Pollination abundance index without zero values

Dear community

I would like to compare the pollination abundance index in spring from approx 150 1 km squares on 25 m spatial resolution (1’600 grid points per square) for present and future climate scenarios.

I am modelling an individual InVEST model for each 1 km squares. In doing so, I can determine individual relative species abundacne as input (within the guild table). climate change is considered by the distribution of the wild bee species under future climate scenario (output of species distribution models) and therefore adapted relative species abundance as input.

Presliminary results from 15 squares

  • The pollinator abundance index (median) is quite low and therefore also the difference betwen present and future climate. The min is always zero and hte maximum is between 0.1 and 0.4.
  • This finding is probably not only because “habitat” masks “climate change”, but also because there are many “zero” grid points within a square.

My question

  • What do you think about modelling the pollination abundance index for grid points with value > 0. The median per square is therefore based on grid points with values >0. Specifically for the climate change question it makes sense for me (If you have zeros on both, present and future climate, they are not because of the climate change).
  • Another idea is to model the index just for one land-use categorie, to disentangle land-use (just land-use not land-use scenarios) and climate change effect?

Kind regards