Conceptual model of degradation for understory plant communities in longleaf pine woodlands.

<p>Understory degradation (deviation in community composition from reference site conditions) is predicted to increase with occurrence of agricultural history, increasing overstory density, and declining fire frequency. Note: not all combinations of model components are presented in this figure and, while depicted as a linear process in this conceptual diagram, nonlinearities may exist during restoration from degraded states. Model is based on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0086604#pone.0086604-Walker1" target="_blank">[8]</a>.