Tag Archives: population

Pinning it on the Polar Bear

Image Credit: Christopher Michel, CC BY 2.0, Image Cropped, Brightened

It’s an image that is ubiquitous in the media when the words ‘climate change’ pop up. The lone polar bear, drifting through the sea on a single ice floe. It is an effective image, evoking emotions like pity, loneliness and general despair for the plight of what has become the flagship species of what seems like the entire Arctic. But is associating the health of an entire ecosystem with one species useful, or dangerous?

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Parrots in Norway

Image Credit: Sandeeep Handa, Pixabay licence, Image Cropped

The Norwegian landscape is a beautiful thing. Spruce and pine groves piled on the side of mountains and fjords, moose and deer popping up in backyards, woodbirds flitting about on pristine hiking trails. Parrots screeching bloody murder into your ears as you re-enter the city.

No you did not read that wrong. It’s not happening yet, it in a couple of decades parrots, a type of bird not really associated with the sub-Arctic, could be a regular presence around Norwegian cities. So how could this happen, and why is it really quite concerning?

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Monitoring Freshwater Populations in the Chernobyl Exclusion Zone

Radiation can have extremely negative effects on an individual. But is it as easy to measure its effects on an entire population? (Image Credit: Hnapel, CC BY-SA 4.0, Image Cropped)

Variation in chronic radiation exposure does not drive life history divergence among Daphnia populations across the Chernobyl Exclusion Zone (2019) Goodman et al., Ecology and Evolution, DOI: 10.1002/ece3.4931

The Crux

As anyone who has recently watched HBO’s Chernobyl can tell you, large doses of radiation are capable of doing some pretty serious damage to an organism. But whilst examining the effect of radiation on an individual might be simple, monitoring those effects on a population can be difficult. Whilst radiation negatively effects fitness, it can also help individuals with higher radiation tolerance to reproduce and dominate within the population of a single species, making it difficult to monitor the exact effects of radiation on that population. If a population is filled with only those who were strong enough to survive, you don’t get an idea of the variation in the radiation’s effects.

This week’s researchers tried to break through that problem by looking at different populations of a water flea in Chernobyl’s Exclusion Zone (CEZ) – the area still barred from entry in eastern Europe.

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The Best and Worst Movie Scientists

Image Credit: George Hodan, CC0 1.0, Image Cropped

We look at some of our favourite and least favourite movie scientists. Includes rants about lab coats, self testing and Spiderman.

2:12 – Robert Neville (I Am Legend)
8:32 – Curt Connors (The Amazing Spiderman)
19:38 – Poison Ivy (Batman & Robin)
26:28 – Rhonda LeBeck (Tremors)
30:36 – Victor Frankenstein
34:18 – Ira Kane (Evolution)

You can also find us on iTunes and Google Play.

We also have a bonus episode this week, seeing as we’re on Easter holidays and can’t find the time to record a full one. So please enjoy our analysis of the ecological ramifications of The Snap.

Extreme Warming Events Could Increase Reindeer Population Stability

Extreme warming events may sound like bad news to reindeer, but they could help increase population stability

Extreme warming events may sound like bad news to reindeer, but they could help increase population stability (Image Credit: Christopher Michel, CC BY 2.0, Image Cropped)

More frequent extreme climate events stabilize reindeer population dynamics (2019) Hansen et al., Nature Communications, https://doi.org/10.1038/s41467-019-09332-5

The Crux

Whilst climate change has been causing (and will cause) a myriad of environmental problems, it’s important to remember that not all species will be negatively affected by more extreme weather events. One example is reindeer on the Arctic island of Svalbard, according to this week’s paper.

Taken at face value, an increased frequency of extreme warming events may not sound like a good idea for a cold-adapted species. But despite the fact that it can lead to rain falling and freezing over snow, rendering massive patches of food inaccessible, the authors show that this can actually lead to increased population stability.

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Blending In

In nature, it often pays to blend in to your background, especially if you’re a prey species like the deer mice used in this study. (Image Credit: Gregory Smith, CC BY-SA 2.0, Image Cropped)

Linking a mutation to survival in wild mice (2018) Barret et al. Science, 363, p. 499-504.

The Crux

A big part of ecological studies involves investigating how certain traits or behaviors work (adapted) or don’t work (maladapted) in a specific environment, while scientists who study genetics may investigate specific parts of the DNA that are under selection for specific values of a given trait. Surprisingly, not many studies investigate these two aspects of natural selection simultaneously, instead they will attribute selection to a specific trait value without knowing the genetic mechanisms behind it.

The authors of this study used a well-studied model system of deer mice (Peromyscus maniculatus) to link these two aspects of ecology together, tying a mutation in a gene that codes for coat color into selection in the wild. The study took place in the Sand Hills of Nebraska, a relatively young region (in geological terms) where these mice are expected to have recently adapted to the environment due to strong selection for traits that promote their survival.

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The Culling of Kangaroos

Image Credit: Sam Perrin, CC BY-NC 2.0

Having recently spent some time out in country New South Wales, I thought I’d share a quick description of the sight that greets you when you get out past Deniliquin in southern New South Wales and start driving north. It’s arid land, but it’s might still be beautiful were it not for the dead kangaroos that litter roadsides. You might see fifty on the drive from Albury to Deniliquin, but that quickly turns into hundreds as you go even further inland towards the border with South Australia.

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Rethinking Extinction

Sudan, the last male northern white rhino, 3 years before he passed away, rendering the species functionally extinct. But should species like this be the focus of our conservation efforts?

Sudan, the last male northern white rhino, 3 years before he passed away, rendering the species functionally extinct. But should species like this be the focus of our conservation efforts? (Image Credit: Make it Kenya, Public Domain Mark 1.0, Image Cropped)

Last year saw the death of Sudan, the last known northern white rhinoceros in the world. The story went viral, with the usual bemoaning of the way humans treat our planet, followed shortly by the normal rush back into anonymity for the world’s biodiversity. We are currently part of the most dramatic mass extinction event that the planet has ever seen, and more of these stories crop up every year. But is it a problem that the alarm bells are only raised when a creature hits the critically endangered level? Do we need to start paying more attention to population declines before hey hit such low numbers? And how do we even prioritise conservation efforts?

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Biological Annihilation

The sumatran orangutan, one of many species facing extinction in the earth's sixth mass extinction event

The sumatran orangutan, one of many species facing extinction in the earth’s sixth mass extinction event (Image Credit: Mike Pennington, CC BY-SA 2.0)

Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines (2017) Ceballos et al., Proceedings of the National Academy of Sciences of the USA, DOI: https://doi.org/10.1073/pnas.1704949114

Guest Post by Jonatan Marquez

The Crux

The rate at which species and populations have been going extinct in the last couple of centuries has well and truly earned the title of the planet’s sixth mass extinction event. However, most people rarely realize the severity of the situation. Hearing about the loss of two vertebrate species a year or having the last of some far-off species die out doesn’t see to cause much concern in the general public.

A species extinction is always preceded by population declines and extinctions. Perhaps highlighting the state of natural communities at this level might put the severity of the situation in better context. For example, the Living Planet Index (LPI) estimates that between 1970 and 2012, wildlife abundance has decreased by 58%. This paper focuses on the state and trends of populations of vertebrates by analysing i) the proportion undergoing declines or shrinkages, ii) the global distribution of population reduction events and iii) the general scale of population declines among mammal populations.

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The American Mink

The American Mink is pretty much a Norwegian mainstay these days. So what sort of impact have they had?

The American Mink is pretty much a Norwegian mainstay these days. So what sort of impact have they had? (Image Credit: Ryzhkov Sergey, CC BY-SA 4.0, Image Cropped)

Fur farming isn’t a topic we’ve had much cause to touch on so far in this series. But today, we look at a species that was introduced specifically for that purpose, whose presence in Europe is disliked by ecologists and animal rights activists alike.

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