7  Theme: Beetle Communities

What: Beetle abundance and species richness

Where: 47 terrestrial NEON sites that span the diverse ecosystems of the U.S.

When: Forecasts for 52 weeks into the future using a weekly time-step. Forecasts that start in the current week are due by Sunday at 12:59 pm (UTC).

Why: Improve understanding of habitat quality, conservation potential, land-use sustainability, and biodiversity change in response to global change and ecological disturbances

Who: Open to any individual or team that registers.

How: REGISTER your team and submit forecast. If you registered for the Round 1 (2021) and are using the same team and method then you do not need to re-register.

The video below is an overview of the Beetle Communities Challenge that was recorded for the 2021 Early Career Annual Meeting

7.1 Overview

Biodiversity monitoring is critical for understanding environmental quality, evaluating the sustainability of land-use practices, and forecasting future impacts of global change on ecosystems. Sentinel species give forewarning of environmental risk to humans, so are particularly useful for such monitoring and forecasting efforts because they can provide surrogates for other co-located components of biodiversity (Sauberer et al. 2004).

Ground beetles (Family: Carabidae) are appropriate candidates for biodiversity monitoring and ecological forecasting as they are well-studied sentinel species that are geographically widespread, and their community dynamics are particularly congruent with the diversity of other invertebrates (Holland 2002; Lundgren & McCravy 2011; Bousquet 2012; Hoekman et al. 2017). Therefore, monitoring carabid communities and forecasting changes in their species richness and abundance can be useful in studying edge effects and habitat quality (Magura 2002), conservation potential (Butterfield 1995), land-use sustainability (Pearce & Venier 2006) and biodiversity change in response to global change and ecological disturbances (Koivula 2011). Most ecological forecasting models are limited in the geographic scale and also suffer from scarcity of temporally extensive data. Further, most existing forecasting efforts focus on a single species (Humphries et al. 2018) with limited community-wide forecasts at the continental scale. Developing forecasts for community-scale metrics (i.e., species richness, abundance) and evaluating such models for accuracy and generalizability can help test our scientific knowledge of spatial (geographical turnover) and temporal (seasonal, inter-annual) carabid community dynamics (Dietze et al. 2018). Such forecasting models can inform regional or local habitat management, identify where biodiversity monitoring efforts should be prioritized, and shed light on what data or modelling techniques are needed to build the best forecasts of ecological dynamics (e.g., can we predict richness or abundance better and why?) (Johansson et al. 2019).

With the long-term, community-wide, continental-scale data collection through the National Ecological Observatory Network (NEON), 181 data products are available for 81 sites in the US (47 terrestrial, at which carabids are sampled, and 34 aquatic). Fully initiated in 2019, this sampling will continue for 30 years (Schimel et al. 2007; 2011). NEON has effectively removed the previous barriers to community-scale forecasting across a broader geographical realm.

7.2 Challenge

This is an open ecological forecasting challenge to forecast carabid species richness, defined as the total number of species, and abundance, defined as the total number of carabid individuals. The forecasts should be done weekly per site for all NEON terrestrial sites with richness being absolute and abundance scaled by the sampling effort. NEON releases carabid sampling data weekly and no sooner than 60 days after collection, so a model submitted on June 30 can include a forecast for the first week of May, and so forth. Teams may use any open data products as drivers of richness and abundance so long as they are not from the month being forecast, and are made publicly available (minimum of URL, but ideally a script). Potential driver data sources include: NEON site data (Soil and sediment data, Terrestrial Plant data, weather data), NOAA forecasts, and beyond.

7.3 Data: Targets

The challenge uses the following NEON data product:
DP1.10022.001: Ground beetles sampled from pitfall traps

A file with previously released NEON data that has been processed into the aggregate “target” variables (richness and abundance) is provided below. The same processing will be applied to new data that are used for forecast evaluation. Further information about data structure, initial code for processing, and example null forecasts is provided in the neon4cast-beetles GitHub repository.

Forecasts will be made on a weekly basis for the abundance of beetles at a given NEON site at a given month (‘abundance’) and the observed species richness (n, number of species) of carabid beetles at each NEON site, each month.

7.3.1 Abundance of beetles (abundance)

Definition

Total number of carabid individuals per trap-night, estimated each week of the year at each NEON site

Motivation

A forecast prediction can be compared against only measured data (i.e. counts) and not latent variables (i.e. true carabid abundance), which are only inferred under specific model assumptions. However, raw count of beetles found in a particular trap depends on many other drivers than local abundance; in particular, the sampling effort. To avoid the need to accurately predict the sampling effort, we compute a target variable as counts per trap-night (number of nights each trap was set at the site; also called ‘catch per unit effort’). We chose this to define this variable in terms of total carabid abundance, rather than resolving to particular taxonomy (in contrast to species-specific relative abundance) because it simplifies issues related to taxonomic resolution of unpinned samples, data latency, and the choice of focal species. As supported by literature (Hoekman et al. 2017 and literature cited therein), we believe that abundance of the beetle family as a whole is an ecologically relevant metric. We considered predictions aggregated to the site level (rather than predicting individual traps or individual plots) to be both the most ecologically meaningful and simplest choice. Traps are typically collected every two weeks. Submitting a forecast for every week avoids the need to predict which weeks of the year collection does or does not occur. See https://github.com/eco4cast/neon4cast-beetles/blob/master/02_targets.R for a programmatic definition of how the abundance metric is defined.

7.3.2 Species richness (n)

Definition

Total number of unique ‘species’ in a sampling bout for each NEON site each week. For this challenge, we define ‘species’ as the taxonomic unit closest to species (e.g., species, genus, morphospecies) for each individual since not all identifications in the raw data are strictly at species-level.

Motivation

A forecast prediction can be compared against only measured data (i.e. observation count of taxonomic units) and not latent variables (i.e. count of species), which are only inferred under specific model and taxonomic assumptions. The number of unique taxonomic identities of beetles in a trap depends on many drivers, including sampling effort. As demonstrated by species rarefaction curves in ecology, the more time a trap is left out, the more individual beetles will fall in, and thus the more species can be expected. However, since perfect species-level data are not available to us and to keep the forecasted variables from being overly derived, we define the target variable as the total number of unique ‘species’ per week per NEON site. For this challenge, we chose to define ‘species’ as the taxonomic unit closest to species (e.g., species, genus, morphospecies) since not all identifications in the raw data are strictly at species-level. Species identifications will be used for individuals identified to sub-species level, as these are uncommon in the raw data. NEON taxonomists identify individuals as morphologically distinct units. Thus, it is reasonable to assert that the count of finest morphologically distinct identification (e.g., species, genus, morphospecies) is biologically meaningful, and thus the count of these is an important focal forecast variable. We focus on the NEON site as the spatial resolution and weekly intervals as the temporal resolution for the same reasons stated in the abundance metric. See https://github.com/eco4cast/NEON-community-forecast/blob/master/02_targets.R for a programmatic definition of how the richness metric is defined.

7.3.3 Focal sites

All 47 NEON terrestrial sites are included

Information on the sites can be found here:

site_data <- readr::read_csv("https://raw.githubusercontent.com/eco4cast/neon4cast-targets/main/NEON_Field_Site_Metadata_20220412.csv") |> 
  dplyr::filter(beetles == 1)
siteID site name vegetation type latitude longtitude NEON site URL
ABBY Abby Road NEON Evergreen Forest|Grassland/Herbaceous|Shrub/Scrub 45.76244 -122.33032 https://www.neonscience.org/field-sites/abby
BARR Utqiaġvik NEON Emergent Herbaceous Wetlands 71.28241 -156.61936 https://www.neonscience.org/field-sites/barr
BART Bartlett Experimental Forest NEON Deciduous Forest|Evergreen Forest|Mixed Forest 44.06389 -71.28737 https://www.neonscience.org/field-sites/bart
BLAN Blandy Experimental Farm NEON Deciduous Forest|Pasture/Hay 39.03370 -78.04179 https://www.neonscience.org/field-sites/blan
BONA Caribou-Poker Creeks Research Watershed NEON Deciduous Forest|Evergreen Forest|Mixed Forest|Woody Wetlands 65.15401 -147.50258 https://www.neonscience.org/field-sites/bona
CLBJ Lyndon B. Johnson National Grassland NEON Deciduous Forest|Grassland/Herbaceous 33.40123 -97.57000 https://www.neonscience.org/field-sites/clbj
CPER Central Plains Experimental Range NEON Grassland/Herbaceous 40.81554 -104.74559 https://www.neonscience.org/field-sites/cper
DCFS Dakota Coteau Field Site NEON Grassland/Herbaceous 47.16165 -99.10656 https://www.neonscience.org/field-sites/dcfs
DEJU Delta Junction NEON Evergreen Forest|Shrub/Scrub|Woody Wetlands 63.88112 -145.75136 https://www.neonscience.org/field-sites/deju
DELA Dead Lake NEON Evergreen Forest|Woody Wetlands 32.54173 -87.80388 https://www.neonscience.org/field-sites/dela
DSNY Disney Wilderness Preserve NEON Pasture/Hay|Woody Wetlands 28.12505 -81.43619 https://www.neonscience.org/field-sites/dsny
GRSM Great Smoky Mountains National Park NEON Deciduous Forest|Evergreen Forest 35.68896 -83.50195 https://www.neonscience.org/field-sites/grsm
GUAN Guanica Forest NEON Evergreen Forest 17.96955 -66.86870 https://www.neonscience.org/field-sites/guan
HARV Harvard Forest & Quabbin Watershed NEON Deciduous Forest|Evergreen Forest|Mixed Forest|Woody Wetlands 42.53691 -72.17265 https://www.neonscience.org/field-sites/harv
HEAL Healy NEON Dwarf Scrub|Evergreen Forest|Shrub/Scrub 63.87580 -149.21335 https://www.neonscience.org/field-sites/heal
JERC The Jones Center At Ichauway NEON Cultivated Crops|Deciduous Forest|Evergreen Forest|Mixed Forest 31.19484 -84.46862 https://www.neonscience.org/field-sites/jerc
JORN Jornada Experimental Range NEON Shrub/Scrub 32.59069 -106.84254 https://www.neonscience.org/field-sites/jorn
KONA Konza Prairie Agroecosystem NEON Cultivated Crops 39.11045 -96.61293 https://www.neonscience.org/field-sites/kona
KONZ Konza Prairie Biological Station NEON Deciduous Forest|Grassland/Herbaceous 39.10077 -96.56307 https://www.neonscience.org/field-sites/konz
LAJA Lajas Experimental Station NEON Cultivated Crops|Grassland/Herbaceous|Pasture/Hay 18.02126 -67.07689 https://www.neonscience.org/field-sites/laja
LENO Lenoir Landing NEON Deciduous Forest|Woody Wetlands 31.85386 -88.16118 https://www.neonscience.org/field-sites/leno
MLBS Mountain Lake Biological Station NEON Deciduous Forest 37.37831 -80.52485 https://www.neonscience.org/field-sites/mlbs
MOAB Moab NEON Evergreen Forest|Shrub/Scrub 38.24828 -109.38827 https://www.neonscience.org/field-sites/moab
NIWO Niwot Ridge NEON Evergreen Forest|Grassland/Herbaceous 40.05425 -105.58237 https://www.neonscience.org/field-sites/niwo
NOGP Northern Great Plains Research Laboratory NEON Grassland/Herbaceous 46.76972 -100.91535 https://www.neonscience.org/field-sites/nogp
OAES Marvin Klemme Range Research Station NEON Grassland/Herbaceous|Shrub/Scrub 35.41060 -99.05878 https://www.neonscience.org/field-sites/oaes
ONAQ Onaqui NEON Evergreen Forest|Shrub/Scrub 40.17760 -112.45245 https://www.neonscience.org/field-sites/onaq
ORNL Oak Ridge NEON Deciduous Forest|Evergreen Forest|Pasture/Hay 35.96413 -84.28259 https://www.neonscience.org/field-sites/ornl
OSBS Ordway-Swisher Biological Station NEON Emergent Herbaceous Wetlands|Evergreen Forest|Woody Wetlands 29.68928 -81.99343 https://www.neonscience.org/field-sites/osbs
PUUM Pu’u Maka’ala Natural Area Reserve NEON Evergreen Forest 19.55309 -155.31731 https://www.neonscience.org/field-sites/puum
RMNP Rocky Mountains NEON Evergreen Forest 40.27590 -105.54596 https://www.neonscience.org/field-sites/rmnp
SCBI Smithsonian Conservation Biology Institute NEON Deciduous Forest|Evergreen Forest|Pasture/Hay 38.89292 -78.13949 https://www.neonscience.org/field-sites/scbi
SERC Smithsonian Environmental Research Center NEON Cultivated Crops|Deciduous Forest 38.89013 -76.56001 https://www.neonscience.org/field-sites/serc
SJER San Joaquin Experimental Range NEON Evergreen Forest|Grassland/Herbaceous|Shrub/Scrub 37.10878 -119.73228 https://www.neonscience.org/field-sites/sjer
SOAP Soaproot Saddle NEON Evergreen Forest|Shrub/Scrub 37.03337 -119.26219 https://www.neonscience.org/field-sites/soap
SRER Santa Rita Experimental Range NEON Shrub/Scrub 31.91068 -110.83549 https://www.neonscience.org/field-sites/srer
STEI Steigerwaldt-Chequamegon NEON Deciduous Forest|Mixed Forest|Woody Wetlands 45.50894 -89.58637 https://www.neonscience.org/field-sites/stei
STER North Sterling NEON Cultivated Crops 40.46189 -103.02929 https://www.neonscience.org/field-sites/ster
TALL Talladega National Forest NEON Deciduous Forest|Evergreen Forest|Mixed Forest 32.95047 -87.39326 https://www.neonscience.org/field-sites/tall
TEAK Lower Teakettle NEON Evergreen Forest|Shrub/Scrub 37.00583 -119.00602 https://www.neonscience.org/field-sites/teak
TOOL Toolik Field Station NEON Dwarf Scrub|Shrub/Scrub 68.66109 -149.37047 https://www.neonscience.org/field-sites/tool
TREE Treehaven NEON Deciduous Forest|Evergreen Forest|Mixed Forest|Woody Wetlands 45.49369 -89.58571 https://www.neonscience.org/field-sites/tree
UKFS University of Kansas Field Station NEON Deciduous Forest|Pasture/Hay 39.04043 -95.19215 https://www.neonscience.org/field-sites/ukfs
UNDE University of Notre Dame Environmental Research Center NEON Deciduous Forest|Mixed Forest|Woody Wetlands 46.23391 -89.53725 https://www.neonscience.org/field-sites/unde
WOOD Chase Lake National Wildlife Refuge NEON Emergent Herbaceous Wetlands|Grassland/Herbaceous 47.12820 -99.24133 https://www.neonscience.org/field-sites/wood
WREF Wind River Experimental Forest NEON Evergreen Forest 45.82049 -121.95191 https://www.neonscience.org/field-sites/wref
YELL Yellowstone National Park NEON Evergreen Forest|Grassland/Herbaceous|Shrub/Scrub 44.95348 -110.53914 https://www.neonscience.org/field-sites/yell

7.3.4 Target data calculation

Ground beetle data are collected at each NEON site every two weeks throughout the sampling season. The sampling season is defined based on measures of growing season, including vegetation indices, phenology, and degree days, for a maximum of 13 bouts per site during which the 10-day average low temperature at the site is >4°C.

Samples are collected from pitfall traps placed at each of the cardinal directions within the 10 plots per site representative of up to three dominant vegetation types. Four traps were placed from 2014-2017 and from 2018 onward the northward plot was eliminated leaving three traps for each plot. Ground beetles from the pitfall traps are removed, sorted, and identified to the lowest possible taxonomic rank or morphospecies. A subset of individuals (up to 467 per site and year) are sent to taxonomic experts for subsequent identification with priority on individuals for which species-level identification was not able to be assigned. Further detail can be found in the NEON Ground Beetle User Guide.

Raw (NEON L1 ground beetle data product DP1.10022.001) are accessible via the NEON data portal, via the NEON API, via R using the neonUtilties package, and via R using neonStore::neon_download. The raw data is also available through the NEON data portal with archived copies at https://data.ecoforecast.org/minio/neonstore.

The raw data is processed to generate total abundance and richness per week per NEON site. All data in the supplied file is available to build and evaluate models before submitting a forecast to challenge. Once new data becomes available, the data are appended to the existing file. Within the challenge scoring, only the new data are used to evaluate previously submitted forecasts.

As part of our reproducible workflow, we provide an R script for producing derived tables of total abundance and richness from the raw NEON data. Our workflow gives preference to expert taxonomist identifications when available. Since expert taxonomy lags behind identifications from the sorting and pinning process, newer data will not be updated with expert taxonomy. The abundance table gives total abundance at each site for each week. The richness table gives an aggregate count of the number of ‘species’ at each site in each week.

Note: The table includes all data that NEON has collected and can be used for building and training models (new data will be posted after forecasts are submitted)

7.3.5 Target file

The code use to process the raw data to the evaluation data can be found here: https://github.com/eco4cast/neon4cast-targets/blob/main/beetles_targets.R

Here is the format of the target file

readr::read_csv("https://data.ecoforecast.org/neon4cast-targets/beetles/beetles-targets.csv.gz", guess_max = 1e6)
# A tibble: 7,220 × 5
   datetime   site_id variable  observation iso_week
   <date>     <chr>   <chr>           <dbl> <chr>   
 1 2016-09-12 ABBY    abundance      1.05   2016-W37
 2 2016-09-12 ABBY    richness      14      2016-W37
 3 2016-09-26 ABBY    abundance      4.45   2016-W39
 4 2016-09-26 ABBY    richness      13      2016-W39
 5 2017-05-01 ABBY    abundance      0.0554 2017-W18
 6 2017-05-01 ABBY    richness      10      2017-W18
 7 2017-05-15 ABBY    abundance      0.180  2017-W20
 8 2017-05-15 ABBY    richness      19      2017-W20
 9 2017-05-29 ABBY    abundance      0.425  2017-W22
10 2017-05-29 ABBY    richness      19      2017-W22
# … with 7,210 more rows

The table has the following columns:

  • datetime: YYYY-MM-DD (the Monday marking the week of sample collection (for training data) or forecast (submission). Per ISO standards, Monday marks the first day of each week.)
  • site_id: NEON site ID
  • variable: abundance of beetles (abundance) or species richness (richness)
  • observation: value of variable
  • iso_week: The ISO-week

7.4 Timeline

The timeline is determined by the data latency provided by NEON. NEON carabid pitfall trap data is released monthly with a latency of at least 60 days after collection. Weekly forecasts were chosen to best match up with NEON’s weekly release of carabid data.

As an example, carabid pitfall trap data released in the last week of June would include data as recent as the last week of April. Thus, a model submitted in the last week of June could include forecasts from May onwards. Then, the forecast update submitted at the end of July can use new May data to help refine June forecasts, or forecasts following June, depending on what drivers are used. The July forecast update is due by 11:59 pm EST on July 31. Forecasts updates will not be considered for weeks where NEON validation data has already been released (i.e., no May forecast updates may be submitted on July 31) or for weeks when no NEON carabid data is available.

Pitfall traps are collected and reset every 2 weeks throughout the growing season. Due to weather and conditions beyond the field team’s control, this collection schedule may not be followed. Thus, the exact collection dates cannot be known until they have happened. Field data are made publicly available on the data portal as the bet_fielddata dataframe no sooner than 14 days after collection. Teams can use bet_fielddata to inform the actual collection schedule. Data with parataxonomist identifications are made publicly available on the data portal as the bet_sorting dataframe no sooner than 60 days after collection. Data are released on the NEON data portal weekly, but may be released on any day of the week. The forecast schedule follows the ISO week standard with weeks starting on Mondays.

7.5 Submissions

The required names for forecasted variables: abundance and richness

The required time unit: date for the Monday of the corresponding isoweek in YYYY-MM-DD format.

Instructions for submitting forecasts are found in Chapter 2

7.6 Meterological inputs for modeling

Information about forecasted meteorology that is available for you to use when generating your forecasts can be found in Chapter 9

7.7 Useful functions

Functions for validating, evaluating and submitting forecasts can be found in Chapter 10

Functions for downloading and working with the meteorology forecasts can be be found Chapter 9

7.8 Null models

One null model is automatically generated each week: the mean null model uses the mean of the historical data for each site.

Code for the mean null model can be found here

7.9 FAQ

Answers to frequency asks questions can be found in Chapter 12

7.10 Design team

Anna Spiers, University of Colorado, Boulder
Carl Boettiger, University of California, Berkeley
Tad Dallas, Louisiana State University
Nico Franz, NEON Biorepository at Arizona State University
Kari Norman, University of California, Berkeley
Thilina Surasinghe, Bridgewater State University
Brett Melbourne, University of Colorado, Boulder
Eric Sokol, NEON
Kelsey Yule, NEON Biorepository at Arizona State University

7.11 Partners

The challenge is hosted by the Ecological Forecasting Initiative (EFI; https://ecoforecast.org/) and its U.S. National Science Foundation sponsored Research Coordination Network (EFI-RCN; https://ecoforecast.org/rcn/).

Data used in the challenge from National Ecological Observatory Network (NEON): https://www.neonscience.org/.

7.12 References

Bousquet, Y. (2012) Catalogue of Geadephaga (Coleoptera: Adephaga) of America, north of Mexico. ZooKeys 245: 1-1722. https://doi.org/10.3897/zookeys.245.3416

Butterfield, J., Luff, M., Baines, M., Eyre, M. (1995) Carabid beetle communities as indicators of conservation potential in upland forests. Forest Ecology and Management 79, 63-77. https://doi.org/10.1016/0378-1127(95)03620-2

Dietze, M.C., Fox, A., Beck-Johnson, L.M., Betancourt, J.L., Hooten, M.B., Jarnevich, C.S., Keitt, T.H., Kenney, M.A., Laney, C.M., Larsen, L.G. (2018) Iterative near-term ecological forecasting: Needs, opportunities, and challenges. Proceedings of the National Academy of Sciences 115, 1424-1432. https://doi.org/10.1073/pnas.1710231115

Gneiting, T., & Raftery, A. E. (2007). Strictly proper scoring rules, prediction, and estimation. Journal of the American Statistical Association, 102(477), 359–378. https://doi.org/10.1198/016214506000001437

Hoekman, D., LeVan, K.E., Gibson, C., Ball, G.E., Browne, R.A., Davidson, R.L., Eriwin, T.L., Knisley, C.B., LaBonte, J.R., Lundgren, J., Maddison, D.R., Moore, W., Niemela, J., Ober, K.A., Pearson, D.L. Spence, J.R., Will, K., Work, T. (2017) Design for ground beetle abundance and diversity sampling within the National Ecological Observatory Network. Ecosphere, 8(4), e01744. https://doi.org/10.1002/ecs2.1744

Holland, J.M. (2002) The agroecology of carabid beetles. Intercept Limited, Andover.

Humphries, G.R., Che-Castaldo, C., Bull, P., Lipstein, G., Ravia, A., Carrión, B., Bolton, T., Ganguly, A., Lynch, H.J. (2018) Predicting the future is hard and other lessons from a population time series data science competition. Ecological Informatics 48, 1-11. https://doi.org/10.1016/j.ecoinf.2018.07.004

Johansson, M.A., Apfeldorf, K.M., Dobson, S., Devita, J., Buczak, A.L., Baugher, B., Moniz, L.J., Bagley, T., Babin, S.M., Guven, E. (2019) An open challenge to advance probabilistic forecasting for dengue epidemics. Proceedings of the National Academy of Sciences 116, 24268-24274. https://doi.org/10.1073/pnas.1909865116

Koivula, M.J. (2011) Useful model organisms, indicators, or both? Ground beetles (Coleoptera, Carabidae) reflecting environmental conditions. ZooKeys, 287-317. https://doi.org/10.3897/zookeys.100.1533

Lundgren, J., McCravy, K. (2011) Carabid beetles (Coleoptera: Carabidae) of the Midwestern United States: A review and synthesis of recent research. Terrestrial arthropod reviews 4, 63-94. https://doi.org/10.1163/187498311X565606

Magura, T. (2002) Carabids and forest edge: spatial pattern and edge effect. Forest Ecology and Management 157, 23-37. https://doi.org/10.1016/S0378-1127(00)00654-X

Pearce, J.L., Venier, L.A. (2006) The use of ground beetles (Coleoptera: Carabidae) and spiders (Araneae) as bioindicators of sustainable forest management: A review. Ecological Indicators 6, 780-793. https://doi.org/10.1016/j.ecolind.2005.03.005

Sauberer, N., Zulka, K.P., Abensperg-Traun, M., Berg, H.-M., Bieringer, G., Milasowszky, N., Moser, D., Plutzar, C., Pollheimer, M., Storch, C. (2004) Surrogate taxa for biodiversity in agricultural landscapes of eastern Austria. Biological Conservation 117, 181-190. https://doi.org/10.1016/S0006-3207(03)00291-X

Schimel, D., Hargrove, W., Hoffman, F., MacMahon, J. (2007) NEON: a hierarchically designed national ecological network. Frontiers in Ecology and the Environment 5, 59-59. https://doi.org/10.1890/1540-9295(2007)5[59:NAHDNE]2.0.CO;2

Schimel, D., Keller, M., Berukoff, S., Hufft, R., Loescher, H., Powell, H., Kampe, T., Moore, D., Gram, W. (2011) NEON Science Strategy: Enabling Continental-Scale Ecological Forecasting. https://www.neonscience.org/sites/default/files/basic-page-files/NEON_Strategy_2011u2_0.pdf