We have been focusing our research on Northwestern North America
Several general ecological/distributional patterns recur in
northwestern North America forest endemic
species. These include: species widespread in xeric
forests (e.g., Ponderosa pine forests); species that have
populations in the mesic forests (i.e., cedar-hemlock forests) of the coastal
ranges and separate (disjunct) populations in the northern Rocky
Mountains; and species that are restricted to forests of the
northern Rocky Mountains. Because both xeric and mesic forests
are the foundation of resource-based industries, which often
place conflicting demands on ecosystems (e.g., recreation/tourism
and timber), assessing the genetic structure of multiple elements
of these ecosystems is critical to the economy of the region.
Comparative phylogeography for these systems can provide for
a wealth of research opportunities; we have begun by conducting
research on the comparative phylogeography of several representative
species representing each of these ecological/distributional
patterns.
1. Mesic Forest Disjuncts.
Northwestern North America contains the world's greatest extent
of mesic temperate coniferous forests. These forests are
characterized by the late successional dominance of western hemlock
(Tsuga heterophyla) and western redcedar (Thuja
plicata), and cedar-hemlock ecosystems occur in two isolated
bands. One occupies the Coast and Cascade Ranges of British Columbia,
Washington, and Oregon; the second occupies the northern Rocky
Mountains of Idaho, northeastern Washington, northwestern Montana,
and southeastern B. C. The two bands are separated from each
other by xeric forests as well as the shrub/steppe and high desert
of the Columbia Basin (i.e., mesic forests are disjunct). Because
over 150 species have been reported to exhibit this disjunct
distribution (including plant, animal and fungal taxa), several
hypotheses have been erected
regarding the genesis of this disjunction. We are ultimately
interested in examining testing these hypotheses in as many species
as possible.
To date, we have data for tailed frogs (Ascaphus truei
& A. montanus), water
voles (Microtus richardsoni),
and the Plethodon vandykei species group of salamanders
(including P. vandykei and
P. idahoensis). Both amphibian
species fit the predictions of the ancient
vicariance hypothesis, whereas waters voles appear to have
achieved the disjuct distribution by dispersal
from the northern Rockies into the Northern Cascades. In
addition, we are collaborating with Steve
Brunsfeld (UofI, Department of Forest Resources) to examine
several plant species, including dusky willow (Salix melanopsis),
western white pine (Pinus monticola)
and a phlox (Collomia heterophylla).
2. Northern Rocky Mountain Endemics.
In addition, there are many plants and animals that are restricted
to the inland portions of the mesic
forests, and we are examining several of these. These include
Red-tailed chipmunks (Tamias
ruficaudus), Columbian ground squirrels (Spermophilus
columbianus), and Idaho giant salamanders (Dicamptodon
aterrimus). We have also collaborated with Steve Brunsfeld
to examine Constance's bittercress (Cardamine constancei).
3. Widespread Xeric Forests
Xeric forests are widespread in northwestern North America
and are dominated by Ponderosa pine. These ecosystems are characterized
by patchy stands of timber separated by intervening grassy areas.
We've begun comparative phylogeography of xeric forest species
by examining two widespread taxa endemic to northwestern North
America: montane voles (Microtus montanus) and yellow-pine
chipmunks (Tamias amoenus).
Two xeric forest taxa endemic to northwestern North America,
Montane voles (Microtus montanus)
and Yellow-pine chipmunks (T. amoenus) are being
examined examined. Mitochondrial sequence data indicate that
T. amoenus harbors extensive genetic
diversity that partitions among mountain ranges. We're also
beginning work on the wandering shrew (Sorex
vagrans).
The long-term goal for this aspect of our research is to develop
a center for ecosystem genetics for northwestern North American
forest ecosystems. The Northwestern North America comparative
phylogeography project is currently funded by NSF/EPSCoR. There is a great deal of room on these projects for
graduate students.
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