Dear natural capital team
I am wondering about the different measures used in publications to validate the “InVEST pollination abundance index” output.,
- Lonsdorf et al. 2009. x: pollinator service score, y: pollen deposition, pollinator richness and abundance.
- Ricketts et al. 2014: x: pollinator abundance index, y: observed pollinator abundance
- Davis et al. 2017: x polinator suply score, y: pollinator abundance
- Kennedy et al. 2013: x: Lonsdorf landscape index, y: bee abundance
- Koh et al. 2016: x: abundance index, y: log (wild bee abundance)
Questions
- Is it adequate to name the InVEST “pollinator abundance index” as "pollinator service score (see Lonsdorf et al. 2009) when considering crop plants, e.g. modelling the pollination abundance index for areas suitable for e.g. apple growing? It is the potential service, not yet the delivered service.
- As InVEST just considers community composition (relative abundance of each species) I am struggling around if richness is the better measure than abundance. What do you think?
Kind regards
Sibylle
Hi Sibylle,
I’m not sure I completely understand the question - the output of the model is an index that should be predictive of the delivered service. I’m not sure what distinction you are making between potential service and delivered service. I suppose it would be a prediction of potential service if you were considering planting a pollinator-dependent crop that is currently not there and a prediction of delivered service if the pollinator-dependent crop was currently there. For the second question, we have used the abundance index to predict both observed abundance and observed richness because they are often correlated. The pollination model is somewhat agnostic of these two measures and it would be up to the user to specify which one is most relevant. In nearly all examples of work we’ve done, a function that relates the InVEST pollinator index to observed abundance or richness was needed (see also Cusser et al. 2023). This was either a saturating function or a log-linear function. We’ve modeled individual bee species and then created a weighted average of the index scores to create a community prediction. We’ve also used observed species abundances to create a weighted average of parameter values to generate a single a proto-bee species, that is meant to represent the community (either total abundance or richness) and found that these two approaches provide nearly identical output predictions. I’m not sure what you mean by “better measure.” Hope this helps a little! Eric
3 Likes
Many thanks @lons0011
We thinks that it is highly important to differentiate between the pollination potential (InVEST abundance index) and the pollination service potential (see e.g. Perennes et al. 2021) (InVEST abundance index cropped by e.g. fruit growing suitability sites). Specifically we want to highlight, that there is a difference between the delivered service prediction and the potential service. Just because there are bees around an apple orchard doesn’t mean that they will pollinate the apple orchard. It is only the potential service, but there are still many factors (temporal synchronity, competition from other flowers, etc.).
Kind regards
Sibylle
