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| Habitat shot of an alvar in Manitoba |
Alvars are a globally rare ecosystems characterized by thin
soil and sparse tree cover over limestone bedrocks. These were first discovered
in Sweden by Carl Linnaeus and were given the name alvar for their barren
appearance. The openness of alvars is
maintained by ecological processes such as erosion, flooding, fire, drought,
frost heaving and grazing. These dynamic ecosystems are home to many rare and
unusual species which are adapted to these disturbances. Alvars are under
threats from garbage dumping, off-road vehicle use, mining, over-grazing,
development and road building.
Recently, alvars were first discovered in the Interlake
region of Manitoba and the Nature Conservancy of Canada and Manitoba
conservation formed the Manitoba Alvar Initiative in order to study and
preserve these unique ecosystems.
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| Map of confirmed alvar areas in Manitoba (Manitoba Alvar Initiative, 2012) |
Work done by the Manitoba
Alvar Initiative (2012) represents
only a “first approximation of alvar types” in Manitoba and the authors
recommend that a “quantitative data-based classification scheme be developed
to refine the conservation status of alvar types, establish site-condition
metrics, recommend compatible land-management activities and advance
conservation activities”.
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| Table of the various alvar types and parameters used to define them |
My current Masters project aims to build on previous work by completing a comprehensive vegetation
survey in order to form a quantitative classification scheme that will verify
the alvar types (grassland, wet grassland, jack pine savannah, oak savannah,
spruce savannah, boreal shrubland, prairie shrubland, intermediate shrubland) proposed
by the Manitoba Alvar Initiative (2012). Additional goals of the project
are to make preliminary observations on how disturbances, such as fire and
grazing, affect the various alvar types.
This season,
species diversity, abundance and environmental data were collected for 103 plots (10mX10m) from June till
August. Locations of rare species, such
as Gastonyi’s Cliffbrake (Pellaea
gastonyi) which only occurs on exposed limestone ridges and tabletops, were recorded. The information
collected from plots will be used to separate alvars into alvar types allowing
for species lists and mapping to be completed for each of the 20 sites on crown
land. The completion of this project will give us a better understanding of a
complex, dynamic and unusual ecosystem so that we can properly manage and
conserve its biodiversity.
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| Cliffbrake growing on exposed limestone ridge |
