Browsing by Author "Bayley, Suzanne"

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    Effects of logging in the southern boreal peatlands of Manitoba, Canada
    (2007) Locky, David; Bayley, Suzanne
    To evaluate changes in surface water chemistry, peat, and the plant community in logged peatlands, we compared plots in 1–4 year old (class I) and 9–12 year old (class II) clearcuts with plots in wooded controls. Indicator species were significantly different between wooded and clear-cut plots but not between clear-cut plot age classes. Surface waters in class I clearcuts had significantly higher temperature and nutrients compared with controls, and this was attributed to warming of the soil, which resulted in faster decomposition and greater nutrient availability. Hummocks, important peatland plant microhabitats, were reduced in height in all clearcuts because of compaction and abrasion. These abiotic changes caused a shift in the plant community. Total plant diversity was approximately 30% higher on clearcuts and consisted primarily of herbs, particularly grasses. However, bryophyte and lichen diversity and cover was greatest in wooded controls. Picea mariana (Mill.) BSP regeneration was not compromised by clear-cutting and was greater in class II clearcuts. Greater diversity and cover of Salix species in class II clearcuts suggests stable shrub community formation, which may be persistent and may slow succession. The use of appropriate equipment to minimize site disturbances while the ground is frozen may reduce long-term shifts in the plant community.
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    Plant diversity in wooded moderate-rich fens across boreal western Canada: an ecoregional perspective
    (2010) Locky, David; Bayley, Suzanne
    Ecoregions are increasingly being used as a framework for conservation planning. The Mid-Boreal Uplands Ecoregion stretches across Canada from Manitoba to British Columbia. From the perspective of conservation and to understand the dynamics of plant diversity and community composition in a common wetland type, we examined the plant communities and environmental variables in 80 wooded moderate-rich fens within this ecoregion. Regional diversity totalled 273 species, with 86 bryophytes and 187 vascular plants. Total diversity was greatest in Manitoba and decreased in a longitudinal trend west through Saskatchewan and Alberta. This may be related, in part, to orographic precipitation at Manitoba sites and a gradient of growing degree days. Richness of locally rare vascular plants exhibited a clear west to east gradient. Ten species of provincially rare vascular plants were observed across the ecoregion, but without pattern. Ordinations and other analyses revealed distinct plant communities for all three locations, with vascular plant assemblages more discrete than bryophyte assemblages. Bryophyte diversity increased with latitude and longitude, whereas vascular plant diversity decreased. Additionally, elevation, precipitation, surface water alkalinity, water temperature, percent overstory density, and peat organic C played a role in determining species richness and community composition. Overall, species composition and diversity in a single wetland type exhibited continuous change across multiple political jurisdictions at the ecoregion scale. Conservation plans for wetlands at the ecodistrict scale may be preferable.
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    Plant diversity, composition, and rarity in the southern boreal peatlands of Manitoba, Canada
    (2006) Locky, David; Bayley, Suzanne
    Plant diversity and rarity have been relatively well studied for bryophytes in Canadian western boreal peatlands, but little information exists for vascular plants. Diversity, community composition, and rarity of bryophytes and vascular plants were determined and relationships examined among these and environmental variables in five peatland types at Duck Mountain, Manitoba: wooded bogs, black spruce swamps, wooded moderate-rich fens, open moderate-rich fens, and open extreme-rich fens. Total diversity was 298 species comprising 86 bryophytes and 212 vascular plants. Mean diversity followed a unimodal distribution over a bog – rich fen gradient. Wooded moderate-rich fens (59.0) and black spruce swamps (53.4) had the highest mean diversity, whereas wooded bogs (32.3) and open extreme-rich fens (34.7) had the lowest mean diversity. Occurrences of locally rare species followed the same general pattern, and provincially rare vascular plants were found primarily in wooded moderate-rich fens and black spruce swamps and were mostly orchids. Reasons for these patterns are complex, but high diversity appears to be related to high habitat heterogeneity and moderate environmental variables, e.g., pH and alkalinity, and low diversity appears to be related to environmental extremes, e.g., pH and alkalinity. Boreal wooded moderate-rich fens and black spruce swamps have comparatively high plant diversity and rarity and require consideration if the focus is biodiversity conservation. This will become increasingly important in landscapes where development pressures are high.