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Desert Fertilization Experiment: investigation of Sonoran desert ecosystem response to atmospheric deposition and experimental nutrient addition, ongoing since 2006
Launched in 2006 with support from the National Science Foundation (NSF) and leveraged by the CAP LTER, the Carbon and Nitrogen deposition (CNdep) project sought to answer the fundamental question of whether elemental cycles in urban ecosystems are qualitatively different from those in non-urban ecosystems. Ecosystem scientists, atmospheric chemists, and biogeochemists tested the hypothesis that distinct biogeochemical pathways result from elevated inorganic nitrogen and organic carbon deposition from the atmosphere to the land. To test the hypothesis, scientists examined the responsiveness of Sonoran desert ecosystems to nutrient enrichment by capitalizing on a gradient of atmospheric deposition in and around the greater Phoenix metropolitan area. Fifteen desert study sites were established, with five locations each west and east of the urban core, and in the urban core in desert preserves. In addition to the gradient of atmospheric deposition in and around the urban core, select study plots at each of the fifteen desert locations receive amendments of nitrogen, phosphorus, or nitrogen + phosphorus fertilizer. Measured variables include soil properties, perennial and annual plant growth, and atmospheric deposition of nitrogen. At the close of the initial grant period, the CAP LTER assumed responsibility for the project, renamed the Desert Fertilization Experiment, which provides a remarkable platform to study the long-term effects of nutrient enrichment on desert ecosystem properties.
Porewater chemistry measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx)
The Georgia Coastal Ecosystems LTER Seawater Addition Long-Term Experiment (SALTEx) is a large-scale field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots, each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. Response measurements include porewater chemistry, specifically concentrations of chloride, sulfate, sulfide, dissolved organic carbon (DOC), ammonium-N, nitrate/nitrite-N, dissolved reactive phosphorus, total phosphorus, total nitrogen, organic nitrogen, carbon:nitrogen (C:N) ratio, organic-carbon:organic-nitrogen ratio, and pH. Samples of source water were taken after collection (seawater, river water) or mixing (mixed seawater and river water in tanks) and analyzed for concentrations of dissolved reactive phosphorus, total phosphorus, ammonium-N, nitrate/nitrite-N, total nitrogen, organic nitrogen. Source water samples from 2016 and beyond also included measurements of dissolved organic carbon (DOC), carbon:nitrogen ratio, organic-carbon:organic-nitrogen ratio, chloride and sulfate.
Plant Responses to the GCE-LTER Seawater Addition Long Term Experiment (SALTEx) from 2013 to 2017
This study was conducted in a tidal freshwater marsh (31°20’16” N, 81°27’52” W) on the Altamaha River, GA. Each plot was defined by a 2.5 m x 2.5 m polycon frame, inserted 12 cm into the soil. The frames had drain holes in the sides above the soil surface that were plugged when plots were watered but open otherwise to allow tidal exchange. The plots were randomly assigned to five treatments. Plots were monitored without imposing any treatments in 2013. Treatments started on April 14, 2014. Plots receive diluted saltwater (press and pulse of saline water treatments, n=6), freshwater (freshwater addition treatment, n=6), or no water additions (control with frame and control treatments, n=6 and 7, respectively). The press plots received additions of a mixture of seawater and fresh river water four times each week. Pulse plots received the same mixture but only for 8 weeks in September and October. The freshwater treatment plots received additions of fresh river water four times each week. To document treatment effects on the plant community, we measured stem height, photosynthesis, and percent cover of plants, and blocking of light by the vegetation. We used the same 0.75 m x 0.75 m subplot inside each plot for plant measurements, and took the measurements 3 – 6 times during each growing season from 2013 to 2017. We measured height of all stems of Zizaniopsis miliacea and Persicaria hydropiperoides, and all leaves of Pontederia cordata. In each plot, we chose the tallest individual of those three species and measured their photosynthetic rates using LCi photosynthesis System (ADC BioScientific Ltd, Hoddesdon, UK). Around the same dates, we also visually estimated the percent cover of Ludwigia repens, Persicaria hydropiperoides, Pontederia cordata, and Zizaniopsis miliacea in the entire 2.5 m x 2.5 m plot. We summed the stem heights by species as a first approximation of species biomass. We measured the photosynthetically active radiation (PAR) above top and underneath
Pred-Ex: Long Term Salt Marsh Predator Exclusion Experiment Conducted at Sapelo Island, GA
In southeastern USA salt marshes, short-term and small-scale experiments indicate that a trophic cascade benefits the foundation plant Spartina alterniflora: marine predators (nekton) positively affect plant biomass by consuming snail and crab herbivores. To test how nekton affect marsh processes when the entire animal community is present, and to test how prior results scale up over time, we conducted a 3-year predator exclusion experiment in a Georgia salt marsh using replicated 19.6 m2 plots. We measured the response of changing density for all marsh invertebrates, conducted snail and crab tethering trials, quantified change in marsh grass biomass, and measured tea bag decomposition rate across all plots.
Ants and Ecosystem Function in Hemlock Removal Experiment at Harvard Forest 2006-2014
Eastern hemlock (Tsuga canadensis) is a foundation species in eastern North American forests. Hemlock stands host unique assemblages of flora and fauna, and the structure of these assemblages is expected to change as hemlock declines due to infestation by the hemlock woolly adelgid (Adelges tsugae) and is removed by pre-emptive salvage logging. A 2003 survey of hemlock stands in central Connecticut and Massachusetts showed that ant species richness and abundance is substantially greater in logged and adelgid-infested hemlock stands than it is in intact hemlock stands (see HF065) and we hypothesized that we would see similar changes in ant species diversity following application of treatments in the Hemlock Removal Experiment at the Simes Tract (see HF118). We further hypothesized that because ants are known to modulate ecosystem function in other habitats that observed changes in ant species diversity would be accompanied by changes in ecosystem processes including soil respiration rate and nitrogen availability. In April 2006, we established a set of sub-plots in all eight canopy manipulation plots of the Hemlock Removal Experiment. In each canopy manipulation plot, we installed two ant exclosure plots, two disturbance control plots, and two control plots. Ant species richness and abundance, as well as effectiveness of the exclosures, is monitored with pitfall traps monthly during the summer. Soil nitrogen availability is measured using resins that are collected every three months, and soil respiration is measured bi-weekly during the growing season.
Harmonic Baseline Experiments for Landsat-Based Forest Condition Monitoring in Southern New England 2017
This dataset was developed as part of a study of harmonic baseline model parameterization for forest condition monitoring using Landsat time series. We implemented a previously published harmonic modeling approach for forest condition monitoring in Google Earth Engine and systematically assessed the relative ability of condition change products generated using various model parameterizations for predicting pest abundances and defoliation during the 2016-2018 Lymantria dispar outbreak in southern New England. We ran a series of 32 experiments that considered a variety of parameter choices for establishing multi-year “baseline” models representing relatively stable forest conditions for each Landsat pixel in our study area. We tested a full set of factors including (a) spectral vegetation index used for model fitting, (b) baseline-modeling period, (c) frequencies of harmonic regression terms, and (d) differences in Landsat time series input imagery. We generated average condition score estimates for each of these 32 baseline parameterizations for a May 1 to September 30, 2017 monitoring period, then used Generalized Linear Mixed Models to test the relationships between ground-based observations of defoliation and defoliator abundance (larva and egg masses). This archived dataset includes the full set of experimental raster results, as well as a “reanalysis” product from a previous implementation of our condition monitoring workflow. More information on model parameterization rankings can be found in the associated publication (Pasquarella et al. 2021).
Plant community responses to functional group and species removals along biodiversity experiment vegetation transects at the Jornada Basin LTER site, 1997-2002
This dataset contains vegetative cover data of plots that have had various plant functional groups or species experimentally removed at the Jornada Basin LTER site in southern New Mexico, USA. This data was collected with the objective to distinguish the differential effects of plant community biomass, functional groups, and biodiversity within functional groups on ecosystem and plant community function. To make these distinctions, treatments were established by the selective removal of plant species or functional groups within experimental plots. There are eight treatments: control (C, no removals); four functional group removal treatments (PG, perennial grass removed; S, shrubs removed; SSh, subshrubs removed; Succ, succulents removed), and three species richness manipulation treatments. Richness manipulations included a simplified treatment (Simp), where only the single most abundant species of each growth form is preserved and all other species in the growth form are removed, a reduced‐Larrea treatment (rL), where the Larrea is assumed to be the dominant and is removed while minority components remain, and a reduced-Prosopsis treatment (rP), where Prosopis rather than Larrea is removed as the shrub dominant. Following treatments, vegetative data was collected by sampling each plot along three transects twice a year (Spring and Fall) for 5 years from 1997-2002 (no data collected in 1998). This data set consists of the date of collection, plot number, treatment type, transect number, quadrat number, species codes, two diameters, height, condition, count, record IDs, and error codes. This study is complete.
Observed phenological indicators and environmental drivers at global change experiments at the Jornada Basin LTER site, 2014-2020
This dataset contains plant phenological data extracted from phenocams installed at a global exchange experiment involving Chihuahuan desert plant communities at the Jornada Basin LTER site in southern New Mexico, U.S.A. Cycles of plant growth, termed phenology, are tightly linked to environmental controls, and our overarching objective in this study is to determine if temperature or precipitation are relatively more important for determining shrub and grass greenup date (start of season) and senescence date (end of season). At these camera locations, we experimentally manipulated incoming precipitation at the Jornada Basin LTER for over a decade and recorded plant leaf phenology at the daily scale for seven years using phenocams. The data here are derived from raw "phenocam" camera data collected at two ongoing studies at the Jornada Basin LTER site, one studying ecosystem responses to long term changes in water and nitrogen availability, and one studying plant productivity and partitioning responses to water availability and herbivory (studies 349 and 456, respectively). Phenocams at the sites have collected images since 2014, and basic color and greenness data extracted from those images are available in a companion dataset on EDI (knb-lter-jrn.210574001). This dataset includes the derived annual and quarterly phenological indices and greenness indices for each plot monitored by phenocams, and temperature and precipitation variables aggregated to the same frequency. The dataset also includes R code and input files used to generate these derived data. See Currier and Sala 2022 for more details. This study is ongoing.
Soil moisture and snowdepth measurements in the Black Sand experiment for East Knoll, Audubon, Lefty, Soddie and Trough, 2018 - 2024.
The purpose of the Black Sand experiment is to measure treatment effects on date of snowmelt on Niwot Ridge. Five sites with paired plots (treatment and control) were implemented across Niwot as part of the extended summer research program in order to understand the effects of earlier snowmelt. This dataset contains measurements of snowdepth throughout the melt season, manual measurements of volumetric water content and temperature data as an indication of snowmelt timing.
Plant species composition 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 in a range of hydrological conditions (e.g. dry meadows, moist meadows, wet meadows). We accelerated snowmelt in one plot of each block by adding chemically inert black sand, while keeping the second plot as an unmanipulated control; black sand was added to these plots after snow had naturally melted. This dataset includes measurements of plant species composition.
ANPP, NDVI and canopy height in black sand extended growing season experiment, 2019 - 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. This dataset includes measurements of aboveground net primary productivity, plant canopy height and NDVI.
Desert Fertilization Experiment: investigation of Sonoran desert ecosystem response to atmospheric deposition and experimental nutrient addition, ongoing since 2006 (Reformatted to the ecocomDP Design Pattern)
This data package is formatted as an ecocomDP (Ecological Community Data Pattern). For more information on ecocomDP see https://github.com/EDIorg/ecocomDP. This Level 1 data package was derived from the Level 0 data package found here: https://pasta.lternet.edu/package/metadata/eml/knb-lter-cap/632/9. The abstract below was extracted from the Level 0 data package and is included for context:
Drought experiment on aquatic vertebrate populations in McRae Creek, HJ Andrews Experimental Forest, 2022
Three distinct reaches in McRae Creek west tributary (MCTW) within the HJ Andrews Experimental Forest in western Oregon were designated for manipulation and data collection. Manipulations included increasing the temperature (T), reducing streamflow (Q), and a reference (R reach). Population estimates of vertebrates, specifically Coastal Cutthroat Trout and Coastal Giant Salamander, were obtained using three-pass depletion methods in each reach. A Before-After-Control-Impact (BACI) design was implemented, distinguishing between the "Before" and "After" periods. "Before" surveys were conducted from July 18th to 20th, 2022, while "After" surveys occurred from September 8th to 9th, 2022. During the surveys, each species was identified, noting life stage, and relevant measurements were taken. For trout, these included the length from the snout to the tail fork (Length_Fork_Vent), the snout to the tail (Length_Tail), and weight. In the "Before" survey, all trout were tagged with elastomer tags: red for the T reach, yellow for the Q reach, and orange for the R reach. Trout larger than 80 mm also received PIT tags in their abdominal cavities. Salamanders were measured similarly, not elastomer or PIT tags were applied. During the "After" survey, no new elastomer or PIT tags were inserted; only previously tagged fish were recorded. Additionally, stream cross-sections were surveyed every 5 meters to document stream dimensions. Recorded data included the location, reach, sample date, BACI status, and distance downstream from the upstream cross-section (0 meters). Measurements at each cross-section included wetted width, bankfull width, and depths at five evenly spaced points. Furthermore, pools were identified and measured in each reach, noting the maximum pool depth, depth at the outflow, width, and length. Temperature sensors were installed in each reach, recording stream temperature every 15 minutes. Sensor locations were recorded as the distance downstream from the top of e
Sediment elevation measurements from the GCE LTER Seawater Addition Long-Term Experiment (SALTEx) sampling sites from July 2013 to August 2022
SALTEx (Seawater Addition Long-Term Experiment) is a field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots, each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. We are measuring soil surface elevation tables (SETs) in the plots as one of the response variables for the SALTEx project.
Percent cover measurements of four site-dominant species from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project
SALTEx (Seawater Addition Long-Term Experiment) is a field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots, each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. Percent cover was measured for four site-dominant species (Zizaniopsis miliacea, Pontederia cordata, Persicaria hydropiperoides, and Ludwigia repens) each July from 2013 to 2022.
Photosynthetic available radiation (PAR) measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project
SALTEx (Seawater Addition Long-Term Experiment) is a field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots, each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. Light availability was measured using photosynthetically active radiation (PAR) both above and below the plant canopy.
Belowground biomass measurements from the GCE-LTER Seawater Addition Long-Term Experiment (SALTEx) Project
SALTEx (Seawater Addition Long-Term Experiment) is a field experiment designed to simulate saltwater intrusion in a tidal freshwater wetland to predict how chronic (Press) and acute (Pulse) salinization will affect this and other tidal freshwater ecosystems. The SALTEx experiment was initiated in 2012 and consists of 31 field plots, each 2.5 m on a side. There are three treatments (Press, Pulse, and Fresh) and two types of controls (with and without sides), each consisting of six replicates. The Press treatment plots receive regular (4 times each week) additions of a mixture of seawater and fresh river water. Pulse plots receive the same mixture of seawater and river water during September and October, which is historically a time of low flow in the river when natural saltwater intrusion occurs. The Fresh treatment plots receive regular additions of fresh river water. Treatment water is added during low tide to facilitate its infiltration into the soil, and all plots are inundated by astronomical tides at high tide. Belowground biomass was sampled from in each plot in March 2017 after 3 years of dosing.
Borrichia removal experiment at Dean Creek marsh on Sapelo Island, Georgia between 1995 and 2001
To examine the effect of Borrichia on Batis and Sarcocornia sp., I completely clipped all vegetation from six 0.5 x 0.5 m quadrats in a mixed stand of the three species at the Dean Creek marsh in June 1995. Six additional plots were left unmanipulated as controls. Removal and control plots were fully interspersed. I clipped Borrichia from the removal plots every 6 months but allowed other plant species to re-colonize.
Seed Bank in Hemlock Removal Experiment at Harvard Forest 2004-2015
The impending loss of hemlock trees due to hemlock woolly adelgid (Adelges tsugae) infestation prompted the need to identify species of plants able to colonize areas where hemlock has been removed. We investigated species present in the seed bank (in 2004 and 2010), the seedling bank (in 2004 and 2010), and seed rain (from 2005-2015) in the Harvard Forest Hemlock Removal Experiment. In 2004, Kelley Sullivan and Aaron Ellison determined the distribution of seeds buried in the soil in the six hemlock and two hardwood stands, before canopy treatments were applied (data files hf105-01, hf105-02). In 2010, Elizabeth Farnsworth and Aaron Ellison examined the distribution of plant species present five years after the simulated hemlock removal experiment was performed and six years after the baseline, pre-treatment study of the seedbank (data files hf105-03, hf105-04, hf105-05). In the 2010 study, we hypothesized that the composition of the seed and seedling banks and seed rain would diverge among the two treatments and the controls, based on the differential impacts of harvesting versus adelgid attack on the standing vegetation. We further hypothesized that the older (deeper) strata of the seedbanks of the treatment plots would have been exhausted over time, thus yielding poor germination relative to the top strata that continually receive seed rain. Identical methods of characterizing the composition of the seedbank and the aboveground vegetation at seedbank core locations were applied in both 2004 and 2010. Additional comparisons were made with long-term data collected on overall plant species composition in the Simes plots (datasets HF 106, HF126), and with data on seed rain (data file hf105-05). This study provides a unique temporal documentation of changes in the seedbank, seed rain, and vegetation under conditions of a changing overstory.
Understory Vegetation in Hemlock Removal Experiment at Harvard Forest since 2003
Hemlock decline in New England is caused by direct and indirect effects of invasion of the hemlock woolly adelgid. Direct damage from the insect is causing gradual mortality of hemlock, and widespread harvesting of hemlock in advance of mortality, in contrast, causes immediate mortality and removal of biomass from the site. Although both processes affect thousands of acres of forest annually we have only a limited understanding of their effects on forest ecosystem function and productivity and the nature of the subsequent forest community. We anticipate that harvesting will yield different consequences than gradual mortality from the insect. Therefore we designed an experiment to simulate these contrasting impacts, by logging or girdling hemlock stands. Results from the experimental treatments are compared to the changes observed in forests that are being infested by the adelgid, and can also be included in integrated analyses of a suite of large experiments that form a core component of the Harvard Forest LTER program.
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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.