Invasive plants are recognized as a threat to ecosystem
integrity and services on the Kenai Peninsula. After an initial inventory of LTEMP
(Long Term Ecological Monitoring Program) plots, systematically distributed
across the Refuge, revealed that invasive plants occurred on less than 4% of
the plots, a survey was designed to target human-disturbed areas of the Refuge.
Following LTEMP protocols, a set of 74 permanent invasive
plant monitoring plots were established in 2006 on human-disturbed areas of the
Refuge (Barnett and Simonson 2007). LTEMP plots on the Kenai Refuge integrate
with the Forest Service’s FIA plots in a gridded system. In addition to
complementing the LTEMP dataset, this additional set of plots provided an
unbiased description of invasion across different anthropogenic disturbance
types, evaluated invasive plant establishment across seismic line (used for oil
and gas exploration) age, and assessed spread of invasion from disturbed
landscape into adjacent undisturbed landscape.
The overall sampling design followed a stratified-random
design. At least ten plots were installed in each main disturbance type,
including seismic lines, campgrounds, right of ways, roads, and oil and gas
roads, with distribution across fine-scale disturbance, such as developed
versus undeveloped campgrounds. Circular multi-scale vegetation plot
measurements included species composition, percent cover, average species
height, ground cover (lichen, litter, moss, scat, rock, soil, standing duff, water,
wood) in nested 1 m2 subplots. Species composition was also measured in 5.64 m
radius circular plots as well as in the entire 7.32 m radius (168m2) circular
Results from the largest plots in the survey (7.32m radius)
included identification of a total of 184 species, of which 28 were invasive
plant species. In the smaller plots (5.64 m radius, comparable to LTEMP), 26
invasive plant species were found. The most frequently found species were
common non-native species including common dandelion, alsike clover, Kentucky
bluegrass, disc mayweed (pineapple weed), bigleaf lupine, common plantain,
quackgrass, and white clover. The greatest number of invasive plants was found
in the oil and gas fields, followed by campgrounds.
Information from this survey contributed to understanding
patterns and distribution of invasion on the Kenai Refuge, and enhanced risk
analysis to prioritize treatment for current invaders based on habitat
vulnerability to invasion. Subsequent monitoring of these plots will be useful
for understanding species composition patterns and shifts both
of native and invasive vegetation over time, as well as providing feedback on
the efficacy of our invasive plant management program.
Barnett, D. T. and Sara E. Simonson, S. E. 2007. Report: An
inventory of vegetation on disturbed areas of Kenai National Wildlife Refuge.
Natural Resource Ecology Lab, Colorado State University, Fort Collins, CO. http://www.fws.gov/uploadedFiles/Barnett_DT_and_Simonson_SE_2007.pdf
J. M., Bowser, M., Berg, E., Magness, D., and Eskelin, T. 2008. Long Term
Ecological Monitoring Program on the Kenai National Wildlife Refuge, Alaska: An
FIA Adjunct Inventory. In: McWilliams, Will; Moisen, Gretchen; Czaplewski, Ray,
comps. 2008.2008 Forest Inventory and Analysis (FIA) Symposium; October 21-23,
2008; Park City, UT. Proc. RMRS-P-56CD. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Research Station. http://www.treesearch.fs.fed.us/pubs/33332
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