Searching For Standouts In The IPCC Reports
Image Credit: bertknot, CC BY-SA 2.0, Image Cropped
Sam Perrin
Why A Big Brain Means A Longer Life (For Parrots)
Image Credit: Patrick Kavanagh, CC BY 2.0, Image Cropped
Coevolution of relative brain size and life expectancy in parrots (2022) Smeele et al., Proceedings of the Royal Society Biological Sciences, https://doi.org/10.1098/rspb.2021.2397
The Crux
Figuring out what exactly drives a species’ lifespan has proved more of a puzzle than it might at first seem. Sure, we can look at a single species and provide a few reasons for why it might live as long as it does, but finding predictable patterns relating different factors to life expectancy (let’s say longevity from here) is a little complex.
Take brain capacity for instance. There are three mostlymain theories (which are all somewhat linked) as to how brain capacity affects longevity. The cognitive buffer hypothesis suggests that the ability to solve puzzles granted by a larger brain enables a species to survive situations that other species couldn’t, giving them a longer lifespan. The expensive brain hypothesis suggests that a brain takes up more energy, therefore slowing growth and extending longevity. And the delayed benefits hypothesis suggests that a larger brain capacity allows for more skilled food-finding techniques, resulting in higher diet quality, less adult deaths, and most importantly, the ability for a longer learning period from their parents, resulting in more skill transfer.
Parrots are very smart creatures, almost on the same level as primates when it comes to relative brain size. Today’s authors wanted to test for links between brain capacity and longevity in parrots, and see if their findings lined up with any of the three hypotheses.
What They Did
The team drew their longevity data from Species 360, an organisation which collects information from conservation bodies worldwide. They used life expectancy as their measure of longevity, and compared it to relative brain size, as well as other features like body mass, latitudinal range and diet, which have been shown to affect longevity before.
The authors also tested a few other models which included measurements of developmental time and parental investment to see if either of these had an impact. Either being important could shed light on whether or not the expensive brain or delayed benefits hypothesis play a part in development.
Did you Know: Parrots As Invaders
Their bright colours and intelligence make parrots an inherently charismatic species, one we often sympathise with when we hear of their threatened status and degraded ecosystems. But some species of parrot are biting back, with rose-ringed parakeets (pictured below) now a damaging invasive species in much of Europe. A warming climate and rising numbers will likely only see their range expand.
Read More: Polly Want A City? Population Boom Sparks Call For Cull Of London’s Invasive Parakeets
What They Found
As suspected, larger parrot species tended to have longer lives. But larger relative brains also led to longer lives, though it wasn’t as large a contributor as body size was. The other parameters, including those related to diet, developmental time and parental investment, didn’t have a meaningful effect on parrot longevity in these models.
One added tidbit – the Cacatua, a genus which includes the sulphur-crested cockatoo (pictured above) were the longest lived birds, with the Large Fig Parrot of South East Asia coming in last, with a life expectancy of under two years.
Problems
Testing hypotheses in science is made easier by the fact that often they’re mutually exclusive, and concluding that research supports one hypothesis is often a direct result of rejecting another. Yet the researchers today were testing three hypotheses that were certainly not mutually exclusive, which really muddies the waters, and makes teasing the effects apart a little difficult.
So What?
The fact that diet and developmental factors had no effect here is interesting, as at least the delayed benefits hypothesis suggests that better diet may lead to longer lives. The expensive brain hypothesis also suggests that increased brain capacity contributes to a longer life by extending development time, so it’s odd that development time had no effect on longevity.
Ultimately the research here doesn’t disprove any of the theories, and perhaps shows most proof for the cognitive buffer hypothesis, suggesting that increased problem-solving abilities can contribute to longer lifespans. Since longer-lived species are often more likely to be threatened, their increased intelligence could be used as a conservation tool, seeing as we humans are often more enamoured with more intelligent species.
Dr. Sam Perrin is a freshwater ecologist who completed his PhD at the Norwegian University of Science and Technology who loves parrots almost enough to wish they would stop messing about and just invade Norway. You can read more about his research and the rest of the Ecology for the Masses writers here, see more of his work at Ecology for the Masses here, or follow him on Twitter here.
We’re In The Sixth Mass Extinction Event
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.
Read moreMore Cephalopod Cinema Please
The Thimble Tickle Giant Squid of 1878 (Image Credit: Julie Potton, CC BY 4.0)
Cephalopods have absolutely everything you could want in a movie hero. Spread across the class Cephalopoda are the cute (baby cuttlefish), the intelligent, the devious (pretending to be a female to get past the males is spectacularly sneaky), the tragic (the plight of the octopus mother is heartwrenching), and even the dramatic (blasts of ink to mark your departure aren’t exactly subtle).
Read moreWhat The Hell Is A Species Anyway?
The Sumatran tiger, which is different from other subspecies of tiger for reasons (Image Credit: Bernard Spragg, CC0 1.0)
We’re only 3 months in, but 2022 has been a hell of a year for species-related controversy. Grolar and pizzly bears have come roaring into public consciousness, researchers proclaimed that the T-Rex we know and love is actually three different species, and soon-to-be minted Doctor Yi-Kai Tea has been sinking and raising some truly glorious fish species like nobody’s business (we call this taxonomic ha-wrasse-ment).
With the classification calamities flying thick and fast, it’s easy to wonder exactly what it is about naming a species that is so damn hard. So let’s have a quick runthrough of what a species is, why taxonomy is so damn complicated, and why it even matters.
Read moreThe Rancor: Textbook Animal Cruelty
No matter the quality of the film, episode or comic, Star Wars has always had immensely cool, and mostly believable creatures. It even boasts one of the best speculative ecology field guides out there, and if you haven’t heard of it before then definitely check out The Wildlife of Star Wars by Bob Carrau and Terryl Whitlatch.
With The Book of Boba Fett having recently sauntered laconically onto our screens, we got a second look at a creature that made a brief but memorable appearance in The Return of the Jedi. That creature is the Rancor, the 5 metre tall basement dwelling biped that Jabba the Hutt (later Boba Fett) fed humans through a trapdoor on a semi-regular basis.
Read moreHow Invasives Get In Your Head (And Your Poop)
Image Credit: Hedera Baltica, CC BY-SA 2.0, Image Cropped
Invasive alien species as an environmental stressor and its effects on coping style in a native competitor, the Eurasian red squirrel (2022) Santicchia et al., Hormons and Behaviour, https://doi.org/10.1016/j.yhbeh.2022.105127
The Crux
We know that human activities can cause enormous stress for local species, and the introduction of invasive species is one of the most harmful stressors on a global basis. We know that new, harmful species can cause local extinctions, but how does their introduction affect the locals on a behavioural level?
Grey squirrels were introduced to Europe last century and have been spreading since, displacing the native red squirrels and wiping them out in many areas. This week’s authors wanted to know exactly how red squirrels’ behaviour changed when the grey squirrels were introduced, by looking in detail at the behaviour of red squirrles in both invaded and non-invaded areas, and seeing if they could see evidence of these changes in the expression of hormones (more on this in Did You Know).
Read moreGood News in Case The Plight Of The Koala Has You Down
The koala being added to the threatened species list, plus the ridiculously warm winter weather that some of the Northern Hemisphere has been experiencing, have really struck home how much damage rampant deforestation and fossil fuel use are doing over this past week. But as always, its important to remember that across some fronts progress is being made. Whether it’s the gradual transition to more sustainable energy use many countries are showing, or heroic conservation efforts by people from every corner of the world, these successes should be spotlighted once in a while! So here’s a dose of optimism.
Read more10,000 Hours Listening For Screaming Koalas
Image Credit: sandid, Pixabay licence, Image Cropped
Mini-acoustic sensors reveal occupancy and threats to koalas Phascolarctos cinereus in private native forests (2021) Law et al., Journal of Applied Ecology, https://doi.org/10.1111/1365-2664.14099
The Crux
Forests that lie on privately owned land make up a huge percentage of Australia’s native forests – over 23%. That’s 164 million hectares, a massive swathe of territory for Australia’s amazing endemic species to call home.
The problem is that because it’s private, it’s often difficult to survey. Which means there’s a huge chunk of an ecosystem that we have very little knowledge about. Sometimes this frustrates, but other times it breeds novel approaches to conservation.
This week’s authors wanted to survey native Australian forests, with one species in mind – the charismatic and oft-threatened koala. They took an approach which brought land-owners on board, and sent them audio recording equipment to register the presence of koalas, in an effort to figure out how many koalas made use of private forests.
What They Did
Spread across Australia’s privately owned forests, the researchers found just under a million hectares worth of land that they estimated to be suitable for koalas. They contacted the owners of said land and explained the project and its significance. Once the owners understood the concept and the work involved, they were sent ‘Audiomoths’ – small recording devices that can be attached to trees in koala habitat and record male koalas bellows during mating season (September to December).
Recording koala bellows isn’t that straightforward though, and many recordings had to be removed from the final results as heavy wind and rain made it difficult to determine what was making what noise.
Once koalas were identified, their presence was modelled against a range of different human impacts, including nearby roads and land clearance, and environmental variables like extent of vegetation and local fire severity.
Did You Know: Koala Extinction
Koalas are notoriously picky eaters, and many people know that they will only eat eucalyptus leaves. Yet it goes further, with some koalas only eating leaves from certain species of eucalyptus tree, having grown so accustomed to these species that their gut bacteria can’t tolerate anything else. It means that relocating koalas can be almost impossible, and that preserving their natural habitat is of the utmost importance (and benefits a huge range of other species).
Read More: What Being Functionally Extinct Means, Why Koalas Aren’t, and Why Things Are Still Pretty Dire
What They Found
The survey resulted in almost 10,000 hours of recordings across 128 properties and three years. Over 1,600 bellows were recorded across 41% of all the sites surveyed.
The only variables which had an affect on koala presence were the proximity of sealed (paved) roads and the vegetation cover. The closer by a sealed road was, the less likely koalas were to show up. Heavily forested areas were also less likely to house koalas, whereas forest that was more fragmented by grassland and open woodland were better suited for them.
Problems
The study mentions early on that there are often differences between private and public forest, yet there’s no comparison here between the two. Using Audiomoths in public nature reserves would have made for a great comparison, particularly to check whether the environmental and human variables affected koalas in the same way. However the constraints here are financial ones, and I think the authors would agree that it’s more interesting the double the data for this particular experiment rather than double the Audiomoth budget and make a comparative study.
So What?
The environmental results here aren’t particularly interesting – koala’s habitat preferences are relatively well studied. What is a real positive is the success of the technique used, that of bringing private landowners on side and getting a wealth of data in return. An added bonus of a project like that is that as well as collecting data, you get the opportunity to share scientific knowledge and teach a group of the public about local wildlife.
Dr. Sam Perrin is a freshwater ecologist who completed his PhD at the Norwegian University of Science and Technology and is currently working as a climate data analyst at Ducky AS. You can read more about his research and the rest of the Ecology for the Masses writers here, see more of his work at Ecology for the Masses here, or follow him on Twitter here.
Running Into Awful Academics At The Movies
Image Credit: KiwiDeaPi, CC BY-SA 3.0
Ecology for the Masses 