Rethinking urban political ecology from the outside in: greenbelts and boundaries in the post-suburban city

This paper engages the existing literature on Urban Political Ecology (UPE) from the perspective of regulating urban expansion through greenbelts. The paper makes a contribution to a better understanding of suburbanisation and postsuburbanisation which have so far not been at the centre of the concerns of UPE. In an era of global suburbanisation greenbelts differ from similar boundary setting exercises in the past and are as varied as the suburbanisation processes and their governance themselves. While conscious of those varieties, we focus here on the Greater Golden Horseshoe (GGH) greenbelt in Ontario that was created by provincial legislation in 2005. With the 2005 legislation, the Ontario government declared 720,000 hectares off limits for conventional urban development. The Greenbelt Act created an expansive area under protection from the Niagara Peninsula in the south to the Bruce Peninsula in the north, the Niagara Escarpment in the west to a series of moraines in the east. We will argue that the GGH greenbelt has become a prime negotiation space for the overall re-regulation of urban political ecologies in Southern Ontario. Largely surrounding the booming Toronto region, the GGH greenbelt is expansion space and projection screen of a suburbanizing region in search of redefinition.     

Poor efficacy of herbicides in biochar-amended soils as affected by their chemistry and mode of action

We evaluated wheat straw biochar produced at 450 °C for its ability to influence bioavailability and persistence of two commonly used herbicides (atrazine and trifluralin) with different modes of action (photosynthesis versus root tip mitosis inhibitors) in two contrasting soils. The biochar was added to soils at 0%, 0.5% and 1.0% (w/w) and the herbicides were applied to those soil-biochar mixes at nil, half, full, two times, and four times, the recommended dosage (H₄). Annual ryegrass (Lolium rigidum) was grown in biochar amended soils for 1 month. Biochar had a positive impact on ryegrass survival rate and above-ground biomass at most of the application rates, and particularly at H₄. Within any given biochar treatment, increasing herbicide application decreased the survival rate and fresh weight of above-ground biomass. Biomass production across the biochar treatment gradient significantly differed (p < 0.01) and was more pronounced in the case of atrazine than trifluralin. For example, the dose-response analysis showed that in the presence of 1% biochar in soil, the value of GR₅₀ (i.e. the dose required to reduce weed biomass by 50%) for atrazine increased by 3.5 times, whereas it increased only by a factor of 1.6 in the case of trifluralin. The combination of the chemical properties and the mode of action governed the extent of biochar-induced reduction in bioavailability of herbicides. The greater biomass of ryegrass in the soil containing the highest biochar (despite having the highest herbicide residues) demonstrates decreased bioavailability of the chemicals caused by the wheat straw biochar. This work clearly demonstrates decreased efficacy of herbicides in biochar amended soils. The role played by herbicide chemistry and mode of action will have major implications in choosing the appropriate application rates for biochar amended soils.     

Why is integrating policy assessment so hard? A comparative analysis of the institutional capacities and constraints

Widely advocated as a means to make policy making more integrated, policy assessment remains weakly integrated in practice. But explanations for this shortfall, such as lack of staff training and resources, ignore more fundamental institutional factors. This paper identifies institutional capacities supporting and constraining attempts to make policy assessment more integrated. A comparative empirical analysis of functionally equivalent assessment systems in four European jurisdictions finds that there are wide-ranging institutional constraints upon integration. These include international policy commitments, the perception that assessment should support rather than determine policy, organisational traditions, and the sectorisation of policy making. This paper concludes by exploring the potential for altering these institutions to make policy assessment more integrated.     

Ecological bases of philopatry and cooperation in Ethiopian wolves

Ecological reasons for philopatry and cooperation are frequently invoked when kin selection is an insufficient explanation. The Ethiopian wolf (Canis simensis) is a specialised rodent hunter that forms family groups with cooperative breeding but also lives as monogamous pairs in suboptimal areas. Given the apparent absence of fitness gains to helpers from cooperative breeding, we set out to explore the benefits accrued by communal territorial defence measured as the acquisition and retention of habitats with more and most preferred rodent prey. Pairs defended relatively large territories to encompass critical amounts of key habitats within a matrix poor in rodents. Groups in optimal areas had relatively small territories and were expansionist, such that wolves in larger packs benefited per capita from increased good-quality foraging habitat. The fitness benefits of philopatry became evident after a rabies epizootic, when philopatry and expansionism prevailed in under-saturated conditions, until large groups split or provided dispersers that established locally. This study shows that high concentrations of prey can shift the balance of costs and benefits towards group living and cooperation in long-lived territorial carnivores, in so far as this dictates immediate rewards accrued from a given increment in territory size, namely greater foraging area per animal, leading to group enlargement and eventual inheritance of breeding space.     

A TECHNIQUE FOR MEASURING SCOUR AND FILL OF SALMON SPAWNING RIFFLES IN HEADWATER STREAMS1

A 30 x 0.9 cm piece of steel rod bent in the shape of an “L” and attached by hose clamps to a 15 x 3.2 cm section of plastic pipe sliding on an 86 x 1.9 cm steel shaft was tested for use in measuring scour and fill of salmon spawning riffles. Installed along channel cross-sections, results of tests at four sites on two hydraulically different streams showed the device to be useful in monitoring event specific scour and fill. Measurement error was estimated to be ± 10 mm.     

Release studies of benzalkonium chloride from hydrogel in a freshwater environment

The use of underwater optical sensors to monitor pollution and climate change processes has led to the development of robust instruments able to be deployed in lakes and seas for months at a time. However, despite this improvement in their durability they are subject to biofouling on their optical ports resulting in erroneous readings. The use of hydrogel coatings containing the cationic surfactant benzalkonium chloride (BAC) has been shown to prevent the development of biofouling for up to 12 weeks in the marine environment. In this study the use of hydrogel coatings in the freshwater environment was less successful with fouling visible at 2 weeks. In both field and laboratory studies a rapid initial loss of BAC from the hydrogel film was observed. The loss is a combination of diffusive and mass flow but the period from 12 to 50 h appeared to fit to diffusion kinetics and a diffusion coefficient of 7.3 x 10(-8) cm2 s(-1) (13 degrees C) was calculated, an order of 10 times greater than that found in seawater. Subsequently the rate of loss of the residual BAC, for which a diffusion coefficient of 5.7 x 10(-10) cm2 s(-1) (15 degrees C) was measured, was too low to prevent the early stages of biofouling.     

Beyond the Guidelines: Practical lessons for monitoring

A series of workshops have provided extensive feedback on a recently published manual, Monitoring Guidelines to Evaluate Effects of Forestry Activities on Streams in the Pacific Northwest and Alaska (Guidelines) (MacDonald et al., 1991). These workshops and other discussions have led to the identification of fourteen additional lessons for monitoring. These lessons are concepts which either were not incorporated into the Guidelines, were not sufficiently emphasized, or which are needed to put the Guidelines in context. The topics include: monitoring as a continuum; defining objectives and hypotheses; peer review; uncertainty and risk; upslope vs. instream monitoring; photo sequences; scale considerations; data storage, data interpretation, and data base management; activities monitoring; and personal commitment as a critical component in monitoring projects. Many of these lessons might appear self-evident, but our experience indicates that they are often ignored. Like the Guidelines, these lessons are widely applicable and should be explicitly recognized when formulating and conducting monitoring projects.     

Operating windows to assess whether monitored natural attenuation is a technically feasible remediation option for BTEX‐contaminated groundwater

When used in combination with source management strategies, monitored natural attenuation (MNA) is likely to be a technically feasible remediation option if the contaminant persistence time along the flow path is less than (a) the transport time to the compliance point and (b) the time available for groundwater remediation objectives to be achieved. Biodegradation is often the most significant natural attenuation process for benzene, toluene, ethylbenzene, and xylenes (BTEX) in groundwater. While BTEX transport rates increase with groundwater velocity, examination of data obtained from the published literature for seven sites undergoing MNA revealed significant positive correlations between groundwater velocity and first‐order biodegradation rates for toluene (r = 0.83, P < 0.05), ethylbenzene (r = 0.93, P < 0.01), m‐ and p‐xylene (r = 0.96, P < 0.01), and o‐xylene (r = 0.78, P < 0.05). This is attributed to increased dispersion at higher velocities leading to more mixing of electron acceptors with the contaminant plume. There was no positive correlation between groundwater velocity and first‐order biodegradation rates for benzene due to noise in the relationship caused by variations in (a) the concentrations of electron acceptors in the uncontaminated groundwater and (b) the proportions of benzene in the total BTEX concentration in the source area. A regression model of the relationship between groundwater velocity and the first‐order biodegradation rate can be used to delineate operating windows for groundwater velocity within which the contaminant persistence time is less than the transport and remediation times for a given source concentration, target concentration, distance to compliance point, retardation factor, and remediation time. The operating windows can provide decision makers with a rapid indication of whether MNA is likely to be a technically feasible remediation option at a given site. © 2005 Wiley Periodicals, Inc.     

Book reviews

Factor Four: Doubling Wealth, Halving Resource Use. Ernst von Weizacker, Amory Lovins & L. Hunter Lovins, 1997, London, Earthscan, ISBN 1 85383 407 6, £15.99 (hbk)

Local and Global: Management of Cities in the Information Age,. Jordi Borja & Manuel Castells, 1997, London, Earthscan, 277pp. ISBN 1 85383 441 6, £19.95 (pbk)

Wasted: counting the costs of global consumption. Michael Redclift, 1996, Earthscan, London, 173pp. ISBN 1 85383 360 6, £32.50(hbk), 1 85383 355 X, £12.95(pbk)

Eco-feminist Natures: race, gender, feminist theory and political action. Noel Sturgeon, 1997, New York, Routledge, ISBN 0 415 912504, £12.99 (pbk)

Global Warming and Global Politics. Matthew Paterson, 1996, London and New York, Routledge, ISBN 0 415 13871 X, US$85.00, UK£50.00, (hbk) ISBN 0 415 13872 8, US$20.99, UK£12.88, (pbk)

Managing for Local Sustainability: policy, problem-solving, practice and place. Valerie M. Brown (Ed.), 1997, Commonwealth of Australia, 314 pp. ISBN 0642 26464 3, Copies of the report can be obtained from: National Office of Local Government Commonwealth Department of the Environment, Sports and Territories, GPO Box 9834, Canberra ACT 2601. Tel: (06) 289 2222; fax (06) 289 2436.

Local Agenda 21, Local Authorities and Tourism: a United Kingdom perspective. David Leslie & Fiona Muir, 1996, Glasgow, Caledonian University, ISBN 0 948255 52 8, £9.00

Straws in the Wind: medieval urban environmental law — the case of Northern Italy. Ronald E. Zupko & Robert A. Laures, 1996, Boulder, CO, Westview Press, 152 pp. ISBN 0 8133 2972 8, £10.00 (pbk)