Native species in a project for introduced species

blue_celery · October 9, 2020, 9:12am

Platform: website

URLs (aka web addresses) of any relevant observations or pages:
https://www.inaturalist.org/observations?iconic_taxa=Plantae&page=17&place_id=any&project_id=aliem&subview=grid

Description of problem (please provide a set of steps we can use to replicate the issue, and make as many as you need.):
Cymbalaria muralis is currently listed as native in the place “Toscana”:
https://www.inaturalist.org/places/toscana#q=cymbalaria%2Bmuralis

Anyway it has been listed in this project that should include only introduced species:
https://www.inaturalist.org/observations?iconic_taxa=Plantae&page=17&place_id=any&project_id=aliem&subview=grid
https://www.inaturalist.org/projects/aliem

twainwright · October 10, 2020, 2:44pm

I think you have been caught by inconsistencies in the checklists for overlapping places. In this instance, the species is listed as “native” in Toscana
https://www.inaturalist.org/check_lists/15834-Toscana-Check-List?q=cymbalaria+muralis
but is listed as “introduced” in, for example, Lucca
https://www.inaturalist.org/check_lists/35955-Lucca-Check-List?q=cymbalaria

I don’t know how the software decides which place checklist to use for an individual observation. To be sure that the project works as expected, I would guess that someone would need to make the status consistent in all the checklists for places in the region covered by the project.

blue_celery · October 10, 2020, 2:32pm

Thank you so much for the explanation. You have found the “bug”.

jwidness · October 10, 2020, 3:36pm

More info:

Remove Ability to Apply Status to Descendant Places

Looks like if any spatially overlapping place (whether or not there is a parent-descendant relationship) has a species marked as Introduced, it will display Introduced for the first such place it finds for a relevant observation. When I go in and manually change the displayed place to Native or Unknown for the species, then it just finds the next spatially overlapping place with Introduced status for the species, and displays that for the observation instead.

In other words, for an observation to display anything other that Introduced status, none of the places that spatially overlap it can have Introduced status for that species, regardless of parent-descendant place relationships.

Makes logical sense with respect to how we define Introduced for a place. But it does mean that addition or removal of Introduced status on large places (currently possible by any user) can cause wild swings in the status displayed for large numbers of observations.

And it also means that any validation or error checking should be based on spatial intersection of place polygons, not on parent-descendant relationships, which involves a lot more computing resources.