Shrub Cover and LAI
for the GL, ED, and SM sites

Shrub cover is the main variable explaining total vegetation cover and leaf area index. Shrub canopy volume was the best predicator of total, wood, and leaf biomass of big sagebrush. Using allometric relations and additional measures of grass and forbs biomass we found the expected biomass trends across all three chronosequences.

This is a powerful confirmation of the chronosequence approach to studying ecosystem response to disturbance. This result gives us the confidence to scale up our ecosystem measures in both time and space.

Scaling CO2 Fluxes at SM Site 1

Preliminary results show Mid-Level and Tower-Level measurements corresponding well, at least in August. Both Mid-level and Tower-level scale measurements encompass ‘whole ecosystem’ measurements, while our current Leaf-level methods do not. The Leaf-level measurements we present here are based on Artemesia tridentata exclusively, coupled with soil respiration.

Future work will focus on two methods to rectify the Leaf-level fluxes.

First, we will perform more Leaf-level gas exchange measurements on the dominant grass and forb species and couple this data with cover data to get a more complete extrapolation of actual Leaf-level activity.

Second, we will analyze leaf area index (LAI) coupled with leaf-level data. We will also continue to gather coincidental flux measurements (fluxes at all three scales) for the field season 2005.

We hypothesize that LAI will be a valuable tool for also adding remote sensing as a fourth level for scaling CO2 fluxes on this landscape.

Eddy Covariance CO2 Fluxes for 3 Months During the Growing Season 2004 on SM Site 1

Water Vapor Fluxes for 3 Months During the Growing Season 2004
on SM Site 1