The northern flying squirrel, Glaucomys sabrinus (Shaw), is an arboreal
sciurid inhabiting forested habitats across North America. Hypogeous fruit bodies of
mycorrhizal fungi (truffles) are a predominant food eaten by northern flying squirrels.
Previous studies have suggested that the abundance of truffles in a stand may be an
important factor associated with the density of northern flying squirrels. Over a twoyear
period, five second-growth western hemlock (Tsuga heterophylla (Raf). Sarg.)
forests in coastal British Columbia were used year-round to sample truffles and to
live trap northern flying squirrels, in order to: (1) describe the occurrence and
production of truffles; (2) determine the importance of truffles in the seasonal diet of
squirrels; (3) identify which truffle taxa were selectively consumed by this species;
and 4) evaluate associations between the density of northern flying squirrels and the
production of truffles. Truffle production from each site was determined using results
from the primary collection period, which included four samples at 10-week intervals
from April 1998 to December 1998. Eleven species representing six genera of
truffles were collected, with Elaphomyces making up over 9 3% of the total number
and 99% of the total biomass. Truffle production at each site during the primary
collection period ranged from 1.68 kg ha⁻¹ year⁻¹ to 15.72 kg ha⁻¹ year⁻¹. Plant
material was a major year-round component of the diet of northern flying squirrels,
suggesting a more generalist feeding strategy than reported elsewhere. Truffle
spores were most frequent in the summer and fall diets. Nine additional truffle taxa
were present in squirrel diets than were collected in the field. Northern flying
squirrels consumed on average 1.9 times more truffle taxa than were found during
concurrent fungal surveys. The fungi genera Elaphomyces and Hydnotrya were
under-represented and several taxa were over-represented in squirrel feces relative
to their abundance at the site. Densities of flying squirrels could not be explained by
truffle production alone at the five sites. Efforts to enhance populations of northern
flying squirrels to improve foraging habitat for the endangered northern spotted owl
(Strix occidentalis caurina Merriam) should consider measures that affect a broad
array of food items and that enhance diversity as well as abundance of food supply.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/14989 |
| Date | 05 1900 |
| Creators | Anderson, Janice |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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