Weather and climate conditions along with seasonally changing biological and biogeochemical processes are important drivers and indicators of terrestrial ecosystem function. To better understand these processes, the NEON project collects data at 47 terrestrial field sites across the United States. When possible, sites are located near NEON’s freshwater aquatic sites. Terrestrial field site locations were selected to be representative of ecosystem features and habitats across the United States within each NEON domain. Twenty of the terrestrial sites are “core” sites meaning they will collect data for the 30-year lifetime of the observatory. The other 27 “relocatable” sites may move throughout the lifetime of the observatory.
At each terrestrial field site, the NEON project collects data to understand changes in climate, surface-atmosphere interactions, biogeochemical processes, organismal populations, and habitat structure.
Three collection systems are used to collect the data:
- Automated instruments that collect data year round
- Observational sampling collected by field scientists during the growing season
- Airborne remote sensing surveys that are scheduled every 3-5 years
The data collection and processing methods used by NEON are standardized and well documented across all sites. NEON data and documentation are open access and available for download via the NEON data portal.
The Power of Co-location
At each field site, NEON collects automated instrument measurements, remote sensing data, field observations and samples in close proximity to each other and at different temporal scales. These activities allow for the quantification of ecological parameters and the detection of multi-faceted ecosystem responses to drivers of change.
In addition, many NEON terrestrial sites are co-located with NEON aquatic sites to allow for additional study of relationships between terrestrial and aquatic ecosystems. Some NEON sites are also located near other long-term ecological research areas (e.g., Toolik Lake and Konza Prairie) to leverage those areas’ existing infrastructure and long-term datasets.
How NEON Extends Terrestrial Ecosystems Research Studies
NEON data collection methods are carefully selected and documented to generate standardized data sets across NEON field sites and that are compatible with existing historical data and/or data collected by other monitoring programs and large-scale data repositories, such as LTER, FluxNet, the USA National Phenology Network, Barcode of Life Data System, and others. Together, NEON and these existing programs will enable a more holistic understanding of terrestrial ecosystems in the United States. In addition to providing open access data and samples, NEON also serves as an infrastructure that researchers may leverage to conduct experiments and collect additional types of data.
Core and Relocatable Terrestrial Sites
NEON terrestrial sites are divided into core and relocatable sites. Data collection methods across core and relocatable terrestrial sites are standardized and comparable. The difference between core and relocatable terrestrial sites are as follows:
- Core sites are located in terrestrial areas, typically managed as wildlands, that are representative of the ecosystem characteristics of the NEON domain they are located within (e.g., the Northeast, the Tundra).These sites are designed to collect data for the 30-year lifetime of the project to form a long-term baseline of observation in minimally managed wildland systems.
- Relocatable site locations are often selected to capture specific environmental gradients or support comparison studies (e.g., forest management effects or dust and nitrogen transport in the Intermountain West) for a period of time. These sites may be moved to study different gradients throughout the 30-year lifetime of the project.
Types of Data Collection at Terrestrial Sites
The NEON Terrestrial Instrument System (TIS) collects meteorological, soil and phenology data at terrestrial field sites.
- Micrometeorological towers: collect weather and climate data, including fluxes of carbon, water, and energy between terrestrial ecosystems and the atmosphere.
- Soil sensor arrays: are installed near the tower to measure physical and chemical properties of soil at various depths, and soil heat flux at the soil surface.
- Precipitation gauges: Primary precipitation is collected using a Double Fence Intercomparison Reference (DFIR) at core sites, secondary precipitation is collected at all relocatable terrestrial sites (and a several core sites) using a tipping bucket on the tower. Throughfalls are also placed in the soil array at most terrestrial sites (typically excluding grasslands or sites with very low canopies).
- Phenocams: A phenocam is mounted at the top of each meteorological tower to capture above canopy phenology. A second camera as well as near the bottom of the tower to capture below canopy phenology.
Smaller meteorological stations outfitted with a subset of the same sensors are installed at aquatic sites, allowing for comparisons of meteorology data between aquatic and terrestrial sites.
The NEON Terrestrial Observation System (TOS) captures data to quantify the long-term dynamics of abundance, diversity, pathogen prevalence, phenology and productivity within an ecosystem. Field ecologists collect a variety of observations:
- Breeding landbirds
- Ground beetles
- Soil microbes
- Terrestrial Plants
- Small mammals
- Canopy foliage
- Plant litter
- Plant roots
- Soil organic and mineral horizons
- Soil nitrogen transformation
Field scientists also collect a suite of observations at aquatic sites that include aquatic plants, aquatic microbes, sediment and more.
The NEON Airborne Observation team conducts remote sensing surveys of each terrestrial field site every 3-5 years. These remote sensing data build a robust time series of landscape-scale changes occurring across ecosystems at each field site. Airborne remote sensing data include:
- Lidar (discrete and waveform)
- Hyperspectral imagery (1m pixels, 426 bands)
- Digital camera imagery (RGB, 10 cm pixels)
Please note that while data collection methods are standardized across sites, some data collection vary by site slightly depending on local and state permits, site restrictions, and differences in vegetation composition.
Accessing NEON Terrestrial Data and Using NEON Infrastructure
NEON data are open access and freely available via the NEON Data Portal. Archival samples are also available upon request. Data from all field sites and years download in standardized formats with associated documentation and metadata including data product user guides and collection protocols. This standardized formatting allows you to easily work with the data using reproducible workflows. NEON also curates code resources to make it easier to work with the data.
NEON field sites also serve as an infrastructure to support additional research. Independent observers and Principle Investigators (PI) may work with Battelle staff on the NEON project to add additional instruments to existing NEON infrastructure and/or conduct additional sampling and/or experiments at NEON terrestrial field sites.
Please note that the NEON project does not own the land for any of its field sites. Instead, Battelle, who manages the NEON project, coordinates and partners with a variety of site hosts to build and operate sites. As a result, permissions for additional non-NEON research activities must be ultimately obtained from site hosts, a process that the NEON project can assist researchers as needed.