La Farge
28 February 2007
Summary of Bryophytes as Bioindicators of anthropogenic and natural environmental change.
C. La Farge PI – Department of Biological Sciences University of Alberta, Edmonton
The research that is proposed for the field season 2007 will address the following objectives
Bryophytes are a dominant component of the flora in the arctic. Their role in the ecosystem has often
been underestimated. The proposed research will examine their role as biomonitors of anthropogenic or
naturally induced environmental change. For example lead isotopes that originate from distant sources
can be traced and found to accumulate in lichen populations of northern ecosystems. This will be tested
for the bryophyte component. Recent studies on Antarctic bryophytes have shown that within a single
plant, genetic mutations occur as a result of high levels of UV radiation. A comparison of samples from
both wet and mesic habitats will provide a comparison of terrestrial versus atmospheric absorbed heavy
metals. Bryophytes may play a key role in sequestering pollutants derived from remote anthropogenic
sources. Given the longevity of many arctic bryophyte populations accumulation of heavy metals may
have a cumulative toxic effect on the biota. Since bryophytes are ingested by invertebrates, which can be
inturn ingested by birds, and lemmings, arctic hare, muskox, and caribou are known to ingest bryophytes,
heavy metals accumulation in bryophytes (as primary producers of the ecosystem) can become
incorporated into the delicate food chain. Cumulative effects in the larger mammals of the ecosystem can
result. The importance of this study in a more remote part of the arctic is to test to what degree is the
heavy metal accumulation detectable in a spatial and temporal framework. How much is absorbed and
sequestered by the bryophyte layer. This will be an important compliment to ongoing research in the
marine and aquatic ecosystems of the north.
Understanding the genetic resources that exist within the bryoflora is a key aspect in evaluating the
biodiversity for the region. The project on the evolution of the arctic flora with respect to dispersal
mechanisms and refugia examines the population level genetic variation of selected common species
which will provide us with a measure of the cryptic biodiversity stored in the northern biota. As well by
examining the phylogenetic relationships of these populations, we can interpret their relationship to
southern populations. The current proposed field season will provide critical specimens from the high
arctic to examine the biological diversity within a locality as well as within the northern Ellesmere Island
region. This will provide a nested analysis of biodiversity of the bryophyte flora. Understanding the
dispersal biology of bryophytes and its relationship to the spatial distributions will enable us to evaluate
the biodiversity of bryophytes as principally clonal organisms. The revegetation of the Arctic Archipelago
has been the subject of recent debate with a number of questions unanswered: 1) Is the existing flora the
result of recolonization by populations south of the maximum ice extent; or 2) is it the result of
revegetation from pockets of Refugia (ice free areas) during the last glaciation; and 3) has isolation of the
northern populations developed pockets of vegetation that have a high concentration of genetic diversity,
such as in the region of Beringia as compared to other parts of the Arctic Archipelago? This research will
help us understand some of the mechanisms of evolution of organisms that are predominantly clonal.
The bryophyte inventory has direct relevance to Park Objectives for the region. Expanding the knowledge
of the bryophyte flora within the park boundary will build on the known floristic diversity and habitat
specialization of arctic bryophytes. Few researchers have studied the bryophyte component of the
Canadian High arctic. The expertise of the PI will provide an efficient means to expand this wanting area
of research.