What is biogeography? Part 1

In my undergrad, I took a course on phytogeography.  When I chose it, it was mainly because there was no lab and I liked the prof!  But it turned out to be one of the most interesting classes I took – the things I learned were wide-ranging in scope and helped me to understand why the world is the way it is.  🙂

This new 5 part series is a peek into biogeography – what it is, how we study it and why it’s important.  And although the focus of the class was on plant dispersal, I will include many animal examples, as most of the core principles apply to all living things.

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Have you ever wondered why Australia is home to so many unique mammals?  Questioned the limited range of species such as Dawn Redwood or California’s Clarkia?  Compared your garden cucumbers to that of the cucumber tree? Or perhaps you’ve fished in both the Atlantic and the Pacific and noticed the striking similarities between shrimp species in these very separate oceans.

All these examples are the result of different types of distribution and can be explained by an interesting field of study called “biogeography”.

Biogeography is defined by Wikipedia as “the study of the distribution of species spatially and temporally”.  This field looks at how species and populations are distributed, usually in references to animals.  Phytogeography is the branch of biogeography that is concerned with the geographic distribution of plant species specifically, from controls on the distribution of individual species ranges (at both large and small scales, see species distribution) to the factors that govern the composition of entire communities and floras.

Biogeography can be divided into two main branches: Ecological biogeography and Historical biogeography. The former investigates the role of current day biotic and abiotic interactions in influencing species distributions; the latter are concerned with historical reconstruction of the origin, dispersal, and extinction of taxa.

When we talk about species distribution, we might be talking about local populations or species as a whole. In both cases, the distribution is affected by factors which include: dispersal ability, abiotic factors (temperature, light, salinity), biological factors (competition, breeding systems, pollinators), historical factors (plate tectonics, glaciation), and human interactions. Over time, some of these factors may become more important than others.

Over the next few blogs, I’ll be taking a closer look at some of these factors and discussing how they have affected current and historical species distribution.

References:

UBC BIOL412 notes, Professor Michael Hawkes

http://en.wikipedia.org/wiki/Biogeography [accessed Nov 23, 2010]