Terrestrial Organisms
NEON collects data that characterize a suite of terrestrial plants, animals, and microbes at terrestrial field sites across the United States. NEON's field technicians regularly sample and observe organisms at field sites, using a robust sampling design, to capture the long-term dynamics of key data including species abundance; biomass and density; community composition and diversity; phenology of plants and mosquitoes; organism size and other trait data; leaf area index; sunlit foliage chemical composition; biomass and chemistry of roots and litterfall; and coarse downed wood volume and bulk density.
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 ecosystem structure and function and disease transmission rates. 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 sentinel taxa within the following groups:
Breeding Landbirds
NEON collects observations of birds at terrestrial field sites to capture interannual variation in avian abundance, diversity, and distribution. The sampling protocol is focused on breeding landbirds, including songbirds and other diurnal birds that that reside in or migrate through terrestrial habitats, however, all bird species observed are recorded in the data. Bird observations are collected using the point count method.
Ground Beetles
Ground beetles are an important family of invertebrates known to strongly influence food web structure, often as key predators or prey species. Ground beetles are found in every NEON Domain, are easy to sample, and changes in their numbers can indicate significant changes in the local ecological community.
Plants
NEON collects terrestrial plant measurements and observations at all terrestrial sites to capture spatial variation and trends over time in plant abundance, diversity, biomass, productivity, phenology, and biogeochemical traits. In addition, information on terrestrial plants in riparian zones along NEON aquatic field sites are collected using a rapid habitat assessment.
Small Mammals
NEON conducts field sampling of small mammals such as rats, mice and voles at most terrestrial field sites (excluding the sites in Hawaii and Puerto Rico). Captured small mammals are identified to species and assessed for sex, age and reproductive condition, and tagged as needed. Traits are measured such as weight and hind foot length, and a suite of biological samples are collected for DNA sequencing and rodent-borne pathogen analyses.
Mosquitoes
NEON samples mosquito populations at terrestrial field sites to characterize patterns of abundance, diversity, phenology, and pathogen status. Mosquitos are collected using Center for Disease Control (CDC) CO2 light traps, then sent to professional taxonomists for identification to species and sex (when possible). A subset of identified mosquitoes are tested for infection by pathogens and some mosquitoes are set aside for DNA barcode analysis.
Soil Microbes
At terrestrial field sites, soil cores are collected for microbial analysis to determine the overall composition and abundance of microbial communities. Soil cores are separated into organic vs mineral horizons and subsampled for analysis of microbial biomass, microbe community composition, microbe group abundance, microbe metagenome sequence, and microbe marker gene sequences.
Ticks
NEON samples tick populations to characterize patterns of abundance, diversity, and pathogen status. Ticks are collected using drag cloths, then counted and categorized by species, sex and life stage. A subset of collected tick nymphs are sent to an external facility where they are tested for tick-borne pathogens.
Spatial Design
Aquatic environments can be partitioned by type of habitat, with organisms inhabiting different habitat types based on their life history and morphological characteristics. For example, in riffles with fast-moving water, organisms, including algae and macroinvertebrates, often have adaptations that allow then to adhere to the stream bottom. In streams, riffles, runs, and pools are the most common habitats. In lakes and rivers, habitats include littoral (nearshore) or pelagic (deep water). In addition, organisms can be living in the benthos (sediment-water interface) or in the water column.
Most NEON aquatic organismal sampling represents a patch of benthos (sediment-water interface) or portion of the water column within the 1 km permitted wadeable stream or river, or within a lake basin. In wadeable streams, samples are collected in the 2 most common types of habitat, as determined by morphology surveys. In lakes and rivers, pelagic samples are collected along with littoral samples. Samples collected in the water column, such as phytoplankton and zooplankton, are collected near the inlet, outlet, and buoy (deepest) sampling locations, with buoy locations accompanied by temperature profile and secchi data. Each sample contains multiple individuals. In most cases, the exact location (latitude and longitude) of each the sample is not tracked recorded as it is intended to represent the overall habitat.
Temporal Design
Aquatic organismal sampling takes place during three, month-long bouts, each year to capture the presence, diversity, and abundance of multiple species and enable data users to correlate multiple data products. The range of dates are determined based on historical data for each site including streamflow, ice on/off days, the accumulation of degree days, weather, and riparian phenology.
Sampling occurs at or near base-flow in streams, during ice-off conditions in all aquatic sites, and will not occur during or directly following a flood in the stream or under ice in a lake. In the event of a flood, researchers will hold sampling for five days to allow the sediments to settle before sampling.
Sample Bout 1: Spring
- As an early-season date, this bout represents a period of rapid biomass accumulation after winter, typically after ice-off (where applicable) and prior to leaf out.
- Bout 1 commences as temperature and light levels begin to increase, promoting an increase in primary productivity and/or a change in riparian phenology
- In high elevation and/or high latitudes, bout 1 only begins after ice-off
Sample Bout 2: Summer
- This bout targets low flows, high light (mid-summer), and maximum greenness of vegetation and riparian phenology
Sample Bout 3: Autumn
- This bout represents the late growing season at each site during leaf-fall.
- Bout 3 commences when light levels begin to decrease and temperatures cool, which results in water column shifts (e.g. decreased lake stratifications, biological community shifts, etc.)
| Data product | Spring (Bout 1) | Summer (Bout 2) | Fall (Bout 3) |
|---|---|---|---|
|
Benthic microbe marker genes |
✔ |
✔ |
✔ |
|
Benthic microbe metagenomics |
|
✔ |
|
|
Periphyton and phytoplankton collection |
✔ |
✔ |
✔ |
|
Aquatic plant point counts |
✔ |
✔ |
✔ |
|
Aquatic plant clip harvest |
|
✔ |
|
|
Macroinvertebrate collection |
✔ |
✔ |
✔ |
|
Macroinvertebrate metabarcoding |
Archive only |
✔ |
Archive only |
|
Zooplankton collection |
✔ |
✔ |
✔ |
|
Zooplankton metabarcoding |
Archive only |
✔ |
Archive only |
|
Fish collection |
✔ |
|
✔ |
|
Riparian vegetation |
|
✔ |
|
*Surface water microbes are collected on a monthly or bi-monthly schedule
Using NEON to Solve Key Questions in Aquatic Organismal Research
NEON collection methods are carefully selected to provide standardized data sets across aquatic field sites and that are compatible with existing historical data and/or data collected by other large-scale networks.
Here is a selection of research questions that could be addressed with NEON organismal data:
- How are aquatic microbial communities impacted by the effects of human activities including agricultural runoff, industrial pollutants and sewage treatment?
- How do changes in microbial communities affect algae, aquatic plant and fish communities (and vice versa)?
- How do aquatic organismal communities change with changing abiotic drivers (integrating aquatic instrumentation and biogeochemistry)?
- How do aquatic organismal communities respond to environmental disturbances, such as hurricanes and droughts? Are they resilient or resistant to disturbance?
- Calculate plant and microalgae percent cover in wadeable streams. How does percent cover change over time and with changing water levels or temperature?
- Are plant communities stable over time at a site? Do some species become more dominant with changing water level or temperature? Are invasive species taking hold in any of the NEON aquatic sites?
- Is it possible to predict the vulnerability of fish communities to non-native species invasion?
- How do predator-prey ratios and interactions change across the NEON network?