Lifestyles choices, socio-economic status, and vegetation dynamics in urban ecosystems: is Raleigh, NC on a path to becoming baltimore, MD?

Background/Question/Methods

Cities are rapidly increasing in spatial extent, with more than half the global population now residing in cities.  Although cities tend to be places of high diversity, studies show neighborhoods consist of relatively homogenous groups of homes with similar demographic characteristics and vegetation structure.  As a result, researchers have theorized that socio-economic status is a key predictor of urban vegetation.  A recent study in Baltimore, MD, however, indicated that this relationship may be more complicated and a dataset that categorize lifestyle choices has higher explanatory power when predicting the variation in urban forest cover.  To evaluate the general applicability of the results from Baltimore, comparisons among cities are needed; certain city characteristics, such as city age, size, or underlying biome, could lead to conflicting results.  Specifically, we expect that younger and smaller cities in forested ecosystems might not exhibit this relationship between lifestyle choices and land cover, because there would be less variation in lifestyle and tree cover.   To test this hypothesis, we replicated an analysis of lifestyle choices, socio-economic status, and land cover.  We conducted a high-resolution land cover classification, and modeled the relationships among forest cover on private residential land, socio-economic status, lifestyle groups, and housing age. 

Results/Conclusions

As was hypothesized, Raleigh had higher tree cover (40%) than Baltimore (27%), but more variation in lifestyle groups.  Raleigh has an even distribution of 40 lifestyles groups, whereas Baltimore has a disproportionally more downscale lifestyle groups (32 groups total, of which 50 % are downscale).  Similar to Baltimore, forest cover in Raleigh is correlated with socio-economic status (R²–0.31) and lifestyle choices (R²–0.46).  It remains to be seen if the relationship between lifestyle groups and ecological processes will be consistent among all cities, especially when evaluating cities that are situated in different biomes.  It seems, however, that this trend would be more likely to exist in sprawling arid and semi-arid cities, where people in certain lifestyle groups may have strong opinions on water use and therefore landscape preferences.  Alternatively, limitations in income may over-ride the strength of lifestyle choices as predictors of vegetation cover.  Further research also needs to be conducted on the mechanism behind these relationships.  Finally, this analysis begs the question:  Is Raleigh becoming more like Baltimore over time?  If cities are becoming more alike one another than their native ecosystem, like the “Convergence Hypothesis” suggests, this trend could have major implications for the sustainability of cities.