food | Ecology for the Masses

Tag Archives: food

Hvorfor er dyr hvor de er?

Posted on May 14, 2019 by Sam Perrin One comment

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), https://doi.org/10.1002/ecs2.2695

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.

Norwegian

Why are animals where they are?

Posted on May 8, 2019 by Sam Perrin One comment

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

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), https://doi.org/10.1002/ecs2.2695

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.

Paper of the Week

Andrew MacDougall: Finding Ecological Solutions for the Farming Industry

Posted on March 7, 2019 by Sam Perrin 2 comments

Image Credit: W.carter, CC0 1.0, Image Cropped

The farming industry has had a strange relationship with ecology over the years. They have been maligned by claims they shoot native species, suck up water greedily from nature and the people, and pollute our countryside with pesticides, all whilst producing the food many of us subsist on. So why haven’t ecologists worked with them more closely?

At the recent NØF 2019 Conference, Tanja Petersen and I sat down with Canadian ecologist Professor Andrew MacDougall, who has been working with the farming industry for the past six years to quantify their contribution to ecosystem services. We talked about the often damaging public perception of farmers, how his stereotypes were challenged by working with them, and the biggest problems the industry will face heading into the next fifty years.

The Forefront

Does the Individual’s Fight For Sustainability Matter?

Posted on January 21, 2019 by Sam Perrin Leave a comment

Plastic manufacturers and fossil fuel corporations seem to be responsible for the majority of the environment’s problems. So can individual choices make a difference? (Image Credit: Jnzsl’s Photo, CC BY 2.0, Image Cropped)

There seems to be a pattern of thought currently floating around regarding sustainable living. How recent it is, I’m not sure exactly. But the take home message goes something like this:

It makes no difference whether an individual tries to live sustainably, big corporations are the ones making all the difference anyway.

Opinions

When the Food Comes to You

Posted on October 11, 2018 by Adam Hasik Leave a comment

A young orca from the southern population chasing its dinner. (Image Credit: JC Winkler, CC BY 2.0, Image Cropped)

Long-distance migration of prey synchronizes demographic rates of top predators across broad spatial scales (2016) Ward et al, Ecosphere, DOI: https://doi.org/10.1002/ecs2.1276

The Crux

Populations that experience some kind of connection are classified as “meta-populations”, as they are all interconnected in some way and can influence one another. Although these populations may be geographically and reproductively isolated, meaning that they are in different places and the organisms from the different populations don’t breed with one another, certain environmental factors may cause these populations to grow or shrink in similar ways.

The key to understanding how this synchrony between the varying populations happens is understanding what connects them. Killer whale (orca) populations in the northeast Pacific Ocean inhabit three distinct areas, with orcas from the northern and southern populations never coming into contact with one another. They do, however, feed on the same salmon populations that migrate from where the southern population lives to the where the northern lives. The authors wanted to find out if this connection via a food source could result in the demographic rates of these distant populations syncing up.

Paper of the Week

Whom to Blame – Cats or Rats?

Posted on August 23, 2018 by Sam Perrin One comment

Feral cats are responsible for the decline of many endemic species worldwide. But will removing them boost rat populations, causing more potential harm? (Image Credit: Brisbane City Council, CC BY 2.0, Image Cropped)

Trophic roles of black rats and seabird impacts on tropical islands: Mesopredator release or hyperpredation? (2015) Ringler et al., Biological Conservation, https://doi.org/10.1016/j.biocon.2014.12.014

Guest post by Bart Peeters

The Crux

For centuries, rats have been portrayed as carriers of diseases and death; whereas our feline friends, worshipped by the ancient Egyptians, will definitely make your YouTube video go viral (a quick Google search of “cat video” shows 1 310 000 000 results). Both have been introduced, either accidentally or deliberately, to islands where endemic species have evolved and adapted to an environment without these generalist predators. So how do you know if eradicating one of them will make things better for the native wildlife?

Before taking radical conservation actions, it may be a good idea to understand how feral cats (the apex predator), rats (the mesopredator) and their common prey are affecting each other. Namely, if you kill all the cats, will there be more rats to prey on seabirds? On the other hand, will killing all the rats really reduce the predation by cats on seabirds?