Small Mammals of the Muskwa-Kechika
Management Area
Table of Contents

DISCUSSION

I. Small Mammal Fauna of the MKMA
Our analysis of the limited available data suggests that the MKMA supports a diverse fauna of bats, insectivores, lagomorphs, and rodents with as many as 36 species potentially occurring within MKMA. The fauna consists largely of small mammals that range throughout the southern Rocky Mountains and boreal forests of western Canada. But, several arctic species such as the Arctic Ground Squirrel (Spermophilus parryii), Northern Red-backed Vole (Clethrionomys rutilus), and possibly the Tundra Vole (Microtus oeconomus) extend into the western portion of the MKMA. The Rocky Mountain Trench and western slope of the Rocky Mountains appear to be barriers that delimit the western limits of these arctic species in the MKMA. Because the MKMA supports considerable ecosystem diversity, it offers considerable potential for studying small mammal community structure and fine scale habitat use in a range of northern ecosystems.

Ecological and physiographic barriers associated with the Rocky Mountain Trench and the eastern and western slopes of the northern Rocky Mountains have promoted taxonomic diversity in the MKMA and form a barrier among several taxa. Therefore, the MKMA has great potential for taxonomic research. The best example is the Northern Red-backed Vole and Southern Red-backed Vole (Clethrionomys gapperi) species. A contact zone between the two species exists somewhere near Summit Pass. Precise boundaries of this zone and the degree of interbreeding among these two species in the contact zone are unknown. A similar pattern is shown by subspecies of several mammals. Two subspecies of the Heather Vole (Phenacomys intermedius intermedius and P. i. mackenzii) come into contact in the MKMA. Some authorities (Cowan and Guiguet 1965) consider the Heather Vole to consist of two species: an eastern form (P. ungava) and a western form (P. intermedius). The races P. i. intermedius and P. i. mackenzii represent these two forms. To what extent they are in contact and interbreed in the MKMA is unknown. Subspecies of the Least Chipmunk (Tamias minimus borealis and T. m. caniceps), Red Squirrel (Tamiasciurus hudsonicus preblei, T. h. columbiensis), are also in contact in the Rocky Mountains area of the MKMA.

II. Limitations of the Inventory Data
Zoogeography and General Distribution
Locality records for small mammals in the MKMA are sparse. They are also biased temporally, spatially, and in terms of inventory techniques. Most of the available records are based on historical museum specimens or observations collected more than 40 years ago. It is conceivable that habitat changes particularly in areas along the Alaska Highway have altered the small mammal distributions and since these early inventories were done. Moreover, because these early inventories involved general museum collecting, modern sampling techniques (e.g., bat detectors or pitfall traps with drift fences) were not employed and records of species rarely captured in conventional small mammal traps such as the Pygmy Shrew (Sorex hoyi) are few. Geographically, the inventory coverage reflects the lack of roads in the MKMA. Of the 665 observations made within the MKMA, 243 are within 1 km of the Alaska Highway, 320 are within 2 km, and 351 are within 5 km. Other areas sampled historically such as Laurier Pass-Redfern Lake were areas accessible by well established pack horse routes. Ecological sampling in representative biogeoclimatic units or Ecosections reflects the bias for sampling along the Alaska Highway. The Hyland Highland and Southern Boreal Plateau ecosections are easily accessible from the highway, as the over represented biogeoclimatic units. A similar bias exists in the numbers of locality records from within the protected areas within the MKMA. Of 17 protected areas, data exists for only 7. Most small mammal records are associated with Muncho Lake and Stone Mountain provincial parks, areas adjacent to the highway. Given the temporal and sampling technique bias virtually the entire MKMA requires additional small mammal inventory work. However, some the most poorly studied areas in the MKMA and highest priority for more inventory are the western portion in the Kechika Mountains and Cassiar Ranges Ecosections.

Predictions of species occurrences and ecosystem association using records adjacent to the MKMA also has limitations because most of these records are historical and share the same biases as the records from within the MKMA boundary. The one exception are the bat surveys conducted in the 1990's (Wilkinson et al 1995; Bradbury et al. 1997; Vonhof et al. 1997) near the MKMA. They applied modern inventory techniques and collected extensive habitat data for their study sites. Their biogeoclimatic zone units and Ecosections occur in the MKMA. However, the bat studies were done in summer and no information exists on bat hibernation sites in northeastern British Columbia (Nagorsen et al. 1993). Because these bats typically move no more than a few 100 kilometres between summer and winter roosts (Nagorsen and Brigham 1993), it is likely that most of these bat species hibernate in northeastern British Columbia. Wilkinson et al (1995) identified potential bat hibernacula along the Alaska Highway but the only survey of these sites was a single visit in February 1997 (see Bradbury et al 1997).

Ecology
Habitat data for the MKMA is largely restricted to occurrences in ecosections and biogeoclimatic zones. Community structure and fine scale habitat use of small mammals in the MKMA are virtually unknown. Because most of the data are derived from general museum collecting, there has been no systematic sampling in representative communities or habitats to determine relative abundance, species composition, and species diversity of small mammals. Modern ecological studies applying a range of trapping methods in various representative habitats are needed on the insectivores and rodents of the MKMA. The one group for which detailed habitat data exist are the bats. However, even those data are limited. Because the focus was on one species, the Northern Long-eared Myotis, it was the only bat tracked by radiotelemetry to determine roosting ecology. Radio-tracking should be applied to other bats found in northeastern British Columbia. Because most of these bats are at the northern limits of their range in northeastern British Columbia any data on their roosting requirements would be invaluable.