Objective:
Quantifying carbon, energy and water balance in ecosystems and understanding the processes regulating them is crucial to effective policy decisions and public understanding of climate change science.
Novelty:
Dryland ecosystems occupy ~45% of global land surface and contain almost twice the carbon stored in temperate forest ecosystems. Despite the large area and carbon stores in these ecosystems, there are large uncertainties on their carbon budgets, due to a lack of research. To reduce these uncertainties, the New Mexico Elevation Gradient of eddy covariance flux towers, directed by Dr. Marcy Litvak and supported by Ameriflux uses these long-term records to, and fill gaps in understanding of the mechanisms regulating carbon, energy and water fluxes in dryland ecosystems of the Southwestern USA .
Design:
Eddy covariance flux towers are located in nine sites, distributed across a 1500 m gradient in elevation, climate and land cover that we refer to as the New Mexico elevation gradient (NMEG). The towers span six ecosystems: C4 dominant grassland, creosotebush shrubland, juniper savanna, piñon‐juniper woodland, ponderosa pine forest and subalpine mixed conifer forest, which collectively represent ~55% of the land cover of the four corner states in the southwestern US. The towers also allow us to quantify both the short and long-term impacts of dominant disturbances occurring in the southwestern USA on ecosystem processes: drought, fire, bark beetle outbreak, spruce budworm outbreak, and extreme freeze events.
Responses:
Continuous, multi‐year observations (since 2007) across this network have allowed us to identify the primary mechanisms regulating carbon, water and energy exchange across a wide range of semi‐arid ecosystems. We also use these datasets to examine how long-term patterns in carbon sequestration and water use vary with changes in climate, vegetation, soil characteristics, and disturbance regime.