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24 results for “gradient experiment”
Macrophyte and microbial mat biomass co-variation along a hydrologic gradient and response to a removal experiment in temporary wetlands Everglades, FL, USA, February 2003 – November 2006
This data package encompasses hydrologic variables, soil depth, hydrologically-regulated macrophyte community types, macrophyte biomass and community structure, and microbial mat biomass that was collected in two observational surveys and one in-situ experimental manipulation in six temporary wetland regions located in the Everglades, FL, USA. The goal of this project was to examine the co-variation in macrophyte and microbial mat biomass along the hydrologic gradient present across wetland regions and to determine the type and strength of interactions occurring between the two communities, which was tested using a biomass (macrophyte or microbial mat) removal experiment. The census observational survey took place at 140 sites from 2003-04-09 to 2004-05-26, which were randomly distributed across the hydrologic gradient present across the six temporary wetland regions. The transect observational survey occurred along six transects and each was deliberately established along the present hydrologic gradient within each region; a total of 254 sites were sampled from 2003-02-19 to 2005-03-04. The experiment took place at three temporary wetland sites with contrasting hydroperiods (3 – 6 months), and four transects were established per site with 24 pairs of control and treatment plots per transect. The removal treatment occurred one year before data collection, and data collection occurred from 2004-06-20 to 2006-11-25. The package includes six datasets, one R code file, and two shape files associated with the R code. Data collection for all datasets is complete. FCE1274_Census_Survey includes hydrologically-regulated macrophyte community type classifications, macrophyte biomass, microbial mat ash-free dry mass, mean soil depth, water depth, mean annual hydroperiod, and vegetation-inferred hydroperiod; each site was sampled once during the survey period and a subset of sites were sampled each year. FCE1274_Transect_Survey includes macrophyte community type classifications
Mass per tiller, nitrogen concentration, stable isotope ratios for carbon and nitrogen from the 1980-82 Eriophorum vaginatum reciprocal transplant experiment along a latitudinal gradient in interior Alaska collected in July, 2011
In 1980-1982, six transplant gardens were established along a latitudinal gradient in interior Alaska from Eagle Creek, AK in the south to Prudhoe Bay, AK in the north. Three sites, Toolik Lake (TL), Sagwon (SAG), and Prudhoe Bay (PB) are north of the continental divide and the remaining three, Eagle Creek (EC), No Name Creek (NN), and Coldfoot (CF), are south of the continental divide. Each garden consisted of 10 individual Eriophorum vaginatum tussocks transplanted back to their home-site, as well as 10 individuals from each of the other transplant sites. The gardens were harvested in 2011. Important variables are garden name, source population, mass per tiller, nitrogen concentration, and stable isotope ratios for Carbon and Nitrogen.
Agronomic Yields on the Biodiversity Gradient Experiment at the Kellogg Biological Station, Hickory Corners, MI (2000 to 2020)
Dataset AbstractAgronomic yields have been measured on the Biodiversity Gradient Experiment since 2000. Samples are collected from the corn, soy and winter wheat plots before harvest by harvesting a subplot with a plot combine. Initial soil moisture from the Biodiversity Gradient baseline sampling is also available for corn, soy and wheat plots.original data source http://lter.kbs.msu.edu/datasets/35
NGE01 Chronic Addition of Nitrogen Gradient Experiment (ChANGE): Assessing threshold responses of plant community composition and ecosystem processes at Konza Prairie
Chronic nutrient additions can lead to drastic shifts in the plant community through time, both within tallgrass prairie in other grassland ecosystems worldwide. Nutrient addition experiments have answered many questions about patterns of diversity loss and community shifts; however, the level of nutrients which must be added to cause community shifts is unknown. To date, all nitrogen (N) addition experiments at Konza have added 10 g m-2 (e.g., NutNet Plots; Phosphorus (P) Plots; Belowground Plots), yet current rates of N deposition are one-tenth of that level. Even predicted rates of future N deposition in grasslands are not expected to exceed 5 g m-2 by the year 2050 and will likely be around 2 g m-2 for most of the US. This mismatch begs the question will 10 g/m2 affect grasslands the same way 2 or 5 g m-2 will? There are two main goals for this long-term experiment (1) to identify the nutrient threshold needed to drive plant community change with nutrient additions, and (2) to determine what factors underlie those threshold responses (build up of nutrients, mycorrhizal loss, invertebrate herbivory). Konza ChANGE is part of a multi-site experiment spanning grasslands on two different continents: North America – tallgrass prairie (KNZ) and shortgrass steppe (SGS), and China – three sites in Inner Mongolia. By including multiple grasslands, we expand our ability to make generalizations about how grasslands are affected by N additions, and whether thresholds, if they exist, vary with precipitation, natural nutrient availability, and species identity/composition. Research Questions: (1) Do ecosystems have N tolerance thresholds above which community composition will change, and does that differ between grassland types (i.e. mesic and xeric grasslands)? (2) Does adding a large amount of nutrients in one season result in an equivalent community change as adding a small amount over multiple years? (For example does 5 g m-2 for 6 years create the same community change as
Resource Gradient Experiment at the Kellogg Biological Station, Hickory Corners, MI (1999 to 2019)
Dataset Abstract This study provides a gradient of 9 different rates of nitrogen fertilization under rainfed and irrigated conditions. Irrigation began in 2003. Corn was grown from 2000-2005 and subsequently the crop rotation (wheat, corn, soybean) followed the crop of the LTER main site. Nitrogen applications differ by crop after 2007. The experiment was moved to its current location on the LTER main site in 2005. The experiment location/history are explained here. Plots are 5×30 m arranged in each of 4 replicate blocks . Crop yields, nitrous oxide and soil temperature, moisture and nitrogen data are available for this study. original data source http://lter.kbs.msu.edu/datasets/36
Alaska Peatland Experiment: 2011 Gradient Root Biomass data taken during peak biomass (late July)
This dataset includes root biomass data taken at peak biomass during the 2011 growing season. Data was collected at the Alaskan Peatland Experiment Gradient site. Root biomass was collected for the root respiration experiment conducted at the Sedge/forb and control plots of the Gradient site. The root respiration experiment was used to partition root respiration from ecosystem respiration a both of these plots.
Latitudinal gradient, MEND experiment, and BioGen experiment relating species richness and net primary productivity (NPP)
<p>Aboveground net primary productivity and species richness.</p>
Latitudinal gradient, MEND experiment, and BioGen experiment relating species richness and net primary productivity (NPP)
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Response of Lake Baikal periphyton to nutrient enrichment at 10 sites across a land use gradient: Results from a nutrient diffusing substrata (NDS) experiment
This data set contains results of a study on the response of benthic algae to experimental nutrient enrichment in the nearshore of Lake Baikal, Russia. Nutrient diffusing substrata (NDS) were deployed at 10 sites across a land-use gradient (from town to forested) during August to September of 2015 . Four NDS treatments were used at each site: 'control', 'added phosphorus', 'added nitrogen' and 'added nitrogen and phosphorus'. NDS tiles were left in the lake for 32-33 days. After retrieval, benthic chlorophyll a levels from all sites were analyzed as an index of periphyton biomass (data in file periphyton_chl_a.csv). Taxonomic identification of algae was done at 4 of the 10 sites (2 developed, 2 undeveloped); cell counts are presented in file 'periphyton_abundance.csv'; biovolumes were determined for the most common taxa and are presented in file 'periphyton_biovolume.csv'.
Soil Moisture in the Biodiversity Gradient Experiment at the Kellogg Biological Station, Hickory Corners, MI (2001 to 2001)
Dataset Abstract Soil moisture measurements from the Fall of 2001 original data source http://lter.kbs.msu.edu/datasets/70
Common-garden experiment reveals clinal trends of bud phenology in black spruce populations from a latitudinal gradient in the boreal forest
<p>Climate warming is modifying the movement of air masses over Northern latitudes, producing warming and cooling events across the boreal regions. These new conditions changes may mismatch plant phenology from weather conditions, and affect the growing period of trees. Understanding the processes of local adaptation in bud phenology can help to predict the response of plants to these rapid and unexpected environmental changes.</p> <p>Our study monitored bud burst and bud set weekly during four growing seasons in black spruce [Picea mariana (Mill.) B.S.P.] saplings planted in a common garden and originating from five provenances representing the whole latitudinal distribution of the closed boreal forest in Quebec, Canada. We compared the variance in bud phenology among populations and years, and analyzed the relationships with the temperatures at the origin sites.</p> <p>Bud burst and bud set occurred in mid-May and mid-July, respectively, with a large variability among provenances and between the study years. A delayed bud phenology was observed in the provenances from warmer sites, with bud burst and bud set being 1.1 and 1.4 days later for every additional degree in mean annual temperature at the origin site, respectively. Populations with earlier bud bursts also showed earlier bud sets, thus the growing season was similar among provenances. The heritability of bud set was higher than that of bud burst, with estimates of 0.26 and 0.21, respectively. On average, variance in bud phenology among provenances reached 5.3%, which was higher than that within provenances (2.6%). The factor year explained 37.7-69.7% of the variance in bud phenology.</p> <p>Synthesis. Results demonstrate the plastic response of bud burst to changing temperatures and suggest the effects of endogenous factors on bud set. The earlier growth reactivation due to global warming occurring under higher frost risks in spring are expected to produce damage to the developing buds. Meanwhile, the ability of bud phenology to match the inter-annual variability in weather could help to cope with the changing environmental conditions expected in the future.</p>
Common-garden experiment reveals clinal trends of bud phenology in black spruce populations from a latitudinal gradient in the boreal forest
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Data from: Plasticity in plant hydraulic traits: An evaluation of a common-taxa experiment across a climatic gradient in the Western U.S.
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Data from: Variation of xylem vessel diameters across a climate gradient: insight from a reciprocal transplant experiment with a widespread boreal tree
Xylem vessel diameters represent an important plant hydraulic trait to ensure sufficient water supply from the roots to the leaves. The ability to adjust the hydraulic pathway to environmental cues is key in order to satisfy transpirational demands and maximize growth and survival. We evaluated the variability of vessel diameters in trembling aspen in a reciprocal transplant experiment. We tested six provenances from three ecological regions of North America planted at four test sites in western Canada. All test sites were established at the same time with the same provenances arranged in a randomized complete block design. Vessel diameter showed a strong interaction of population and test site suggesting a high degree of phenotypic plasticity in this trait. Gaussian kernel density estimates support plastic as well as genetic contributions in vessel diameter control trending from bimodal distributions at the most northern test site towards unimodal distributions at the warmest and mildest test site. Furthermore, we used test site-specific climate data in form of a 2-year, 5-year and 10-year average of 21 directly and derived climatic variables and found that average site-specific vessel diameters correlated strongly with summer moisture availability. A previously found negative relationship with vessel diameter and tree height in central Alberta was also found at two other boreal test sites but reversed at a wetter and milder sub-boreal test site. In summary, vessel diameters were highly plastic in response to different environments and varied with summer moisture availability. The variability of vessel diameter and tree height correlations suggests that vessel diameter alone cannot serve as a reliable proxy for long-term growth performance beyond boreal environments. Instead, selecting aspen populations with a high degree of plasticity in this trait appears to be the safest option for assisted migration and seed transfer programmes under climate change.
Data from: Spatial and temporal aridity gradients provide poor proxies for plant-plant interactions under climate change: a large-scale experiment
1. Plant-plant interactions may critically modify the impact of climate change on plant communities. However, the magnitude and even direction of potential future interactions remains highly debated, especially for water limited ecosystems. Predictions range from increasing facilitation to increasing competition with future aridification. 2. The different methodologies used for assessing plant-plant interactions under changing environmental conditions may affect the outcome but they are not equally represented in the literature. Mechanistic experimental manipulations are rare compared to correlative approaches that infer future patterns from current observations along spatial climatic gradients. 3. Here, we utilize a unique climatic gradient in combination with a large-scale, long-term experiment to test whether predictions about plant-plant interactions yield similar results when using experimental manipulations, spatial gradients or temporal variation. We assessed shrub-annual interactions in three different sites along a natural rainfall gradient (spatial) during 9 years of varying rainfall (temporal) and 8 years of dry and wet manipulations of ambient rainfall (experimental) that closely mimicked regional climate scenarios. 4. The results were fundamentally different among all three approaches. Experimental water manipulations hardly altered shrub effects on annual plant communities for the assessed fitness parameters biomass and survival. Along the spatial gradient, shrub effects shifted from clearly negative to mildly facilitative towards drier sites, whereas temporal variation showed the opposite trend: more negative shrub effects in drier years. 5. Based on our experimental approach, we conclude that shrub-annual interaction will remain similar under climate change. In contrast, the commonly applied space-for time approach based on spatial gradients would have suggested increasing facilitative effects with climate change. We discuss potential mechanisms governing the differences among the three approaches. 6. Our study highlights the critical importance of long-term experimental manipulations for evaluating climate change impacts. Correlative approaches, e.g. along spatial or temporal gradients, may be misleading and overestimate the response of plant-plant interactions to climate change.
Data from: Are variations of direct and indirect plant interactions along a climatic gradient dependent on species' strategies? An experiment on tree seedlings
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Data from: Spatial and temporal aridity gradients provide poor proxies for plant-plant interactions under climate change: a large-scale experiment
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Data from: Variation of xylem vessel diameters across a climate gradient: insight from a reciprocal transplant experiment with a widespread boreal tree
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Data from: Transgenerational and within-generation plasticity in response to climate change: insights from a manipulative field experiment across an elevational gradient
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Accelerating the Conjugate Gradient Method on Distributed-Memory Computers: Software and Experiment Data
<p>This Zenodo record consists of supplementary material for journal article 'Accelerating the Conjugate Gradient Method on Distributed-Memory Computers' by Kozický, Šimeček and Rúra. Archive 'software.zip' contains the source code of the software we used to perform the experiments in our article, archive 'data-experiments.zip' contains the raw data from our experiments and archive 'data-manuscript.zip' contains the result data presented in our article.</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)
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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.