Earlier I wrote a blog comparing diversity of wattles (Acacia) between Queensland and New South Wales. I have now gone back and compared wattle diversity across all the states and the Northern Territory (sorry, not the ACT, the data was too messy).
Western Australia wins! There is not need to be coy about the results because WA wins by a long way in all categories.
For the first table, I exported the Acacia species lists for all the states in the ALA and then calculated the percentage of species in a state that are endemic to that state. There are 1105 Acacia species in the ALA. I know Western Australia is species rich and species endemic but the data are quite spectacular. 41% of the WA Acacia species are endemic, while the next highest in species endemism is Queensland. Fully 2/3 of Acacia species can be found in WA and 1/3 in Queensland, but in WA those species are much more likely to be endemic.
Of course my goal is to compare species data with phylogenetic data so for the next two tables I am only using the 510 species in my phylogeny, yes I know I have to finish the new larger dataset someday.
These data are not too different, except that the WA endemism is a lot lower (27 instead of 41). This is probably due to a new endemic species being recently described to science and are found in small geographic areas. That makes sense because a species with a larger range would be more likely to be found and described. It also shows that the sampling in my tree is a bit biased to eastern Australian species. I will have to work on that, but they are easier to collect, especially since I lived in Canberra.
Now what you have been waiting for: Phylogenetic Diversity (PD).
As expected the percentage PD is higher than percent of species (compare first columns of these two tables). This is because knowing a species in a phylogeny gives you more information than just knowing it taxonomically (Garry Jolley-Rogers and I have a paper in review discussing this idea. It is a topic of a future blog.)
I need to explain endemic PD. It is the evolutionary history endemic to that state. (This is the sum of the branch lengths in the phylogeny of the endemic species in a state. This is mostly tip branches and the interior branches of the phylogeny until it reaches a node that is shared with a species that is not endemic to that state. Hmm I should write a PD blog too.)
The percentages of endemic PD are remarkably similar to the endemic species. They should be similar but it surprises me that they are that similar.
Hmm, what will happen when I finally get that next phylogeny done and have most of those new endemic WA species in the phylogenetic tree. Will the endemic PD creep closer to the 41% seen in species diversity? If the newly added species are closely related to the ones in the phylogeny already, (as expected if they occur due to recent taxonomic splitting), then the endemic PD should not increase that much, but if the new species are new lineages without close relatives already in the phylogeny, then the PD will increase more.
Take home message: I need to work on that new phylogeny.
Next I will do some comparisons to WA. I am curious to know which states shares more species and PD (evolutionary history) with WA. What state do you think it is? Add it to comments.