Effect of native and invasive cordgrass on Macoma petalum density, growth, and isotopic signatures

Ecosystem engineers can influence community and ecosystem dynamics by controlling resources, modifying the flow of energy or biomass, or changing physical characteristics of the habitat. Invasive hybrid cordgrass (Spartina alterniflora × Spartina foliosa) is an ecosystem engineer in salt marshes in San Francisco Bay, California, U.S.A. that raises intertidal elevations and may be either increasing C₄ plant carbon input into food webs or tying up carbon in a form that is not usable by consumers. A manipulative experiment compared abundance, growth, and stable isotope (δ¹³C and δ¹⁵N) composition of the clam Macoma petalum (=M. balthica) among native marsh, hybrid Spartina, and mudflats in central San Francisco Bay. We found higher densities (individuals m⁻²) of M. petalum on mudflats compared to either native or hybrid Spartina (p < 0.001). Macoma petalum shell growth was significantly greater in mudflats than in either vegetation type in 2002 (p = 0.005) but not 2003. Differences in shell growth between native and hybrid Spartina were not significant. Stable isotope results showed differences between habitats in δ¹³C but not δ¹⁵N. Carbon signatures of M. petalum placed in Spartina were much more depleted than the isotopic signature of Spartina. Neither native nor hybrid Spartina appears to be a significant carbon source for M. petalum in San Francisco Bay, and we found no evidence that hybrid Spartina contributes carbon to M. petalum beyond what is provided by S. foliosa, despite the hybrid's much greater biomass. Our results show that loss of mudflat habitat, rather than increased input of C₄ carbon, is the greatest effect of the invasion of hybrid Spartina on M. petalum.     

Food Deserts in the Prairies? Supermarket Accessibility and Neighborhood Need in Edmonton,Canada*

The U.S. and U.K. literatures have discussed “food deserts,” reflecting populated, typically urban, low‐income areas with limited access to full‐service supermarkets. Less is known about supermarket accessibility within Canadian cities. This article uses the minimum distance and coverage methods to determine supermarket accessibility within the city of Edmonton, Canada, with a focus on high‐need and inner‐city neighborhoods. The results show that for 1999 both of these areas generally had higher accessibility than the remainder of the city, but six high‐need neighborhoods had poor supermarket accessibility. We conclude by examining potential reasons for differences in supermarket accessibility between Canadian, U.S., and U.K. cities.     

Can we sustain sustainable agriculture? Learning from small-scale producer-suppliers in Canada and the UK

There has been particular interest in 'alternative' food over the last 10 years, with many policymakers and researchers throughout the Minority World following a growing number of consumers and producers in supporting organic farming and a host of 'alternative' food networks. To date, there has been a tendency for theory and policy to emerge somewhat divorced from the grounded practices and experiences of producer-suppliers themselves within these networks. Urging a shift from 'alternativity' to 'sustainability' as a more critical and valuable tool to analyse food networks, this paper draws upon in-depth ethnographic research with small-scale producer-supplier case studies in south Wales and southern Ontario. In so doing it explores often overlooked voices and stories within sustainable food discourses. Focusing on the value of farmer-led understandings and responses, the paper highlights important implications for policymakers and consumers and outlines future research on sustainable food networks.     

Soil degradation: a global problem endangering sustainable development

1 Introduction Soil is not only the major natural resource on which human being depends for the production of food, feed, fiber, renewable energy and raw materials, but also plays a key role in maintaining the complex terrestrial ecosystems and climate systems of this planet. Recent rapid increase in the human population is placing a great strain on the worlds soil resources. Only about 11% of the global land surface covered by the soils are being used to raise crops and livestock, in other …     

Virtual vegetables and adopted sheep: ethical relation, authenticity and Internet-mediated food production technologies

Associating ideas related to cultural geographies of 'quality' food production and consumption with recent discussion of Internet technologies, virtuality and simulation, this paper examines two newly constituted Internet enterprises offering customers 'virtual' experiences of food production, and 'quality' food products in which they have invested. The paper shows how these enterprises are associated with particular types of geographical and ethical relation, and a search for 'authentic', connected, relationships with food, farming, locality and 'nature'. These relationships are constituted in an assemblage of things held together by flows of food, products, money and electronic communication. The paper ends by suggesting a number of theoretical ideas that might usefully be explored in empirical research into Internet-mediated food production.     

合肥市耕地和粮食可持续发展研究

收集1980～1999年合肥市耕地、人口、粮食等资料，定量分析在城市化快速发展下耕地的数量、质量变化和耕地减少的形式以及人口、粮食的变化，并用回归法分析它们的变化趋势。研究认为，在2005，2010年合肥市食物保障能力分别为97％和95％，对粮食生产与其影响因素进行了灰色关联分析，提出提高粮食产量的对策和实现途径。     

A FOOD GEOGRAPHY OF THE GREAT PLAINS

ABSTRACT. This article explores the regional identity of the Great Plains through its foodways using 744 responses from a mailed survey that asked participants to plan a representative menu for their locale. The strongest association is with beef—not surprising in an area known for cattle ranching. Other commonalities include potatoes, beans, and corn. Differentiation within the region is marked by preparation methods for beef as well as emphases on cornbread and peach cobbler in the south, rhubarb pie in the north, tortillas and sopapillas in the southwest, and pickles in two separate clusterings.