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27 results for “leafing density”
Data for a leaf litter decomposition study and soil density fractionation analysis at a whole-watershed fertilization experiment in a temperate forest
To assess how elevated N deposition influences leaf litter decomposition dynamics and soil organic matter formation in a temperate deciduous forest, we coupled a reciprocal transplant leaf litter decomposition study with an analysis of the distribution of soil organic matter in mineral associated and particulate organic matter fractions at a long-term, whole-watershed, N fertilization experiment. We found that nearly 30 years of N additions slowed decay rates by about 11% for leaf litter decomposed in the fertilized watershed, regardless of the watershed from which the initial litter was collected. An apparent consequence of the altered rates of decomposition was that the soil in the fertilized watershed had about a 40% greater fraction of SOM in light particulate organic matter compared to the reference watershed, which was positively correlated with the bulk soil carbon to nitrogen ratio. Collectively, our results suggest that under conditions of N saturation, the physical transfer pathway of SOM formation is favored, which can have important implications for the future of the soil organic matter stock and nutrient cycling.
Effect of plant density and light availability on leaf damage in Manilkara bidentata
Variation in herbivory is often associated with plant density and light environment. To determine the effect of these variables on herbivory we studied leaf production and herbivory on saplings, juveniles and adults of Manilkara bidentata (Sapotaceae) in the Luquillo Experimental Forest (LEF), Puerto Rico. The major herbivore of M. bidentata is microlepidoptera leaf miner (Acrocercopssp.; Gracillariidae). To determine the effect of plant density on herbivory, 24 - 20 x 20 m plots were established and the density of saplings, juveniles and adults were determined. Leaf production, herbivory and growth were measured on all saplings in the plots. In addition, plant density was determined in 8-20 x 20 m plots surrounding the 24 focal plots. The effect of light environment was determined by comparing leaf phenology, leaf quality and herbivory in the vertical and horizontal profile. Sapling density in 60 x 60 m plots was associated with increased levels of herbivory. In the vertical profile, leaf production was continuous in the canopy and synchronous for juveniles and saplings and herbivory increased from the canopy (1.3%) towards the understory (35.6%). In the horizontal profile leaf production was related with the light environmen. Saplings in low light environment produced leaves in June, while plants in gaps had a broader peak of leaf production. Differences in leaf phenology did not result in differences in herbivory possibly because there was high variation in herbivory among leaves. Although many saplings lost more than 80% of new leaf area, there was no detectable effect on plant growth. Support for this work was provided by grants BSR-8811902, DEB-9411973, DEB-9705814 , DEB-0080538, DEB-0218039 , DEB-0620910 , DEB-1239764, DEB-1546686, and DEB-1831952 from the National Science Foundation to the University of Puerto Rico as part of the Luquillo Long-Term Ecological Research Program. Additional support provided by the University of Puerto Rico and the International
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>
Data from: Density-dependent disease, life history tradeoffs, and the effect of leaf pathogens on a suite of co-occurring close relatives
1. Plant pathogens reduce the performance of their hosts and therefore may contribute to ecological mechanisms of coexistence. In Chesson's framework, pathogens contribute to stabilizing mechanisms when they intensify negative intraspecific interactions, such as density-dependent disease. Additionally, pathogens contribute to equalizing mechanisms when they reduce differences in performance among species. Life history tradeoffs predict higher susceptibility to pathogens in rapidly growing species, which could equalize performance among fast- and slow-growing species in the presence of pathogens. 2. In a coastal prairie in California, we studied the impact of leaf diseases on the performance of seventeen coexisting species of Trifolium and Medicago ("clovers"). We transplanted clovers in randomized arrays into the natural prairie community in three years of common garden experiments. We quantified infection rates by isolating fungi from leaves, and we measured disease severity as percent leaf area damaged. In a fungicide experiment, we measured the impact of infection on biomass and survival. We assessed whether disease on transplants was positively related to natural abundance of that species in the surrounding community, which we monitored over 5 years. We assessed life history tradeoffs by testing whether more rapidly growing species were more susceptible to pathogens. 3. Rank abundance of clover species was stable over five years despite marked environmental fluctuations. Across hosts, fungal infection was not linearly related to density, although transplants of species that were locally absent showed lower and more variable infection. Disease severity was greater for more abundant species in only one of three years, and response to fungicide was not stronger in more abundant species. Faster-growing species experienced greater fungal infection. Consistent with predictions of the leaf economic spectrum, the impact of infection on faster-growing species was less negative than for slower-growing species. 4. Our results suggest that life history tradeoffs in plant-pathogen interactions may contribute to equalizing mechanisms among species in this guild, but that the combined effects of greater infection with greater tolerance may limit rather than promote coexistence. We also found modest evidence that density-dependent disease may contribute to stabilizing mechanisms. Lack of host specificity, rapid evolution of host use, and temporal variation in climatic conditions may all influence the role that pathogens play in coexistence of these closely related plants.
Effects of tree species diversity and conspecific seedling density on insect herbivory and pathogen infection on big-leaf mahogany seedlings
<p>The Janzen-Connell Hypothesis (JCH) predicts that attack by specialist enemies on seedlings increases with conspecific seedling density, but studies have rarely experimentally tested for the contingency of such effects on tree community context (e.g., diversity, composition) and measured responses by different enemies (e.g. herbivores, pathogens). We conducted a field study in a large-scale system evaluating tree species diversity and conspecific density effects on leaf damage on mahogany (<em>Swietenia macrophylla</em>) seedlings. We established quadrats of eight levels of seedling density across mahogany tree monocultures and species polycultures including mahogany, and recorded percent leaf damage by insects and percent leaf necrosis by a pathogenic fungus on mahogany seedlings. We found contrasting effects of tree species diversity on insects and pathogens. Whereas diversity did not affect leaf damage by insects, it had a significant negative effect on leaf necrosis by pathogens. On average, percent leaf necrosis on mahogany seedlings in polyculture was half of that observed in monoculture. We discuss the potential influences of changes in mahogany tree density vs. frequency (relative to other tree species) driving this diversity effect. Unexpectedly, we found no effect of seedling conspecific density on either leaf insect or pathogen damage (i.e., density-independent attack). Likewise, we found no significant tree diversity by seedling density interaction, indicating that attackers were consistently unresponsive to variation in seedling density across two levels of tree diversity. Overall, this study provides a unique test of the JCH by experimentally evaluating seedling density and tree diversity effects on contrasting plant enemies, shedding light on enemy controls over plant recruitment.</p>
Nutrients from spawning salmon influence leaf area, tissue density, and nitrogen-15 in riparian plant leaves
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Leaf habit, maximum height, and wood density of tropical woody flora in Africa: Phylogenetic constraints, covariation, and responses to seasonal drought
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Data from: Density-dependent disease, life history tradeoffs, and the effect of leaf pathogens on a suite of co-occurring close relatives
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Wood density and leaf size jointly predict woody plant growth rates across (but not within) species along a steep precipitation gradient
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Effects of tree species diversity and conspecific seedling density on insect herbivory and pathogen infection on big-leaf mahogany seedlings
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FAB 1 Leaf Herbivory:FAB 1 : Forests and Biodiversity Experiment - High density diversity
A forest biodiversity experiment (FAB) focused on trees of our region investigates the consequences of multiple dimensions of tree diversity for soil, food webs, plant communities and ecosystems. FAB is designed to unravel effects of three forms of biological diversity: species richness (SR), functional diversity (FD), and phylogenetic diversity (PD). We define FD as the representation of multiple traits of leaves, roots, seeds, and the whole organism that are correlated with species positions along gradients of resource supply, growth, and decomposition. PD is the representation of evolutionary lineages measured as the genetic distances between species. While PD and FD are often correlated, convergent evolution and adaptive differentiation can decouple them. When functional traits that drive specific ecosystem functions are not phylogenetically conserved, PD and FD may give contrasting predictions. SR, PD, and FD are not independent, and we posit that PD may help explain SR effects, and FD may help explain both PD and SR effects. Thus FAB is designed to examine the separate and combined effects of all three components of diversity for multiple ecosystem functions and to distinguish between ???sampling??? and ???complementarity??? effects of biodiversity. Due to the long lag between planting tree seedlings and determining effects of tree composition and diversity on ecosystem functioning, fewer experiments have been established to elucidate the role of biodiversity in the functioning of forest ecosystems than grassland experiments. FAB will contribute to this gap and is a member of the IDENT and TreeDiv network of forest biodiversity experiments (www.treedivnet.ugent.be). Hypotheses: 1. PD, FD, and SR will all contribute to increased productivity, stability, and diversity of other trophic levels (herbivores, predators, parasitoids, soil microbes, soil flora and fauna) as well as to greater soil C sequestration. 2. Because PD incorporates both the number of species a
Tilia americana leaf senescence phenology:FAB 1 : Forests and Biodiversity Experiment - High density diversity
A forest biodiversity experiment (FAB) focused on trees of our region investigates the consequences of multiple dimensions of tree diversity for soil, food webs, plant communities and ecosystems. FAB is designed to unravel effects of three forms of biological diversity: species richness (SR), functional diversity (FD), and phylogenetic diversity (PD). We define FD as the representation of multiple traits of leaves, roots, seeds, and the whole organism that are correlated with species positions along gradients of resource supply, growth, and decomposition. PD is the representation of evolutionary lineages measured as the genetic distances between species. While PD and FD are often correlated, convergent evolution and adaptive differentiation can decouple them. When functional traits that drive specific ecosystem functions are not phylogenetically conserved, PD and FD may give contrasting predictions. SR, PD, and FD are not independent, and we posit that PD may help explain SR effects, and FD may help explain both PD and SR effects. Thus FAB is designed to examine the separate and combined effects of all three components of diversity for multiple ecosystem functions and to distinguish between ???sampling??? and ???complementarity??? effects of biodiversity. Due to the long lag between planting tree seedlings and determining effects of tree composition and diversity on ecosystem functioning, fewer experiments have been established to elucidate the role of biodiversity in the functioning of forest ecosystems than grassland experiments. FAB will contribute to this gap and is a member of the IDENT and TreeDiv network of forest biodiversity experiments (www.treedivnet.ugent.be). Hypotheses: 1. PD, FD, and SR will all contribute to increased productivity, stability, and diversity of other trophic levels (herbivores, predators, parasitoids, soil microbes, soil flora and fauna) as well as to greater soil C sequestration. 2. Because PD incorporates both the number of species a
Atmospheric pollutant concentrations and leaf chemistry variables collected along gradients of median household income and traffic density in Salt Lake Valley, UT
<p>We utilize traffic density and <i>Convolvulus arvensis </i>leaf chemistry<i> </i>to understand spatial patterns linking atmospheric pollution and household income in the Salt Lake City metropolitan area, USA. We hypothesize that traffic density will explain variation in atmospheric NO<sub>x</sub> and O<sub>3</sub> concentrations. In addition, we expect foliar <span>%N and nitrogen isotope ratios (</span>δ<sup>15</sup>N) to be elevated and carbon isotope ratios (δ<sup>13</sup>C) to be depleted on high traffic density roads<span>. These hypotheses were supported: we found the</span><span> highest</span><span> NO<sub>x</sub> and lowest O<sub>3</sub> concentrations on high-traffic density roads. Also, NO<sub>x</sub> concentrations were higher in low-income neighborhoods. Low-income neighborhoods contained a greater density of high-traffic roads than high-income neighborhoods. Foliar %N was highest in low-income neighborhoods and was correlated with NO<sub>x</sub> and O<sub>3</sub></span>, while δ<sup>15</sup>N was more depleted with increasing O<sub>3</sub>. These findings indicate that the distribution of high-traffic density roads plays a significant role in inequities in pollution exposure between high- and low-income neighborhoods, which is reflected in leaf chemistry.</p>
LiDAR-derived voxel-based leaf area density distribution data of urban trees
<p>This dataset includes 3D tree models and radiative transfer codes used in a paper entitled "Simulating the 3D distribution of absorbed shortwave radiation in a tree crown: comparison of simplified and Monte Carlo models" submitted to the JGR: Atmospheres.</p>
Data from: High-density genetic map construction and QTL mapping of leaf and needling traits in Ziziphus jujuba Mill.
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Atmospheric pollutant concentrations and leaf chemistry variables collected along gradients of median household income and traffic density in Salt Lake Valley, UT
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Data from: The genetic architecture of constitutive and induced trichome density in two new RIL populations of Arabidopsis thaliana: phenotypic plasticity, epistasis, and bidirectional leaf damage response
Background: Herbivory imposes an important selective pressure on plants. In Arabidopsis thaliana leaf trichomes provide a key defense against insect herbivory; however, trichome production incurs a fitness cost in the absence of herbivory. Previous work on A. thaliana has shown an increase in trichome density in response to leaf damage, suggesting a mechanism by which the cost associated with constitutively high trichome density might be mitigated; however, the genetic basis of trichome density induction has not been studied. Results: Here, we describe the mapping of quantitative trait loci (QTL) for constitutive and damage induced trichome density in two new recombinant inbred line populations of A. thaliana; mapping for constitutive and induced trichome density also allowed for the investigation of damage response (plasticity) QTL. Both novel and previously identified QTL for constitutive trichome density and the first QTL for induced trichome density and response are identified. Interestingly, two of the four parental accessions and multiple RILs in each population exhibited lower trichome density following leaf damage, a response not previously described in A. thaliana. Importantly, a single QTL was mapped for the response phenotype and allelic variation at this locus appears to determine response trajectory in RILs. The data also show that epistatic interactions are a significant component of the genetic architecture of trichome density. Conclusions: Together, our results provide further insights into the genetic architecture of constitutive trichome density and new insights into induced trichome density in A. thaliana specifically and to our understanding of the genetic underpinnings of natural variation generally.
Data from: The genetic architecture of constitutive and induced trichome density in two new RIL populations of Arabidopsis thaliana: phenotypic plasticity, epistasis, and bidirectional leaf damage response
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Data from: Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area
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TRANSPARENT TESTA GLABRA1 (TTG1) regulates leaf trichome density in tea (Camellia sinensis)
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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.