This implies that the plants and animals had to transverse water, and in some cases oceans.
Evolutionists are left with three main mechanisms:
(1) connections by
now submerged land bridges;
(2) island hopping across a series of
adjacent islands, if close together; and
(3) rafting on vegetation,
sometimes across vast oceans.
Land bridges and island hopping have not become popular ideas, though
the Bering Land Bridge is an exception.
As a result, many scientists
have no choice but to opt for the third option, rafting dispersal,
despite it being considered impossible a few decades ago.
---There have been several recent observations of successful rafting of
lizards on pieces of floating vegetation after storms, giving support
for rafting. When a hurricane ripped up vegetation on Caribbean islands,
some lizards survived on vegetation rafts, and colonized other islands
in the area.
----Log mats or possibly very large pumice rafts can explain some of the perplexing biogeographic observations..... these could aid post-Flood dispersion:
“Another application [of the log mat model] is that some of the floating
debris likely survived the Flood.”
Millions of logs of various sizes likely floated on the oceans for a few hundred years after the Flood.
Transport would begin when a log mat beached, for instance at low
tide.
Animals would meander onto it. When the log mat resumed floating,
possibly after a storm or the rising of the tide, currents would carry
the animals to distant shores.
However, it is questionable
that very large Ice Age mammals, like mammoths, could be transported
long distances on log mats. The only alternative is dispersal by land
bridges.
.... it is unlikely that God would have told Noah and the animals to
spread over the earth knowing there was no way to accomplish this:
“Bring out with you every living thing that is with you of all flesh—birds and animals and every creeping thing that creeps on the earth—that they may swarm on the earth, and be fruitful and multiply on the earth” (Genesis 8:17, ESV).
Three land bridges have been proposed: 
(1) the connection between
continental Europe and England at the Dover Strait;
A land bridge once existed across the Dover Strait connecting the United Kingdom with continental Europe early in the Ice Age. Sonar features of the bottom of the English Channel at and near Dover Strait the closest approach of England and France.
(2) the connection
between Asia and North America across the Bering Strait;
The Bering Land Bridge aided dispersal of animals to the Americas. This land bridge not only exposed the Bering Strait, but
also exposed much of the continental shelves of Siberia and Alaska
creating a path into the Americas.
CMI