Author Archives: Sam Perrin

A ‘Stepping-Stone’ Approach to Endangered Species Release

Image Credit: Guy Monty, Image Cropped, CC BY-NC-SA 2.0

Optimizing release strategies: a stepping-stone approach to reintroduction (2019) Lloyd et al., Animal Conservation, 22.

The Crux

Restoring endangered species through breeding the species in captivity has become common practice over the last century, and has led to the successful recovery of many species. But the process is complicated, as there are always dangers inherent in releasing species that have become used to captivity back into the wild.

This week’s researchers wanted to test a new approach: rather than releasing species directly back into an area where they have disappeared from, they wanted to first release individuals into an already-occupied habitat patch, where predators and prey were present but the species had a high survival probability. This would be a stepping stone before a second release, intended to restore a population in a new area.

What They Did

The species here is the Vancouver Island marmot (Marmota vancouverensis), found only in the mountains of Vancouver Island, Canada. Conservation breeding started in 1997, with the wild population dropping below 30 in 2003. Marmots from four different Canadian institutions were transferred to one of the institutions, the Mt. Washington Marmot Recovery Centre, to undergo a period of quarantine before release.

Some of these marmots were then released for a year into a safe area on Mount Washington, Vancouver Island – the ‘stepping stone’. They were then released into a more challenging area on Vancouver Island, along with captive marmots who had not been exposed to the stepping stone, and wild marmots translocated from Mount Washington. These groups enabled the researchers to compare survival.

The researchers then modelled the survival of each marmot group against the release type, as well as the year and location of release.

Did You Know: Species Tracking

GPS technology has come a long way in recent years, and it has benefited ecologists enormously. This study utilised radio tracking on the miniscule marmot. But the size of radio trackers in the past often made them unethical. Australian Rakalis were notorious for being able to remove almost any radio tracker. However with advances in technology have come significant advances in our understanding of animal movement. Sirtrack in New Zealand are now able to place a radio tracker on a dragonfly.

What They Found

Marmots released into the stepping stone environment had high survival rates initially. These dropped when they were translocated to the wild, but rebounded after a year, coming close to the other wild marmots. Captive marmots released directly into the wild, however, had low survival rates for the first two years before rebounding, suggesting that there is potentially a two year acclimation period for the species.


The experiment required a very specific type of habitat. It needed to have predators and prey, but not so many that the marmots are likely to be hunted at natural levels. In this experiment, human activities on Mount Washington kept predator levels low. This sort of habitat is not always possible to locate, especially for larger species.

So What?

Being able to increase the survival rates of captive-bred species is obviously a huge boost. As highlighted above though, this method is not simply possible for all species. However it does give conservationists a clear avenue forward for further research.

And lastly, studies like this really highlight the role human land use clearance plays in lowering species survival rates. The larger the suitable habitat area for a species, the more likely we are to be able to find suitable stepping stone environments for them.

Why Australia is Approaching a ‘Climate Change’ Election

Image Credit: Tim J Keegan, CC BY-SA 2.0

This weekend, Australia will have a federal election. My country will vote, not on an individual leader, but on the party that will form government for the next 3-4 years. We’ve been led by the conservative Liberals (yes, the right-wing party are called the Liberals, it’s stupid) since 2013, and that time in Australia has not been kind to the environment. A tax on carbon was repealed almost as soon as it was implemented, prioritising large businesses has caused potentially irreversible damage to iconic ecosystems around the country, and a disregard for the potential impacts of climate change have been a trademark of the present government.

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Hvorfor er dyr hvor de er?

Image Credit: Endre Gruner Ofstad, CC BY-SA 2.0

Guest post by Endre Grüner Ofstad. English version here.

Use, selection, and home range properties: complex patterns of individual habitat utilization (2019) Endre Ofstad et al., Ecosphere, 10(4),

Det essensielle

Stedene man finner dyr omtales gjerne som dyrets habitat. Habitat er et relativt vagt begrep. Hvor individ oppholder er som regel et utfall av en rekke vurderinger: hvor finner en mat, hvor unngår man rovdyr og hvor finner man noen å parre seg. Individ avveier blant disse for å maksimere hvor mange avkom de kan tilføre fremtidige generasjoner (også kalt for ‘fitness’).

Når vi skal vurdere hvilke habitat dyr befinner seg i så jobber vi som regel med habitatseleksjon. Habitatseleksjon er hvor mye et habitat blir brukt i forhold til hvor tilgjengelig det er, dvs. hva er den relative sannsynligheten for at et dyr vil bruke et habitat hvis det får muligheten. Hvor mye tid et individ velger å bruke (eller tettheten av individ) i et habitat er som regel en god indikator på hvor viktig et gitt habitat er. Habitatseleksjon blir derfor ofte brukt til å identifisere hvilke habitat forvaltningen bør iverksette tiltak.

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Ecology of the GoT Dragons

Adam and Sam talk macroecology and that’s pretty much it. How small would these dragons be? It’s very anti-climactic. We’ll do a supplemental later. Also SPOILERS. Though as we were a week behind, there’s some stuff that is currently incorrect re: the current status of the GoT dragons. Spoilers.

04:02 – Everyone’s Favourite Dragons
13:15 – The Ecology of the Dragons
40:13 – Balerion the Big Boi vs. The US Military

And as usual, you can check out last week’s podcast on the physiology of these flappy flaps flaps below.

Why are animals where they are?

Guest post by Endre Grüner Ofstad. Norwegian version available here.

Use, selection, and home range properties: complex patterns of individual habitat utilization (2019) Endre Ofstad et al., Ecosphere, 10(4),

The Crux

The areas in which we find an animal is often called its ‘habitat’. Yet it’s a fairly ambiguous term. Where animals are found is usually the outcome of a range of considerations, primarily foraging, predator avoidance and mating opportunities. Animals trade-off among these in order to maximise their contribution to future generations (i.e. ‘fitness’).

When considering which habitats we most likely find animals one often works with habitat selection. Habitat selection is how much a certain habitat type is used compared to its availability, i.e. what is the relative probability that an animal will use a given habitat upon encounter. The amount of time an individual spends (or density of individuals) in a habitat is usually a good proxy for the importance the habitat to the animals. Therefore we often use this to evaluate which areas to target for management and conservation efforts.

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Towards Gender Equity in Ecology: Part Two

Professors Amy Austin, Eva Plaganyi, Anne Sverdrup-Thygeson, Prue Addison and Johanna Schmitt (not pictured) share their views on gender equity in ecology (Image Credit from left: Amy Austin, CSIRO, NMBU, Prue Addison; All images cropped, CC BY-SA 2.0)

In Part Two of our ongoing look at gender equity in ecology, four prominent female ecologists share their thoughts on how gender equity in ecology has progressed, and where it needs to go from here.

For Part One of this series, click here.

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Dag Hessen: Communicating Science Through Children’s Literature

Image Credit: Dag Hessen, University of Oslo

The past couple of years has seen younger generations become increasingly active with regards to environmental change. Recent protests worldwide, spearheaded by people like Greta Thunberg, have been incredibly encouraging to watch. So it’s important that scientists continue to improve our ability to communicate science to children.

On that note, I spoke to Dag Hessen, Norwegian ecologist and writer, who has published several science books, also successful children’s books. We spoke about the importance of explaining ecological concepts to children, the process of writing a book, and dealing with a different form of writing.

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