A common caricature of Young Earth Creationism (which I believe is even present on the BioLogos site; I may have to double check) is that they believe all animals, plants, and especially human beings were specially created more or less in their present forms 6 to 10 thousand years ago. However, as I read modern-day YEC literature, they appear to be moving farther and farther away from this belief. In fact, a whole field of study has been created by the YECs called “baraminology,” which comes from the Hebrew words “bara” and “min,” meaning “create” and “kind” respectively.
Essentially, God created a number of kinds of animals (corresponding roughly with the genus classification, though some might extend it upwards to family), which then rapidly evolved through speciation after the flood to arrive at the vast array of species we have today.
This is certainly a step in the right direction, but I am concerned that perpetrating the above caricature of YECism is somewhat dishonest, because many prominent YECs have conceded the point that yes, speciation does occur and has occurred on a spectacular level. See here, for example: https://thenaturalhistorian.com/2015/12/30/dodging-darwin-how-ken-hams-ark-encounter-is-slowly-embracing-evolution/.