Apply POWO only to countries where no expert checklist available [feature request]

[ojalaquellueva]

Motivation: POWO is an unreliable source of species native status information, assembled by quasi-algorithmic means, and should be used only where higher quality information not available.

Example: POWO lists Eleagnus umbellata (autumn olive) as native to Minnesota. This species is an aggressive invasive in North America, native to Asia only. See: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:927281-1.

[ojalaquellueva]

The most straightforward solution is to apply only one checklist when >1 is available for a given political entity. Would also need to store this ranking in the database. Allowing user to set checklist order via the API or web interface would be an additional challenge.