This study examines the distributional equity of urban tree canopy (UTC) cover for Baltimore, MD, Los Angeles, CA, New York, NY, Philadelphia, PA, Raleigh, NC, Sacramento, CA, and Washington, D.C. ...using high spatial resolution land cover data and census data. Data are analyzed at the Census Block Group levels using Spearman's correlation, ordinary least squares regression (OLS), and a spatial autoregressive model (SAR). Across all cities there is a strong positive correlation between UTC cover and median household income. Negative correlations between race and UTC cover exist in bivariate models for some cities, but they are generally not observed using multivariate regressions that include additional variables on income, education, and housing age. SAR models result in higher r-square values compared to the OLS models across all cities, suggesting that spatial autocorrelation is an important feature of our data. Similarities among cities can be found based on shared characteristics of climate, race/ethnicity, and size. Our findings suggest that a suite of variables, including income, contribute to the distribution of UTC cover. These findings can help target simultaneous strategies for UTC goals and environmental justice concerns.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
► We find a strong negative correlation between tree cover and an index of crime. ► This relationship is found across an urban to rural gradient. ► The magnitude of this association is stronger on ...public lands relative to private. ► In a few isolated areas, crime is positively related to tree cover. ► Tree planting prioritizations should incorporate public safety concerns.
The extent to which urban tree cover influences crime is in debate in the literature. This research took advantage of geocoded crime point data and high resolution tree canopy data to address this question in Baltimore City and County, MD, an area that includes a significant urban–rural gradient. Using ordinary least squares and spatially adjusted regression and controlling for numerous potential confounders, we found that there is a strong inverse relationship between tree canopy and our index of robbery, burglary, theft and shooting. The more conservative spatially adjusted model indicated that a 10% increase in tree canopy was associated with a roughly 12% decrease in crime. When we broke down tree cover by public and private ownership for the spatial model, we found that the inverse relationship continued in both contexts, but the magnitude was 40% greater for public than for private lands. We also used geographically weighted regression to identify spatial non-stationarity in this relationship, which we found for trees in general and trees on private land, but not for trees on public land. Geographic plots of pseudo-t statistics indicated that while there was a negative relationship between crime and trees in the vast majority of block groups of the study area, there were a few patches where the opposite relationship was true, particularly in a part of Baltimore City where there is an extensive interface between industrial and residential properties. It is possible that in this area a significant proportion of trees is growing in abandoned lands between these two land uses.
The global reach of human activities affects all natural ecosystems, so that the environment is best viewed as a social-–ecological system. Consequently, a more integrative approach to environmental ...science, one that bridges the biophysical and social domains, is sorely needed. Although models and frameworks for social-–ecological systems exist, few are explicitly designed to guide a long-term interdisciplinary research program. Here, we present an iterative framework, "“Press-–Pulse Dynamics"” (PPD), that integrates the biophysical and social sciences through an understanding of how human behaviors affect "“press"” and "“pulse"” dynamics and ecosystem processes. Such dynamics and processes, in turn, influence ecosystem services -–thereby altering human behaviors and initiating feedbacks that impact the original dynamics and processes. We believe that research guided by the PPD framework will lead to a more thorough understanding of social-–ecological systems and generate the knowledge needed to address pervasive environmental problems.
Cities around the world are facing an ever-increasing variety of challenges that seem to make more sustainable urban futures elusive. Many of these challenges are being driven by, and exacerbated by, ...increases in urban populations and climate change. Novel solutions are needed today if our cities are to have any hope of more sustainable and resilient futures. Because most of the environmental impacts of any project are manifest at the point of design, we posit that this is where a real difference in urban development can be made. To this end, we present a transformative model that merges urban design and ecology into an inclusive, creative, knowledge-to-action process. This design-ecology nexus-an ecology for cities-will redefine both the process and its products. In this paper we: (1) summarize the relationships among design, infrastructure, and urban development, emphasizing the importance of joining the three to achieve urban climate resilience and enhance sustainability; (2) discuss how urban ecology can move from an ecology of cities to an ecology for cities based on a knowledge-to-action agenda; (3) detail our model for a transformational urban design-ecology nexus, and; (4) demonstrate the efficacy of our model with several case studies.
Ecological homogenization of urban USA Groffman, Peter M; Cavender-Bares, Jeannine; Bettez, Neil D ...
Frontiers in ecology and the environment,
February 2014, Letnik:
12, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, ...residential lots, commercial areas, and aquatic features. We hypothesize that this homogenization extends to ecological structure and also to ecosystem functions such as carbon dynamics and microclimate, with continental-scale implications. Further, we suggest that understanding urban homogenization will provide the basis for understanding the impacts of urban land-use change from local to continental scales. Here, we show how multi-scale, multi-disciplinary datasets from six metropolitan areas that cover the major climatic regions of the US (Phoenix, AZ; Miami, FL; Baltimore, MD; Boston, MA; Minneapolis-St Paul, MN; and Los Angeles, CA) can be used to determine how household and neighborhood characteristics correlate with land-management practices, land-cover composition, and landscape structure and ecosystem functions at local, regional, and continental scales.
Humans promote and inhibit other species on the urban landscape, shaping biodiversity patterns. Institutional racism may underlie the distribution of urban species by creating disproportionate ...resources in space and time. Here, we examine whether present‐day street tree occupancy, diversity, and composition in Baltimore, MD, USA, neighborhoods reflect their 1937 classification into grades of loan risk—from most desirable (A = green) to least desirable (D = “redlined”)—using racially discriminatory criteria. We find that neighborhoods that were redlined have consistently lower street tree α‐diversity and are nine times less likely to have large (old) trees occupying a viable planting site. Simultaneously, redlined neighborhoods were locations of recent tree planting activities, with a high occupancy rate of small (young) trees. However, the community composition of these young trees exhibited lower species turnover and reordering across neighborhoods compared to those in higher grades, due to heavy reliance on a single tree species. Overall, while the negative effects of redlining remain detectable in present‐day street tree communities, there are clear signs of recent investment. A strategy of planting diverse tree cohorts paired with investments in site rehabilitation and maintenance may be necessary if cities wish to overcome ecological feedbacks associated with legacies of environmental injustice.
Changes in land use, land cover, and land management present some of the greatest potential global environmental challenges of the 21st century. Urbanization, one of the principal drivers of these ...transformations, is commonly thought to be generating land changes that are increasingly similar. An implication of this multiscale homogenization hypothesis is that the ecosystem structure and function and human behaviors associated with urbanization should be more similar in certain kinds of urbanized locations across biogeophysical gradients than across urbanization gradients in places with similar biogeophysical characteristics. This paper introduces an analytical framework for testing this hypothesis, and applies the framework to the case of residential lawn care. This set of land management behaviors are often assumed—not demonstrated—to exhibit homogeneity. Multivariate analyses are conducted on telephone survey responses from a geographically stratified random sample of homeowners (n = 9,480), equally distributed across six US metropolitan areas. Two behaviors are examined: lawn fertilizing and irrigating. Limited support for strong homogenization is found at two scales (i.e., multi- and single-city; 2 of 36 cases), but significant support is found for homogenization at only one scale (22 cases) or at neither scale (12 cases). These results suggest that US lawn care behaviors are more differentiated in practice than in theory. Thus, even if the biophysical outcomes of urbanization are homogenizing, managing the associated sustainability implications may require a multiscale, differentiated approach because the underlying social practices appear relatively varied. The analytical approach introduced here should also be productive for other facets of urban—ecological homogenization.
•Front yard landscaping has an association with crime, adjusting for several control variables.•Crime correlates negatively with yard trees, garden hoses/sprinklers, lawns, and pervious area.•Crime ...is positively associated with litter, desiccated lawns, uncut lawns, among other factors.•Results add to the evidence that crime is deterred by “cues to care”.•They also add to the evidence that landscaping draws more “eyes on the street”.
We analyzed the relationship between crime and indicators of residential yard management in Baltimore City and County. Data came from a survey we conducted of over one thousand front yards that included more than 40 indicators relating to lawns, trees, shrubs, beds and other features. These indicators were related to point counts of crime at the 150m scale using a combination of ordinary least squares, spatial error, and Poisson regressions. After controlling for income, population density, block-scale tree canopy, and housing type, we found a consistently significant relationship between crime and a number of indicators of yard management. Yard-level variables that were negatively associated with crime included: the presence of yard trees, garden hoses/sprinklers, and lawns, in addition to the percentage of pervious area in a yard. Those positively associated with crime included presence of litter, desiccation of the lawn, lack of cutting of the lawn, and number of small trees in front of or adjacent to the property. While these results do not establish causality, they add evidence to a growing literature that suggests the possibility of several mechanisms by which environmental design may reduce crime: “cues to care” (the inverse of the “broken window” hypothesis) can lead to reduced crime by signaling to criminals the presence of social capital and the active involvement of neighbors in community spaces; and more appealing landscaping draws more “eyes on the street,” which in turn deters criminals.
Urbanization, an important driver of climate change and pollution, alters both biotic and abiotic ecosystem properties within, surrounding, and even at great distances from urban areas. As a result, ...research challenges and environmental problems must be tackled at local, regional, and global scales. Ecosystem responses to land change are complex and interacting, occurring on all spatial and temporal scales as a consequence of connectivity of resources, energy, and information among social, physical, and biological systems. We propose six hypotheses about local to continental effects of urbanization and pollution, and an operational research approach to test them. This approach focuses on analysis of "megapolitan" areas that have emerged across North America, but also includes diverse wildland-to-urban gradients and spatially continuous coverage of land change. Concerted and coordinated monitoring of land change and accompanying ecosystem responses, coupled with simulation models, will permit robust forecasts of how land change and human settlement patterns will alter ecosystem services and resource utilization across the North American continent. This, in turn, can be applied globally.
With the rapid growth of cities worldwide, there is a need to better understand factors contributing to life satisfaction in urban environments. Using data from a long-term study of the Baltimore ...metropolitan region, we build on existing social scientific literature to examine a suite of theoretical factors that have been proposed to explain higher life satisfaction. We find support for many previous theoretical arguments in the literature. Importantly, however, our findings reveal that these results are strikingly scale dependent. For individuals, higher incomes contribute to higher levels of satisfaction, yet social capital does not. For neighborhoods, more social capital strongly increases satisfaction, but higher incomes do not; and access to a clean natural environment always contributes to higher satisfaction, regardless of the scale of analysis. Given these findings, we conclude with the observation that future research must carefully match the “scale” of life satisfaction measurements with the explanatory variables used.
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