[R] succession time series graph

[David Bird]

Dear gracious R community,

I would like to produce charts of phytoplankton biomass changes
through time. Each species has a line, and the biomass varies in
mirror form along the line for each species along the X time axis.
Here is an example of what I'd like to do:
http://www.er.uqam.ca/nobel/r30240/Succession.jpg

Any suggestions?

Thanks
David Bird
UQAM, Montreal