Lichen Trimlines in the Peace-Athabasca Delta: Variations in Flora, Form, and Disturbance Regime

Lichen trimlines are characteristic of aquatic systems where lichen-covered rocks border fluctuating water bodies. This study examined water-origin saxicolous lichen trimlines on acidic metacrystalline bedrock outcrops in the Peace-Athabasca Delta, northern Alberta, Canada. Twenty-seven species of saxicolous lichens were found in the vicinity of the trimlines. Species richness above the trimline (26 species) was almost twice that found below the trimline (14 species). Colonization lag time, differences in susceptibility to disturbance, and site influences on lichen establishment and survival might be involved in the absence of many species below trimlines. In frequently inundated areas, rock surfaces are dominated by the amphibious lichens Staurothele fissa and S. drummondii. The dominant lichen colonizer below trimlines was Physcia caesia. Other important colonizers below trimlines included Phaeophyscia sciastra and Physcia dubia, and on rocks fertilized by bird feces, Xanthoria elegans. A curious feature of the saxicolous flora was the presence of many calciphiles. Variations in trimline form and height and constituent species are related to the hydrologic and disturbance regime. Trimlines in perched basins tend to be near current water level, horizontal, and distinct, and indicate a relatively stable, infrequently flooded environment. Trimlines at open-drainage sites tend to be high above current water, wavy, and indistinct, and indicate a strongly-pulsed environment with frequent disturbances. Those at restricted-drainage basins are variable in form and height and disturbance regime

Impaired wetlands in a damaged landscape: the legacy of bitumen exploitation in Canada

This work is a scientific monograph that examines the flora and vegetation of natural mineral wetlands in comparison to mineral wetlands affected by bitumen exploitation. The work is of broad relevance because (a) wetland loss and degradation is a global problem; (b) the continued global increase in fossil fuel exploitation is resulting in widespread damage; and (c) bitumen (tar sands, oil sands) exploitation is a rapidly growing and destructive set of activities. The core of the work is a meta-analysis of 417 vegetation plots

A Proposal for the Political Economy of Green Criminology: Capitalism and the Case of the Alberta Tar Sands

Green criminology was proposed in 1990 to broaden the discipline and illustrate how environmental crime, deviance, and inequality can be interpreted through a critical lens influenced by political economic theory. Green criminology has yet to fulfill that theoretical promise. Instead, the political economic perspective on green criminology remains underdeveloped. The purpose of this work is to contribute to further development of a political economic green criminology by laying out the connection between ecological Marxism and green criminology. To carry out this task we describe five propositions that criminologists must consider when developing a green criminology from a political economic perspective. Importantly, these propositions suggest that the environmentally destructive forces of capitalism are opposed to nature. That is, we argue that green criminologists must come to recognize that capitalism and nature cannot both survive over the long run, and in criminological terms, capitalism is therefore a crime against nature