Biogeography deals with the distribution of species and vegetation types, from global to local scale. Today we know that dispersal limitations are common and that species occurrences depend on a balance between dispersal, tolerance to environmental factors, interactions with other species (competition, herbivory, predation) and random population extinctions.
Linnaeus emphasized the reproductive potential of plants (how the plants from a single place have been able to spread over the entire earth), but he also writes: Now the task remains to show how all the plants within this limited area were able to find the suitable soil for themselves, as well as how the animals found the climate that each of them needs. These formulations may give the impression that Linnaeus believed that all species could potentially reach everywhere, and that it is only the adaptation to the local environment that determines whether they can survive. However, the examples of dispersal biology above show that Linnaeus binds together knowledge of the species' environmental requirements and dispersal ability to understand how they can grow at different heights on a mountain, in different climate zones, on different continents and in different environments. He emphasizes that the difference in flora between alpine areas is due to the plants not being able to spread everywhere, and he imagines that plants from the Alps would thrive in the Swedish mountains if only they were helped along the way to get there (Du Rietz, 1957).
Formal definition of the vegetation regions in Sweden came after Linnaeus, but he laid the foundation by describing a coniferous forest region in the north and a deciduous forest region in the south, and how the beech tree replaces the spruce in southern Scania (Du Rietz, 1957). He emphasized the importance of the northern limit of the oak at the river Dalälven, which later became an important part of the definition of "limes Norrlandicus" - the southern border of the boreal zone.
|Du Rietz, G.E. 1957. Linnaeus as a phytogeographer. Vegetatio 7: 161-168