Relationship between structural complexity and biological diversity in a forest ecosystem.
Proulx, Raphaël*,1, Parrott, Lael1, 1 Complex Systems Laboratory, Montréal, Québec, Canada
ABSTRACT- Current measures of biological diversity have limited ability to accommodate the recently discovered consequence of scale (sensu Mandelbrot). This study thus aims to establish whether structural complexity indices derived from digital photos correlate to conventional diversity measures at small spatial resolution. From May to August 2004, exhaustive diversity counts (i.e., number of species, phenotypes, and individuals) were carried out over 225 cubic structures distributed across 25 sites on Mount St-Hilaire (Quebec, Canada). Each cubic structure was laterally photographed on two sides using appropriate settings to permit valuable comparisons between sites. Sites were selected to cover a large spectrum of physical and biological diversity, ranging from 0 to 10 species inside a given sampling unit. Information theoretic indices were calculated from the photos to evaluate complexity in the HSI color space (Hue, Saturation, and Intensity). Our results support the hypothesis that more diversified sites possess more complex structures than depauperate ones. We found a strong positive correlation (r=0.96) between the number of species found in our cubic structures and the average complexity obtained from our photos. The use of digital images in the field could provide a simple, rapid and low-cost technique for tracking ecosystem change.These findings open up the way to utilize holistic measures for monitoring ecological integrity at different spatial and temporal scales.
Key words: complexity, diversity, images, scales
All materials copyright The Ecological Society of America (ESA), and may not be used without written permission.