Floristic variation along the HVDC transmission line right-of-way in Manitoba
The floristic variation was examined along the high voltage direct current (HVDC) transmission line right-of-way, which extends from the 50oN to the 56oN latitude in Manitoba. Over its 895 km length the right-of-way intersects six of the recognized natural vegetation zones in the province. The right-of-way (ROW) plant community at each site was compared to an adjacent, relatively undisturbed community, which was designated as a control area (CONTROL). The ROW communities differ from the CONTROL communities in both species composition and physiognomy. The majority of ROW communities are characterized by a high graminold richness and a high graminoid cover, principally as a result of such disturbances as grazing, mowing, herbicide treatment, and fire. Most of the CONTROL communities are elther woodland or forest areas. The overstory of the CONTROL communities is dominated by aspen (Populus tremuloides) in the southern woodlands, while in the northern forests the canopy is comprised mainly of either black spruce (Picea mariana), jack pine (Pinus banksiana), or aspen, or a mixture of these...