up the La Selva fauna reveals no disproportionately large pool of undiscovered ant species in the canopy. The "last biotic frontier" for tropical ants has been the rotten wood, leaf litter, and soil of the forest floor.</p>
Data from: Interspecific variation in conspecific negative density dependence can make species less likely to coexist
Conspecific negative density dependence (CNDD) is thought to promote plant species diversity. Theoretical studies showing the importance of CNDD often assumed that all species are equally susceptible to CNDD; however, recent empirical studies have shown species can differ greatly in their susceptibility to CNDD. Using a theoretical model, we show that interspecific variation in CNDD can dramatically alter its impact on diversity. First, if the most common species are the least regulated by CNDD, then the stabilising benefit of CNDD is reduced. Second, when seed dispersal is limited, seedlings that are susceptible to CNDD are at a competitive disadvantage. When parameterised with estimates of CNDD from a tropical tree community in Panama, our model suggests that the competitive inequalities caused by interspecific variation in CNDD may undermine many species' ability to persist. Thus, our model suggests that variable CNDD may make communities less stable, rather than more stable.
Data from: Genetic sampling for estimating density of common species
Understanding population dynamics requires reliable estimates of population density, yet this basic information is often surprisingly difficult to obtain. With rare or difficult-to-capture species, genetic surveys from noninvasive collection of hair or scat has proved cost-efficient for estimating densities. Here, we explored whether noninvasive genetic sampling (NGS) also offers promise for sampling a relatively common species, the snowshoe hare (Lepus americanus Erxleben, 1777), in comparison with traditional live trapping. We optimized a protocol for single-session NGS sampling of hares. We compared spatial capture–recapture population estimates from live trapping to estimates derived from NGS, and assessed NGS costs. NGS provided population estimates similar to those derived from live trapping, but a higher density of sampling plots was required for NGS. The optimal NGS protocol for our study entailed deploying 160 sampling plots for 4 days and genotyping one pellet per plot. NGS laboratory costs ranged from approximately $670 to $3000 USD per field site. While live trapping does not incur laboratory costs, its field costs can be considerably higher than for NGS, especially when study sites are difficult to access. We conclude that NGS can work for common species, but that it will require field and laboratory pilot testing to develop cost-effective sampling protocols.
Density-dependent within-patch movement behavior of two competing species
<p class="MsoNormal">Movement behavior is central to understanding species distributions, population dynamics and coexistence with other species. At present, relatively little is known about how conspecific and interspecific competitor density affect movement behavior. We conducted releases of two species of competing <em>Tribolium</em> flour beetles at different densities, alone and together in homogeneous microcosms, and tested whether their recaptures-with-distance were well described by a random-diffusion model. We also determined whether mean displacement distances varied with the release density of conspecific and heterospecific beetles. A diffusion model provided a good fit to the redistribution of <em>T. castaneum</em> and <em>T. confusum </em>at all release densities, explaining an average of >60% of the variation in recaptures. For both species, mean displacement (directly proportional to the diffusion rate) exhibited a humped-shaped relationship with conspecific density. Finally, we found that both species of beetle impacted the within-patch movement rates of the other species, but it depended on density. For <em>T. castaneum</em> in the highest density treatment, the addition of equal numbers of <em>T. castaneum</em> or <em>T. confusum</em> had the same effect, with mean displacements reduced by approximately one-half. The same result occurred for <em>T. confusum</em> released at an intermediate density. In both cases, it was total beetle abundance, not species identity that mattered to mean displacement. We suggest that displacement or diffusion rates that exhibit a nonlinear relationship with density or depend on the presence or abundance of interacting species should be considered when attempting to predict the spatial spread of populations.</p>
Wood density and leaf size jointly predict woody plant growth rates across (but not within) species along a steep precipitation gradient
<p>1. Functional traits have been proposed to define key dimensions of plant ecological strategies, but we lack consensus on whether traits can accurately predict plant demography. Despite theoretical expectations, it has been challenging to find consistent relationships between functional traits and growth. 2. In this study, we quantified inter- and intraspecific trait variation and individual growth rates of woody plants across a steep moisture gradient that varies 10-fold in annual precipitation (350–3,700 mm) in southern Chile and used a hierarchical Bayesian model to predict growth as a function of trait values. 3. We show that large-leaved species with lower stem tissue density exhibited the fastest growth rates, and these two traits exhibited the highest proportion of interspecific variation. Predictions of growth improved considerably (R2 of the best model increased from 0.28 to 0.49) when species-level multiple traits and their interactions were considered. The inclusion of intraspecific trait variation (ITV), however, did not improve models of growth rate. 4. We found that trait-growth rate relationships were not always consistent across levels of biological organization; relationships observed at the interspecific level did not necessarily hold at the intraspecific level. We found that the relationships between wood density or leaf size and growth were consistent in direction across the precipitation gradient, and the relationships between leaf economics traits and growth were weak and site-specific. 5. Synthesis. Although using more than one functional trait considerably improved growth predictions, wood density and leaf size successfully predicted growth rates across (not within) species, which is consistent with a whole-plant carbon economy. We assert that these two traits are intimately linked and ultimately describe a continuum of plant architecture and carbon economy that covers multiple trait syndromes.</p>
Elucidating the association of trichome and stomatal densities across species
<p>Previous studies suggested a trade-off between trichome density (<em>D</em><sub>t</sub>) and stomatal density (<em>D</em><sub>s</sub>) due to shared cell precursors. We clarified how, when, and why this developmental trade-off may be overcome across species. We derived equations to determine the developmental basis for <em>D</em><sub>t</sub> and <em>D</em><sub>s</sub> in trichome and stomatal indices (<em>i</em><sub>t</sub> and <em>i</em><sub>s</sub>), and the sizes of epidermal pavement cells (<em>e</em>), trichome bases (<em>t</em>) and stomata (<em>s</em>), and quantified the importance of these determinants of <em>D</em><sub>t</sub> and <em>D</em><sub>s</sub> for 78 California species. We compiled 17 previous studies of <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> relationships to determine the commonness of <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> associations. We modelled the consequences of different <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> associations for plant carbon balance. Our analyses showed that higher <em>D</em><sub>t</sub> was determined by higher <em>i</em><sub>t</sub> and lower <em>e</em>, and higher <em>D</em><sub>s</sub> by higher <em>i</em><sub>s</sub> and lower <em>e</em>. Across California species, positive <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> coordination arose due to <em>i</em><sub>t</sub>-<em>i</em><sub>s</sub> coordination and impacts of the variation in <em>e</em>. A <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> trade-off was found in only 30% of studies. Heuristic modeling showed that species sets would have the highest carbon balance with a positive or negative relationship or decoupling of <em>D</em><sub>t</sub> and <em>D</em><sub>s</sub>, depending on environmental conditions. Shared precursor cells of trichomes and stomata do not limit higher numbers of both cell types, or drive a general <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> trade-off across species. This developmental flexibility across diverse species enables different <em>D</em><sub>t</sub>-<em>D</em><sub>s</sub> associations according to environmental pressures.<sub> </sub>Developmental trait analysis can clarify how contrasting trait associations would arise within and across species.</p>
Insect root feeders incur negative density-dependent damage across plant species in an alpine meadow
<p>Although herbivores are well known to incur positive density-dependent damage and mortality, thereby likely shaping plant community assembly, the response of belowground root feeders to changes in plant density has seldom been addressed. Locally rare plant species (with lower plant biomass per area) are often smaller with shallower roots than common species (with higher plant biomass per area) in competition-intensive grasslands. Likewise, root feeders are often distributed in the upper soil layers. We hypothesized therefore that root feeders would incur a negative density (biomass) dependent damage across plant species. To test this hypothesis, we investigated the diversity and abundance of plant and root feeder species in an alpine meadow, and determined the diet of the root feeders using metabarcoding. Across all species, root feeder load decreased with increasing aboveground plant biomass, root biomass, and total plant biomass per area, indicating negative density dependence of damage across plant species. Aboveground plant biomass per area increased with increasing individual plant biomass and root depth per area across species, suggesting that rare plant species were smaller in size and had shallower root systems compared to common plant species. Both root biomass per area and root feeder biomass per area decreased with soil depth, but the root feeder biomass decreased disproportionally faster compared to root biomass with increasing root depth. Root feeder load decreased with increasing root depth, but was not correlated with the feeding preference of root feeder species. Moreover, the prediction derived from a random process incorporating vertical distributions of root biomass and root feeder biomass significantly accounted for interspecific variation in root feeder load. In conclusion, the data indicate that root feeders incur negative density-dependent damage across plant species. On this basis, we suggest that manipulative experiments should be conducted to determine the effect of the negative density-dependent damage on plant community structure, and that different types of plant-animal interactions should be concurrently examined to fully understand the effect of plant density on overall herbivore damage across plant species.</p>
Fig. 1 in Effect Of Farming And Rainfall On The Species Diversity, Population Density And Community Structure Of Birds Breeding In The Kalahari Woodland, Ne Namibia
Fig. 1. The location of the transect (indicated with red arrow).
Fig. 2 in Effect Of Farming And Rainfall On The Species Diversity, Population Density And Community Structure Of Birds Breeding In The Kalahari Woodland, Ne Namibia
Fig. 2. Monthly rainfall in Katima Mulilo in 2014 and 2015.
Fig. 4 in Effect Of Farming And Rainfall On The Species Diversity, Population Density And Community Structure Of Birds Breeding In The Kalahari Woodland, Ne Namibia
Fig. 4. Percentage of main nesting guilds in 2014 and 2015.
Turning summer into winter: nutrient dynamics, temperature, density dependence, and invasive species drive bioenergetic processes and growth of a keystone coldwater fish
<p>A combination of global changes such as species invasions, climate change, and nutrient pollution have altered ecosystems, food webs, and the bioenergetic processes that control growth. These changes are especially pronounced in freshwater ecosystems and often lead to rapid variation in fish growth and dependent ecosystems services such as fishery yield. Understanding the mechanisms driving growth responses to environmental change is important for interpreting past dynamics and sustainably managing ecosystems. This study uses integrated bioenergetics and growth modeling to understand how nutrient dynamics, species invasions, and changing temperatures have altered growth of the keystone pelagic whitefish (<em>Coregonus</em> <em>wartmanni</em>) in Lake Constance, Germany from 1925 to 2020. Growth variation was modeled by allowing covariates to alter temperature-dependent consumption, while size-specific metabolism varied only with temperature. Consumption and growth increased strongly to a maximum with phosphorous, and this effect was stronger when intraspecific competition (measured as whitefish biomass) was low. Increasing whitefish biomass reduced growth under mesotrophic conditions, but had no effect under oligotrophic conditions. In contrast, increasing competition with invasive three-spined stickleback (<em>Gasteosteus</em> <em>aculeauts</em>) was predicted to reduce growth even under oligotrophic conditions. The invasion has effectively turned summer into winter for whitefish, with older fish ceasing to grow and younger fish losing up to 10% of their body weight during the normal growing season in subsequent years. Warming is predicted to further reduce whitefish growth due to competition with invasive stickleback, which would further alter zooplankton food availability and reduce already low fishery yields. These results demonstrate the importance of considering biotic interactions and synergistic effects in global change studies, as well as the value of mechanistic-based models for understanding effects. Similar growth responses to ecosystem change are likely within and across ecosystems, and bioenergetic models can help understand effects to support informed ecosystem management.</p>
Data availability: Random encounter model is a reliable method for estimating population density of multiple species using camera traps
<p>Data of the paper entitled "Random encounter model is a reliable method for estimating population density of multiple species using camera traps" published on Remote Sensing in Ecology and Conservation</p>
FIGURE 2 in Egg Number Varies With Population Density; A Study Of Three Oribatid Mite Species In Orchard Habitats In Egypt
FIGURE 2:: Average population densities of the three studied species as a function of sampling time. Means are given with their standard errors. For each vegetation type, means were taken over three different sites (cf. Fig. 1) and three replicate samples within a site.
FIGURE 1 in Egg Number Varies With Population Density; A Study Of Three Oribatid Mite Species In Orchard Habitats In Egypt
FIGURE 1: Map of Al-Gharbia Governate in Egypt, indicating the three sampling areas (Tanta, Al Mahalla Al Kobra and Kafr Al Zayat). The inset shows the location of Al-Gharbia in Egypt. In each area, three orchards were sampled four times in a year. The same three types of orchard were selected in each area. The distance between locations varies from 19 to 38 km; the distance between sites within one location is 1-2 km.
FIGURE 3 in Egg Number Varies With Population Density; A Study Of Three Oribatid Mite Species In Orchard Habitats In Egypt
FIGURE 3: Relationship between population density and fecundity of the three studied species. The data (pooled over three samples per site) are for all sites, vegetation types and seasons together.
Estimated densities of activity from: Characterising diel activity patterns to design conservation measures: Case study of European bat species
<p>Estimated densities of activity calculated in <em>"Characterising diel activity patterns to design conservation measures: case study of European bat species"</em> (see Materials and Methods for more information on these calculations).</p> <p>The files named "<em>densitiyAllYear</em>" correspond to the estimated densities based on our entire dataset.</p> <p>The files named "<em>densitiySpring</em>" correspond to the estimated densities based on a subset of our dataset comprising only monitoring carried out between 1 March and 21 June.</p> <p>The files named "<em>densitiySummer</em>" correspond to the estimated densities based on a subset of our dataset comprising only monitoring carried out between 22 June and 21 August.</p> <p>The files named "<em>densitiyAutumn</em>" correspond to the estimated densities based on a subset of our dataset comprising only monitoring carried out between 22 August and 31 October.</p> <p>The first column of each file (<em>"PercentageNight"</em>) corresponds to the percentage of the night elapsed (0 % = sunset time, 100 % = sunrise time), the second to the estimated activity density (<em>"Density"</em>).</p>
Data and R scripts for: Ant invasions is associated with lower root density and different root distribution of a foundational savanna tree species
<p>Some invasive ants have worldwide distributions and impose substantial impacts on human society and native biodiversity. Yet we know little about how ants impact soil ecosystems in general, much less how soil ecosystems shift when invasive ants move in. We excavated the coarse roots of a monodominant savanna tree in invaded and uninvaded areas to test the hypothesis that the presence of invasive ants would be associated with changes in root distribution and biomass across the landscape. We found that in the presence of invasive ants, trees had a shifted distribution of lateral coarse roots, with proportionally less root biomass near the surface and far from tree stems. In addition, the density of lateral coarse-root biomass was ~20% lower for trees within invaded landscapes. Our results suggest that soil-nesting invasive ants can drive important changes in rooting strategy for a tree species that serves a foundational role in the biogeochemical cycles of vertisol savannas.</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.