The boreal forest of Canada extends across 58% of Canada’s land area providing a large
range of ecosystem services including flood control, water filtration, and carbon storage.
Despite conservation efforts to protect this ecosystem, the boreal region is still under
stress from global stressors including climate change. Anthropogenic climate-change is
expected to raise temperatures and decrease precipitation over much of the boreal region
increasing the duration and magnitude of droughts. This potential change to a more arid
climate could have drastic affects on water levels and stream flows across much of the
boreal region. Changes in hydrology, as a consequence of anthropogenic climate change,
may result in large changes to aquatic ecosystems. To assess the susceptibility of lakes to
climate in northwestern Ontario over the past two millennia, sediment cores from a
headwater lake were obtained from near-shore cores to reconstruct changes in drought.
The cores were located at a depth where changes in pelagic and benthic diatom
assemblages (P: B boundary) were apparent in modern-day sediments because the
location has been shown to be susceptible to change. The lake chosen for reconstruction
was Gall Lake, a small (surface area = 19 ha, max depth = 18 m, mean depth = 8.5 m),
mesotrophic lake (total phosphorus (TP) level of 12.3 μg/L, July 2008), with a gentlysloping
eastern basin. This headwater lake in the Winnipeg River Drainage Basin
(WRDB) is part of a hydrologically-rich region that is expected to experience increased
aridity. Multivariate analysis of diatom assemblages over the past two millennia
suggested that the instrumental record does not encompassed the natural variability of
this system. The largest decreases in diatom-inferred (DI) depth were synonymous with
iii
the Medieval Climate Anomaly (MCA), a phenomenon not yet observed this far
northeast in North America. The MCA has been proposed as a surrogate for climate
change over the next century, therefore the prolonged aridity observed in Gall Lake could
aid in the calibration of general circulation models currently used to forecast changes in
climate, as well as a scenario that can be used to develop adaptation strategies to future
environmental change. / Thesis (Master, Biology) -- Queen's University, 2011-05-27 17:41:02.022
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6542 |
| Date | 07 June 2011 |
| Creators | HAIG, HEATHER A |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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