Our research focuses on the population dynamics of plants and how they are influenced by impacts of natural disturbances and global environmental change. We are particularly interested in the interactive effects of fire, grazing and drought in grasslands and woodlands in southern Australia, and how climate change, fragmentation and shrub encroachment affect ecosystems.

Tuesday, 7 May 2013

Borrowing from others

I've been a little snowed under these last few weeks, so haven't been able to Blog as much as I'd like. But I have some interesting posts in the pipeline.......

For this post, I'd like to point you to a couple of fascinating bits of ecology that I've come across recently. I think they are worth sharing here. Both are challenging, but for different reasons.

Angela Moles, in a TedTalk, talks about invasive plant species in Australia. But not in the way many of you might expect. Ang takes a different approach to invasives. She talks about how, once introduced to Australia, exotic species should be expected to evolve into unique 'new' Australian species. Once species have been transported to Australia, they are isolated - so gene flow potentially stops. Or at the least, is mixed by the introduction of different genotypes from the source. Then, local adaptation kicks in. Exotic species in Australia often exist in a very different context to their point of origin. Soils will be poorer (mostly in N and P), climate is more variable (and extreme) in many cases, and interactions with herbivores and pollinators will likely be altered. Under such circumstances, plants are likely to 'evolve' to suit their new habitats. Given enough time, they should also evolve to be reproductively isolated from plants derived from their source of origin (i.e. new species). Just like Darwin's finches!

You may not agree with Ang here - particularly because of the impacts that exotic plants can have on native plant communities (although it should be noted that in many bits of bush, some exotic species do seem to coexist happily with native species, e.g. Aira spp in grasslands). You can see her talk at: http://www.youtube.com/watch?v=5EV3ZTzSzZE

The second piece of interesting ecology comes from Jeremy Fox. He has a terrific Blog called Dynamic Ecology. I highly recommend it. He covers a range of topics in ecology (almost daily) - from theoretical ecology, to doing experiments, to cool T-shirts for science nerds.

In a old Blog (October 2012), Fox outlines what he thinks is one of the most important contributions to ecology in recent years. He summarises (beautifully) an emerging topic in the field of community assembly: phylogenetic community ecology. If you don't know what this is, then you should read his Blog.

Put simply, co-occurrence of phenotypically-similar species indicates “habitat filtering”, meaning roughly that community membership reflects species’ abilities to tolerate the local abiotic environment. Conversely, co-occurrence of phenotypically-different species means that similar species are being competitively excluded (= limiting similarity). If, as is often the case, phenotypic traits are phylogenetically conserved, so that closely-related species tend to be phenotypically similar, co-occurrence of closely-related species (“phylogenetic clustering” or “attraction”) implies habitat filtering, while co-occurrence of distantly-related species (“phylogenetic repulsion” or “overdispersion”) implies competitive exclusion. This is a simple, novel, creative, and relatively easy-to-implement idea, and so it’s no surprise that it took off.

The problem is, this “simple logical framework” is wrong! That is why you need to read Fox's Blog: http://dynamicecology.wordpress.com/2012/10/09/can-the-phylogenetic-community-ecology-bandwagon-be-stopped-or-steered-a-case-study-of-contrarian-ecology/