Tag Archives: predation

The Early Mouse Gets the Cheese

For small animals like the mouse, predators are a constant concern (Image Credit: Jess, CC BY-NC 2.0)

Maximising survival by shifting the daily timing of activity (2019) van der Vinne et al., Ecology Letters, https://doi.org/10.1111/ele.13404

The Crux

All animals need to eat food to survive and maintain their energy balance, but unlike us they can’t just order a pizza and have the food brought to them. They must always forage for food themselves, and every time that they do they expose themselves to predators. Small mammals like mice balance this trade-off by foraging for food at night, when their risk of predation is lowest.

One interesting strategy that mice can employ is to switch their foraging from the nighttime to the day, if they cannot get enough resources during the night or if their nighttime predation risk increases. The authors of today’s paper wanted to develop a model to predict under what conditions these temporal switches would occur, a model which they then tested with mice in the field.

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Living Among Beasts: Sharing the Burden of Conservation

African forest elephants populations are declining rapidly due to local human pressures. But is it fair to expect other humans to live among potential threats to their livelihood?

African forest elephants populations are declining rapidly due to local human pressures. But is it fair to expect other humans to live among potential threats to their livelihood? (Image Credit: Ray in Manila, CC BY 2.0, Image Cropped)

Some species of animal do a better job of capturing our attention than others. For many of us, the exotic nature of these animals is often the kicker. Think of the majesty of an elephant strolling across the savannah, or the romanticised stalk of the tiger through the jungle. Yet while the public ogles these creatures in the wild or at the local zoo and mourns the decline of their wild populations or the reported deaths of iconic individuals, we often ignore the harsh reality: that there are people who live in close proximity to these animals, to whom they represent a day-to-day threat. So how does our attitudes to charismatic species in places like Africa and Asia here need to shift, and where can we start?

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Keep Your Eyes Open

Natural selection favors a larger eye in response to increased competition in natural populations of a vertebrate (2019) Beston & Walsh, Functional Ecology, doi: 10.1111/1365-2435.13334

The Crux

Studying the evolution of traits in response to selection pressure often helps us understand why species look and act the way they do. Selection pressure can include the need to find food before other members of your species, or the need to escape predation.

But what happens when improving your ability to obtain resources also means you’re more vulnerable to predation? Which will win out? This paper looks at a small species of freshwater fish, Rivulus hartii, and determines which of the two pressures contributes most to the evolution of the size of their eye.

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Finished Before You Even Started

Predators are known to affect prey while they are adults and juveniles, but what about when they haven’t even hatched yet?  (Image Credit: Mark Jones, CC BY 2.0, Image Cropped)

Predation risk affects egg mortality and carry over effects in the larval stages in damselflies (2018) Sniegula et al., Freshwater Biology, p. 1-9

The Crux

In the natural world, one of the most dangerous things that a prey animal has to worry about is a predator. These organisms depend on the prey for their sustenance, and as such have become very good at finding ways to eat them. These are known as direct effects, as a predator eating prey is a direct interaction.

Another aspect of the predator-prey relationship is that of indirect effects, or effects that a predator has on prey that don’t involve it eating the prey animal. These can include predator-induced changes in the prey’s behavior, immune function, or even survival. These indirect effects are usually studied in prey species that are adults or juveniles, but the authors of today’s paper were interested in what indirect effects predators had on the eggs of prey species.

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How to Ecology Your Dragon

Image Credit: DreamWorks Dragons, 2012

In our second week on the dragons of Dreamworks’ How to Train Your Dragon trilogy, we have a flamin’ good time discovering why those dragons are WAY too wacky, exactly how much intraspecies predation goes on in Berk and why you should really make up your mind about domestication.

03:49 – Vikings in Cinema
10:57 – Ecology of the Dragons
29:17 – Toothless vs. the Furious Five

You can also find us on iTunes and Google Play.

Peter Unmack & Karl Moy: Saving an Endangered Fish from Extinction

A release of the formerly endangered Running River Rainbowfish. So how were they brought back from near-extinction?

A release of the formerly endangered Running River Rainbowfish. So how were they brought back from near-extinction? (Image Credit: Karl Moy, University of Canberra, CC BY-SA 4.0, Image Cropped)

We talk a lot about getting the public interested in conservation and ecosystems on Ecology for the Masses, but we’ve rarely talked about how conserving a species is actually accomplished. Where does funding come from? How do you decide which individuals to save? And how do you allow a population room to grow?

In 2015, Peter Unmack was sampling in the Burdekin river system in northern Queensland, Australia, when he noticed an alien population of Eastern Rainbowfish had established in Running River. Specifically a 13km stretch bounded by two gorges, which housed the Running River Rainbowfish, a species distinct to this one stretch. Knowing that the presence of the Eastern Rainbowfish could spell the extinction of the local species, he started a crowdfunding initiative, and essentially saved the Running River Rainbowfish. I spoke to Peter and postgraduate student Karl Moy about the conservation effort.

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Quantifying the Effect of an Invader

The Raccoon Dog, an alien species, has made its way to Sweden recently. But what sort of effect does it have on the native fauna?

The Raccoon Dog, an alien species, has made its way to Sweden recently. But what sort of effect does it have on the native fauna? (Image Credit: Prue Simmons, CC BY 2.0, Image Cropped)

Nest predation by raccoon dog Nyctereutes procyonoides in the archipelago of Northern Sweden (2018) Dahl & Åhlen, Biological Invasions, https://doi.org/10.1007/s10530-018-1855-4

The Crux

We’ve spoken about biological invasions at length on EcolMass, and the detrimental effects that the arrival of a new species can have on native populations. Yet eradication is often impossible, and management expensive, so before taking extensive action, it’s always important to ensure that an alien species IS having a negative effect.

The raccoon dog is an Asian species, closely related to foxes, that was introduced to Europe in the early 20th century and has since spread into Scandinavia. Voracious predators that could spread further north due to climate change, our paper this week looks at the extent of their impact on the ecosystems they’ve spread to.

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