Terrestrial Observations

NEON collects data that characterize a suite of terrestrial plants, animals, pathogens and microbes at terrestrial field sites across the continent. The project’s organismal sampling design captures the long-term dynamics of abundance, diversity, pathogen prevalence, phenology and productivity.

Sampling methods

NEON uses a standardized, consistent sampling strategy across sites, time and focal taxa. The project locates organismal sampling plots across each terrestrial site, within key identified vegetation types, to capture site heterogeneity and support site-wide characterization of organismal dynamics. NEON also samples organisms within the tower footprint to detect connectivity between organismal data and flux tower measurements. Sampling methods are standardized to ensure comparable data across NEON sites and between vegetation types. Learn more about the protocols and science designs that inform terrestrial organismal data collection methods or explore summary handouts in the data portal Document Library

Sentinel taxa: indicators of ecosystem health

NEON organismal sampling focuses on sentinel taxa, which are sensitive organisms that indicate the health of an ecosystem and provide data relevant to public health. Changes in community dynamics of sentinel taxa affect ecological processes, such as disease transmission rates, agricultural pest control, and ecosystem structure and function.

Sentinel taxa data collected at terrestrial field sites

NEON sentinel taxa selection criteria include: 1) wide geographical distribution for standardized sampling; 2) varied life histories, including lifespan and reproductive rates, that affect the rates of response to drivers such as climate change; 3) phylogenetic diversity; and 4) relevance to infectious disease ecology. NEON samples the sentinel taxa within the following groups:

  • Plants
  • Soil microbes
  • Breeding landbirds
  • Small mammals (rodents and shrews)
  • Ground beetles (family Carabidae)
  • Mosquitoes (family Culicidae)
  • Ticks (order Ixodida)

Integrated sampling design

NEON integrates terrestrial organismal sampling with tower sensor measurementssoil sensor measurements and sampling, and airborne remote sensing data, to support ecosystem level characterization of processes and conditions, such as carbon cycling, biodiversity and ecosystem productivity. Where logistically possible, NEON colocates aquatic sites with terrestrial sites to support understanding of linkages across atmospheric, terrestrial and aquatic ecosystems.

Key organismal sampling data

NEON field technicians regularly sample and observe organisms at field sites and collect relevant data including:

  • Species abundance and density
  • Community composition and diversity
  • Phenology of plants and mosquitoes
  • Organism size and other trait data
  • Leaf area index
  • Canopy chemical composition
  • Litterfall (i.e., dead plant material, such as leaves, bark, needles, and twigs)

Pathogen Data and Samples

A subset of mosquitoes and ticks collected at NEON sites and tissue samples collected from rodents captured during small mammal trapping are tested to detect infection by target pathogens. These include Flaviruses such as West Nile virus in mosquitoes, bacteria including the etiological agent of Lyme disease in ticks, and antibodies to Hantaviruses in rodent blood samples. Results of pathogen testing are used to estimate the prevalence of target pathogens at NEON sites and track how infection rates change through time.

Insect flume study

NEON staff conducted a performance study of combinations of three trap types, two forms of dry ice and three wind speeds to inform site and sampling design to prevent interference with CO2 sensors and to ensure standardized, high-quality data. Learn more about NEON's insect flume study here.

Physical Properties of Soil

NEON collects physical properties data of soils in several ways at all terrestrial field sites. The sampling occurs in close proximity to organismal sampling and within the airshed of the instrumented towers to establish connectivity with atmospheric and aboveground organismal measurements. Biotic and abiotic elements of soil affect the movement and availability of water and elements across ecosystems, determine the availability of nutrients to vegetation and organisms, and play a central role in the global carbon cycle. 

Initial Soil Characterization of soil megapits

During site construction, NEON collects soil from each horizon at a single, temporary soil pit at terrestrial field sites, called the "megapit" due to the size and depth of the sample. Megapit soil samples characterize the soil conditions at the time of site construction. The pit is located in the locally dominant soil type, near the instrumented NEON tower, and is selected to be representative of the soil sensor locations. In addition to the megapit, the Observatory collects soil pit samples from a number of 1 meter deep pits distributed throughout the site for a one-time characterization of soil properties. NEON works with the U.S. Department of Agriculture (USDA), Natural Resources Conservation Service Kellogg Soil Survey Laboratory to perform a suite of chemical and physical analyses on each soil sample. Results of these analyses and other relevant information are documented in the sample data. The list of laboratory analyses performed and associated data are available upon request

Megapit sample archiving methods

Before NEON deposits samples in the Soil Archive, soil are air-dried, mineral soil are sieved (2 mm) and organic soil are broken up and mixed by hand in the laboratory. NEON archives a total of 1.2 to 3.6 kilograms of soil from each horizon. The total sample is split between at least four amber glass jars that are stored in locked, water-resistant and fire-resistant cabinets at ambient room temperature. After collection, megapit soil samples are stored in the NEON Soil Archive and available upon request to support community research. Surface soil samples are archived at external facilities, where archiving methods may differ; additional archiving methods are in development.

Megapit sample analysis

NEON works with the U.S. Department of Agriculture, Natural Resources Conservation Service Kellogg Soil Survey Laboratory, to perform a suite of chemical and physical analyses on each soil sample. Results of these analyses and other relevant information are documented in the soil sampling data. The list of laboratory analyses performed and associated data are available upon request. NEON also uses information collected from pits to calibrate soil and carbon dioxide (CO2) and moisture sensors installed in plots across NEON terrestrial sites.

Periodic collection of soil cores

Every five years, field technicians collect soil cores from plots at terrestrial sites. Each plot is split into quadrants: three soil cores 30 cm deep and 0.5 m apart are collected from each quadrant and combined as a single soil composite representative of that quadrant. Surface soil samples are archived at external facilities, where archiving methods may differ from those below; additional archiving methods are in development.

NEON Observational Sampling (OS) Data Availability by Site by Year

Download this sortable spreadsheet to better understand which data products were sampled or are planned to be sampled from which field sites by year. Data may not yet be available on the portal, but are expected to be available by Fall 2018. For current data availability visit The Data Portal.


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