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Sampling methods and population prediction in Lambdina fiscellaria lugubrosa (Lepidoptera: geometridae) in British Columbia Liang, Qiwei
Abstract
Outbreaks of Lambdina fiscellaria lugubrosa in British Columbia have always been preceded by a rapid population growth. Sampling methods and population prediction models are needed to provide forest managers with the capability of monitoring and predicting populations of the insect. I sampled eggs, larvae, pupae and adults of Lambdina fiscellaria lugubrosa at various locations in the province of British Columbia from 1992 to 1994. Population estimates of eggs and larvae, directly obtained from habitat units, were fitted to theoretical spatial distribution and mean - variance models. Sampling plans, based on fixed sample size, sequential sampling, and binomial sampling methods, were developed. Pupae were sampled with burlap traps of different designs. Because more pupae were trapped in two or three layers of burlap than in a single layer, traps with at least two layers are recommended for future use. The strong linear relationship of pupal density between burlap traps and open tree bark units validated the use of burlap traps as a sampling tool. Spatial continuity of larval and adult densities was found along forest roads, although the range and magnitude of the spatial dependence varied significantly between years and among sites. Also, larval and adult densities along the road were closely related to those within the stands. The results showed a great potential of roadside sampling for the management of this insect. Regression models showed strong quantitative relationships of population estimates between successive life stages, which can be used to predict population density. Defoliation prediction was conducted with discriminant analysis, in which defoliation classes were related to insect population estimates and tree DBH. Like many other studies in insect sampling, the insect samples were non-random in this study. Randomization tests were used to validate results from conventional statistical analyses and to examine the general necessity of using randomization tests in insect sampling. The results suggested that non-random insect samples do not seriously hamper the use of conventional statistical analyses. The implications of this study to the management of western hemlock looper and other forest insects were discussed.
Item Metadata
Title |
Sampling methods and population prediction in Lambdina fiscellaria lugubrosa (Lepidoptera: geometridae) in British Columbia
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1997
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Description |
Outbreaks of Lambdina fiscellaria lugubrosa in British Columbia have always been
preceded by a rapid population growth. Sampling methods and population prediction
models are needed to provide forest managers with the capability of monitoring and
predicting populations of the insect.
I sampled eggs, larvae, pupae and adults of Lambdina fiscellaria lugubrosa at various
locations in the province of British Columbia from 1992 to 1994. Population estimates of
eggs and larvae, directly obtained from habitat units, were fitted to theoretical spatial
distribution and mean - variance models. Sampling plans, based on fixed sample size,
sequential sampling, and binomial sampling methods, were developed. Pupae were
sampled with burlap traps of different designs. Because more pupae were trapped in two
or three layers of burlap than in a single layer, traps with at least two layers are
recommended for future use. The strong linear relationship of pupal density between
burlap traps and open tree bark units validated the use of burlap traps as a sampling tool.
Spatial continuity of larval and adult densities was found along forest roads,
although the range and magnitude of the spatial dependence varied significantly between
years and among sites. Also, larval and adult densities along the road were closely related
to those within the stands. The results showed a great potential of roadside sampling for
the management of this insect.
Regression models showed strong quantitative relationships of population estimates
between successive life stages, which can be used to predict population density. Defoliation prediction was conducted with discriminant analysis, in which defoliation classes were
related to insect population estimates and tree DBH.
Like many other studies in insect sampling, the insect samples were non-random in
this study. Randomization tests were used to validate results from conventional statistical
analyses and to examine the general necessity of using randomization tests in insect
sampling. The results suggested that non-random insect samples do not seriously hamper
the use of conventional statistical analyses.
The implications of this study to the management of western hemlock looper and
other forest insects were discussed.
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Extent |
7371628 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-04-02
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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 |
10.14288/1.0076933
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1997-05
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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.