| Summary: | Three separate but related studies examined collembolan populations under singlespecies
forest stands and how these forest covers might influence feeding in Collembola. In
November 1993, a preliminary investigation examined the effects of single-species conifer
stands on the density and species diversity of soil collembola on southern Vancouver Island,
British Columbia. The top 3 cm of 4.4 cm diameter soil cores, sampled from experimental
plots of western redcedar, Douglas-fir, western hemlock, and Sitka spruce, were extracted for
collembola using a high gradient extractor. Average linkage cluster analysis of Renkonen's
percentage similarity and Morisita's similarity indices did not indicate distinct collembolan
communities under each conifer species. However, the density and species richness of
collembola under the four conifer species were sufficiently different to imply that further
investigation was warranted.
A second study was conducted in November 1995 and in May 1996. Soil cores were
collected and extracted from two replicate plots of the four conifer species at three different
sites located on southern Vancouver Island. Results of this study reflected those ofthe
preliminary investigation. Distinct collembolan communities among each ofthe conifer species
were not clearly demonstrated using Morisita's similarity index and average linkage clustering.
However, significant differences in collembolan density and species richness among conifer
species were found using the GLIMMEX procedure in SAS. Collembolan density and species
richness was lowest under the western redcedar plots and highest under the Sitka spruce plots.
The Modified Simpson's and the Modified Shannon-Wiener indices demonstrated that the
structure of the collembolan communities varied only slightly under the different conifer
species and was most often characterized by one or two dominant collembolan species and
several rare species. Percent moisture content, bulk density and pH were determined from each
soil core extracted for collembola. Statistical analysis of these data revealed no significant
differences among conifer species.
In the third investigation, the feeding attributes of collembola species, sampled in the
previous investigation from Sitka spruce, Douglas-fir, and western redcedar, were assessed by
analysis of the gut contents of mounted specimens. Statistical analysis of the results from five
common species found no significant differences in the feeding habits within a collembolan
species and between collembolan species among the three conifer species.
In November 1993, a preliminary investigation examined the effects of single species
conifer stands on the abundance and species diversity of soil collembola on southern Vancouver
Island, British Columbia. The top 3 cm of 4.4 cm diameter soil cores, sampled from
experimental plots of western redcedar, Douglas-fir, western hemlock, and Sitka spruce, were
extracted for collembola using a high gradient extractor. Average linkage cluster analysis of
Renkonen's percentage similarity and Morisita's similarity indices did not indicate distinct
collembolan communities under each conifer species. However, the density and species
richness of collembola under the four conifer species were sufficiently different to imply that
further investigation was warranted.
A second study was conducted in November 1995 and in May 1996. Soil cores were
collected and extracted from two replicate plots of the four conifer species at three different
sites located on southern Vancouver Island. Results of this study reflected those of the
preliminary investigation. Distinct collembolan communities among each of the conifer species
were not clearly demonstrated using Morisita's similarity index and average linkage clustering.
However, significant differences in collembolan abundance and species richness among conifer
species were found using the GLIMMEX procedure in SAS. Collembolan density and species
richness was lowest under the western redcedar plots and highest under the Sitka spruce plots.
The Modified Simpson's and the Modified Shannon-Wiener indices demonstrated that the
structure ofthe collembolan communities varied only slightly under the different conifer
species and was most often characterized by one or two dominant collembolan species and
several rare species. Percent moisture content, bulk density and pH were determined from each
soil core extracted for collembola. Multivariate analysis of this data revealed no significant
differences among conifer species.
In the third investigation, the feeding attributes of collembola species, sampled in the
previous investigation from Sitka spruce, Douglas-fir, and western redcedar, were assessed by
analysis ofthe gut contents of mounted specimens. Statistical analysis of the results from five
common species found no significant differences in the feeding habits within a collembolan
species and between collembolan species among the three conifer species.
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