To standardize the consideration of threats during species assessments, the International Union for the Conservation of Nature (IUCN) developed a threat classification system. Finally, over 23 000 known or suspected contaminated sites have been identified and classified in urban, rural, and remote areas across Canada, many of which are contaminated with petroleum hydrocarbons, metals, and (or) persistent organic pollutants, such as polychlorinated biphenyls ( Government of Canada 2017c). Runoff from urban, agricultural, and industrial landscapes contaminates Canada’s groundwater and downstream aquatic ecosystems ( Government of Canada 2017b). For example, close to 700 pipeline spills over the last decade resulted in the release of natural gas, crude oil, and other substances to the Canadian environment ( National Energy Board 2019). In addition to these intentional discharges, pipeline and other transportation incidences result in the accidental release of pollutants to the environment. Over 2000 wastewater facilities across the country contribute to the over 150 billion litres of untreated and undertreated sewage that is discharged into Canadian waterways every year ( Government of Canada 2017a). These include pollutants released into the air, land, and water from oil and gas extraction, manufacturing, mining, quarrying, electricity, and other sectors, including municipal wastewater treatment plants ( Government of Canada 2018). On an annual basis, about 5 million tonnes of pollutants, including over 320 substances, are released to the environment from more than 7000 facilities across Canada ( Government of Canada 2018). Numerous sources of pollution are of concern to Canada’s biodiversity.
#Grant cj fracked ecology drivers
Pollution can also compound the effects of other drivers of decline, weakening populations already affected by loss of habitat, overexploitation, or other threats ( Brook et al. Notably, pollutants not only have direct toxic effects on organisms, but may also potentially cause harm through indirect pathways (e.g., trophic cascades Kidd et al. Nonetheless, sublethal effects of environmental pollutants on individuals can reduce their fitness, leading to population-level impacts (e.g., Kidd et al. However, many pollutants cause sublethal effects on wildlife that are less obvious and more challenging to assess ( Nilsen et al. 2018) or upwelling of anoxic bottom waters (e.g., Rao et al. Similarly, nutrient pollution can lead to rapid mortality of fish or waterfowl as a result of the production of potent toxins in algal blooms (e.g., Papadimitriou et al. 2014) or wildlife deaths after contact with cyanide-bearing wastes from gold mining ( Donato et al. In some cases, pollution can cause sudden and immediate mortality, such as an oil spill leading to massive kills of birds (e.g., Haney et al. Pollution of the air, soil, and water is a significant threat to many species ( Novacek and Cleland 2001 Dudgeon et al. Clearly, a quantitative approach is needed to make accurate estimates of the scope of pollution as a threat to species at risk in Canada. Experts frequently identified scope of pollution as absent or negligible even for species with extensive co-occurrence with pollution sources, especially vascular plants. Furthermore, we found a weak correlation between the scope of the threat of pollution as assessed by COSEWIC expert panels and the geographic overlap of species occurrences and pollution sources that we determined with our quantitative method. Using this method, we quantified the geographic co-occurrence of 488 terrestrial and freshwater species and pollution sources and determined that, on average, 57% of the mapped occurrences of each species at risk co-occurred with at least one pollution source. Here, we describe a spatially explicit, quantitative method for assessing the scope of pollution as a threat to species at risk in Canada. Currently, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) relies on expert opinion to assess the scope (i.e., the proportion of a species’ population that may be affected) of pollution to species at risk. Pollution is a pervasive, albeit often invisible, threat to biodiversity in Canada.
0 kommentar(er)
