Nagy (2009) demonstrated that ecosystem carbon storage in sections of the Florida Panhandle is closely related to land use/cover.  As an example, C storage was greater in urban systems (forests and lawns) than in plantation or naturally regenerated forests in rural areas. The reasons for this difference are thought to be related to the exclusion of fire from urban systems (and its prevalence in rural forests of that region) as well as the tendency of urban forests to be older than rural forests, consequently  representing larger standing crops of biomass.  These differences suggest that further insight into how land use/cover affects C processing and turnover would be very useful in understanding C dynamics along a coastal landscape.  

A litter decomposition study is being installed across the urban – rural gradient to collect information on C dynamics that can complement the existing C storage data.   The literature indicates that there is no consensus regarding the nature of urban effects on decomposition as illustrated by the contrasting results of Pouyat et al (1997) and Carreiro et al. (1999).  In the Pouyat study, decomposition and nitrogen mineralization rates were found to be higher in urban settings over a 6 month period. Litter fragmentation by earthworms and warmer temperatures in the urban areas were suggested as causes of the rate increase. In contrast, Carreiro et al. reported slower mass loss over 150 days with urban compared to rural litter and noted that the lower litter quality observed in the urban settings could be a contributing factor.  Both of these studies occurred in New York and were short term in nature and, consequently, there is a need for longer term studies under different climatic conditions found in the South.  

OBJECTIVES

The objectives of this study are to:

1.    Evaluate decomposition across different land uses in the Florida Panhandle.

2.    Assess how decomposition varies across natural forests and plantations.

3.    Identify differences in decomposition rate across an array of urban conditions. 

Through this study, the following questions will be examined.  Will the fertilization that is prevalent in urban areas improve litter quality and dominate the decomposition comparisons across land uses? Alternatively, would the narrower soil C:N ratios known to occur after moderate intensity fires which commonly occur in the plantation and natural forests offset the influence of urban fertilization?  Does the warmer microenvironment afforded by urban ‘heat islands’ represent a measurable driver of decomposition rates in the Southeast?   These and other questions compel further inquiry into how C processing may shift as urbanization is superimposed onto forested landscapes in a coastal setting.