The objective of this study is to examine succession processes for a proposed continuum of vacant lot management types in an urbanized watershed in Baltimore City, Maryland. The study applies a contemporary view of succession as a type of vegetation dynamics. Three types of vacant lots selected for this study are community gardens, unmanaged vacant lots, and “Clean & Green” lots. Drawing from urban ecological theory which recognizes humans as important agents shaping ecological patterns and processes, the study hypothesizes that management is a key driver of vegetation diversity for vacant lots. It proposes that species assemble into functional vegetation groups based on life history traits in response to management and disturbance. It proposes that vacant lots with a suite of management activities may result in higher vegetation diversity, and thus, greater numbers of functional vegetation groups. For this research, a data analysis approach is used to analyze the species distribution and abundance patterns with the objective of identifying combinations of species grouped by life history traits.
Results/Conclusions
This oral presentation focuses on the preliminary results for herbaceous species identified and management activities for a subset of community gardens, “Clean & Green” and unmaintained vacant lot systems. Findings indicate that “Clean & Green” and unmaintained lot systems share fourteen species in common. Cluster analyses for “Clean & Green” systems show close clustering of species such as prostrate pigweed (Amaranthus albus), wood sorrel (Oxalis L.) and smooth crab grass (Digitarium ischaemum Schreb.) while unmaintained vacant lot systems showed close clustering of species such as Queen Anne’s lace (Daucus carota), dandelion (Taraxacum officniale) and English plantain (Plantago lancelota). Principal component analyses show that 50% or more of variance is attributed to three to five species for both “Clean & Green” lots and unmaintained vacant lot systems. The most frequent management activities for “Clean & Green” and unmaintained lots are mowing and trash removal, while trash removal, watering, and weeding are the most frequent management activities for community gardens. These results provide preparation for future analyses using classification trees to relationships between type of vacant lot system, management frequencies, and life history traits of species.