Why do small islands that are distant from a mainland tend to have fewer plant species than large islands that are close to a mainland?

Small islands are more often round$-$shaped which gives them a higher ratio of edge habitat for plants.

Distant islands are harder to get to and require specialized seed dispersal strategies.

Small islands support smaller plant populations that are more prone to extinction.

Distant islands are colonized more often by non$-$native plants that outcompete native plants.

Small islands may have fewer types of plant habitats than large islands.