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Grass Lake


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AB
Canada

Establishment report on the Mildred Lake native and cultivated grass reclamation trial


Author(s): Tomm, H. O.

Year: 1982

Abstract:
The adaptability of native and cultivated grasses to oil sands disturbances is being studied in a field trial in northeastern Alberta. The native grasses originated from the mountains and foothills of the province. The trial was established on blended materials consisting of native sand, clayey overburden and peat. Nine native grasses and eight cultivated grass varieties were seeded in June of 1981. A description of the site, a summary of experimental procedures and first-year results are included in the report.

Long term prediction of vegetation performance on mined sands


Author(s): Bliss, L. C.

Year: 1977

Abstract:
This project on the \"Long Term Prediction of Vegetation Performance On Mined Sands\" (V.E.6.1) was undertaken to provide management with answers on the predictive ability to maintain different kinds of vegetation on raw sands. The research was designed as an integrated, multi-disciplinary program that would concentrate on the role of water stress in a dynamic soil-plant-atmosphere system of a planted grass cover and a natural Jack pine forest. To date only the latter project has been initiated because of the lack of funding and approval to work on the GCOS dike in 1975. This and the Syncrude dyke represent the worst (driest) environmental situation and therefore revegetation of other sand deposits should be more easily accomplished. The Richardson Fire Tower site was chosen because of the representativeness of its Jack pine - lichen woodland on deep sands, a forest type so characteristic of northeastern Alberta. The results of the first full year show that climatically this southwest-facing sand slope warms more rapidly in spring than do level sites at Mildred Lake and Fort McMurray and that the 1976 summer was above normal for temperature. Precipitation was near normal based upon the 1941 - 1970 period. Of the >60 days of precipitation, over 60% were 4 mm or less and thus little if any water entered the soil due to tree, lichen, and litter interception. Both needle duff and lichens provide a significant barrier to surface evaporation compared with open sand. Resistance to evaporation is 2 to 3 times greater with a lichen cover than with litter. The soils are very porous which is advantageous for water entrance, thus preventing erosion but porosity is a disadvantage in maintaining higher water levels near the soil surface for plant growth. These soils recharge during snowmelt in late March - early April; little runoff occurs and over the summer soil water drawdown takes place. Soil moisture content (volume basis) is generally 8 - 15% near the surface in spring, but by late September is 1 - 3% at all depths. Xylem water potentials, a measure of tree water content, were never very low (mean maximum at dawn -5 to -7 atm. and mean minimum at midday -11 to -14 atm.) which reflect a year of average precipitation with frequent light rains and periodic heavier storms. Transpiration and stomatal closure were controlled largely by vapour pressure deficits. Jack pine avoided spring drought by remaining dormant when air and needle temperatures were above freezing, yet when soils were still frozen. Although Jack pine did not show indications of severe drought in a relatively moist summer, it did develop xylem water potentials of -16 to -18 atm., values which are probably detrimental to many of the species being used in revegetation trials on the dike (Bromus inermis, Phleum pratense, and species of Agropyron). This means that potential species must be drought hardy and tested under laboratory rather than only under field conditions to determine their survival under severe drought conditions that may occur but once in 30 to 50 years. The studies of mycorrhizae show that a large number of species of fungi infect the roots of Jack pine and that the infecting flora from disturbed soils (old burns) is quite different from that of undisturbed forests. Since mycorrhizae are critical for the proper growth and survival of pines, care in innoculating tree seedlings with the proper species is essential. The energy and water balance mathematical model predicts the heat and water status of the Jack pine forest. Examination of the model outputs suggests that late season resistance to water uptake occurs because of increased root resistance in autumn. If this is confirmed with further experimental data, and model runs, it means that fall droughts may be especially critical because of the reduced ability of the trees to absorb water through their roots. A second field season coupled with the laboratory studies to determine lethal and sublethal levels of water stress in Jack pine will provide the added inputs to the models necessary for predicting tree response to severe climatic stress. These data, gathered in a highly integrated manner, will permit the calculation of tree survival on sands, be they dikes or other kinds of mined sand, in terms of soil water content and tree density (including crown extent) in relation to the exceptional dry year that may occur once in 30 to 50 years. Data from field trials of grasses or woody species, without supporting measurements of plant physiological responses to environmental conditions cannot provide this essential predictive tool for management unless the one in 30 to 50 year drought cycle is encountered. It is for this reason that modelling of the data in order to predict plant response to unusual environmental conditions becomes so useful. In summary, this study should be able to provide sufficient data to determine whether or not an open stand of Jack pine or similar conifer is the desired end point in maintaining vegetation at a low maintenance cost on sands, the result of open pit mining of the oil sands.

Oil sands sludge dewatering by freeze-thaw and evapotranspiration


Year: 1993

Abstract:
The dewatering of oil sands sludge is a major technological, economical, and environmental challenge to the oil sands industry of northeastern Alberta. Sludge is a mixture of small mineral particles (less than 44 µm in diameter), residual bitumen from the extraction process, and water. Sludge consolidates at the bottom of tailings ponds to approximately 30% solids in 2 years and will remain at this level of solids and water indefinitely. At 30% solids, sludge acts as a liquid; unstable and extremely low in strength. Approximately 25 million cubic metres of sludge at 30% solids are produced each year by the two operating extract ion plants owned by Syncrude Canada Ltd. and Suncor Inc. More than 500 million cubic metres of sludge have been produced over the first 20 years these plants have operated. The experiments detailed in this report show that it was possible to increase the solids content of sludge to 50% solids by adding three parts sand (tailings sand) to one part sludge. At 505 solids, the sand-sludge mixture was semi-plastic, but extremely weak. One thousand parts per million of lime were needed to keep the sand from segregating from the sludge. Drainage of sand-sludge mixtures, even under the pressure of self-consolidation, was slow and uneconomical. The sand-sludge mixture had to be dewatered to 85% solids content before its shear strength was sufficiently high to support machine traffic or the overboarding of more sand-sludge mixture. At 85% solids, the sand-sludge mixture had a shear strength in excess of 100 kPa. Freezing and thawing sludge (without sand) caused the solids content to increase from 30% to 50%. Another 10% increase in solids content was achieved by several more cycles of freezing and thawing. At 50% solids, sludge was semi-plastic. Ditches or grooves ploughed into the sludge remained, but the shear strength was very low (less than 2 kPa). Sludge without sand needed at least 80% solids to have sufficient shear strength (more than 100 kPa) to support machinery traffic or sludge overboarding. If snow was removed from the surface periodically, the sludge froze to 165 cm depth in one winter in Mildred Lake, the Syncrude Canada Ltd. plant and mine site, approximately 40 km north of fort McMurray, Alberta. If the snow cover was left in place, freezing was restricted to 30cm. Laboratory and pilot-plant experiments showed that the amount of sludge that could be frozen in one winter could be increased by freezing the sludge in thin layers. Using this technique, a layer only a few centimetres deep was deposited and left to freeze for a day or two; as soon as it was frozen, a second layer was deposited. Layered freezing was also slightly more effective at dewatering sludge than freezing a pool of sludge from the top down. The water released from the sludge during the thaw period rose almost immediately to the sludge surface. Surface water had to be drained away to allow further dewatering, either by evaporation or vegetation-controlled evapotranspiration. Standing water on the sludge surface prevented the establishment and growth of adapted vegetation by floating seeds, making the rooting medium unstable, or inhibiting oxygen flux to the root zone. If the water was removed, two species of plants—reed canary grass and western dock—were well adapted to the sludge environment and capable of removing enough water from the sludge to dry it to 80% solids. Reed canary grass was the best adapted plant to both sludge and sand-sludge mixtures. Furthermore, reed canary grass grew from small sections of its own rhizome, known as sprigs. Starting plants on sludge with sprigs of reed canary grass may allow for large scale (hundreds of hectares) dewatering by vegetation. Sprigs were easy to spread, not subject to movement by wind or small amounts of water, and fast to establish new plants. Sludge at 50% solids that was planted to reed canary grass was dewatered to 80% solids in one growing season. At 80% solids the sludge had a shear strength of 120 kPa and could support machine traffic of any kind or the overboarding of several metres of liquid sludge. However, the rapid removal of surface water and the quick establishment of a dense plant community were essential. Otherwise, dewatering during the summer months was minimal, less than a 5% increase in solids from May to October. Sand-sludge mixtures were also dewatered by freezing and thawing. A 1 year dewatering cycle that included freezing and thawing and summer evaporation, but no plant controlled evapotranspiration, increased the solids content of a 2-m deep sand-sludge mixture from 50% to 80% solids. Reed canary grass and western dock also grew well on sand-sludge mixtures and aided in dewatering, if the surface water was removed.

Performance of grasses shrubs and trees on disturbed soil at the AOSERP Mildred Lake camp experimental area


Year: 1980

Abstract:
The plants referred to in this report were initially established on the AOSERP Mildred Lake Camp area in 1977. The objectives of the program were to establish grass, shrub and tree species for evaluation of their response, particularly their reproduction response, to the climatic and edaphic conditions north of Fort McMurray. Over the 1977 growing season, 50 species and/or sources of grasses were spring seeded, 47 species and/or sources were started in containers and transplanted to the field and 24 species and/or sources were fall seeded. In addition, 12 woody plant species and/or sources were also planted in the field after growth in the greenhouse in containers. This report discusses the results of an evaluation of the plants conducted in late August and September, 1979.

Potential impacts of beaver on oil sands reclamation success - an analysis of available literature


Year: 2013

Abstract:
The North American beaver (Castor canadensis) is a large semi-aquatic rodent that has played a central role in shaping the Canadian boreal landscape, and colonial Canadian history. Exploitation of North American beaver populations to supply the European hat industry spurred the westward expansion of European explorers and traders into the continental interior. With intensive unregulated harvest, beavers virtually disappeared across much of their range; though populations are recovering, the species is only about 10% as abundant as it was before the fur trade took its toll. As a result, much of the recent ecological history of the Canadian boreal forest has occurred in the absence of this keystone ecosystem engineer, and the ecological state that we perceive as natural is in many regions quite different than it was a century ago. Beavers, while playing an important role in structuring streams and wetlands by altering vegetation communities and water flow patterns, may also affect human structures. In the mineable oil sands region of northeastern Alberta, much of the landscape will be impacted by mining. Mine sites will have to be reclaimed, and those reclaimed sites will consist of engineered landforms (including water bodies and waterways); the long-term hydrological and ecological function of those sites may be vulnerable to beaver activity. In an effort to determine if approaches exist that could manage the risk of beavers colonizing and negatively impacting reclaimed sites, we performed an extensive literature search and analysis. Our objective was to examine characteristics of beaver ecology that might potentially impact reclamation plans, and to identify possible methods to mitigate those impacts. We also include information on traditional use, historical abundance, and current abundance in the mineable oil sands region to provide important historical and ecological context. Although beavers inhabit a range of aquatic habitats, the focus of our review is on watercourses that could be dammed by beavers. Of the aquatic habitats which will be constructed during reclamation, these systems are probably the most vulnerable to impacts from beaver activity. Note, however, that inlet and outflow streams from lakes may be vulnerable to beaver activity, which could impact the performance of constructed lakes in a variety of ways. Beavers alter stream form and function, create wetlands, and change vegetation patterns. The most important predictor of beaver occurrence is stream gradient, with low gradients being associated with higher beaver activity. Stream depth and width, soil drainage, and stream substrate are also important. Although beavers may also respond to vegetation factors, such as tree or shrub species and density, hydrological factors are more important predictors of beaver occupancy of a site. The primary forage preferred by beavers includes deciduous tree and shrub species. Aspen (Populous tremuloides) is the species most preferred by beaver, and is a common component of reclamation plantings and natural recolonization of reclamation sites in the oil sands region. Beavers are central-place foragers, meaning foraging is concentrated around a central home base. They typically harvest deciduous trees and shrubs up to 60 m or more from the water, but most harvest occurs less than 30 to 40 m from the water’s edge. Predation (and predation risk) restricts the size of beavers’ foraging areas, and may also regulate their population size. Management of wolf populations to limit predation on caribou in northeastern Alberta may have significant indirect effects on beaver abundance and distribution by releasing them from predation pressure. The boreal forest ecosystem of Canada evolved over millennia with the beaver as a keystone species altering hydrological systems, creating vast areas of wetlands and beaver meadows, changing vegetation communities and modifying geomorphological processes. Reclamation of functional ecosystems in the region must therefore integrate beavers and their engineered structures. The most ecologically- and cost-effective approach is to design reclaimed areas with the objective of including beaver, but directing beaver activity to areas away from vulnerable reclamation structures. Ecological function requires the presence of beaver on the post-reclamation landscape, and the species is important to First Nations peoples and other trappers in the area. Although beaver abundance can be expected to increase in the area after reclamation, their activities will result in the replacement of existing vegetation with species of lower nutritional quality to beaver (conifer trees). This is expected to result in a beaver population decline and then stabilization over time. With beavers an integral component of the functional landscape, it is important to create “beaver exclusion zones” to ensure that the impact of the species is diverted to areas where beaver activity does not damage reclamation structures. There are very few existing studies of beaver impacts to reclaimed areas. Incorporating ecologically-based strategies for keeping beaver density low in sensitive areas at the outset of a reclamation project, and then monitoring the effectiveness of that strategy, is the best advice that can be derived from our analysis of the existing literature. Beavers could be discouraged from settling at a site by creating streams with steep gradients (>10%) that are wide and deep enough to ensure substantial water flows, are armoured with rock or cobble bottoms, and are bordered by coniferous tree species and/or grass and sedge species. Trees should be planted at high density to prevent growth of shrubs and deciduous trees in the understory, as these are preferred by beaver. Deciduous vegetation should not be planted during reclamation near sites where beavers are to be excluded, and it may be necessary to remove existing deciduous trees and shrubs and replace them with conifers, grasses and sedges in these areas. Although planting specific types of vegetation may be used to discourage beavers from settling a certain area in the short term, natural succession could eventually result in other vegetation communities attractive to beavers. Therefore, unless long-term vegetation management is envisioned, reclamation plans should not rely on using vegetation to dissuade beaver activity in sensitive areas alone, though this approach may be used in combination with other methods, especially in the few decades immediately following reclamation. Note that the goal is to plan for a maintenance-free environment in which ongoing beaver control is unnecessary, and the use of multiple strategies in tandem to guide beaver activity is more likely to achieve this goal. More active, maintenance-intensive techniques could be used to limit the damage caused by beaver dams to sensitive areas. These techniques include lethal (e.g., kill trapping or shooting) and nonlethal (e.g., relocation) methods to reduce population density. However, these methods require constant effort, and can be expensive. Another approach is to manipulate water flow through existing beaver dams using pipe drainage systems; this allows the beaver dam to stay in place, while reducing the risk that it will trap enough water to be dangerous if the dam should fail. Again, however, these drainage systems require long-term maintenance. One approach may be more sustainable in the long term and require less maintenance: minimize or maximize water flow through engineered channels, as beavers are less likely to use very low-flow and very high-flow watercourses. Note that beavers may still affect these channels, especially when population densities are high or other habitat is unavailable; however, the probability of beavers affecting very low-flow or high-flow channels is lower than for watercourses with more moderate flows. Creating several dispersed low-flow channels may make an area less desirable to beavers compared to a single moderate flow channel. Similarly, multiple low- to moderate-flow channels could be created, with some having characteristics that attract beavers (“decoys”) and others that do not (“exclusions”), allowing water flow to continue through some channels even in the presence of beavers. “Pre-dam” fences can be installed on decoy streams to create a structure to encourage beavers to occupy a site where damage is not a concern. Discharge could be controlled by regulating water flow through exclusion streams that are not dammed, or by installing flow devices though dams on decoy streams. A similar approach might be used on culverts that allow streams to flow beneath roadways; flow devices could be used proactively at these sites, and/or oversized culverts could be installed to allow maintenance of the natural width of the stream channel and reduce the noise of running water, which attracts beaver activity. Although many different landforms on the reclaimed landscape may be vulnerable to beaver activity, a few are considered critical areas where beaver impacts must be controlled, including the outlets of lakes, side-hill drainage systems, and constructed peatlands. Beaver activity at the outlet of constructed lakes could cause instability in containment structures, negatively affect littoral and riparian zones around the lake, and increase the probability of catastrophic outburst flooding. Damming of side-hill drainage systems could cause stream avulsion and routing of water flow into a new pathway not engineered for a stream, causing increased erosion. Flooding of constructed peatlands could convert them to open-water systems, thereby subverting their intended ecological function. These critical areas should be protected from beaver activities, while other areas should be designed to accommodate this important species. In practice, several different approaches – tailored to specific situations and landforms – will be necessary to develop and implement plans that accommodate beavers as a part of the post-reclamation landscape. As so few data exist to inform effective reclamation in the presence of beavers, all of the methods we suggest carry an unknown degree of risk. This risk can be decreased in the future by adapting methods based on observed effectiveness. We recommend implementing a research and adaptive management program on the influence of beavers on reclamation within the context of oil sands reclamation in northeast Alberta. Lack of existing information, particularly in northeast Alberta, illustrates the need to implement research that documents the positive and negative influence of beavers on reclamation sites and tests alternative methods to prevent negative and support positive influences. Otherwise reclamation strategies will be ad-hoc and tenuous, with a mixed success rate. A research and monitoring program would ideally contribute to a standardized strategic approach to mitigating negative beaver influences on reclamation of watercourses in the oil sands region. Beavers are, to a certain extent, unpredictable. No single approach will guarantee that a site will be unaffected by beaver activity. We suggest that multiple management approaches be simultaneously implemented at sites that are particularly vulnerable or critical for the functioning of the reclaimed landscape (e.g., outlet streams from constructed lakes). It is impossible to predict all eventualities, as the character of the reclaimed landscape will change over time due to successional processes, fire, global climate change, and resource extraction. The information we provide is the best available based on limited current knowledge, and provides the best chance for minimizing risk while accommodating this keystone species. Ultimately, the presence of beavers on reclaimed oil sands leases will increase biodiversity, enhance ecosystem goods and services, and assist in developing ecosystems that are consistent with natural systems in the boreal region.

Potential impacts of beaver on oil sands reclamation success–an analysis of available literature


Year: 2013

Abstract:
The North American beaver (Castor canadensis) is a large semi-aquatic rodent that has played acentral role in shaping the Canadian boreal landscape, and colonial Canadian history. Exploitation of North American beaver populations to supply the European hat industry spurred the westward expansion of European explorers and traders into the continental interior. With intensive unregulated harvest, beavers virtually disappeared across much of their range; though populations are recovering, the species is only about 10% as abundant as it was before the furtrade took its toll. As a result, much of the recent ecological history of the Canadian boreal forest has occurred in the absence of this keystone ecosystem engineer, and the ecological state that we perceive as natural is in many regions quite different than it was a century ago. Beavers, while playing an important role in structuring streams and wetlands by altering vegetation communities and water flow patterns, may also affect human structures. In the mineable oil sands region of northeastern Alberta, much of the landscape will be impacted by mining. Mine sites will have to be reclaimed, and those reclaimed sites will consist of engineered landforms (including water bodies and waterways); the long-term hydrological and ecological function of those sites may be vulnerable to beaver activity. In an effort to determine if approaches exist that could manage the risk of beavers colonizing and negatively impactingreclaimed sites, we performed an extensive literature search and analysis. Our objective was to examine characteristics of beaver ecology that might potentially impact reclamation plans, and to identify possible methods to mitigate those impacts. We also include information on traditional use, historical abundance, and current abundance in the mineable oil sands region to provide important historical and ecological context. Although beavers inhabit a range of aquatic habitats,the focus of our review is on watercourses that could be dammed by beavers. Of the aquatic habitats which will be constructed during reclamation, these systems are probably the most vulnerable to impacts from beaver activity. Note, however, that inlet and outflow streams fromlakes may be vulnerable to beaver activity, which could impact the performance of constructed lakes in a variety of ways. Beavers alter stream form and function, create wetlands, and change vegetation patterns. The most important predictor of beaver occurrence is stream gradient, with low gradients being associated with higher beaver activity. Stream depth and width, soil drainage, and stream substrate are also important. Although beavers may also respond to vegetation factors, such astree or shrub species and density, hydrological factors are more important predictors of beaver occupancy of a site.The primary forage preferred by beavers includes deciduous tree and shrub species. Aspen(Populous tremuloides) is the species most preferred by beaver, and is a common component of reclamation plantings and natural recolonization of reclamation sites in the oil sands region. Beavers are central-place foragers, meaning foraging is concentrated around a central home base. They typically harvest deciduous trees and shrubs up to 60 m or more from the water, but mostharvest occurs less than 30 to 40 m from the water’s edge. Predation (and predation risk) restricts the size of beavers’ foraging areas, and may also regulate their population size. Management of wolf populations to limit predation on caribou in northeastern Alberta may have significant indirect effects on beaver abundance and distribution by releasing them frompredation pressure.The boreal forest ecosystem of Canada evolved over millennia with the beaver as a keystone species altering hydrological systems, creating vast areas of wetlands and beaver meadows,changing vegetation communities and modifying geomorphological processes. Reclamation offunctional ecosystems in the region must therefore integrate beavers and their engineered structures. The most ecologically- and cost-effective approach is to design reclaimed areas withthe objective of including beaver, but directing beaver activity to areas away from vulnerablereclamation structures. Ecological function requires the presence of beaver on the post-reclamation landscape, and the species is important to First Nations peoples and other trappers in the area. Although beaver abundance can be expected to increase in the area after reclamation, their activities will result in the replacement of existing vegetation with species of lower nutritional quality to beaver (conifer trees). This is expected to result in a beaver population decline and then stabilization over time. With beavers an integral component of the functional landscape, it is important to create “beaver exclusion zones” to ensure that the impact of thespecies is diverted to areas where beaver activity does not damage reclamation structures.There are very few existing studies of beaver impacts to reclaimed areas. Incorporating ecologically-based strategies for keeping beaver density low in sensitive areas at the outset of a reclamation project, and then monitoring the effectiveness of that strategy, is the best advice thatcan be derived from our analysis of the existing literature. Beavers could be discouraged from settling at a site by creating streams with steep gradients (>10%) that are wide and deep enoughto ensure substantial water flows, are armoured with rock or cobble bottoms, and are bordered byconiferous tree species and/or grass and sedge species. Trees should be planted at high density to prevent growth of shrubs and deciduous trees in the understory, as these are preferred by beaver. Deciduous vegetation should not be planted during reclamation near sites where beavers are to be excluded, and it may be necessary to remove existing deciduous trees and shrubs and replace them with conifers, grasses and sedges in these areas. Although planting specific typesof vegetation may be used to discourage beavers from settling a certain area in the short term,natural succession could eventually result in other vegetation communities attractive to beavers. Therefore, unless long-term vegetation management is envisioned, reclamation plans should notrely on using vegetation to dissuade beaver activity in sensitive areas alone, though this approachmay be used in combination with other methods, especially in the few decades immediately following reclamation. Note that the goal is to plan for a maintenance-free environment in whichongoing beaver control is unnecessary, and the use of multiple strategies in tandem to guidebeaver activity is more likely to achieve this goal. More active, maintenance-intensive techniques could be used to limit the damage caused bybeaver dams to sensitive areas. These techniques include lethal (e.g., kill trapping or shooting)and nonlethal (e.g., relocation) methods to reduce population density. However, these methodsrequire constant effort, and can be expensive. Another approach is to manipulate water flowthrough existing beaver dams using pipe drainage systems; this allows the beaver dam to stay in place, while reducing the risk that it will trap enough water to be dangerous if the dam shouldfail. Again, however, these drainage systems require long-term maintenance.One approach may be more sustainable in the long term and require less maintenance: minimize or maximize water flow through engineered channels, as beavers are less likely to use very low-flow and very high-flow watercourses. Note that beavers may still affect these channels,especially when population densities are high or other habitat is unavailable; however, the probability of beavers affecting very low-flow or high-flow channels is lower than forwatercourses with more moderate flows. Creating several dispersed low-flow channels maymake an area less desirable to beavers compared to a single moderate flow channel. Similarly, multiple low- to moderate-flow channels could be created, with some having characteristics thatattract beavers (“decoys”) and others that do not (“exclusions”), allowing water flow to continuethrough some channels even in the presence of beavers. “Pre-dam” fences can be installed ondecoy streams to create a structure to encourage beavers to occupy a site where damage is not aconcern. Discharge could be controlled by regulating water flow through exclusion streams that are not dammed, or by installing flow devices though dams on decoy streams. A similar approach might be used on culverts that allow streams to flow beneath roadways; flow devices could be used proactively at these sites, and/or oversized culverts could be installed to allowmaintenance of the natural width of the stream channel and reduce the noise of running water,which attracts beaver activity.Although many different landforms on the reclaimed landscape may be vulnerable to beaver activity, a few are considered critical areas where beaver impacts must be controlled, includingthe outlets of lakes, side-hill drainage systems, and constructed peatlands. Beaver activity at the outlet of constructed lakes could cause instability in containment structures, negatively affectlittoral and riparian zones around the lake, and increase the probability of catastrophic outburstflooding. Damming of side-hill drainage systems could cause stream avulsion and routing ofwater flow into a new pathway not engineered for a stream, causing increased erosion. Floodingof constructed peatlands could convert them to open-water systems, thereby subverting theirintended ecological function. These critical areas should be protected from beaver activities,while other areas should be designed to accommodate this important species.In practice, several different approaches – tailored to specific situations and landforms – will benecessary to develop and implement plans that accommodate beavers as a part of the post-reclamation landscape. As so few data exist to inform effective reclamation in the presence ofbeavers, all of the methods we suggest carry an unknown degree of risk. This risk can bedecreased in the future by adapting methods based on observed effectiveness. We recommend implementing a research and adaptive management program on the influence of beavers onreclamation within the context of oil sands reclamation in northeast Alberta. Lack of existing information, particularly in northeast Alberta, illustrates the need to implement research thatdocuments the positive and negative influence of beavers on reclamation sites and testsalternative methods to prevent negative and support positive influences. Otherwise reclamationstrategies will be ad-hoc and tenuous, with a mixed success rate. A research and monitoring program would ideally contribute to a standardized strategic approach to mitigating negativebeaver influences on reclamation of watercourses in the oil sands region. Beavers are, to a certain extent, unpredictable. No single approach will guarantee that a site willbe unaffected by beaver activity. We suggest that multiple management approaches besimultaneously implemented at sites that are particularly vulnerable or critical for the functioning of the reclaimed landscape (e.g., outlet streams from constructed lakes). It is impossible topredict all eventualities, as the character of the reclaimed landscape will change over time due tosuccessional processes, fire, global climate change, and resource extraction. The information weprovide is the best available based on limited current knowledge, and provides the best chancefor minimizing risk while accommodating this keystone species. Ultimately, the presence of beavers on reclaimed oil sands leases will increase biodiversity, enhance ecosystem goods andservices, and assist in developing ecosystems that are consistent with natural systems in the boreal region.

Reclamation with native grasses in Alberta: Field trial results


Year: 1986

Abstract:
Between 1978 and 1981 the Alberta Forest Service established 10 native grass field trials. The general objectives were: (1) to select the most promising native grass species for reclamation of high elevation disturbances in the Eastern Slopes; (2) to design and evaluate native grass seed mixtures; and (3) to develop recommendations for establishing and maintaining native grasses on high elevation disturbances. This report gives the first long-term results from these trials. Species performances were generally poor in the species adaptability trials at Cadomin. The wheatgrasses, especially Agropyron dasystachyum, A. trachycaulum and A. trachycaulum 'Revenue ' performed best overall. Phleum alpinum, Poa interior and Trisetum spicatum were considered failures. Contrastingly, most species performed reasonably well in the species adaptability trial at Mildred Lake. On both trial sites the cultivated species performed equally as well as their native counterparts. The performance of the native grass mixture was poor in the nurse crop x fertilizer rate x seeding rate trials at Cadomin. Fertilization produced a significant increase in plant cover. Neither the nurse crop nor the seeding rate treatments had any significant effect on the performance of the seed mixture. Seed mixtures containing wheatgrass species, especially dasystachyum, performed best in the four seed mixture trials. In contrast, the only seed mixture lacking a wheatgrass generally had the poorest results. The cultivated companion crops had little or no effect on the plant cover of the native grass mixtures. The best native grass mixtures performed equally as well as the best cultivated grass-legume mixtures. In the establishment methods trial at Cadomin the most successful treatments were those that covered and protected the seed. Drill seeding and broadcast seeding followed by application of a mulch produced the highest plant covers. The hydroseeding treatments, in which the seed and mulch were applied together, gave the lowest plant covers. The results from this trial suggested that native grasses, if established properly, can produce adequate cover for erosion control purposes. The revegetation treatments were generally more successful on the native mineral soil than the coarser textured overburden. Most species produced higher plant cover on the mineral soil. Furthermore, the mineral soil supported substantially higher species richness (number of species), indicating the plant communities were more diverse on mineral soil than overburden.

Revegetation research : 1976 progress report, sub-projects VE 7.2, 7.3, and 7.4


Year: 1977

Abstract:
Laboratory studies were conducted during 1976 to investigate native grasses and legumes potentially useful for revegetation on various soils. Plant growth was tested in various soils with and without the addition of fertilizer in the greenhouse and ill growth chambers. The Genera tested were: Agropyron Alopecurus, Bromus, Calamagrostis, Festuca, Phalaris, Phleum, Poa, Puccinellia, Astragalus, Hedysarum, Lupinus, Oxytropis, Glycyrrhiza, Lathyrus, Thermopsis, and Vicia. Field studies were conducted at Woodbend Station, Devon. Germination and early establishment were observed on unscarifled, fall-planted and scarified, spring-planted legumes. Work was begun at the Alberta Environment Research Station at Vegreville. Native grasses, naturalized grasses, agricultural varieties of grasses, and native and agricultural varieties of legumes were planted to be evaluated in the uniformity garden. Ft Fort McMurray, research areas were partly established on the Great Canadian Oil Sands Ltd. tailings dike site and the AOSERP Mildred Lake facility. The development of the seed production test sites at Peers, Waskatenau, and High Level were continued. Native species of legumes were seeded at the Peers legume seed-increase nursery. Native grass seed for plants which had been sown the previous year at four different sites in Alberta were harvested. The following tentative conclusions may be used for the planning of Future studies: (i) Plant growth can be established on tailings sand if there is adequate moisture present, but time of planting seems to be a critical factor in establishment; (ii) Native legumes can produce root nodules without the add1tion of inoculum, but capacity to produce nodules on tailings sand varies among species; (iii) Nutrient requirements and soil preferences of native species vary widely. However, it is difficult to establish plant growth on soils with a low pH, a high conductivity (i.e. high salt concentration), or, a high aluminum level; (iv) A high level of available fertilizer may wholly or partially inhibit germination of native legumes and some native grasses. The optimum concentration of fertiIizer is higher for plant growth than for seed germination in some native legumes, but the optimum is determined in part at least by the amount and type of amendment used to ameliorate the tailings sand; and (v) Amendment of tailings sand with silt may cause soil compaction and have subsequent adverse effects on the penetration of the cotyledons through the substrate. In sand amended with peat, the roots of the seedlings tend to remain in the amended layer. The optimum amount of amendment seems to depend to some extent on the species used.

Revegetation research: 1976 progress report. Sub-Projects VE 7.27.3 and 7.4


Year: 1977

Abstract:
Laboratory studies were conducted during 1976 to investigate native grasses and legumes potentially useful for revegetation on various soils. Plant growth was tested in various soils with and without the addition of fertilizer in the greenhouse and ill growth chambers. The Genera tested were: Agropyron Alopecurus, Bromus, Calamagrostis, Festuca, Phalaris, Phleum, Poa, Puccinellia, Astragalus, Hedysarum, Lupinus, Oxytropis, Glycyrrhiza, Lathyrus, Thermopsis, and Vicia. Field studies were conducted at Woodbend Station, Devon. Germination and early establishment were observed on unscarifled, fall-planted and scarified, spring-planted legumes. Work was begun at the Alberta Environment Research Station at Vegreville. Native grasses, naturalized grasses, agricultural varieties of grasses, and native and agricultural varieties of legumes were planted to be evaluated in the uniformity garden. Ft Fort McMurray, research areas were partly established on the Great Canadian Oil Sands Ltd. tailings dike site and the AOSERP Mildred Lake facility. The development of the seed production test sites at Peers, Waskatenau, and High Level were continued. Native species of legumes were seeded at the Peers legume seed-increase nursery. Native grass seed for plants which had been sown the previous year at four different sites in Alberta were harvested. The following tentative conclusions may be used for the planning of Future studies: (i) Plant growth can be established on tailings sand if there is adequate moisture present, but time of planting seems to be a critical factor in establishment; (ii) Native legumes can produce root nodules without the add1tion of inoculum, but capacity to produce nodules on tailings sand varies among species; (iii) Nutrient requirements and soil preferences of native species vary widely. However, it is difficult to establish plant growth on soils with a low pH, a high conductivity (i.e. high salt concentration), or, a high aluminum level; (iv) A high level of available fertilizer may wholly or partially inhibit germination of native legumes and some native grasses. The optimum concentration of fertiIizer is higher for plant growth than for seed germination in some native legumes, but the optimum is determined in part at least by the amount and type of amendment used to ameliorate the tailings sand; and (v) Amendment of tailings sand with silt may cause soil compaction and have subsequent adverse effects on the penetration of the cotyledons through the substrate. In sand amended with peat, the roots of the seedlings tend to remain in the amended layer. The optimum amount of amendment seems to depend to some extent on the species used.