Background
Hysteresis is the phenomenon in which the value of a physical property lags behind changes in the effect causing it. In ecology, hysteresis reflects historical dependency in ecological dynamics, such that the order of previous events can influence current events. Lagging response or hysteresis is inherent in ecological processes (e.g., mosquito hatch lagging behind rainfall), and recognizing and accounting for this is essential for robust identification and analysis of ecological interrelationships. The identification of ecological data interconnections can lead to understanding perturbations, which is key to ecosystem management. In addition, effective ecological management requires that resilience (amount of perturbation required to change states or resistance to change of an ecological state) of the ecosystem must also be understood. Detection and discovery of data interrelationships may lead to the realization of perturbations and resilience to the perturbations.
NSF’s National Ecological Observatory Network (NEON) is a first-of-a-kind continental-scale observatory with an unprecedented array of publicly available atmospheric, terrestrial, and aquatic data products systematically collected at 81 field sites following consistent protocols to enable users to develop new understanding of interconnections and response to climate over the 30-year lifetime of the program across the United States (including Alaska, Hawaii, and Puerto Rico). NEON provides the opportunity for identification of previously unknown interconnections between various data types, which has the potential to provide fundamental data for recognizing ecological interrelationships and development of methods to explore and recognize time lag between environmental drivers and ecological response.
Approach
This project used a straightforward approach where the starting point was with well-known data interrelationships and then expanded with analyses to identify and evaluate less well-known or previously unrecognized interrelationships. NEON has aquatic and terrestrial field sites characterized using three data collection systems:
Automated instruments that collect data year-round
Observational sampling collected by researchers during the growing season
Airborne remote sensing surveys that are scheduled every 3-5 years
This research focused on terrestrial data collected via automated instruments and observational sampling. The technical research objective was to determine interrelationships between data to enable ecological hysteresis studies. The project included the following four primary technical tasks:
Data product selection for interrelationship analysis
Protocol development for analysis of ecological interrelationships
Protocol expansion
Application extension
Accomplishments
A protocol for discovery of ecological interrelationships was successfully developed and tested using a diverse array of NEON terrestrial data types from a variety of NEON domains. The protocol is broadly applicable to other data products including NEON aquatic data, as issues of time lag and hysteresis are fundamental across ecology. Several specific avenues for future work were identified while conducting this Targeted Research project.