On the precipice
Species which exist in fragmented, isolated and reduced populations have elevated extinction risk. Not only are they more susceptible to demographic and environmental stochasticity, which can easily wipe out small populations, but they also suffer from a range of genetic impacts. Notably, populations often lose significant amounts of genetic diversity as they reduce in size, potentially losing important adaptive diversity enabling them to respond to current and future environmental change. At the same time, random genetic drift becomes stronger relative to natural selection, reducing the efficacy of selection to be able to increase the frequency of favourable alleles and reduce the frequency of maladaptive ones. Together, these impacts create feedback loops which hasten the decline into the extinction vortex.
How can species respond to environmental change?
If you’re a somewhat avid (or even cursory) reader of The G-CAT, you may remember my wrap-up post at the conclusion of my PhD in 2020 which described the various chapters of my thesis. Well, I’m pleased to announce that data chapter 2 of that thesis – on the comparative phylogeography of two threatened Australian freshwater fishes – has just been published in the journal BMC Ecology and Evolution. It’s a pretty complex paper which tackles genetic diversity, phylogenetics, demographic history, species distribution models and how these interact together to understand the evolutionary history of these species in a comparative framework. Feel free to check it out (it’s open access and free to read!) here.
The roles of aridification and sea level changes in the diversification and persistence of freshwater fish lineages
The process of publishing science is a lengthy one – there are many rounds of revisions, assessments, and review required before a paper can be published. With that, I’m very proud to announce that the first paper from my PhD has recently been published in the journal Molecular Ecology. This paper is a collection of a lot of complex analyses, and addressing some relatively complicated biogeographical questions, so I’ve decided to provide a simplified summary here.
Predicting the future for biodiversity
Conservation biology is frequently referred to as a “crisis discipline“, a status which doesn’t appear to be changing any time soon. Like any response to a crisis, biologists of all walks of life operate under a prioritisation scheme – how can our finite resources be best utilised to save as much biodiversity as possible? This approach requires some knowledge of both current vulnerability and future threat – we need to focus our efforts on those populations and species which are most at-risk of extinction in the near (often immediate) future.
Of alleles and selection
If you’ve read this blog more than once before, you’re probably sick of hearing about how genetic variation underlies adaptation. It’s probably the most central theme of this blog, and similarly one of the biggest components of contemporary biology. We’ve talked about different types of selection; different types of genes; different ways genes and selection can interact. And believe it or not, there’s still heaps to talk about! Continue reading