Research
PNW
Funded Projects
2001
2000
1999
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1997
1996
1995
PNW Project Overview 1996
The Biodiversity of Invertebrates in Coarse Woody Debris in Managed 50-70 year-old Stands on the Olympic Peninsula, Thinned to Create Late Successional Habitat
Principal
Investigators:
Dr.
Robert L. Edmonds, University of Washington, College of Forest Resources
Dr. Jim Marra, University of Washington, College of Forest Resources
Awarded: $33,605
Project
Description:
As
part of the USDA Forest Service Habitat Development Study (HDS) in the
Olympic National Forest, this project is a continuation of pretreatment
investigations into the invertebrate community inhabiting coarse woody
debris (CWD) in 50-70 year old managed forest. Thinnings have been
scheduled at HDS sites within these forests to create late successional
habitat, particularly for small mammals. The influence of log species
(Douglas-fir versus western hemlock), types of fungal decay (brown rot
versus white rot), decay class (I versus III), and diameter class in
invertebrate density will be determine at four site locations (Quinault,
Soleduck, Quilcene, and Hood Canal). Pretreatment data are important to
obtain to determine year-to-year variability and eventual treatment
effects. This study will contribute to the formulation management
strategies attempting to maintain biological diversity on lands also used
for commercial timber production.
Project Status:
An
oral presentation, poster presentation and peer-reviewed publication have
been completed for this project. Project
continued with 1997 funds.
Oral
presentation:
Marra,
J.L. 1996. The density of soil invertebrates on clearcut and forested
sites on the Olympic Peninsula. Washington State Department of Natural
Resources, Olympia, WA.
Poster Presentation:
Marra, J.L. and R.L. Edmonds.
1996. Density of coarse woody debris invertebrates in 50 year-old
Douglas-fir/western hemlock stands on the Olympic Peninsula, Washington.
Northwest Scientific Association and The Wildlife Society Annual
Meeting, Pacific Lutheran University. Tacoma, Washington.
Peer-reviewed publication:
Edmonds, R.L., J.L. Marra, A.K. Barg, and G.B. Sparks. 1997. Influence of
forest harvesting on soil organisms and decomposition in western
Washington.
In: Proceedings of the California forest soils council winter
meetings, Sacramento, CA, Feb 23-24, 1996, USDA Forest Service, Redding
CA.
Peer-reviewed Publication Abstract:
As
part of the Habitat Development Project, a pre-treatment study
investigating the factors affecting the density of invertebrates
inhabiting coarse woody debris was initiated.
Four sites on the Olympic Peninsula (Hood Canal, Quilcene,
Quinault,
and Sol Duc) were compared to determine the effects of different
characteristics of CWD, such as diameter, species, decay class, moisture
content, and type of fungal decay, on invertebrate density.
Sampling was conducted from June 5-8, 1995. Four groups, Acari, Collembola, Coleoptera, and Diptera
represented 99% of the total relative abundance of CWD samples.
Differences among sites were significant but varied among groups.
Quinault produced the highest densities of Acari, at 176,546 m-3
where Hood Canal produced significantly higher densities of Coleoptera and
Diptera with densities of 2,428 m-3 and 9,040 m-3
respectively. Coleoptera was
the only group with a significant response to changes in CWD species with
significantly higher densities on Douglas-fir logs (2,036 m-3),
when compared to western hemlock (1,086 m-3).
Difference in diameter appeared to be very significant, but may be
an artifact of the method of sampling and not due to any inherent
difference in quality between large and small logs.
Further analysis is needed to determine the effects of diameter.
Within the range of factors considered for this study, state of
decay appeared to have the greatest influence on Acari with a density of
187,082 m-3 for decay class III logs compared to 102,098 m-3
for decay class II logs. Decay state was also important for Coleoptera, which also
favored decay class III over III (2,255 m-3 and 867 m-3).
Advanced brown rot occurred with greater frequency in our samples
than white rot. Invertebrate
density was significantly higher in brown rotted wood samples (264,912 m-3)
when compared to white rot. Within
site factors were as important in determining patterns of invertebrate
abundance in CWD as between site factors.