Can community gardens and farmers' markets relieve food desert problems? A study of Edmonton,Canada

This article integrates community gardens and farmers' markets into a spatial analysis of food deserts in the City of Edmonton, Canada. Our results show that community gardens and farmers' markets can improve fresh food accessibility and help relieve food desert problems to some extent, especially for mature, inner-suburban neighborhoods. However, based on the minimum road network distance and high need indicators, four neighborhoods throughout the city can still be considered as food deserts even after farmers' markets and community gardens are taken into consideration. Regression results reveal that community gardens tend to cluster with supermarkets, so that neighborhoods that have poor access to supermarkets also tend to have limited access to community gardens.     

Strengthening the core,improving access: Bringing healthy food downtown via a farmers' market move

Diet-related diseases are a major public health concern, and food environment research explores how built environmental interventions can address nutritional inequalities. Yet other, more direct intervention approaches may also yield positive benefits for residents living in food deserts. This paper presents a case study of a farmers' market move and its effects on healthy food accessibility and customer characteristics in a community with many food deserts. 844 surveys collected in 2011 and 2015 determine customer purchasing patterns and demographics at the Flint (Michigan) Farmers' Market. The market move has meant improved healthy food accessibility for mobility-constrained and low-income residents throughout the region. Counter to past research suggesting that farmers' markets tend to serve higher income groups, socioeconomically disadvantaged people constitute a major consumer demographic at Flint's market. The results of this research have broad utility for communities seeking to ameliorate the challenges of bringing healthy food to isolated food deserts by demonstrating that positioning healthy food in a prominent, central location will attract residents from such neighborhoods while engaging a broad clientele.     

The Effects of Spatial Scale and Aggregation on Food Access Assessment: A Case Study of Tucson,Arizona

Adequate access to healthy food has become a social issue due to the recent Great Recession and heightened levels of unemployment. Geographers have focused their attention on how to accurately evaluate food access and how to identify and delineate food deserts; that is, low-income neighborhoods where affordable and healthy food is lacking or limited. Findings of recent food access studies are, however, dramatically inconsistent. We argue that spatial scale and the level of aggregation used in constructing food access measures could account for a major portion of the varying results. We draw on an empirical study in the Tucson, Arizona, metropolitan area, to examine how varying geographic scales and aggregation methods affect food access assessment. We also provide an analysis to show how spatial scale and aggregation practices lead to inconsistent conclusions about food access and designation of food deserts.     

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.     

Comparing Measures of Accessibility to Urban Supermarkets for Transit and Auto Users

Research on access to healthy foods often emphasizes the spatial proximity of residents to food stores like supermarkets as a way to gauge overall accessibility. Much of the literature has focused on locating the closest facility, assuming that access to one food store is sufficient. Given evidence that access to multiple healthy food stores can improve diets, however, this article examines how closest facility measures differ from cumulative opportunity accessibility measures across space in a medium-sized U.S. city. Differences in access between automobile and transit riders, using realistic travel time costs, are also considered. Results demonstrate that the two types of accessibility measures produce different accessibility geographies and that there are disparities in access for those dependent on transit. These findings indicate that researchers should carefully consider whether access to one supermarket opportunity is enough and pay special attention to the mode residents rely on to access food.     

Food deserts? Healthy food access in Amsterdam

Healthy food environments are imperative for public health. Access to supermarkets that offer wholesome food products at low prices varies across space and over socioeconomic status and ethnic neighborhoods. This research examined food inequalities in Amsterdam, the Netherlands. Supermarket accessibility was calculated and linked to property prices and the share of native Dutch people on a geographic micro-scale with a spatial resolution of 100 meters. Mann–Whitney tests and Spearman correlations were used to test differences and associations between accessibility, property prices, and the share of natives per area. The spatially explicit contextual neural gas approach was used for data clustering. The results show access differences in supermarkets in favor of areas with high property prices and those areas with a large share of native Dutch people. The correlations indicate that low-priced areas and those with a low share of native Dutch people have a lower supermarket density, but the results are the opposite when proximity to and variety of supermarkets are examined. The clustering revealed no evidence of undersupplied areas. Pronounced inequalities in access to healthy food could not be confirmed. On the basis of this analysis, there is no urgent need for policymakers to intervene in the geographies of supermarkets.     

Potential food deserts and food oases in a post-communist city: Access,quality, variability and price of food in Bratislava-Petržalka

Delimitation tools and definitions of food deserts have not been internationally unified so far. Such comprehension ambiguity may lead to variability in research methods as well as to terminology mismatch in the research. In general, assessment of accessibility of selected (large-scale) food stores network in a region is considered as a suitable tool to identify the food deserts, but this is certainly not the only approach. In our paper some other approaches (such as measuring quality, variability and food price) are assessed together with supermarkets and hypermarkets accessibility examination. Results gained by analyses based on various methodological approaches are then compared and confronted, which simultaneously allows us to compare the individual approaches. For our case study purposes, the largest housing estate in Slovakia's capital city was selected.     

Measuring Individuals' Spatial Access to Healthy Foods by Incorporating Mobility,Time, and Mode: Activity Space Measures

Spatial access to healthy foods has drawn growing attention regarding the relationship with people's health conditions and demographic and socioeconomic characteristics. Individuals' differences and the impact of travel behaviors on food accessibility, however, are rarely studied. This study incorporates mobility, time, and transportation mode components to measure each individual's access to healthy foods. We employed three activity space measures to estimate food accessibility: route network buffer, time-weighted standard deviational ellipse (SDE), and mode-weighted SDE. Food accessibility in three activity spaces shows similar variabilities. Geographic size and spatial access to healthy foods differ significantly by income and employment for all three activity space measures. People with higher incomes and those who are currently employed are likely to have larger activity spaces and higher food accessibility. As age increases, people tend to increase their size of activity spaces (in both SDE measures) and food accessibility significantly. Females are likely to have smaller activity spaces and less accessibility to healthy foods (only in the time-weighted SDE measure). Geographic size and spatial access do not differ significantly by education and number of vehicles per household. Although three activity spaces are highly correlated in both geographic size and spatial access, differences still exist among them.     

Using simulated data to investigate the spatial patterns of obesity prevalence at the census tract level in metropolitan Detroit

Obesity is a serious public health problem in the United States. It is important to estimate obesity prevalence at the local level to target programmatic and policy interventions. It is challenging, however, to obtain local estimates of obesity prevalence because national health surveys such as the Centers for Disease Control and Prevention (CDC) Behavioral Risk Factor Surveillance System (BRFSS) are not designed to produce direct estimates at the local levels (e.g. census tracts) due to small population samples and the need to preserve individual confidentiality. In this study we address the problem of estimating local obesity prevalence rates by implementing a spatial microsimulation modeling technique to proportionally replicate the demographic characteristics of BRFSS respondents to census tract populations in metropolitan Detroit. Obesity prevalence rates are examined for high and low spatial clusters and studied in relation to the U.S. Department of Agriculture's (USDA) measures of low-income neighborhoods and local food deserts and CDC's measure of healthy and less healthy food environments currently used to target obesity reduction initiatives. This study found that obesity prevalence was largely clustered in the City of Detroit extending north into contiguous suburbs. The spatial patterns of highest obesity prevalence tracts were most similarly aligned with USDA-defined low-income tracts and CDC's less healthy food tracts. The locations of USDA's food desert tracts rarely overlapped with the highest obesity prevalence tracts. This study demonstrated a new methodology by which to assess local areas in need of future obesity interventions.     

The role of socio-economic status and spatial effects on fresh food access: Two case studies in Canada

This article comprehensively explores the effects of socio-economic status on residents' fresh food access in Saskatoon and Regina, Saskatchewan, Canada. Spatial effects potentially resulting from agglomeration of food retailers and clustering of neighborhoods with similar characteristics have been integrated into analysis using spatial regression models. Key findings include: areas with a larger percentage of population density, single-parent households, senior populations, higher educational populations, and minority groups tend to have higher access to supermarkets and local grocery stores, although the effects vary by city. Areas with higher private car access are more inclined to be farther from these food retailers, meanwhile the influence of public transportation is found to be insignificant in both cities. Regression results demonstrate that ignoring spatial interaction leads to overestimates of the true disparities when investigating food-access inequality among residents with different socio-economic status.     

Port Cities as Areas of Transition: Ethnographic Perspectives. Waltraud Kokot,Mijal Gandelsman-Trier,Kathrin Wildner,and Astrid Wonneberger,editors

Research on the impact of the built environment on obesity and access to healthful foods often fails to incorporate information about how individuals interact with their environment. A sample of 198 low-income WIC recipients from two urban neighborhoods were interviewed about where they do their food shopping and surveys were conducted of food stores in their neighborhoods to assess the availability of healthful foods. Results indicate that participants rarely shop at the closest supermarket, traveling on average 1.58 miles for non-WIC food shopping and 1.07 miles for WIC shopping. Findings suggest that access to healthful foods is not synonymous with geographic proximity.     

Analyzing Accessibility Using Parcel Data: Is There Still an Access–Space Trade-Off in Long Beach,California?

This article analyzes the impact of changing housing and neighborhood characteristics on the accessibility of neighborhood businesses using Long Beach, California, as a case study. Although advocates of smart growth and New Urbanism encourage land use mixing, aggregate-level analysis can be too coarse to pick up on fine-grained aspects of urban streetscapes. This study uses assessor parcel records and a point-based business establishment data set to analyze city-wide patterns of accessibility from individual dwelling units to thirty-one types of neighborhood businesses, including grocery stores, service shops, drug stores, doctor's offices, and banks. Regression results compare parcel-level and neighborhood-level drivers of accessibility between 2006 and 2015 to gauge the aggregated effect of recent economic, demographic, and built environment changes on this aspect of urban spatial structure. Larger homes in older, multiunit buildings and higher income neighborhoods show substantial increases in accessibility to most establishment types, suggesting a trend toward both greater accessibility and larger dwelling units—despite the traditional trade-off between access and space. Although gradual increases in home and business density increased overall accessibility over this period, weaker neighborhood-level results indicate that this trend is less pronounced in high-poverty and non-white areas.     

Variation in low food access areas due to data source inaccuracies

Several spatial measures of community food access identifying so called “food deserts” have been developed based on geospatial information and commercially-available, secondary data listings of food retail outlets. It is not known how data inaccuracies influence the designation of Census tracts as areas of low access. This study replicated the U.S. Department of Agriculture Economic Research Service (USDA ERS) food desert measure and the Centers for Disease Control and Prevention (CDC) non-healthier food retail tract measure in two secondary data sources (InfoUSA and Dun & Bradstreet) and reference data from an eight-county field census covering 169 Census tracts in South Carolina. For the USDA ERS food deserts measure accuracy statistics for secondary data sources were 94% concordance, 50–65% sensitivity, and 60–64% positive predictive value (PPV). Based on the CDC non-healthier food retail tracts both secondary data demonstrated 88–91% concordance, 80–86% sensitivity and 78–82% PPV. While inaccuracies in secondary data sources used to identify low food access areas may be acceptable for large-scale surveillance, verification with field work is advisable for local community efforts aimed at identifying and improving food access.     

How do changes in the daily food and transportation environments affect grocery store accessibility?

A healthy food environment is an important component in helping people access and maintain healthy diets, which may reduce the prevalence of chronic disease. With few exceptions, studies on healthy food access in urban regions typically ignore how time of day impacts access to food. Similarly, most extant research ignores the complexities of accounting for the role of transportation in spatial access. Examining healthy food access is important, especially for populations whose day-to-day schedules do not align with a typical work schedule. This study profiles novel methods that can be used to examine the daily dynamics of food access in Toronto, Ontario, using grocery stores as a case study to examine the changing geographies of food access over a 24-h period, and the impact of a changing public transit schedule on food access. Walking and automobile travel times are also reported. Results indicate that access to grocery stores is severely diminished for large parts of the city in the late night and early morning, and that public transit travel times are higher and more variable in the early morning hours. Ultimately, this research demonstrates the need for further study on how residents with nonconventional schedules experience, and are affected by, the dynamic food and transportation environments. Future research should build upon the methods presented here to include a broader range of food retailers.     

Patterns of lizard species richness within National Parks and Biosphere Reserves across North America's deserts

Warm deserts world-wide provide habitats for rich lizard species assemblages; North American deserts are no exception, however the desert regions of the US and Mexico are experiencing increasing habitat changes from multiple anthropogenic sources. Our objective here was to document current lizard species richness patterns across the North American deserts within the existing network of conservation areas. We identified 110 lizard species occurring across one or more of the 19 sites we analyzed. Three species richness hot spots were identified; a northern Baja California faunal extension into southern California in the US, and in Mexico, two sites within the state of Coahuila, as well as high endemism in the Cape Region of Baja California Sur. Species richness was associated with sites where desert ecoregions overlap and with insular isolation. Our uncertainty regarding how species will respond to the multifaceted aspects of global change is such that large protected natural areas with complex topography may be the most effective strategy for protecting desert lizards along with overall biodiversity. The 19 sites we analyzed represent the cores of a more robust conservation network that will be needed for the protection of biodiversity across North American Deserts.     

中国北方沙漠地区全新世气候变化的周期性探讨

随着高精度全新世气候变化研究的深入,千、百年尺度上气候波动、周期性变化和气候事件不断被发现。北大西洋深海沉积物中发现的IRD事件、千年尺度上的约1500年周期性气候振荡已经被许多研究者共识,并在陆地湖泊、冰心乃至沙地和沙漠的沉积物中均有发现。百年尺度上的512年、400年、200年等周期性气候振荡还有待深入研究。研究表明,全新世以来,中国北方地区沙漠的扩大与缩小与全球气候的周期性变化具有密切的相关性,尤其是与千年尺度上的1500年的周期性震荡有关;数年-数十年尺度上的周期性气候振荡对我国沙尘暴的发生起着明显的控制作用。     

Desert detritivory: Nutritional ecology of a dung beetle (Pachysoma glentoni) subsisting on plant litter in arid South African sand dunes

Dry conditions limit microbial decomposition of plant litter in deserts, which leaves a primary role to detritivorous macroarthropods. In the sandy arid strip along the west coast of South Africa, such detritivores include the large scarabaeid dung beetle Pachysoma glentoni. Highly unusual among dung beetles, this species collects surface litter and drags it into an underground storage and feeding chamber which is abandoned after 6–7 days. Fresh stores for single beetles and for breeding pairs (mean depths: 30 and 39 cm) contained about 1.1 and 2.9 g organic matter, respectively. Using ergosterol as a biomarker for fungal biomass, we tested the hypotheses that (1) the dry detritus takes up water underground; (2) this promotes fungal growth on the detritus, and (3) fungi are the main food of the beetles. These hypotheses were disproved, but the stored litter, including floral remains, was shown to have relatively high quality (mean atomic C:N ratio: 35) and the beetles assimilated about 60% of it. Estimated weekly water gain per beetle, supplied entirely by the food, was about 0.6 g. Our results highlight unique nutritional adaptations to survival in deserts without the usual dung beetle food: wet dung of large herbivores.     

Food deserts,activity patterns, & social exclusion: The case of Tokyo,Japan

This study attempts to identify areas with a high level of discrepancy in the probability for an individual to exceed the threshold of walking time for grocery shopping. It is based on an assumption that a higher discrepancy is associated with more relative disadvantages for socially excluded people, the elderly, with no car and unemployed. A geographically weighted logistic model that incorporates individual constraints and spatial accessibility is developed to yield a probability, capturing the spatial variation of relations of factors. In the city of Tokyo, the north-eastern area shows a significant discrepancy for the socially excluded group. The distribution of high level of discrepancy differs compared to that of the area with low accessibility. This study's methodology and results provide convincing evidence that in determining food desert areas, relative accessibility estimated with personal attributes should be taken into account.     

Evaluating the Effects of Geographic Contexts on Individual Accessibility: A Multilevel Approach1

Centrality within a city and neighborhood characteristics have often been used as indicators of access to employment and services in statements about urban form and accessibility, but there are reasons to question the appropriateness of doing so. This paper evaluates the importance of geographic context within the urban environment (both location within cities as well as neighborhoods characteristics) for individuals in Portland, Oregon. Because conventional accessibility measures cannot incorporate individual characteristics, space-time individual accessibility measures were used with multilevel modeling to isolate the effects of individual level variations from that of geographical context. The results show that the influence of context on individual accessibility is weak, as accessibility tends to reflect individual and household characteristics rather than the local urban environment. Accessibility cannot be determined from location within cities, or from land uses around an individual's home, implying that the use of urban design to influence accessibility is inappropriate.     

中国沙漠和沙地的资源优势与农业发展

人口、粮食、土地之间的矛盾已成为今后我国几十年的主要问题。我国后备土地资源的68%分布在干旱、半干旱地区,其中沙漠和沙地面积辽阔,类型繁多,涉及212个县(旗)、48×106人。我国的沙漠和沙地具备适度开发利用的水资源依托,具有灌溉、雨养和高寒农业等特殊环境,是栽培作物和养殖家畜的集中区,许多尚无饲养或尚无栽培种类可以取代的野生动植物具有独特经济价值和高度的抗性。我国的沙地持续利用技术体系已初步建立,形成了一整套具有中国特色的流沙固定技术,结合各地的具体条件创建了许多成功的区域开发治理模式。沙漠和沙地开发必须摆脱传统的农业利用模式,依靠科技进步,多采光、少用水,结合资源条件、市场需求、投资能力,有计划、有步骤地规模开发。