The Cliff Ecology Research Group (CERG), Department of Integrative Biology, University of Guelph,... more The Cliff Ecology Research Group (CERG), Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada, has been in existence since 1985 when its members began working on the ecology of the Niagara Escarpment (fig. 1). In 1988 they discovered a stand of ancient trees growing on the cliffs and in 1989 they discovered that in fact the escarpment cliffs support the oldest and least disturbed forest ecosystem in Canada. Individual living trees older than 1,300 years are still present and the forest appears to be in steady state. CERG's work on the ancient trees led to the idea that cliffs serve as refuges for many species including ancient humans. That observation led to the development of the Urban Cliff Hypothesis that is described in this paper and was presented at the international symposion on " The Natural City, " Toronto, 23-25 June, 2004, sponsored by the University of Toronto's Division of the Environment, Institute for Environmental Studies...
Salt marshes are a type of coastal wetland that are affected by dynamic coastal processes. Ice bl... more Salt marshes are a type of coastal wetland that are affected by dynamic coastal processes. Ice blocks and wrack (mats of plant debris) regularly float onto northern marshes and become stranded, affecting vegetation and soil accretion. There is little research regarding the capacity of ice and wrack to transport viable plant propagules onto marshes where they can colonize, which may be particularly important at barren new salt marsh restoration sites. Contributions of sediment by ice may also be important at restoration sites to raise the marsh platform to elevations appropriate for plant colonization. We collected ice (n = 27) and wrack (n = 18) samples at marshes in the Bay of Fundy, ran germination trials with the contents, and measured the quantity of sediment in the ice. We found viable propagules from halophytic and non-halophytic species in wrack, and viable propagules of Sporobolus pumilus in ice. Additionally, we found sediment densities between 0.01 and 4.75 g·cm−3 in ice b...
Water uptake from vegetation can govern plant productivity through different mechanisms in natura... more Water uptake from vegetation can govern plant productivity through different mechanisms in natural terrestrial ecosystems. However, the ability of plants to regulate water can be viewed as an ecosystem service in urban regions, where vegetation in constructed ecosystems can help reduce stormwater runoff through their root systems. However, there is no knowledge on how root traits operate in extensive green roofs, an increasingly popular form of green infrastructure, as the substrate environment has an extremely shallow substrate depth (~20 cm) and a lack of biological legacy. In this study, I found that stormwater performance is not solely a function of rooting depth; rather, a multitude of belowground traits govern water regulation in this novel ecosystem that may optimize transport capacity, soil exploration and root construction costs. Overall, this study parallels findings from natural ecosystems and provides practitioners with new tools to create a more functional green roof.
Constructed ecosystems like green roofs are increasingly deployed in cities to mitigate issues as... more Constructed ecosystems like green roofs are increasingly deployed in cities to mitigate issues associated with urbanization. To minimize the cost of green roof infrastructure, shallow growing media (substrate) for plants is often employed. Spatial heterogeneity in substrate depth has also been hypothesized to allow greater plant species diversity without adding to the weight. Stress and competition can change green roof plant communities after initial planting, but little is known about the long-term effects of spatial heterogeneity on vegetation composition and functional characteristics. Our goal was to determine how green roof plant communities and, in turn, functional plant traits, change over time in response to environmental stress and substrate heterogeneity. This four-year experiment used four substrate depth treatments: three with homogenous substrate depths of 5 cm, 10 cm, and 15 cm, and one treatment with a heterogenous substrate depth that varied between 5 cm and 15 cm (5/15 cm). The volume of the substrate in the 10 cm treatment and 5/15 cm treatment was equal. By the end of this four-year experiment, variation occurred between treatments for community composition and functional diversity, with the greatest species richness observed in the least stressful treatment (15 cm) and the greatest functional diversity and evenness observed in the most stressful treatment (5 cm). Additionally, each treatment had lower functional diversity after four years compared to the initially planted community. When the heterogenous 5/15 cm treatment was compared to the homogenous 10 cm treatment, there were no differences in the number of plant species, but the treatments contained two distinct plant communities. Furthermore, the 5/15 cm treatment supported taller species, a trait value associated with reduced stormwater runoff and substrate temperature. This finding indicates that creating green roofs with a heterogenous substrate depth could improve overall green roof function without increasing roof weight. Substrate depth can be manipulated by green roof designers to alter vegetation characteristics, but species and functional diversity showed opposite trends along the depth gradient.
Abstract Global social and economic changes, alongside climate change, are affecting the operatin... more Abstract Global social and economic changes, alongside climate change, are affecting the operating environment for agriculture, leading to efforts to increase production and yields, typically through the use of agrochemicals like pesticides and fertilizers, expanded irrigation, and changes in seed varieties. Intensification, alongside the expansion of agriculture into new areas, has increased harvest, but has also had numerous well-known impacts on the environment, ultimately resulting in a loss of resilience and lack of sustainability in agro-ecosystems. Combined with features of agricultural systems such as the differential movement of ecosystem services, and interactions among ecosystem services driven in part by management choices, such intensification has disrupted key feedbacks in agricultural systems. These changes have tended to perpetuate the management choices that have led to efficient, productive agriculture, often at the expense of nature and the provision of important nonfood ecosystem services. Here, we explore how agriculture functions as a complex adaptive system. We assess how recent changes have interacted with agro-ecosystem features to result in a loss of resilience, and suggest key research directions to help harmonize production and ecosystem function, drawing primarily on Canadian examples. Enhancing the resilience of agricultural landscapes is critical to the long-term sustainability of agriculture in a rapidly changing world.
Container gardens are used in cities around the world where access to soil at ground level is lim... more Container gardens are used in cities around the world where access to soil at ground level is limited. They represent artificial ecosystems but often provide the only vegetation in some highly urbanized locations, and have been used in vertical and horizontal forms of living architecture. Although there are many container gardens in urban areas, container gardening as a component of more broadly considered green infrastructure seems to be unappreciated. The aim of this review is to elucidate potential ecosystem services provided by container gardening. The ultimate goal of this review is to recognize the value of container gardens in order to promote them as part of green infrastructure in urban areas. The ecosystem services which container gardens provide were sorted into the following categories (1) Provisioning (food production and security); (2) Regulating (stormwater management, improvement of air quality, energy savings and thermal comfort); (3) Habitat/Supporting (plant biodi...
We review what is known about ecosystem service (ES) delivery from agricultural dykelands and tid... more We review what is known about ecosystem service (ES) delivery from agricultural dykelands and tidal wetlands around the dynamic Bay of Fundy in the face of climate change and sea-level rise, at the outset of the national NSERC ResNet project. Agricultural dykelands are areas of drained tidal wetland that have been converted to agricultural lands and protected using dykes and aboiteaux (one-way drains or sluices), first introduced by early French settlers (Acadians). Today, Nova Scotia’s 242 km system of dykes protect 17,364 ha of increasingly diverse land uses—including residential, industrial, and commercial uses as well as significant tourism, recreational, and cultural amenities—and is undergoing system modernization and adaptation. Different ES are provided by drained and undrained landscapes such as agriculture from dykelands and regulating services from wetlands, but more complex dynamics exist when beneficiaries are differentiated. This review reveals many knowledge gaps abou...
The Cliff Ecology Research Group (CERG), Department of Integrative Biology, University of Guelph,... more The Cliff Ecology Research Group (CERG), Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada, has been in existence since 1985 when its members began working on the ecology of the Niagara Escarpment (fig. 1). In 1988 they discovered a stand of ancient trees growing on the cliffs and in 1989 they discovered that in fact the escarpment cliffs support the oldest and least disturbed forest ecosystem in Canada. Individual living trees older than 1,300 years are still present and the forest appears to be in steady state. CERG's work on the ancient trees led to the idea that cliffs serve as refuges for many species including ancient humans. That observation led to the development of the Urban Cliff Hypothesis that is described in this paper and was presented at the international symposion on " The Natural City, " Toronto, 23-25 June, 2004, sponsored by the University of Toronto's Division of the Environment, Institute for Environmental Studies...
Salt marshes are a type of coastal wetland that are affected by dynamic coastal processes. Ice bl... more Salt marshes are a type of coastal wetland that are affected by dynamic coastal processes. Ice blocks and wrack (mats of plant debris) regularly float onto northern marshes and become stranded, affecting vegetation and soil accretion. There is little research regarding the capacity of ice and wrack to transport viable plant propagules onto marshes where they can colonize, which may be particularly important at barren new salt marsh restoration sites. Contributions of sediment by ice may also be important at restoration sites to raise the marsh platform to elevations appropriate for plant colonization. We collected ice (n = 27) and wrack (n = 18) samples at marshes in the Bay of Fundy, ran germination trials with the contents, and measured the quantity of sediment in the ice. We found viable propagules from halophytic and non-halophytic species in wrack, and viable propagules of Sporobolus pumilus in ice. Additionally, we found sediment densities between 0.01 and 4.75 g·cm−3 in ice b...
Water uptake from vegetation can govern plant productivity through different mechanisms in natura... more Water uptake from vegetation can govern plant productivity through different mechanisms in natural terrestrial ecosystems. However, the ability of plants to regulate water can be viewed as an ecosystem service in urban regions, where vegetation in constructed ecosystems can help reduce stormwater runoff through their root systems. However, there is no knowledge on how root traits operate in extensive green roofs, an increasingly popular form of green infrastructure, as the substrate environment has an extremely shallow substrate depth (~20 cm) and a lack of biological legacy. In this study, I found that stormwater performance is not solely a function of rooting depth; rather, a multitude of belowground traits govern water regulation in this novel ecosystem that may optimize transport capacity, soil exploration and root construction costs. Overall, this study parallels findings from natural ecosystems and provides practitioners with new tools to create a more functional green roof.
Constructed ecosystems like green roofs are increasingly deployed in cities to mitigate issues as... more Constructed ecosystems like green roofs are increasingly deployed in cities to mitigate issues associated with urbanization. To minimize the cost of green roof infrastructure, shallow growing media (substrate) for plants is often employed. Spatial heterogeneity in substrate depth has also been hypothesized to allow greater plant species diversity without adding to the weight. Stress and competition can change green roof plant communities after initial planting, but little is known about the long-term effects of spatial heterogeneity on vegetation composition and functional characteristics. Our goal was to determine how green roof plant communities and, in turn, functional plant traits, change over time in response to environmental stress and substrate heterogeneity. This four-year experiment used four substrate depth treatments: three with homogenous substrate depths of 5 cm, 10 cm, and 15 cm, and one treatment with a heterogenous substrate depth that varied between 5 cm and 15 cm (5/15 cm). The volume of the substrate in the 10 cm treatment and 5/15 cm treatment was equal. By the end of this four-year experiment, variation occurred between treatments for community composition and functional diversity, with the greatest species richness observed in the least stressful treatment (15 cm) and the greatest functional diversity and evenness observed in the most stressful treatment (5 cm). Additionally, each treatment had lower functional diversity after four years compared to the initially planted community. When the heterogenous 5/15 cm treatment was compared to the homogenous 10 cm treatment, there were no differences in the number of plant species, but the treatments contained two distinct plant communities. Furthermore, the 5/15 cm treatment supported taller species, a trait value associated with reduced stormwater runoff and substrate temperature. This finding indicates that creating green roofs with a heterogenous substrate depth could improve overall green roof function without increasing roof weight. Substrate depth can be manipulated by green roof designers to alter vegetation characteristics, but species and functional diversity showed opposite trends along the depth gradient.
Abstract Global social and economic changes, alongside climate change, are affecting the operatin... more Abstract Global social and economic changes, alongside climate change, are affecting the operating environment for agriculture, leading to efforts to increase production and yields, typically through the use of agrochemicals like pesticides and fertilizers, expanded irrigation, and changes in seed varieties. Intensification, alongside the expansion of agriculture into new areas, has increased harvest, but has also had numerous well-known impacts on the environment, ultimately resulting in a loss of resilience and lack of sustainability in agro-ecosystems. Combined with features of agricultural systems such as the differential movement of ecosystem services, and interactions among ecosystem services driven in part by management choices, such intensification has disrupted key feedbacks in agricultural systems. These changes have tended to perpetuate the management choices that have led to efficient, productive agriculture, often at the expense of nature and the provision of important nonfood ecosystem services. Here, we explore how agriculture functions as a complex adaptive system. We assess how recent changes have interacted with agro-ecosystem features to result in a loss of resilience, and suggest key research directions to help harmonize production and ecosystem function, drawing primarily on Canadian examples. Enhancing the resilience of agricultural landscapes is critical to the long-term sustainability of agriculture in a rapidly changing world.
Container gardens are used in cities around the world where access to soil at ground level is lim... more Container gardens are used in cities around the world where access to soil at ground level is limited. They represent artificial ecosystems but often provide the only vegetation in some highly urbanized locations, and have been used in vertical and horizontal forms of living architecture. Although there are many container gardens in urban areas, container gardening as a component of more broadly considered green infrastructure seems to be unappreciated. The aim of this review is to elucidate potential ecosystem services provided by container gardening. The ultimate goal of this review is to recognize the value of container gardens in order to promote them as part of green infrastructure in urban areas. The ecosystem services which container gardens provide were sorted into the following categories (1) Provisioning (food production and security); (2) Regulating (stormwater management, improvement of air quality, energy savings and thermal comfort); (3) Habitat/Supporting (plant biodi...
We review what is known about ecosystem service (ES) delivery from agricultural dykelands and tid... more We review what is known about ecosystem service (ES) delivery from agricultural dykelands and tidal wetlands around the dynamic Bay of Fundy in the face of climate change and sea-level rise, at the outset of the national NSERC ResNet project. Agricultural dykelands are areas of drained tidal wetland that have been converted to agricultural lands and protected using dykes and aboiteaux (one-way drains or sluices), first introduced by early French settlers (Acadians). Today, Nova Scotia’s 242 km system of dykes protect 17,364 ha of increasingly diverse land uses—including residential, industrial, and commercial uses as well as significant tourism, recreational, and cultural amenities—and is undergoing system modernization and adaptation. Different ES are provided by drained and undrained landscapes such as agriculture from dykelands and regulating services from wetlands, but more complex dynamics exist when beneficiaries are differentiated. This review reveals many knowledge gaps abou...
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