Using stomatal density as an indicator of urban habitat quality
Poor health quality on the lower west side of Buffalo has been associated with air quality and traffic patterns related to the Peace Bridge U.S. / Canada crossing. Although several epidemiological studies have supported this association, a New York State DEC report conducted from 2012-13 indicated air quality at the Peace Bridge meets national standards and other contributing factors, such as smoking, household conditions, and poverty could explain the increased asthma cases. Therefore, it is necessary to use other biological indicators for air quality that would not be influenced by social / economic factors. Increased stomatal density has been used extensively as an indicator of increased air pollution in urban settings. In this study, stomatal density in the Sugar Maple (Acer saccharum) was determined for several city parks in Buffalo NY over a two year period from 2013-2014. Impressions of the lower epidermis were made using clear nail polish, mounted on a slide and then counted using a compound microscope at 400x. Results were analyzed using a One Way ANOVA for each year of study.
The 2013 study indicated a significantly higher stomatal density for Front Park (located adjacent to the Peace Bridge) when compared to Masten Park and Conway Park (p< 0.001; located approximately 4 km and 6.22 km respectfully from the Peace Bridge). More parks were compared in 2014 and similar results were found: stomatal density was significantly higher in Front Park than in Conway Park, Masten Park, MLK Park, and South Park (p<0.025: located 6.22km, 4.0km, 7.6 km and 8.35km respectfully from the Peace Bridge) but not for Cazanovia Park (p=0.44; located 7.5 km from the Peace Bridge). Previous studies reported higher prevalence of asthma and higher hospital discharge rates for individuals from neighborhoods surrounding Front Park when compared to neighborhoods surrounding the other parks sampled in this study. Asthma prevalence in neighborhoods adjacent to Cazanovia Park were lower than those in neighborhoods adjacent to Front Park but higher than neighborhoods around the other parks studied. Therefore these results support the hypothesis that the Peace Bridge traffic and the resulting air quality is likely contributing to poor health quality for the surrounding neighborhoods.