Low potential for evolutionary rescue from climate change in a tropical fish (2020) Morgan et al., PNAS, https://doi.org/10.1073/pnas.2011419117
As the planet warms thanks to climate change, the massive bodies of water that are our oceans grow hotter. Since they’re larger, and much poorer conductors of heat, they don’t tend to vary in temperature as much as the land does, which means many species will have to get used to longer, warmer periods.
If species can adapt to hotter temperatures through thermal acclimation, ecosystems may not be too harshly affected. However if they’re unable to adapt, marine ecosystems may undergo rapid changes as they lose native species. Today’s researchers looked at a key study species – the zebrafish – in order to figure out how well fish can respond to increasing temperatures.
Image Credit: bertknot, CC BY-SA 2.0, Image Cropped
Let’s face it, IPCC reports are never a fun read. They’re a damming assessment of our ability to take care of the only planet we’ve got. Piecing through them to find the key takeaways is likewise a tough task, but since the final report (for this round) has now been submitted, I thought I’d reflect on what I’ve learned going through each step of the report over the last year.
Image Credit: Patrick Kavanagh, CC BY 2.0, Image Cropped
In my last post we talked about using images as data. This time we’ll consider another non-traditional source of data: the results of other investigations. Using results to generate more results? That seems weird… at first. But think about how science progresses. We build on other studies all of the time! Sometimes we use others’ findings as a jumping off point. Other times, studies invite us to see if we can reproduce their findings under new conditions or with respect to our own study site or species of interest.
How melanism affects the sensitivity of lizards to climate change (2022) Mader et al. , Functional Ecology, https://doi.org/10.1111/1365-2435.13993
Image credit: Tony Rebelo, CC BY-SA 4.0, via Wikimedia Commons
Climate change is a fact of life. Every day we uncover more of the negative effects it will have on the various animals, plants, and fungi in the natural world. Species range contractions are one such effect, and they occur when the area that a given species normally occupies shrinks. They are directly linked to a species’ risk of extinction, with this risk growing as a species inability to adapt to new environments grows. Though the theory sounds logical, many of the exact mechanisms behind range contractions are still unknown.
Ectotherms are organisms that depend on the surrounding environment to regulate their own body temperature, making them particularly vulnerable to climate change. Many different biological mechanisms are involved in regulating temperature, but the ability to reflect solar radiation is a key player. Indeed, the ability of organisms to reflect solar radiation (aka energy from sunlight) is part of the thermal melanism hypothesis (see Did You Know?). Melanistic (darker) organisms may be favored under climate change, due to the protection against UV radiation provided by melanin. However, melanistic individuals are more prone to increased heating, which can be bad. Today’s authors sought to understand how climate change would affect melanistic organisms.
Image Credit: Bernard Dupont, CC BY-SA 2.0, Image Cropped
The urgency behind the most recent IPCC report has thankfully garnered it a lot of attention worldwide*. It’s a report that was very frank in its desperation for people to take this threat as seriously as possible. Yet both this report and the one that hit us in February also made mention of one other key factor that has been swept under the rug – the ability of functioning ecosystems to both mediate and mitigate the impact of climate change.
Alongside a wealth of other benefits we gain from biodiversity, ecosystems play vital roles in helping us withstand the rigours of climate change. Wetlands and rivers protect us from increased flooding. Forests help mitigate extreme heat waves. Peatlands, mires, and permafrost are all crucial carbon sinks. Yet as species disappear, these ecosystems deteriorate, as pieces of the complicated web that they’re made up of disappear. It’s why the concept of mass extinction is so frightening.
But what is mass extinction? We often hear about the concept of a mass extinction, and the question of whether we’re currently in the sixth mass extinction is constantly thrown around. So let’s have a quick look at exactly what extinction itself means, what a mass extinction is, and why it’s increasingly obvious that we’re in one.
Image Credit: Tristan Schmurr, CC BY 2.0, Image Cropped
“I’m not going to do it and put our kids’ economic future at risk.”
This is a quote that reverberated around Australia in mid 2019. It was uttered by Prime Minister Scott Morrison, upon being pressed on how serious a stance against climate change he would take if he won the then-upcoming federal election.
It’s a story that sadly plays out worldwide, with many politicians and members of the public opting to prioritise economic growth over the more pressing action required to combat climate change. The emotional twist is usually the same – “climate change is bad, but you still need money”.
Testing the parasite-mediated competition hypothesis between sympatric northern and southern flying squirrels (2022) O’Brien et al. 2022, International Journal for Parasitology: Parasites and Wildlife, https://doi.org/10.1016/j.ijppaw.2021.11.001
Image credit: Stephen Durrenberger, CC BY-NC-SA 2.0, Image Cropped
One consequence of climate change is that organisms move to new habitats, as they try and track suitable environmental conditions. This can result in closely related species coming into contact with one another, which in turns drives competition among these organisms. Competition between these organisms can manifest as either direct competition (where two organisms directly compete with one another for food or habitat), but it can also manifest as apparent competition.
Apparent competition happens when species A serves as a food source for predators or parasites, which increases the numbers of predators/parasites in the environment. This increase in predators or parasites then puts more pressure on species B. Apparent competition via parasitism was actually a major driver for the decline of red squirrels in the UK, as the introduced grey squirrel brought along squirrelpox virus that had severe effects on the red squirrels.
If one species is more tolerant to a parasite than another, this can result in competitive exclusion, where one species outcompetes the other species to such an extent that the outcompeted species goes locally extinct. This is particularly important when a climate-mediated range expansion brings two species together that share parasites. Today’s authors sought to quantify how infection by parasites affected a vulnerable population after a range expansion by a potential reservoir species.
Fur colour in the Arctic fox: genetic architecture and consequences for fitness (2021) Tietgen et al., Proceedings B, https://doi.org/10.1098/rspb.2021.1452
Researchers who try to understand the dynamics of wild populations often look at how different traits affect the survival and reproduction of different individuals within those populations. Usually, the investigated traits are visible and easy to observe, like an animal’s size or their colour. However, there may be cases where the important traits are not as conspicuous or even hidden behind more striking features.
The arctic fox (Vulpes lagopus) occurs with two distinct fur colours, often called morphs. The two most common are the white morph and the blue morph. Which of these morphs is more common depends on the population. In Norway, the white morph is more common but in recent years an apparent increase in foxes of the blue morph has been observed. Previous research has shown that blue arctic foxes are usually fitter, but until now there hasn’t been a good explanation of why.
We wanted to dive a little bit deeper into the differences between the two colour morphs, explore the genetics behind this trait and seeing whether we could find any “hidden” traits connected to fur colour that could explain the difference in fitness between the two morphs.