Koalas are gorgeous, no doubt. But does their overwhelming charisma mean that we forget about other species? (Image Credit: Erik Veland, CC BY-SA 3.0)
Australia plays host to a wonderful range of very endearing species. Tourists come from the world over to get up close with kangaroos or koalas. But the charisma of these animals can often lead to issues, whether it’s prioritisation of resources for them over other more endangered species, or even to the detriment of the species themselves.
Doctor Kath Handasyde of Melbourne University has been working with Australian field wildlife for almost 40 years, and is perhaps the most charismatic teacher I had during my Bachelor’s at the same institute. During my time in Melbourne, I had the chance to talk to Kath about the sometimes problematic role of charismatic species in Australian wildlife conservation.
On the left, a thriving wetland. The right, an arid forest. (Image Credit: Sam Perrin, CC BY-SA 4.0)
I’m standing on the dry side of the Murrumbidgee floodplain in country Australia. I say dry side, because whilst I’m standing on the harsh, dusty platform of soil and desiccated leaves that is pretty standard for this area, 15 metres away there’s a thriving wetland environment. It boasts waterbirds, a flock of emus, thirsty kangaroos, and fish. All that’s separating the wetland and dry land on which I stand is a road, only about half a metre above water level.
Species richness is much higher in waters near the equator, but do we see that in a phylogenetic tree? (Image Credit: Rich Brooks, CC BY 2.0)
An inverse latitudinal gradient in speciation rate for marine fishes (2018) Rabosky et al., Nature doi:10.1038/s41586-018-0273-1
The tropical regions of the Earth are the most species-rich and diverse ecosystems on the planet, with this diversity and species-richness declining as you move further and further from the equator. One hypothesis explaining this is that speciation rates are simply higher in the tropics, meaning that more species are evolving in a given time in the tropics than anywhere else. To test for this, the authors used the largest phylogenetic tree available and analyzed speciation rates (how many new species evolve from older species) per million years.