[R] finding significant change points after fitting GAM using TPRS

[Deahn DonnerWright]

Does anybody know if code or functions exist for determining significant
change points after fitting GAM in 'mgcv' using thin plate regression
spline and 'ts' bases?  I would like to identify years where the curvature
or change in trajectory of a longterm annual population curve is
significant.  Thank you.

Deahn DonnerWright
email: ddonnerwright at fs.fed.us