A digital photography protocol for the rapid assessment of herbaceous communities in riparian buffers

Abstract

Abstract Close-range digital photography is a promising tool for monitoring plant communities, yet this technology has not been used to indicate changes to the compositional and functional characteristics of riparian vegetation buffers in agro-ecosystems. We tested a photographic protocol using image indices to monitor differences in the compositional (species diversity) and functional characteristics (plant height, flowering and leaf traits) of 28 herbaceous communities repeatedly surveyed over an entire growing season. Specifically, we used known vegetation properties to predict image texture and geometric patterns. Our results revealed that image texture decreased with increasing plant height, leaf polyphenol content and species diversity. Low texture values in close-range digital images were typically found in tall, flowering, and functionally diversified assemblages consisting mostly of forbs species. In contrast, species assemblages dominated by grasses or sedges presented more random geometric patterns and images with higher texture values. Further tests of this photographic protocol will have to explore other image indices and extend its application to other ecosystems.