Development of a Domain Map for Nodes of the National Ecological Observatory Network (NEON)

The National Ecological Observatory Network (NEON) will be the first ecological measurement system designed both to answer regional- to national-scale scientific questions and to have the interdisciplinary participation necessary to achieve credible ecological forecasting and prediction. Capabilities provided by this infrastructural investment will transform the science of ecology by enabling the integration of research and education from natural and human systems. A National Network Design Committee (NNDC) of 15 individuals has been tasked with providing a baseline design for NEON, including the continental-scale deployment of NEON network resources. A system of identical nodes, each representing environments within a mother geographic "domain" was envisioned. Each node would itself consist of sub-node components, and all nodes would be focused in unison on a few transformational ecological questions of national relevance. The NNDC adopted a strategy of pre-stratification to help determine an optimum number of nodes and to maximize node representativeness. To better sample a phenomenon as diverse as the ecological environments of the United States, those environments were first divided into a set of more homogeneous "strata." Samples could then be arrayed within each stratum, ensuring that NEON nodes are representative of the entire range of environments within the United States. Ecoregions have classically been used by ecologists for such national stratification. Ecoregions have historically been drawn using human expertise in a qualitative, weight-of-evidence approach. To construct NEON domains, a more transparent and repeatable process was needed. Multivariate clustering based on national maps of 9 ecologically relevant climatic "state" variables was used to repeatably define 25 national climatic zones. These 25 climate zones were combined with dynamic air mass seasonality data to create 20 NEON domains, each having similar climate. Such domains are defensible in that the method used to generate them is empirical and data-driven. This analysis was also used, along with budgetary constraints, to determine the number of nodes that would be necessary to adequately sample the climatic environments within the lower 48 United States. A preliminary version of the NEON Domains map was unveiled at the August 2005 ESA meeting in Montreal. Such domains provide the NEON design with a statistically based scientific underpinning, and will make NEON the first national ecological network that has been statistically designed prior to deployment.