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Responses of ground beetle (Coleoptera: carabidae_ species and assemblages to forest practices in the interior Douglas-fir forests of British Columbia Jarrett, Jeffrey R.
Abstract
The Opax Mountain Silvicultural Systems Project was initiated in 1993 to address concerns over the widespread use of uniform stand-level partial cutting in the dry Douglas-fir forests of BC's Southern Interior. Various alternative harvesting methods were tested, and responses of several wildlife indicator groups were measured. The following study examined responses of ground beetle (Coleoptera: Carabidae) species and assemblages using a variety of diversity indices. The alternative harvesting practices were: 1) 20% and 2) 50% removal using individual-tree selection (I.T.S.); 3) 20% and 4) 50% removal using patch-cuts of 0.1, 0.4, and 1.6 ha; 5) 35% removal using 50% I.T.S. on 70% of the treatment area, leaving 30% in reserves; and 6) uncut controls. Results showed that species richness, evenness, and heterogeneity were greater in logged treatments. However, only in the heterogeneity values of Mud Lake assemblages (1996/1997) was there a general increase in diversity that accompanied either an increase in percent forest removal, or a change from control to I.T.S. to patch-cut methods of harvest. Other than taxonomic distinctness, no other distinctness index decreased in logged treatments, and none of the distinctness indices displayed any trend in decreasing with an increasing percentage of forest removal, or to a change from control to I.T.S. to patch-cut methods of harvest. In multivariate analysis, carabid assemblages within each site (Mud Lake and Opax Mountain.) showed patch-cut treatments to cluster/map together and I.T.S. treatments to cluster/map together. Dominance structure tables generally showed that carabid assemblages from lower percent removal treatments, as well as from I.T.S. methods, to most resemble dominance structure found in control blocks. Species analysis showed that carabid species respond to logging in a variety of ways. Because every method of harvest evidently benefited some species at the expense of others, no one treatment appears sufficient for the whole carabid community. Instead, a mix of harvesting methods that maintained the greatest number of all native forest species, including sensitive species, and over an indefinite period of time, would be the best strategy for the preservation of carabid biodiversity.
Item Metadata
Title |
Responses of ground beetle (Coleoptera: carabidae_ species and assemblages to forest practices in the interior Douglas-fir forests of British Columbia
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2003
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Description |
The Opax Mountain Silvicultural Systems Project was initiated in 1993 to address
concerns over the widespread use of uniform stand-level partial cutting in the dry
Douglas-fir forests of BC's Southern Interior. Various alternative harvesting methods
were tested, and responses of several wildlife indicator groups were measured. The
following study examined responses of ground beetle (Coleoptera: Carabidae) species
and assemblages using a variety of diversity indices. The alternative harvesting practices
were: 1) 20% and 2) 50% removal using individual-tree selection (I.T.S.); 3) 20% and 4)
50% removal using patch-cuts of 0.1, 0.4, and 1.6 ha; 5) 35% removal using 50% I.T.S.
on 70% of the treatment area, leaving 30% in reserves; and 6) uncut controls.
Results showed that species richness, evenness, and heterogeneity were greater in
logged treatments. However, only in the heterogeneity values of Mud Lake assemblages
(1996/1997) was there a general increase in diversity that accompanied either an increase
in percent forest removal, or a change from control to I.T.S. to patch-cut methods of
harvest. Other than taxonomic distinctness, no other distinctness index decreased in
logged treatments, and none of the distinctness indices displayed any trend in decreasing
with an increasing percentage of forest removal, or to a change from control to I.T.S. to
patch-cut methods of harvest. In multivariate analysis, carabid assemblages within each
site (Mud Lake and Opax Mountain.) showed patch-cut treatments to cluster/map
together and I.T.S. treatments to cluster/map together. Dominance structure tables
generally showed that carabid assemblages from lower percent removal treatments, as
well as from I.T.S. methods, to most resemble dominance structure found in control
blocks. Species analysis showed that carabid species respond to logging in a variety of
ways.
Because every method of harvest evidently benefited some species at the expense of
others, no one treatment appears sufficient for the whole carabid community. Instead, a
mix of harvesting methods that maintained the greatest number of all native forest
species, including sensitive species, and over an indefinite period of time, would be the
best strategy for the preservation of carabid biodiversity.
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Extent |
7761341 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-11-17
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0091169
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2004-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.