The USA-National Phenology Network (USA-NPN) connects backyard and amateur naturalists, resource managers, scientists, and policy makers in a collective effort toward understanding the phenology of plants and animals and the interaction of these phenologies with natural ecological systems. At the core of the Network are standardized protocols for field observation of plant and animal phenology, either individually or together. These protocols, described by the National Phenology Monitoring System (NPMS), include a set of recommended species and the criteria for their selection; definition of phenophases (an observable state or phase in the annual life cycle of a plant or animal); and instructions for site selection, sampling design, observation recording, and observation reporting. The National Coordinating Office (NCO) of the USA-NPN, implemented the framework of the NPMS (version 0.09), in 2009 with protocols for the monitoring of 213 plant species (presented online at www.usanpn.org). In 2010, we are adding approximately 160 animal species and their respective phenophases to the NPMS (version 0.10). The animal species and additional recommended plant species will be available for widespread monitoring. A unique feature of the recommended protocols is that the observer records the status of all possible phenophases for the plant or animal at each observation – phenophase status monitoring. Phenophase status monitoring provides continuous information about the phenology of the species, in opposition to the historically traditional method of phenology monitoring – phenological event monitoring – in which the observer only records the defined, time-limited beginning or end of a phenophase. Additionally, phenophase event monitoring provides information on the length of a phenophase and captures repeating phenophases; it provides data for better interpretation of the connection between plant and animal phenology.
The collection, archiving, and dissemination of standardized phenology data are important for a number of scientific and applied applications. Researchers can use the collected phenology data for remote sensing studies, analysis of species response to environmental variability, and for linkages between biochemical and hydrologic cycles, among other applications. In the applied arena, phenology data is important for managing human health risks, such as pollen release; the timing of agricultural planting, pest treatments, and harvesting; and wildlife and fisheries management. Ultimately, a national phenology database will provide important input for the decision making needed for societal adaptation to climate change.