Answer to Question #246202 in Ecology for Liana

Question

Why are there fewer plant species in northern Europe than in southern Europe? 

Answer 1

Historically, it is assumed that Europe lost many of its temperate tree species thanks to the east-west orientation of its mountain ranges.

As glaciers advanced from the north, species were pushed farther and farther south until they hit physical barriers in the terrain like the Alps. With nowhere to go but up, many species that couldn’t handle either the rate of climate change or the altitude adjustment in the north and simply winked out of existence. Fossil evidence from Europe provides plenty of evidence that northern Europe was once home to far more tree species$.$