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6,175 results for “composition”
Seedling composition, growth, and dynamics in tropical rain forest, La Selva, Costa Rica (1983-1996)
Recruitment, growth, and survivorship of the regeneration stages of trees and lianas were studied in old-growth tropical rain forest at La Selva Biological Station of the Organization for Tropical Studies (OTS), near Puerto Viejo de Sarapiquí, Heredia Province, in the Caribbean lowlands of Costa Rica. A total of 48 permanent seedling transects each measuring 10 m x 0.5 m were established at random locations within three La Selva permanent forest inventory plots. The forest plots occupy contrasting landforms: Plot 1 (4.4 ha), old alluvial terrace; Plot 2 (4.0 ha), swamp forest and low hills; and Plot 3 (4.0 ha), steeply dissected terrain with residual volcanic soils. Seedling locations are georeferenced within the grid system of the permanent forest inventory plots, facilitating spatial analysis of seedling populations with respect to adult cohorts. Beginning in June 1983, all seedlings ≤ 0.5 m in height belonging to tree and liana species capable of reaching 10 cm diameter at breast height (dbh) at maturity were tagged, identified to species or morphospecies, mapped to the nearest cm, and measured in height to the nearest cm. Over a period of 18 months, a total of 6403 seedlings belonging to 167 species were tagged. Monitoring and re-measurement of all tagged individuals continued through November 1996. Data include 17 census dates over a period of 13.5 years. At the time of the final census, only 97 individuals (1.52% of the tagged seedlings) were still alive, representing 43 species (25.7% of the initial number). The largest surviving seedling had grown in height from 4 cm to 13 meters during the study period. This dataset on the regeneration stages in old-growth tropical rain forest in the La Selva permanent inventory plots forms a complement to the studies of long-term growth and demography of these species and assemblages at adult stages within the plots. Forest inventory data for trees and lianas ≥ 10 cm dbh in the permanent plots in which the seedling transec
H2Ohio Wetland Monitoring Program Vegetation Community Composition, Biomass, and Nutrient Content across Ohio, USA (2021-2022)
This data package includes vegetation community composition, percent cover, biomass, and nutrient concentration data from wetland projects across Ohio, USA, monitored by the H2Ohio Wetland Monitoring Program. Monitoring began in July 2021 and is ongoing, with annual updates planned. While data collection varies by site, most wetlands are surveyed to characterize vegetation and estimate nutrient stocks through community composition assessments and biomass sampling. Sampling points are randomly generated within and up to 5 meters outside the approximated wetland boundary. Surveys are conducted at points where wetland species (FAC–OBL) are present using a 1×1 meter quadrat to record species composition and percent cover. At approximately half of these locations, a 0.25×0.25 meter quadrat is placed outside the northeast corner to collect vegetation samples for nutrient analysis. In these smaller quadrats, community composition and percent cover are recorded prior to sampling aboveground biomass and, at approximately one third of those sites, belowground biomass. Datasets collected by the H2Ohio Wetland Monitoring Program containing surface water and soil nutrient concentration from samples collected at Ohio wetlands during the 2021–2022 sampling period can be found in an accompanying data package (edi.2087) at https://doi.org/10.6073/pasta/297bd6d93b4fcc8416e4225834db380e.
Woody vegetation composition and structure at long-term monitoring plots on the Stevenson-Hamilton Research Supersite, Kruger National Park, South Africa (2012)
This dataset contains measurements of woody vegetation composition and structural attributes collected in 2012 from long-term ecological monitoring plots located on the Stevenson-Hamilton Research Supersite in the Kruger National Park, South Africa. The study region is characterized by granitic soils, broad-leaved savanna vegetation, and a long history of fire, herbivory, and climate-driven ecological dynamics. Vegetation surveys were conducted in sixteen 0.25-ha sampling plots to quantify woody species composition, stem density, and size structure. Additional measurements of vegetation structure were collected, including grass biomass, canopy cover, canopy height, and canopy diversity, providing a broader assessment of both woody and herbaceous layers. These data establish an important baseline for monitoring ecological change, evaluating woody vegetation dynamics under variable fire and herbivore regimes, and supporting ongoing research on savanna ecosystem functioning within the Kruger National Park.
Riparian Woody Vegetation Composition and Structure in Long-Term Monitoring Plots Along the Sabie River, Kruger National Park (2011-2012)
This dataset contains measurements of woody vegetation composition and structural attributes collected in 2009 and 2010 from 15 long-term riparian monitoring plots located along the Sabie River in the southern region of the Kruger National Park, South Africa. The Sabie River is the park’s most perennial river system and supports diverse riparian plant communities influenced by hydrological variability, flooding dynamics, sediment deposition, herbivory, and climate-driven disturbance. Within each monitoring plot, field teams recorded woody species identity, stem density, plant height, and stem diameter. Additional structural and condition indicators were collected, including canopy breakage, evidence of bark stripping, resprouting status, and whether individuals were toppled or alive at the time of sampling. These structural attributes provide detailed assessments of disturbance impacts and vegetation condition within riparian zones. Data collection followed the same standardized protocols as the Southern Granites long-term vegetation monitoring program, allowing for cross-site comparisons between upland savanna and riparian systems. This dataset provides a baseline for evaluating long-term ecological change in riparian woody plant communities and supports ongoing research on the ecological functioning and resilience of river corridors in Kruger National Park.
Composition and biodegradability of dissolved organic matter leached from eroding coastal soils and permafrost in seawater, from Drew Point, Alaska
Eroding permafrost coastlines export significant quantities of organic carbon (OC) to the marine environment, similar in magnitude to riverine particulate OC fluxes to the Arctic Ocean. Moreover, erosion rates are predicted to increase due to warming temperatures, declines in sea ice, and increasing waves. While erosion primarily mobilizes organic matter in the particulate form, this material can be leached to dissolved organic matter (DOM). This DOM may be incorporated by microbial communities and fuel marine food webs or decomposed to form greenhouse gases like carbon dioxide and methane. Many studies show that permafrost-derived organic matter can be rapidly decomposed in soils and freshwater, but few studies examine the fate of permafrost organic matter in seawater. To address this knowledge gap, we designed a laboratory experiment to leach coastal soils and permafrost in seawater and examine the composition and biodegradability of leached DOM. Coastal soil/sediment was cored near Drew Point, Alaska in 2019, representing three horizons found within rapidly eroding permafrost bluffs: seasonally thawed active layer soils, Holocene terrestrial soils and/or lacustrine sediments, and late-Pleistocene relict marine sediments. To measure dissolved organic carbon (DOC) leaching yields, we placed soil/sediments in Beaufort Sea seawater for 24 hours before filtering to remove particulates. To measure biodegradable dissolved organic carbon (BDOC), we conducted an aerobic incubation experiment following the methods suggested by Vonk et al. (2015). Briefly, leachates were incubated at approximately room temperature for 26 and 90 days to measure DOC loss due to remineralization and/or incorporation into microbial biomass. Additionally, we used chromophoric dissolved organic matter (CDOM) measurements and ultra-high resolution mass spectrometry (FT-ICR MS) to examine the initial leachate DOM composition. References: Vonk, J. E., Tank, S. E., Mann, P. J., Spencer, R. G. M., Tre
Critical slowing down: vegetation height, cover and composition assess resilience of tidal fresh, brackish and salt marshes following experimental disturbance at twelve sites across the estuarine landscape
We investigated the relative recovery rates of vegetation cover, vegetation height and community composition over a period of >10 years after experimental disturbance in 12 tidal marshes (two oligohaline, three mesohaline and seven polyhaline sites) across the estuarine landscape on the coast of Georgia, USA. Vegetation was removed from three by three meter plots (four per site) with herbicide in 2006 followed by repeated clipping through 2009. Vegetation height, cover and composition was assessed in experimental and control plots (4 of each per site) from 2010 to 2020. The goal of the study was to assess how quickly the sites recovered from disturbance, how this varied in different types of marshes, and how results varied depending on whether recovery was assessed by vegetation height, cover or composition.
Inorganic Nitrogen Pools and Tree Composition in Hemlock Removal Experiment at Harvard Forest 2007-2009
This study assessed how the change in leaf litter input and environmental conditions, from that of hemlock stands to earlier successional deciduous stands, will affect inorganic nitrogen availability at the interface of the mineral soil and LFH horizons. In early October 2007 we exchanged 0.5 x 0.5 m "loaves" of LFH horizons from hemlock and deciduous stands between forest types, while keeping control plots in the original forest stands. Inorganic nitrogen outputs from the litter loaves were monitored for 20 months using ion-exchange resins, removing and replacing the resins three times at 5 - 8 month intervals. Results indicated that there were differences between the control hemlock and deciduous loaves - NO3 and NH4 availability were higher in deciduous stands. However, the transfer of litter loaves from one stand type to another did not reveal changes in nutrient availability due to a shift in habitat. Rather, the methodology of moving litter loaves to a new site caused greater changes in nutrient availability, particularly over the summer months.
Imputed Forest Composition Map for New England Screened by Species Range Boundaries 2001-2006
Initializing forest landscape models (FLMs) to simulate changes in tree species composition requires accurate fine-scale forest attribute information mapped contiguously over large areas. Nearest-neighbor imputation maps have high potential for use as the initial condition within FLMs, but the tendency for field plots to be imputed over large geographical distances results in species frequently mapped outside of their home ranges, which is problematic. We developed an approach for evaluating and selecting field plots for imputation based on their similarity in feature-space, their species composition, and their geographical distance between source and imputation to produce a map that is appropriate for initializing an FLM. We applied this approach to map 13m ha of forest throughout the six New England states (Rhode Island, Connecticut, Massachusetts, New Hampshire, Vermont, and Maine). The map itself is a .img raster file of FIA plot CN numbers. To access FIA data from this map, one has to link the mapcodes in this map to FIA data supplied by USDA FIA database (https://apps.fs.usda.gov/fia/datamart/datamart.html). Due to plot confidentiality and integrity concerns, pixels containing FIA plots were always assigned to some other plot than the actual one found there.
Molecular composition of dissolved organic matter in NTL-LTER lakes detected by Fourier-transform ion cyclotron resonance mass spectrometry
The composition of dissolved organic matter (DOM) varies widely in the environment due to distinct sources of the material and subsequent processing. DOM composition drives its reactivity in terms of many processes including photochemical reactions, microbial metabolism, and carbon cycling within water bodies. This study uses ultra-high resolution mass spectrometry via a Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR MS) to evaluate DOM composition at the molecular level to determine differences in DOM composition among the NTL-LTER lakes. Whole water samples were collected from the surface of each lake near the shore on August 18th and 19th in 2016 in. Ultraviolet-visible spectra were recorded as light absorbance can also give information about DOM composition. Additionally, concentrations of anions, cations, and pH were measured waters because these can all alter DOM reactivity in the environment. Both water chemistry and DOM composition vary widely among the lakes with the bogs displaying the most terrestrial-like signature in DOM and the oligotrophic lakes show more microbial-like or environmentally processed DOM.
Molecular composition of dissolved organic matter from Lake Mendota from June – November 2017, analyzed by Fourier-transform ion cyclotron resonance mass spectrometry
Dissolved organic matter (DOM) is a complex mixture of organic compounds found in all natural waters. Its composition affects its reactivity towards numerous processes. Its composition is a function of both its source (e.g., allochthonous or autochthonous) as well as the extent of environmental processing it has undergone (e.g., chemical or biological degradation). Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) allows for the characterization of dissolved organic matter at the molecular level. The water sample was collected near the NTL-LTER research buoy on Lake Mendota. Formula assignments were made to raw mass to charge ratios detected in the mass spectrum using a custom processing script and resulting in a list of chemical formulas making up the DOM sample.
Microbial Community Composition in Lakes - Taxonomic/Ecological characteristics of the sample at North Temperate Lakes LTER 2000 - 2007
Microbial community composition is inferred by a combination of automated ribosomal intergenic spacer analysis (ARISA) and PCR-generated clone library analysis. Clone libraries include both the 16S rRNA gene and the 16S-23S ribosomal intergenic spacer fragment. Phylogenetic assignments for individual ARISA fragments are obtained by comparing the ARISA fragment length from each clone to all of the profiles stored in our database. We have analyzed over 3900 clones obtained from 41 lakes that represent the range of trophic types found in temperate landscapes. Querying by a combination of taxonomic and ecological characteristics of the sample allows the user to retrieve sample information [sample IDs, sample dates, lake information (region, type, size, depth) and physical/chemical data (water temperature, clarity, pH, DOC, SUVA, TN, TP, nitrates/nitrites)] and clone information [clone IDs, sequence data, and characteristics of the sequence (length, chimera status, accession number, taxonomic affiliation)]. The data can be filtered by ecological characteristics of the sample [lake name, sample date, lake information (region, type, size, depth)] and taxonomic characteristics of the community members [clone ID, ARISA fragment length (raw or binned), and/or taxonomic characteristics (Phylum and Phylum-Class)]. The output can include links to individual sample records, which contain links to the taxonomic composition of the sample inferred by dynamically matching clones to ARISA fragments in the individual sample. The output can also include links to clone records directly (though this creates a very large number of lines in the output and is not recommended). Project ID's 30 Lakes - Survey of 30 lakes in northern and southern Wisconsin. June, August and October, 2002. See http://microbes.limnology.wisc.edu/lakes30.html. Lake Characteristics. CB0000 - Time series monitoring microbial community composition in Crystal Bog. 2000-2002. CBX_02 - Food web manipulation experiment i
Microbial Community Composition in lakes - Ecological characteristics of the sample at North Temperate Lakes LTER 2002 - 2007
Microbial community composition is inferred by a combination of automated ribosomal intergenic spacer analysis (ARISA) and PCR-generated clone library analysis. Clone libraries include both the 16S rRNA gene and the 16S-23S ribosomal intergenic spacer fragment. Phylogenetic assignments for individual ARISA fragments are obtained by comparing the ARISA fragment length from each clone to all of the profiles stored in our database. We have analyzed over 3900 clones obtained from 41 lakes that represent the range of trophic types found in temperate landscapes. Querying by ecological characteristics of the sample allows the user to retrieve sample IDs, sample dates, lake information (region, type, size, depth) and physical/chemical data (water temperature, clarity, pH, DOC, SUVA, TN, TP, nitrates/nitrites). The data can be filtered by lake name, sample date, lake information (region, type, size, depth), and physical/chemical data (water temperature, clarity, pH, DOC, SUVA, TN, TP, nitrates/nitrites). The output includes links to individual sample records, which contain links to the taxonomic composition of the sample inferred by dynamically matching clones to ARISA fragments in the individual sample
Microbial Community Composition in Lakes - Taxonomic characteristics of the clones at North Temperate Lakes LTER 2000 - 2007
Microbial community composition is inferred by a combination of automated ribosomal intergenic spacer analysis (ARISA) and PCR-generated clone library analysis. Clone libraries include both the 16S rRNA gene and the 16S-23S ribosomal intergenic spacer fragment. Phylogenetic assignments for individual ARISA fragments are obtained by comparing the ARISA fragment length from each clone to all of the profiles stored in our database. We have analyzed over 3900 clones obtained from 41 lakes that represent the range of trophic types found in temperate landscapes. Querying by taxonomic characteristics of the clone allows the user to retrieve clone IDs, sequence data, and characteristics of the sequence (length, chimera status, accession number, taxonomic affiliation). The data can be filtered by clone ID, ARISA fragment length (raw or binned), and/or taxonomic characteristics (Phylum and Phylum-Class). The output includes links to individual clone records, which contain more detailed information about how the clone was generated (researcher, library ID, project ID, primer sets used, etc.).
Zooplankton community composition and trait data for Green Lakes Valley, 2009 - ongoing.
Starting in 2012 zooplankton sampling at Green Lake 4 was included in the long term monitoring data set at Niwot Ridge. Immediately after the ice has completely melted from the lakes, zooplankton samples are taken once a week for six consecutive weeks at the deepest portion of the lake from an inflatable raft. Zooplankton were sampled at the deepest location of each lake by pulling a conical net (Wisconsin net) vertically through the water column (i.e., vertical tow sample). For each zooplankton sample obtained, adult organisms were identified to species, or lowest taxonomic level (Chydoridae sp. and Bosminidae sp.). Larvae of cladocerans were counted together as neonates; calanoid and cyclopoid copepodites were counted together as nauplii. Individual body lengths of the first 50 -100 (when possible) individuals of each taxon were recorded using a calibrated eyepiece micrometer and means reported.
Plant species composition for sensor network array, 2017 - ongoing.
Above-ground plant species cover was recorded for vegetation plots in the sensor network, starting in 2017. Cover was measured annually at peak biomass using a 100 point-intercept method.
Plant species composition in ITEX subplots in black sand extended growing season experiment, 2018 - 2023.
As a result of climate change, the Rocky Mountain Front Range is experiencing warmer summers and earlier snowmelt. Due to the importance of snow for regulating soil temperature, growing season length, and available moisture in alpine ecosystems, even small shifts in the snow-free period could have large impacts. The focus of the Black Sand Extended Growing Season Length Experiment is to examine how terrain-related differences in climate exposure influence the way alpine habitats respond to climate change via earlier snowmelt. To simulate how climate exposure may affect plant communities, NWT LTER researchers established 5 experimental sites, each containing a pair 10 x 40m rectangular plots. These sites include north and south facing aspects, subalpine and alpine tundra meadows and a range of hydrological conditions (e.g. dry meadows, moist meadows, wet meadows). We accelerated snowmelt in one plot at each site by adding chemically inert black sand, while keeping the second plot as an unmanipulated control; black sand was added to control plots after snow had naturally melted. We used open top warming chambers (OTCs) to increase summer temperature in three subplots within each of the 10 x 40 m plots. This dataset includes measurements of plant species composition within all snow and warming treatments.
Small mammal species composition data for Niwot Ridge, 1981 - 1990.
Small mammals were live trapped during the summer of each year at various locations on Niwot Ridge. Species trapped included pikas (Ochotona princeps), marmots (Marmota flaviventris), deer mice (Peromyscus maniculatus), voles (Microtus longicaudus, Microtus montanus, and Phenacomys intermedius), and pocket gophers (Thomomys talpoides). Pocket gophers were only trapped through the summer of 1983. Mice and voles were trapped using Sherman traps, while Tomahawk traps were used to trap both the pikas and marmots. Sherman gopher traps were used to trap gophers. The mice and vole traps were placed 10 meters apart in parallel rows in grids containing from 25 to 100 traps; weather permitting, these traps were placed for 3 consecutive nights every 1 or 2 weeks from June to August. The pikas, marmots, and gophers were trapped during late summer of each year; consult Halfpenny et al. (1984; 1987) for a general description of these trap locations, as well as descriptions of baiting and handling techniques and surrounding vegetation communities. Pika and marmot traps were selectively placed in areas where evidence of these animals existed. In the case of the pocket gophers, traps were placed below ground in active mounds. For pikas, marmots and pocket gophers, traps were set during the day and were checked every 2 hours. After determining and recording species, sex, age, reproductive status, weight, health, and trap location, trapped animals were permanently tagged and released. An additional quality-controlled, derived data-table (pikas_no_recap.cr.data.csv) was added to the original dataset in 2022. This data table is derived from the original capture data, but includes only year-unique captures, where each year-unique capture is the "best" one for comparison with other year-unique captures. For comparability among years, the best capture for comparability among years is usually the first capture of the year, representing the animal's baseline weight for the year (weight appea
Plant species composition data for Saddle grid, 1989 - ongoing.
Permanent 1 m^2 vegetation plots were established near each of the 88 Saddle grid stakes in 1989 by Marilyn Walker, who led the sampling effort until 1997. To estimate plant canopy cover, point quadrat measurements have been made at irregular intervals from 1989 to the present (1989, 1990, 1995, 1997, 2006, 2008 and yearly from 2010 onward). The point-quadrat technique used for sampling was described in Spasojevic et al. (2013) and Auerbach (1992). Auerbach, N. 1992. Effects of road and dust disturbance in minerotrophic and acidic tundra ecosystems, northern Alaska. University of Colorado, Boulder, Colorado, USA. Spasojevic, Marko J, William D Bowman, Hope C Humphries, Timothy R Seastedt, and Katharine N Suding. Changes in alpine vegetation over 21 years: Are patterns across a heterogeneous landscape consistent with predictions?” Ecosphere 4, no. 9 (2013): 1–18. https://doi.org/10.1890/es13-00133.1.
Bee species abundance and composition in three ecosystem types at the Sevilleta National Wildlife Refuge, New Mexico, USA
This study was designed to examine community- or population-level fluctuations in bee species at the Sevilleta National Wildlife Refuge, both intra- and inter-annually. From 2002 to 2019, passive funnel traps were used to collect bees at three sites, each representing a different ecosystem type of the southwestern U.S. (Plains grassland, Chihuahuan Desert grassland, and Chihuahuan Desert shrubland). Bees were collected during each month from March through October, and were identified to species by taxonomic experts.
Particulate organic carbon and particulate organic nitrogen concentrations and stable isotope composition of seawater sampled during the Antarctic Circumnavigation Expedition (ACE) during the Austral Summer of 2016/2017.
<p><strong>Dataset abstract</strong></p> <p>This dataset contains particulate organic carbon and particulate organic nitrogen concentrations and stable isotope composition (delta 13C and delta 15N) sampled during the Antarctic Circumnavigation Expedition (ACE) Leg 1-3. Water samples were collected from the underway seawater supply every 3 hours, filtered onto pre-combusted glass fibre filters, acidified to remove inorganic compounds and analysed for both elements on the same filter using an elemental analyser. These samples provide an estimate of the organic carbon and organic nitrogen concentration and carbon and nitrogen stable isotope composition of living and detrital particles > 0.7 micrometres in size.</p> <p><strong>Dataset contents</strong></p> <ul> <li>README.txt, metatdata, text</li> <li>data_file_header.txt, metadata, text</li> <li>ace_uw_poc_pon_blanks_20200512CURRSGCMR.csv, data file, comma-separated values</li> <li>ace_uw_poc_pon_20200512CURRSGCMR.csv, data file, comma-separated values</li> </ul>
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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.