Rebecca C. Rooney

Oil sands mining and reclamation cause massive loss of peatland and stored carbon

We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services.

River Connectivity Affects Submerged and Floating Aquatic Vegetation in Floodplain Wetlands

The submerged and floating plant communities in floodplain wetlands of the Upper Columbia River have never been described. To explore mechanisms behind the influence of the annual flood pulse on vegetation, we investigated how species group into flood response guilds whose distributions vary along a connectivity gradient between 44 floodplain wetlands and the river, how connectivity influences water and sediment, and to what degree the effect of connectivity on vegetation is mediated by its effects on these environmental variables. We characterised assemblages with cluster and indicator species analysis, as well as non-metric scaling ordination and tested a structural equation model, which defined the relationship between assemblage composition, sediment and water quality, and connectivity to the river. We found four assemblages, each associated with different water and sediment conditions, and positioned at differing degrees of connectivity. The model provided a good fit to the data. We conclude that in highly connected floodplain wetlands the direct effect of flooding supersedes the influence of water and sediment quality in structuring vegetation assemblages. Yet where flooding is less intense, these environmental variables resume their structuring role.

Replacing natural wetlands with stormwater management facilities: biophysical and perceived social values

Urban expansion replaces wetlands of natural origin with artificial stormwater management facilities. The literature suggests that efforts to mimic natural wetlands in the design of stormwater facilities can expand the provision of ecosystem services. Policy developments seek to capitalize on these improvements, encouraging developers to build stormwater wetlands in place of stormwater ponds; however, few have compared the biophysical values and social perceptions of these created wetlands to those of the natural wetlands they are replacing. We compared four types of wetlands: natural references sites, natural wetlands impacted by agriculture, created stormwater wetlands, and created stormwater ponds. We anticipated that they would exhibit a gradient in biodiversity, ecological integrity, chemical and hydrologic stress. We further anticipated that perceived values would mirror measured biophysical values. We found higher biophysical values associated with wetlands of natural origin (both reference and agriculturally impacted). The biophysical values of stormwater wetlands and stormwater ponds were lower and indistinguishable from one another. The perceived wetland values assessed by the public differed from the observed biophysical values. This has important policy implications, as the public are not likely to perceive the loss of values associated with the replacement of natural wetlands with created stormwater management facilities. We conclude that 1) agriculturally impacted wetlands provide biophysical values equivalent to those of natural wetlands, meaning that land use alone is not a great predictor of wetland value; 2) stormwater wetlands are not a substantive improvement over stormwater ponds, relative to wetlands of natural origin; 3) stormwater wetlands are poor mimics of natural wetlands, likely due to fundamental distinctions in terms of basin morphology, temporal variation in hydrology, ground water connectivity, and landscape position; 4) these drivers are relatively fixed, thus, once constructed, it may not be possible to modify them to improve provision of biophysical values; 5) these fixed drivers are not well perceived by the public and thus public perception may not capture the true value of natural wetlands, including those impacted by agriculture.

Freshwater rainbow trout (Oncorhynchus mykiss) farming affects sediment and pore-water chemistry

Marine aquaculture has come under scrutiny, whereas little is known about the nature and extent of the effects of cage aquaculture in freshwater. We describe the development of changes in sediment and pore-water chemistry caused by an experimental Oncorhynchus mykiss farm located in freshwater Lake 375 (Experimental Lakes Area, north-western Ontario, Canada) during its first two production cycles along a distance transect from the cage. Significant changes in sediment chemistry were quick to develop; pore-water ammonia was elevated under the cage after 1 month and sediment nutrients were elevated 1 month later. The effects on the benthic environment were spatially localised, although variables responded to different extents. Within 16 months, nutrient concentrations in surface sediment reached an asymptote, whereas concentrations of metals and ammonia continued to increase. Copper (Cu) and zinc (Zn) concentrations under the cage reached levels that exceed sediment quality guidelines and may cause adverse biological impacts. An anti-fouling coating applied to the net pen was the major source of Cu, whereas Zn originated also from fish feed. Ammonia and pH are recommended for inclusion in monitoring programs because they were sensitive to fish farming and are biologically relevant. We also suggest inclusion of Cu and Zn in monitoring programs at farms with treated nets.

Natural capital and the political economy of wetland governance in Alberta

ABSTRACT The legitimacy of wetland decisions depends on how science and values are integrated and reflected in wetland management decisions. Natural capital and ecosystem services (ES) have become integral to how we think about ecosystem management however there is no consensus on how these concepts should be applied in management. Through the example of Alberta’s wetland policy, we show how policies designed to mainstream natural capital and ES in decision-making are aligned with liberal governance arrangements that emerged in the nineteenth century. There is a governance gap between individual wetland decisions and collective ecological outcomes. The Alberta wetland policy highlights three challenges to embracing the natural capital metaphor in a liberal government context: lack of consensus on policy objectives; case by case enforcement of policy leading to continued wetland drainage; and minimal consequences for non-compliance. The combination of norms about what is fair in terms of government intervention in land use decisions and scientific uncertainty about wetland ecosystem function makes it difficult to achieve consensus on limits to wetland loss contributing to continued loss of wetland ecological function. The discussion highlights the necessity of renewed political discourse about freedom, power, and justice in relation to collective economic and ecological security.

Wetland microhabitats support distinct communities of aquatic macroinvertebrates

ABSTRACT The drivers of aquatic macroinvertebrate distribution in Prairie Pothole Region wetlands are not as well understood as in other aquatic ecosystems (e.g. rivers or lakes). We collected aquatic macroinvertebrates from 35 fishless prairie pothole wetlands in Alberta, including two habitat zones: the emergent zone and the open-water zone. Within each zone, we collected a vegetation sample and a water column sample, thus capturing four distinct microhabitats. We tested for community differences among these microhabitats with nested ANOVAs, looking at macroinvertebrate abundance, taxa richness, and evenness. We also visualized trends in community composition among the microhabitats with nonmetric multidimensional scaling ordination. Interestingly, we observed no difference in macroinvertebrate communities between the open-water and the emergent habitat zones. However, we found significant differences in richness and evenness between water column and vegetation sample types nested within habitat zones. Additionally, we observed high taxonomic turnover between sample types. Our results emphasize the importance of within-zone microhabitats in structuring aquatic macroinvertebrate communities in prairie pothole wetlands, and the relative insignificance of emergent and open-water habitat zone distinctions. Future analyses of macroinvertebrates in wetlands should sample both the vegetation and the water column, regardless of habitat zone, to prevent biased surveys of macroinvertebrate communities.

Plant community, environment, and land-use data from oil sands reclamation and reference wetlands, Alberta, 2007–2009

Our goal was to evaluate the success of wetland reclamation efforts on oil sands mining company lease-holdings in Alberta, Canada. Already, 60 200 ha of land have been disturbed by mining, and an additional 419 800 ha will be mined in the future. Wetland reclamation efforts have been underway for 35 years, and current mine closure plans call for the construction of 15 840 ha of wetland habitat. There are, however, no accepted criteria by which the Alberta Government can evaluate constructed wetlands. We employed the reference condition approach, comparing reclamation wetlands to appropriate natural analogues with plants as bioindicators of wetland condition. The data set includes 74 wetlands, spanning a range in salinity, nutrient levels, size, and degree of human disturbance. Reclamation wetlands include those contaminated with oil sands tailings (oil sands process affected, OSPA, n = 13) and those free from tailings (oil sands reference, OSREF, n = 12). In contrast, some natural wetlands are exposed to agricultural impacts (AG, n = 12), but the majority represent our least-disturbed condition (reference wetlands, REF, n = 37). The data set includes species relative abundance from plant communities in the wet meadow, emergent, and open-water vegetation zones. In addition, we measured water and sediment chemistry variables and physical variables to quantify local environmental conditions. We also quantified land use surrounding 45 of the wetlands in a series of nested buffers ranging from 300 m to 2000 m from the edge of each wetlands open-water zone. This data set represents the most comprehensive, publicly available data on reclamation wetlands from the lease areas of the two largest oil sands mining companies. It may be used to investigate changes in wetland plant community composition along both natural and human-caused environmental gradients, including contamination by oil sands mine tails. The data could also inform studies into the effects of surrounding land use on wetland plants and local-level environmental conditions. Information about reclamation wetlands could serve as a basis for tracking reclamation trajectories over time, whereas information about reference wetlands could be used to characterize natural variability in plant communities in shallow open-water wetlands from the Boreal Plains ecoregion.

A methodology for relating wetland configuration to human disturbance in Alberta

ContextWidespread loss of wetland ecosystems resulting from human land use highlights the need for a reclamation strategy that can sustain wetland ecosystem services. Since wetland function partly depends on landscape structure, reclamation and monitoring can be aided by knowing the differences in wetland configuration between undisturbed and disturbed landscapes.ObjectivesIdentify a parsimonious set of landscape metrics for quantifying wetland configuration and land-cover composition, and quantify how these metrics vary with anthropogenic disturbance.MethodsA large suite of landscape metrics quantifying area/edge, shape, aggregation, and diversity were calculated for landscapes in the Grassland, Parkland, and Boreal Natural Regions of Alberta. Variable reduction techniques were applied to identify representative metrics. These representative metrics were related to anthropogenic disturbance using non-parametric tests.ResultsThe spatial configuration of wetlands in low-disturbance and high-disturbance landscapes were significantly different from other landscapes. Aggregation metrics were the most commonly identified measures of wetland configuration independent of wetland-proportion in the landscape.ConclusionsOur findings provide insight for reclamation and monitoring by showing that some aspects of wetland configuration vary independently of composition, and therefore both need to be considered when parameterizing the design of reclaimed landscapes. We suggest that using landscape metrics in a reference condition approach is appropriate for evaluating landscape degradation and for setting landscape reclamation targets and monitoring programs.