Northern Prairie Wildlife Research Center
Butterflies of Glacier National Park, Montana
Results
Species Richness Through Time
Fifty-six of the 89 butterfly species historically known to occur in the park
were found during the 1 July-9 September 1987 censusing (Appendix). Because
field work did not begin until 30 June in 1987, several of the early species
are not represented. Earlier censusing (beginning 1 June) in 1988 and 1989 resulted
in slight increases in the numbers of species sighted (69 and 65, respectively).
Two species (Lycaena hyllus and Nymphalis californica) absent
from both the Kohler and Garth lists were found in 1987; four additional species
(Callophrys sheridanii, Vanessa carye annabella, Satyrium saepium and
Neophasia menapia) were found in 1988, and three more species were found
in 1989 (Callophrys polios, Speyeria aphrodite and Danaus plexippus).
Due to taxonomic changes, some taxa previously recognized as species are now
recognized as subspecies. Thus, the total number of taxa observed during the
3-yr censusing was 84 and the new taxa total for the Park is 97. Habitat preferences
as observed in this research are noted in Appendix I. Species dependent upon
rare habitats (e.g., Euphydryas gillettii or Colias nastes) may
be over-represented in this database because of my over-representation of rare
habitats.
On comparing the results of this study with the Garth and Kohler records,
I noted that all but three of the species on Kohler's list had been sighted
within the last decade and most had been seen within the past few years. Colias
pelidne and Everes comyntas had not been sighted since 1935 and
Papilio bairdii had not been observed since 1950. Polygonia comma
and Papilio glaucus are included on Kohler's list, but are eastern
species. Because P. comma probably is a misidentification, it was removed
from the list. Papilio canadensis previously was considered to be a
subspecies of P. glaucus. Colias alexandra is quite scarce in
western Montana; most records of this taxon are C. occidentalis columbiensis
(Steve Kohler, pers. comm.).
Monitoring
Application of a G-test to the 1988 and 1989 butterfly data revealed several
statistically significant differences (Appendix). There were significant changes
in the occurrence of 24 of the 97 taxa between 1988 and 1989; 15 species increased
in abundance in 1988 and nine in 1989.
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