Evolution

Mixing fishes and climate change – adaptation by hybridisation

thegcatblogLeave a comment

Adapting to a changing world

The global climate is changing at an unprecedented rate, approaching conditions last seen globally over 3 million years ago. Impacted by the compounding effects of climate change, habitat modification, invasive species and direct exploitation (e.g., fishing and hunting), species across the globe are threatened with extinction. Key to the effective management of global biodiversity is the understanding of how species may (or may not) rise to the challenge of climate change: can species adapt? Which species will adapt? How will they adapt? The answers to these questions are elusive and complicated.

Continue reading →

Runaway inbreeding: how runs of homozygosity impact conservation management

thegcatblogLeave a comment

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.

Continue reading →

A tale of two fishes: how standing genetic diversity influences species responses to environmental change

thegcatblogLeave a comment

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.

Continue reading →

Conservation applications of functional variation

thegcatblog1 Comment

From genotype to phenotype

One fundamental aspect of conservation and evolution research is the implicit connection between genetic variation, phenotypic characteristics, and their influence on Darwinian fitness. Genetic diversity underpins many aspects of the adaptive potential of a population, and many of the fundamental concepts of the field rely on the assumed connection between genetic and phenotypic characteristics. But this connection is neither straightforward, nor always predictable.

Continue reading →