Dear Natural Capital Project Forum,
I am trying to identify the best strategy for incorporating variable hydrology into the InVEST Habitat Quality model. I have used the model before, but am working on a different group of organisms that require more complexity.
For the new model, we have 6 different levels of surface water frequency estimates for our landscape and would like to use this information to incorporate one or more hydroperiod related threats. As I understand it, we have three strategies to accomplish this:
- Build one raster layer with the water frequencies as the value for each grid cell, which becomes the only hydroperiod threat raster layer. Here I worry that the units of this raster layer will not align with other threat layers (e.g., presence/absence of roads). I also don’t completely understand where this threat raster cell value is incorporated into the habitat quality metric. The benefit of this approach is that there is only one hydroperiod threat layer and therefore it does not dilute the impact of other threats.
- Incorporate each of the six surface water frequencies as separate threat layers with different sensitivities based on their anticipated impact. Here I worry that having six threat layers just to deal with hydroperiod will dilute the impact of other threat layers. When I say dilution, I’m referencing the calculation of habitat quality that incorporates a multiplier based on the weight of the specific threat relative to the total threat weights in the model.
- Incorporate each of the six surface water frequencies as a separate threat layer with the same sensitivities but different threat weights. As with the above option, I worry that having six threat layers just to deal with hydroperiod will potentially dilute the impact of other threat layers.
Any thoughts on best practices for the InVEST Habitat Quality model?