Biogeography and Ecology in Tasmania

This is a collection of scientific articles about different animal groups in Tasmania, and the effects the created their distributions. Each chapter is a paper summarizing the information they have about a general biotic group. Earthworms in one chapter, birds in another, and so on.

It was published in the mid-1970s, although I was sure I'd seen a publication date from the early 2000s. This is a bit of an issue, not just because some of the information is doubtlessly out of date, but because at the time, there were large sections of the island that hadn't even been surveyed. This comes up in the aquatic animal sections especially, when the various authors note that there are several lakes in more remote parts of the country that they have no idea what lives in them. And when the information on what is present is limited, so are the inferences or theories one can make about why. But I was curious about the animal life present in Tasmania, and this is a good place to start.

Each section is written by a different author, and so there's some variation in how readable each section is. Some writers lean more heavily on scientific terminology than others, and some just plain have a better grasp of writing English the others. The last section, on the history of conservation efforts and future problems had some curious wording and phrasing choices.

They authors also take different approaches to the subject. D.G. Thomas' chapter on birds doesn't focus on which particular species are present and their ecology. It's more what determined which species made it to Tasmania, and why they succeeded or failed in establishing a permanent population. It draws heavily from MacArthur and Wilson's theory of island (our insular) biogeography, which was less than 15 years old at the time this book was published. R.H. Green's chapter on mammals discusses major habitat types, then does a brief section on each indigenous species, their ecology, and how their numbers seem to be doing in the face of human expansion and compared to similar species on the island, or compared to any populations that might remain on the Australian continent.

Turns out there are quite a few species that were ultimately out-competed or otherwise driven to extinction on Australia that have a remnant population in Tasmania. Because the species that out-competed them didn't make it south before the Bassian Land Bridge became the Bass Strait, and thus could not make it to Tasmania in time.

'As previously suggested (Williams, 1970b) in general terms, one explanation may for the greater abundance in lakes in the south-west may be that since many of these are remote, they do not (yet?) contain the introduced trout, Salmo trutta, a known predator of Anaspides tasmaniae, and it is in the absence of this fish which allows continued survival of the syncarid in habitats which were previously perhaps more typical for it over the whole of the island.'