Place: If it already exists on Google Maps do I need to create it also in iNaturalist?

[alexis_orion]

when you filter for observations, they are filtered by the polygon.
if you want you can filter observations by the bounding box as well.
see: https://forum.inaturalist.org/t/how-to-use-inaturalists-search-urls-wiki/63

@tiwane

Search by bounding box or circle

If you’d like to search an area that doesn’t have a place ID, you can put in a rectangular bounding box or a circle with a defined center and radius. These must be added to the URL manually.
For example, https://www.inaturalist.org/observations?nelat=30.849458&nelng=-94.939413&swlat=30.220087&swlng=-95.792015 finds observations in a rectangular area north of Houston, Texas. You can use Google maps to find the lat/long points – just click on the map and it will give you the numbers.
And https://www.inaturalist.org/observations?lat=38.92&lng=-77.07&radius=16 finds observations around Washington, DC.