Urban Parks as Habitat Networks: Promoting Resident Wellbeing Through Biodiverse Greenspace November 23, 2018 J Cameron Parkin Maya Przybylski
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CONTENTS Summary Drawing List 1. Introduction 1.1. Biophilia and Urbanism 1.2. Approach 2. Methods 2.1. Network Components and Habitat Types 2.2. Fabric Sensing 2.3. Network simulation 2.4. Scenario testing 2.5. Intervention suggestions 3. Conclusions 3.1. Regional Connectivity 3.1.1 Forest and Open Woodland 3.1.2 Grassland and Scrub 3.1.3 Lake and Shoreline 3.1.4 Marsh and River 3.2. Effect of future developments 3.2.1 Forest and Open Woodland 3.2.2 Grassland and Scrub 3.2.3 Lake and Shoreline 3.2.4 Marsh and River 3.3 Network suggestions 3.3.1 Patch Add 3.3.2 Patch Enhance 3.3.3 Ecotone Spread 3.3.4 Matrix Smooth Bibliography
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SUMMARY Using species and habitat information gathered from open data sources and a computational workflow developed in previous work, this research models bird movement between varying types of habitats surrounding Toronto’s Port Lands and Eastern Waterfront. The findings are presented in a series of maps that vividly illustrate regional habitat networks. Proposed developments in the region are tested for their effects on the networks, and a network intervention suggestions are made. By illuminating the ecological context surrounding Quayside and the Eastern Waterfront area, this research identifies opportunities for new developments to leverage these habitat networks to support and engage bird populations, strengthening regional ecosystems and improving neighbourhood vitality and wellbeing.
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DRAWING LIST Panel 1
Regional Resistance Maps GIS data gathered from: City of Toronto Open Data Toronto Region Conservation Authority, accessed thorough Scholars GeoPortal Google Maps Aerial Imagery
Fig 1.1 Fig 1.2 Fig 1.3 Fig 1.4
Forest and Woodland Regional Resistance Map Grassland and Scrub Regional Resistance Map Lake and Shoreline Regional Resistance Map Marsh and River Regional Resistance Map
Panel 2
Regional Habitat Networks and Sightings Sighting data gathered from: eBird.com Cornell Lab of Ornithology, All About Birds.
Fig 2.1 Fig 2.2 Fig 2.3 Fig 2.4
Forest and Woodland Regional Habitat Network and Sightings Grassland and Scrub Regional Habitat Network and Sightings Lake and Shoreline Regional Habitat Network and Sightings Marsh and River Regional Habitat Network and Sightings
Panel 3
Regional Habitat Network and Sightings Overlay Sighting data gathered from: eBird.com Cornell Lab of Ornithology, All About Birds.
Fig 3.
Regional Habitat Network and Sightings Overlay
Panel 4
Site Development Resistance Maps Pt 1 GIS data gathered from: City of Toronto Open Data Toronto Region Conservation Authority, accessed thorough Scholars GeoPortal Google Maps Aerial Imagery Development data gathered from: Sidewalk Labs Waterfront Toronto UrbanToronto.ca
Fig 4.1 Fig 4.2 Fig 4.3 Fig 4.4
Forest and Woodland Resistance Map Before Development Forest and Woodland Resistance Map After Development Grassland and Scrub Resistance Map Before Development Grassland and Scrub Resistance Map After Development
Panel 5
Site Development Resistance Maps Pt 2 GIS data gathered from: City of Toronto Open Data Toronto Region Conservation Authority, accessed thorough Scholars GeoPortal Google Maps Aerial Imagery Development data gathered from:
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Sidewalk Labs Waterfront Toronto UrbanToronto.ca Fig 5.1 Fig 5.2 Fig 5.3 Fig 5.4
Lake and Shoreline Resistance Map Before Development Lake and Shoreline Resistance Map After Development Marsh and River Resistance Map Before Development Marsh and River Resistance Map After Development
Panel 6
Site Development Habitat Networks Pt 1
Fig 6.1 Fig 6.2 Fig 6.3 Fig 6.4
Forest and Woodland Habitat Network Before Development Forest and Woodland Habitat Network After Development Grassland and Scrub Habitat Network Before Development Grassland and Scrub Habitat Network After Development
Panel 7
Site Development Resistance Maps Pt 2
Fig 7.1 Fig 7.2 Fig 7.3 Fig 7.4
Lake and Shoreline Habitat Network Before Development Lake and Shoreline Habitat Network After Development Marsh and River Habitat Network Before Development Marsh and River Habitat Network After Development
Panel 8
Site Development Habitat Network Overlay Before
Fig 8.
Site Development Habitat Network Overlay Before
Panel 9
Site Development Habitat Network Overlay After
Fig 9.
Site Development Habitat Network Overlay After
Panel 10
Network Intervention Suggestions Before Development
Fig 10.1 Fig 10.2 Fig 10.3 Fig 10.4
Patch Add Suggestions by Habitat Before Development Patch Enhance Suggestions by Habitat Before Development Ecotone Spread Suggestions by Habitat Before Development Matrix Smooth Suggestions by Habitat Before Development
Panel 11 Fig 11.1 Fig 11.2 Fig 11.3 Fig 11.4
Network Intervention Suggestions After Development
Patch Add Suggestions by Habitat After Development Patch Enhance Suggestions by Habitat After Development Ecotone Spread Suggestions by Habitat After Development Matrix Smooth Suggestions by Habitat After Development
Panel 12
Site Species Sighting data gathered from: eBird.com
Fig 12.
Species seen surrounding Quayside the last five years
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1. INTRODUCTION 1.1. Biophilia and Urbanism Literature shows that as populations move to urban centers, there is a need for people to have access to thriving, biodiverse green space to foster mental health and environmental responsibility. Specifically, in the field of environmental psychology, there has been recent findings that a quantifiable “connectedness with nature” is linked to wellbeing1, and that that biodiversity is perceived by the public and is positively linked to wellbeing2. At the same time, experts in landscape architecture and urbanism critique existing approaches to providing green space in cities, which often lead to sterile, ornamental lawns that limit urban biodiversity3. To move beyond this approach, experts call for more dynamic and complex strategies in fostering urban ecology. As a response, this research employs computational methods of modeling habitat networks as part or a design methodology that thrives amidst the complexity and dynamic nature of urban and ecological systems. 1.2. Approach Due to the fragmented nature of greenspace in urban centers, it is useful to understand these greenspaces as a network, forming a larger habitat. While habitat as patch networks is not a new idea, the advancement of geographic information systems (GIS), computation, and graph theory, have allowed recent strides in sensing, simulating, and evaluating habitat networks in landscape ecology. Recent work by our team has seen the adaptation of patch network principles in creating digital workflows and tools that reveal avian habitat networks in the dense urban fabric and offer opportunities for strategic intervention. These network tools take a unique agent-based approach to simulating species movement through complex fabric, before suggesting various typologies of interventions in key locations. For this study, these tools have been deployed to study Habitat networks in Toronto’s eastern waterfront area. This report explains the methodology followed to create a set of drawings that illustrate avian habitat networks at two different scales and two development scenarios. The first scale looks at the region of Toronto that surrounds the eastern waterfront, and the second focuses on the area containing Sidewalk Lab’s Quayside Development and Don River’s mouth naturalization project. The first development scenario evaluates the urban fabric as-is, and the second includes the proposed Quayside, Port Lands Vision, Bayside Development, and 3C Waterfront Development. Beyond explaining the production and reading of these drawings, the report will conclude with a brief description of the results of the studies. 2. METHODS Note: The methods section contains excerpts from Coding a Biophilic Core: Digital Design Tools for Toronto’s Avian Habitat Networks which is the masters thesis by J Cameron Parkin where the background processes deployed in this report were developed. Note: The methods outlined in this section comprise the “background intellectual property” outlined in Schedule C of the Research Agreement. 2.1. Network Components and Habitat Types (indented portions excerpted from Coding a Biophilic Core) In Landscape Ecology, the three components of patch networks are:
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Renate Cervinka, Kathrin Röderer and Elisabeth Hefler, "Are Nature Lovers Happy? on various Indicators of Well‐ being and Connectedness with Nature," Journal of Health Psychology 17, no. 3 (2012), 379. 2 Richard Fuller et al., "Psychological Benefits of Greenspace Increase with Biodiversity," Biology Letters 3, no. 4 (2007), 390‐394. 3 Michael Hough, Cities and Natural Process (London ; New York: Routledge, 1995). Urban Parks as Habitat Networks | 6
A patch is a significant area of fabric that can support species populations. Based on a review of literature in landscape ecology, several qualities of patches have been identified as important factors in their success as part of an avian habitat network. The two most important qualities are the size and proximity of the patches. Beyond this, a constantly varying edge condition and large ecotone,4 as well as a high number of cavities and overall height of patch all contribute to its success.5 The matrix is the fabric between patches that is not conducive to ecological habitation. Therefore, birds must move through the matrix to utilize a network of patches. Matrices can have varying levels of resistance caused by physical and environmental barriers which distort bird’s paths of travel and affect the distance they can travel from one patch to another. An ecotone is the transition space between two habitat types, or in the case of this study, between a patch habitat and the matrix around it. Ecotones offer many benefits to a patch including increased biodiversity due to more variation in habitat and protection by acting as a buffer to the patch. An additional attribute, which greatly impacts this study, is the ability for an ecotone to promote bird movement from patch to patch through the matrix by softening what could be a harsh threshold. To account for the habitat preferences of different birds, networks in this study are broken into four habitat groups based on the Cornell Lab of Ornithology’s Habitat categories: Forest and Woodland Grassland and Scrub Lake and Shoreline Marsh and River 2.2. Fabric Sensing (indented portions excerpted from Coding a Biophilic Core) To generate responsive habitat networks, resistance maps are created to illustrate the ability for birds to move through or occupy urban fabric. The resistance map is made up of multiple GIS and aerial imagery layers that are assigned a gray value based on the resistance level of their contents. Features with high levels of resistance such as highways and tall buildings are darker, and features that accommodate birds such as tree canopies and other natural ground covers are lighter. Individual layers used to build the resistance map were gathered from City of Toronto Open Data, Toronto Region Conservation Authority, and Google Maps Aerial Imagery. The layers include: Building Massing Streets and Arteries City Wetland
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Wenche E. Dramstad, James D. Olson and Richard T. T. Forman, Landscape Ecology Principles in Landscape Architecture and Land‐use Planning, eds. James D. Olson and Richard T. T. Forman (Cambridge Mass.; Washington, DC: Harvard University Graduate School of Design ;Island Press; American Society of Landscape Architects, 1996). 5 Michael W. Strohbach, Susannah B. Lerman and Paige S. Warren, "Are Small Greening Areas Enhancing Bird Diversity? Insights from Community‐ Driven Greening Projects in Boston.(Report)," Landscape and Urban Planning 114 (2013), 69. Urban Parks as Habitat Networks | 7
City Vegetation City Greenspaces TRCA Wetland TRCA Vegetation TRCA Forest TRCA Beach/Bluff TRCA Meadow Aerial Imagery Trees Aerial Imagery Grass Landcover Data Water Bodies and Rivers The layers are overlaid to create a bitmap that represents the sum of all the information. The grey value of each layer, and its weight when it is overlaid are based on an understanding of how different urban elements effect accommodation or resistance of birds. The map is then blurred to reduce the effect of insignificant elements and allow for more consistent digital sampling of the image. Through the digital sampling of gray values, this resistance image can now inform what portions of fabric are considered a habitat patch, and how species moment will be affected by the matrix. 2.3. Network simulation (indented portions excerpted from Coding a Biophilic Core) The resistance map is sampled and any point with a high value relating to avian occupation is considered a habitat point. These points are combined into habitat patch polylines. Patches area created at different thresholds, with stronger patches being drawn darker. “Agents” are then emitted outward from the patches into the matrix. As they move, these agents sense a portion of the resistance map in front of them, constantly moving forwards and towards areas that better support birds. If on their journey, one of these agents arrives at another patch, it stops moving and its path is solidified as a connection. Agents that do not reach a patch in 1000m of travel are disregarded. Once the paths are complete, they are evaluated based on their length and the resistance they meet to dictate whether they are kept and how dark they are drawn. 2.4. Scenario testing To test the effect of development scenarios in avian habitat connectivity, updated resistance maps were created using available information on the Quayside, Port lands Vision, Bayside Development, and 3C Waterfront Development. Habitat network simulations could then be run before and after the developments to compare the results. 2.5. Intervention suggestions (indented portions excerpted from Coding a Biophilic Core) For a habitat network to be successful, it is important that the quality and arrangement of the patches, ecotones, and matrix are all contusive to species movement. To improve the habitat networks sensed, a series of intervention typologies have been developed. These typologies are placed using a tool that reads the networks and resistance maps. When placed, the series of intervention suggestions act as a starting point to begin examining locations where the network can be strengthened. The intervention types are as follows: Patch Add: Where travel distances between patches are too far, a habitat patch is added to increase stepping stone movement. To place Patch Add interventions, network paths are Urban Parks as Habitat Networks | 8
evaluated based on length. Where the length exceeds 400 meters, a midpoint is placed to indicate the need for an additional patch. Closely spaced points are then conglomerated into patches that serve as intermediate stops on multiple paths of travel. Patch Enhance: Where green space exists but does not have the characteristics to accommodate bird populations, the qualities of the habitat are improved. To identify portions of the fabric that have potential to support bird populations, the tool takes the values sampled from the resistance maps and highlights those within a certain range. Ecotone Spread: Where strong ecological territory borders areas of high resistance, this transition is blurred to encourage species movement through the matrix and offer variation in habitat. To place the Ecotone Spread intervention sites, the resistance map is sampled, and anytime an area of very low resistance borders and area of very high resistance, an ecotone is placed to encourage birds to cross this boundary. Matrix Smooth: Where the matrix offers high resistance along identified paths of travel and around patches, safety and accommodation of urban fabric is increased to boost willingness and ability of birds to move between patches. To locate Matrix Smooth interventions, areas of fabric with high resistance values that are within a certain radius of a patch or path are extracted from the resistance map and highlighted. 3. CONCLUSIONS 3.1. Regional Connectivity (Panel 1-3) As expected, Toronto Island, Leslie Street Spit, Cherry Beach, Woodbine Beach, and the Don Valley Ravine register as very strong habitats covering many habitat preferences. These areas also contain sightings of a large number of bird species. Sidewalk Lab’s Eastern Waterfront focus area directly borders many of these habitats and this plays a key role on the region’s habitat connectivity. Currently, the major waterfront habitats including Toronto Island, Leslie Street Spit, Cherry Beach, Woodbine Beach are highly connected to each other, but high levels of resistance in the city prevent these habitats from connecting to the ravine system. A well-designed Port Lands, in conjunction with a naturalized don could enhance connections between these two strong, but currently separate habitat networks. In looking at the individual regional habitat networks, specific opportunities and limitations can be noted: 3.1.1. Forest and Open Woodland ‐ The vegetation surrounding the railway in the north eastern region of the maps offers one of the few opportunities to connect the Corktown Common and Port Lands to and Don Valley Ravine. ‐ Vegetation bordering the GO Transit Don Yard offers a strong patch that may eb at jeopardy in future developments. ‐ Many sightings of forest and woodland dwelling birds outside of habitat patches suggest these birds are capable of moving through the matrix, likely due to the presence of street trees. 3.1.2. Grassland and Scrub ‐ Large open areas in Port Lands allow for grassland and scrub species to move freely between open lot patches, connecting the waterfront habitats to Corktown Commons and the base of the Don. ‐ The upper Don Valley habitat is disconnected due to lack of open space North of the Port Lands.
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Few sightings of grassland and scrub species in the matrix point to conflict between these species’ need for open space and the dense development of the city
3.1.3. Lake and Shoreline ‐ Lake and shoreline Specie benefit from strong continuous habitat along the series of waterfront habitats. ‐ Sidewalk Lab’s Quayside site has an opportunity to connect to waterfront parks to the West that have high sightings and some habitat. 3.1.4. Marsh and River ‐ Marsh habitat is fairly limited to Toronto Island, Leslie Street Spit, and Cherry Beach, and some river habitat exists in the upper portion of the Don River in the map. ‐ Pervasive hard paving and water edges greatly limit wetland habitat connectivity and the ability for those species to penetrate the city. 3.2. Effect of Future Developments (Panel 4-9) The proposed developments in the site area have both positive and negative effects on network connectivity, as they affect each habitat type differently: 3.2.1. Forest and Woodland The elimination of open wooded lots and the rail yard vegetation removed some very strong connecting patches, limiting penetration of forest and woodland species into the city. However, the Lower Don Lands naturalization proposal contains enough tree canopy to register as a series of weak forest/woodland patches. If these patches are strong enough, they could extend the habitat network towards the quayside site and provide an opportunity to link into a larger network. As seen with many of the habitat types, the connection between Cherry Beach and the Don Lands naturalization park exists but is weak due to the dense residential development. 3.2.2. Grassland and Scrub The loss of the large open lots removes a couple strong patches, but once again, the mouth naturalization could extend the network to the west towards Quayside and other large developments. In addition to the design of well composed forest patches, some species’ need for open space should be considered when developing in this region. 3.2.3. Lake and Shoreline The lake habitat does not experience a lot of change, except for the residential development slightly breaking up the already weak canal habitat. When designing riparian zones, it should be considered whether they are designed for wetland birds, river birds, or shoreline birds. 3.2.4. Wetland and River Wetland and river habitat connectivity is greatly improved by the Don River mouth naturalization, which registers in these maps as a strong patch. This provides potential to connect to the waterfront habitats to the river and wetland habitat moving up the don valley. Again, connection between the mouth naturalization and Cherry Beach is heavily blocked be the residential development and would greatly benefit from the network suggestions outlined in the following section. 3.3. Network suggestions (panel 10-11)
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Based on the interventions suggested by the tool for different habitat networks, the following may be useful points of investigations. These interventions are highlighted on the intervention suggestion maps in the drawing set. 3.3.1. Patch Add ‐ Two strong locations to add a patch or corridor emerge that would help connect the Lower Don Lands and the series of waterfront habitats. These would befit multiple habitat types. ‐ Additional waterfront parks could help connect Quayside to waterfront habitats farther west. ‐ A forest patch should be considered where the rail yard vegetation exists now. 3.3.2. Patch Enhance ‐ Mouth naturalization should be carefully designed to accommodate as many species as possible by providing multiple habitat types. This will be key in linking Quayside into larger habitat networks. ‐ Open Lawns in the port lands would benefit network of they had more natural grassland cover. 3.3.3. Ecotone Spread ‐ The border between the Lower Don Lands mouth naturalization and adjacent developments will be key design area to promote permeability. 3.3.4. Matrix Smooth ‐ ‐ ‐
Residential Development in the Port Lands could pose a serious threat to bird species if not carefully designed. The noise and physical barrier of the Gardiner and Don Valley expressways currently contribute to the disconnect between waterfront habitats and Don Valley Ravine. If large amounts of traffic exist on new Port Lands roads, species movement through the development could be discouraged.
While quayside does not show up in the network suggestions or habitat maps, adding more habitat has opportunity to connect to all four habitat groups via the Lower Don Lands naturalization project, if in turn has connectivity to the waterfront habitats and Don Valley Ravine.
BIBLIOGRAPHY
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References Cervinka, Renate, Kathrin Röderer, and Elisabeth Hefler. 2012. "Are Nature Lovers Happy? on various Indicators of Well- being and Connectedness with Nature." Journal of Health Psychology 17 (3): 379. Dramstad, Wenche E., James D. Olson, and Richard T. T. Forman. 1996. Landscape Ecology Principles in Landscape Architecture and Land-use Planning, edited by James D. Olson, Richard T. T. Forman. Cambridge Mass.; Washington, DC: Harvard University Graduate School of Design ;Island Press; American Society of Landscape Architects. Fuller, Richard, Katherine Irvine, Patrick Devine-Wright, Philip Warren, and Kevin Gaston. 2007. "Psychological Benefits of Greenspace Increase with Biodiversity." Biology Letters 3 (4): 390-394. Hough, Michael. 1995. Cities and Natural Process. London ; New York: Routledge. Strohbach, Michael W., Susannah B. Lerman, and Paige S. Warren. 2013. "Are Small Greening Areas Enhancing Bird Diversity? Insights from Community- Driven Greening Projects in Boston.(Report)." Landscape and Urban Planning 114: 69. Data Cornell Lab of Ornithology. “All about Birds, Bird Guide.” Cornell University. Accessed Feb, 2017. eBird Basic Dataset. Version: EBD_relMay-2013. Cornell Lab of Ornithology, Ithaca, New York. May 2013. Open Data Toronto TRCA accessed through Scholars Geoportal
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