Heavy metal (HM) contamination is known to play a key role in community composition of a habitat. The level of impact is dependent upon which metals are present and to what degree. While many studies have looked at the impact of a limited number of HMs on specific taxa, only a few have attempted to discern their impact on community structure and even less have studied the impact of a suite of HMs. Our study was conducted in Cleveland, OH, an industrial Midwest City that, due to economic downturn, holds over 20,000 vacant lots. With the recent push to utilize these lands in cities to boost biodiversity, and knowing that industrial cities often suffer from HM contamination, this study investigated the extent of HM contamination in vacant lots and its effect on the diversity of soil fauna. Our study focused on heavy metals with environmental toxicity potential and metals used in construction and found on demolition sites. Soil cores were collected in early and late summer of 2014 and 2015 from eight neighborhoods (2014: two sites per neighborhood, 2015: four sites per neighborhood) across the Cleveland landscape. Between years, vegetation treatments were installed and these plots were included in the 2015 samples. Burlese funnels were used to determine soil fauna composition. Soil samples were sent to an environmental laboratory on campus (STAR) for heavy metal analysis. Generalized linear models (GLM) were run with the following fixed effects: sampling period (early vs late summer), neighborhood, treatment, sampling period * neighborhood, and neighborhood * treatment. Redundancy analysis (RDA) was used to evaluate relationships among the HMs and soil fauna.
Results/Conclusions
We found that diversity of soil fauna was significantly correlated to neighborhood (site location within the city) and that the response was further increased when neighborhood and sampling period (early summer vs late summer) were tested together. HM levels varied dramatically among neighborhoods but no relationships were found between any individual HM and any of the soil fauna taxa. Although significant relationships were not found, Acari, Collembola, and Formicidae were shown to be influenced by the variation in HM levels in the RDA analysis. We have shown that HMs do impact soil biota but not to the extent expected. Our next steps include vegetation and landscape analyses in an effort to further explore the factors affecting soil biota diversity.