Field Report - Webber et al. Michigan State University (MSU)

Long-term studies of Tundra dynamics

The Arctic Ecology Laboratory at Michigan State University is currently working on two separate yet interacting Awards:

1. Response of Arctic Tundra to Variation in Temperature - this project is part of ITEX (International Tundra Experiment) and has passive manipulative warming experiments in wet meadow and dry heath communities at both Barrow and Atqasuk. ITEX is plot based and focused at the species to community scale.

2. Forecasting Arctic Vegetation (FAV) - this project is investigating the interaction between land cover change, climate change, and surface disturbance. FAV is focused between community and landscape scales.

Field team for 2001 summer and general comments:

This summer we were assisted in the field by 6 undergraduates from Michigan State University partially funded by supplemental NSF REU funds, and Andrea Kuchy from Florida International University as part of our collaborations with Steve Oberbauer.

The MSU field team included Patrick Webber, Diane Ebert-May, Craig Tweedie, Bob Hollister, Steve Rewa, Devan Berry, Dustin Bronson, Paula Crouse, Eric Hammerbacher, Alaina Herrmann, and Amy Wren.

We would like to thank BASC and VECO for their extensive and faultless logistic support throughout the summer. We are also appreciative for the loan of flux equipment from the Oechel and Gamon/Huemmerich working groups when we experienced severe mechanical problems mid-season.

Collaborators:

This year we have benefited from expanded collaborations with several colleagues, for example, Steve Oberbauer, Chuck Racine, John Gamon and Fred Huemmerich, and Walt Oechel. Two colleagues from Michigan State University who were exploring possible new avenues for their research also joined us in the field. They were Alan Prather and Alan Fryday of the MSU Herbarium. Prather is a vascular plant systematist and a specialist on plant and animal interactions and co-evolution and Fryday is a polar and alpine lichenologist.

ITEX at Barrow and Atqasuk:

This summer was the 6th and 8th consecutive years of ITEX research at Atqasuk and Barrow respectively. The Projects' current focus is synthesis, consolidation of field effort and functional integration. Hollister leads the synthesis effort with preparation of his dissertation. Significant findings to date have lead to the design of a field protocol that consolidates and reduces our former intensive field effort yet continues to gather informative data suitable for long term, efficient and low impact monitoring. We hope to continue this scaled-down version of our ITEX program in the future. This summer's work tested our new field protocols collecting data on microclimate, active layer dynamics, plant phenology, and plant growth within open-topped chamber and control plots. We continued our NATEX collaborations with Oberbauer, conducting weekly and fortnightly diurnal plot based CO2 flux measurements at our ITEX sites in Barrow and Atqasuk respectively. We completed 8 diurnals in Barrow and 6 in Atqasuk from snow melt in early June until the end of the field season in mid August. Resin membranes were also deployed. Collaborations and integrative efforts with Oberbauer and Gamon and Huemmrich are linking seasonal patterns in plant phenology with plot based CO2 flux and hyperspectral optical properties including NDVI. This effort, together with integration with the Oechel group is tightening links between our ITEX and FAV projects and allowing us to scale-up to the landscape level as discussed below.

FAV

To date, the FAV project has focused on the re-sampling of marked plots established in 1972 during IBP at Barrow and in 1975 during the RATE program at Atqasuk. Analyses to date have assessed the successional direction of community change since the first sampling of each plot. Results suggest wet and mesic sites change to a greater extent than dry sites and changes at Barrow have been greater than those at Atqasuk. Most of the changes documented are consistent with the thaw lake cycle sensu Britton 1965, Billings and Peterson (1975) and Webber (1978). Following our plot-based resampling effort and also a resampling of the former IBP Site 4 microtopographic grid (Walker 1977), the focus of field efforts this year was a re-resampling of former IBP Site 4. This is a ca. 4.3ha site marked with stakes on a 10m x 10m grid design. Re-sampling efforts repeated former measurements made in 1972-73 including a detailed vegetation map, and recording of seasonal thaw depth, microtopographic position and relative elevation at each of the 10m grid points across the site. Preliminary analyses suggest a general drying of the grid since the early 1970's.

This summer also saw Rewa begin fieldwork towards his masters thesis on the long term recovery of off-road vehicle disturbance near Barrow. Rewa sampled 25 track systems at four localities including track systems formerly studied in the early 1970's by Peterson (1978) near former IBP site 1 and Abele and Atwood (1976) at a CRREL test track near West Twin Lake. Measurements included plot and landscape scale vegetation sampling and classification, seasonal thaw depth, soil moisture content and microtopographic variation.

Late in the summer of 2000 we acquired, through collaboration with BASC, panchromatic and multispectral IKONOS imagery for the Barrow Environmental Observatory. This summer we developed a hierarchical classification of the imagery including a series of decision rules for each class. We have been working on the classification as part of a contractual agreement with a former masters student of our working group Brian Noyle at Pacific Meridian Resources/Space Imaging (see Noyle 1999). Our classification has yielded extraordinary high resolution. We have been able to classify separately, polygon troughs, rims and low centers. We postponed an accuracy assessment of the classification until next year when it is hoped real-time survey grade DGPS will be available in Barrow.

We also continued collaborative efforts with John Gamon (CSULA) and Fred Huemmrich (NASA/GSFC) (funded through CIFAR/IARC), who are using hyperspectral remote sensing techniques at various spatial scales to examine relationships between optical properties and ecosystem function at Barrow and Atqasuk, including our ITEX sites. Our collaborative efforts expanded this year to include Oberbauer and the Oechel working group. Together, we are attempting to model ecosystem Carbon flux by integrating and scaling up plot-based measurements of CO2 flux taken by the Oechel working group and Oberbauer using hyperspectral remote sensing techniques, our vegetation classification, and the IKONOS imagery. Preliminary results appear promising and we will be presenting these at the LAII meetings in Salt Lake City in November.

In late July, Racine and Tweedie camped near the Kokolik River ca. 200km southwest of Atqasuk, site of a lightning initiated tundra fire in 1977. Two of five sites initially established and studied by Johnson, Viereck, Brown and Hall were relocated and resampled. The sites had not been visited since 1982. Relocated sites were located in shrub tundra and tussock tundra. Preliminary analyses suggest there has been significant shrub expansion following recovery from the fire.

As part of our effort to assess decadal change in tundra systems, Diane Ebert-May conducted a resampling of her thirty 10m2 plots established in a range of vegetation communities on Niwot Ridge, Colorado in 1971 as part of IBP and previously resampled in 1991 (Ebert 1973 and Ebert May 1976). Analyses of this dataset are ongoing.