Performs distance sampling analyses on a number of species
at once and can account for unidentified sightings, model uncertainty
and covariate uncertainty. Unidentified sightings refer to sightings
which cannot be allocated to a single species but may instead be
allocated to a group of species. The abundance of each unidentified
group is estimated and then prorated to the species estimates. Model
uncertainty should be incorporated when multiple models give equally
good fit to the data but lead to large differences in estimated
density / abundance. Covariate uncertainty should be incorporated
when covariates cannot be measured accurately, for example this is
often the case for group size in marine mammal surveys. Variance
estimation for these methods is via a non parametric bootstrap.
The methods implemented are described in Gerodette T. and Forcada
These methods were designs to replicate the analyses of those in Gerrodette and Forcada (2005) Currently we are still in the testing phase to ensure the methods in mads match those of Gerrodette and Forcada Our pro-rating methods for individuals are the same, but in addition we also pro-rate clusters. We do not perform model averaging only model selection at each iteration. There may be small differences in how covariate uncertainty is incorporated.
Gerodette, T. and Forcada, J. 2005. Non-recovery of two spotted and spinner dolphin populations in the eastern tropical Pacific Ocean. Marine Ecology Progress Series 291:1-21.