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Initial land use category results
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Hi all--
I did analyses for mammals, birds, and plants by land use intensity category yesterday, and there are some kind of surprising results.
First,
http://www.columbia.edu/~dff2101/FD-Ag/Mammals/Anova_plots-Mammals.pdf
This shows is a significant decline in FD, no change in Q, and little variation in H' or S with the land use intensities -- so using FD reveals a change in the actual functional composition of the communities, unlike just using traditional species richness indices!
One hitch: when incorporating abundance (using Rao's Q), this pattern disappears -- and generally has no difference across land uses. But remember this downgrades the loss of rare species.
Birds:
the patterns are all as you would expect, with losses of species and FD with increasing land use intensity. Again, Q shows no difference between land uses, while FD does.
What I can't explain as easily are the patterns for plants:
Species richness S and shannon diversity H' show dramatic changes, especially from 'natural' to any land use, and both FD and Q reflect the big drop between 'Natural' and 'Low'... but medium intensities show surprisingly high functional diversity, as measured either with abundances (Q) or without (FD). ... not sure what to say about this one.
Still to do: look at changes in FD and Q after subtracting the change due to species number decline alone; make plots for each paper ranking FD and Q by land use intensity.
I did analyses for mammals, birds, and plants by land use intensity category yesterday, and there are some kind of surprising results.
First,
http://www.columbia.edu/~dff2101/FD-Ag/Mammals/Anova_plots-Mammals.pdf
This shows is a significant decline in FD, no change in Q, and little variation in H' or S with the land use intensities -- so using FD reveals a change in the actual functional composition of the communities, unlike just using traditional species richness indices!
One hitch: when incorporating abundance (using Rao's Q), this pattern disappears -- and generally has no difference across land uses. But remember this downgrades the loss of rare species.
Birds:
the patterns are all as you would expect, with losses of species and FD with increasing land use intensity. Again, Q shows no difference between land uses, while FD does.
What I can't explain as easily are the patterns for plants:
Species richness S and shannon diversity H' show dramatic changes, especially from 'natural' to any land use, and both FD and Q reflect the big drop between 'Natural' and 'Low'... but medium intensities show surprisingly high functional diversity, as measured either with abundances (Q) or without (FD). ... not sure what to say about this one.
Still to do: look at changes in FD and Q after subtracting the change due to species number decline alone; make plots for each paper ranking FD and Q by land use intensity.