I am studying how the biodiversity within the weedbeds of a freshwater lake has changed and one parameter I would like to investigate is species diversity using Simpson's Index. The data I have available is the wet weights and dry weights for each species from quadrat sampling. I do not have available the actual number of plants within each quadrat. For another comparison, I am using the Proportional Index of Community Similarity. Can either of these data sets be used in the Simpson's Index of Diversity? My problem is that many of the weights are less than one, which gives me a negative value when trying to calculate Simpson's Index. Is there a proper transformation that I can do with the data?
Thank you in advance, Todd Shuskey -- " The will to succeed is important, but what's more important is the will to prepare." - Bob Knight Todd Shuskey Biology Instructor 33 Watkins Avenue Perry High School Perry, NY 14530 (585) 237-0270 x1100 Website <http://www.perry.k12.ny.us/webpages/tshuskey/>
