LE3 .A278 2004

2004

Reekie, Edward

Acadia University

Master of Science

Masters

Biology

Biology

Atlantic Coastal Plain species include some plants considered rare in Canada, and often found only in South-western Nova Scotia. Frequently found on lakeshores, these species appear sensitive to hydrological patterns which are drastically altered by damming. Various key points during the hydrological cycle are affected by damming, including a later (spring) drawdown of water (shortening the growing season), a later (autumn) refilling of basins (leaving plants vulnerable to frost damage) and a larger within year variation in water levels. The purpose of this study was to examine tolerance limits of rare coastal plain species and similar species found growing with them, and also examine reservoirs in order to identify factors that may be preventing rare coastal plain species from colonizing reservoir shorelines. Using elevated boxes planted at two times, the effect of growing season length and soil moisture content on seven species (4 coastal plain--'Hydrocotyle umbellata, Sabatia kennedyana, Coreopsis rosea'and 'Panicum longifolium ' and 3 associated species--'Eleocharis acicularis, Viola lanceolata' and 'Panicum spretum') were examined. Analysis of niche breadth for survival showed the common species to be more tolerant in general, although analysis of niche breadth for growth showed no difference between coastal plain and associated species. All common species survived to some extent in the harsh winter conditions of the gradient boxes, while the only coastal plain species to survive was 'C. rosea'. The lower niche breadth for survival of the rare species and lower winter survival may both have a part to play in the absence of rare coastal plain species on the reservoir shoreline.

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