The Splus code, survive.ssc, for estimating seedling survival from count data is below. Please be aware that this model was fit in 1999 using a now long obselete version of Splus--thus the code will undoubtedly require modification to work in current versions of Splus or R. In addition, the Splus code calls three C routines, Design.mat.c, Gap.beta.c, and Qfun.c. These portions of the code were exported to C to increase the speed of the program. The code contained in these files is very specific to the particular problem addressed in Beckage et al., Journal of Ecology, 2005. I would suggest that this code would be most useful as a starting point for application to similar problems rather than being used simply as is. Finally, the code comes with no guarantees whatsoever with regards to accuracy or correctness.