Quaternary geology of the Campbellford, Trenton, Consecon, Tweed, Belleville, Wellington, Sydenham, Bath, and Yorkshire Island map-areas, Ontario /

Sediment relationships observed during geological mapping in southeastern Ontario indicate a relatively simple deglaciation history for the area during late Wisconsin time. The ice from the north (part of the Lake Simcoe lobe) and the Lake Ontario ice lobe, which were coalesced during most of late Wisconsin time, initially separated along the crest of the Oak Ridges Moraine. Available data indicate that the Oak Ridges Moraine is composed primarily of sediments pre-late Wisconsin in age capped by late Wisconsin till and interlobate deposits. Retreat of the northern ice was relatively steady and resulted in the deposition of the Dummer Moraines, a facies of the drumlinized till to the south. Retreat of the Lake Ontario ice lobe into the Lake Ontario basin was interrupted by a re-advance which covered the southeastern half of the map area. The northern ice had already retreated from the area by this time. The Lake Ontario lobe was fed through the St. Lawrence Valley, indicating that the Ottawa Valley was ice filled at this time. High level glacial lakes fronted the ice during deglaciation. These waters quickly fell to low levels as the ice retreated from the St. Lawrence Valley, opening lower outlets.

The effect of moisture on decomposition processes in the disturbed peatlands of the Wainfleet bog /

The purpose of this study was to determine the effect of increased soil moisture levels on the decomposition processes in a peat-extracted bog. Field experiments, in which soil moisture levels were manipulated, were conducted using 320 microcosms in the Wainfleet Bog from May 2002 to November 2004. Decomposition was measured using litter bags and monitoring the abundance of macro invertebrate decomposers known as Collembola. Litter bags containing wooden toothpicks (n=2240), filter paper (n=480) and Betula pendula leaves (n=40) were buried in the soil and removed at regular time intervals up to one year. The results of the litter bag studies demonstrated a significant reduction of the decomposition of toothpicks (p<0.001), filter paper (p<0.001), and Betula pendula leaves (pdisturbed peatland and that the greatest reductions in decomposition can be obtained by restoring the soil moisture levels near those of undisturbed conditions.

Introduced taxa in disturbed ecosystems

In the literature, introduced taxa are assumed to be present, more abundant, and occupy greater physical space in portions of ecosystems disturbed by human activity. This study tested this principle in two sites, Short Hills provincial Park ("SHU) and Backus Woods ("B~l"). spatial distribution of introduced taxa of vegetation, isopods, and earthworms was determined with the runs test along 300m transects encompassing gradients of anthropogenic disturbance severity. The hypothesis was that introduced taxa would be aggregated along these transects; the null hypothesis was that they would not be aggregated. The null hypothesis was rejected for the introduced taxa as a unit, and vegetation and earthworms individually. Introduced taxa were aggregated along 53.33% (N~30) and 57.14% (N~21) of the transects in SH and BW (respectively). Introduced vegetation (90.00%, N~10 and 100.00%, N~7) and earthworms (50.00%, N~10 and 50.00%, N~8) were also significantly aggregated within the sites. Introduced isopods, however, were not significantly aggregated at either place (20. 00%, N-=10 and 16. 67%, ~J~6). This study demonstrated that introduced taxa are aggregated within ecosystems disturbed by human activity. However, since introduced isopods were not significantly aggregated it was also shown that taxa respond differently.