Digital Photography and Image Analysis to Measure Vegetative Cover in the Biocore Prairie – Caitlin Butte

(L&S Honors Sophomore Honors Research Apprenticeship recipients)

Estimating ground coverage is a very useful procedure for characterizing vegetation and assessing its growth and development over time. Visual estimation methods are most widely used, but show high variation due to human subjectivity. We developed an alternative method for estimating ground cover using short range digital photography and image analysis to estimate coverage for 0.5 m2 plots in the Biocore Prairie and in artificial plots with known two-dimensional areas. We found this technique was highly precise with 4% or lower variation and was reliable above a threshold of 5% bareground. Conversely, visual estimations yielded estimations with variation of 5-12% that was consistent over a wide range of cover (15-80%). Image analysis may be implemented when more precise and reliable coverage approximations are needed.