Tag Archives: range

It Pays to Break from the Crowd

Image Credit: Pete, CC BY-NC 2.0

Increased reproductive success through parasitoid release at a range margin: Implications for range shifts induced by climate change (2020) MacKay, Gross, & Ryder, Journal of Biogeography, https://doi.org/10.1111/jbi.13795

The Crux

Predicting the response of organisms to climate change is a challenge for ecologists and wildlife managers alike. Fortunately, some responses are common enough that it is still possible to make fairly accurate predictions about them without too much information. One common response is that of the range shift, whereby a population of organisms facing some alteration (eg. climate change) in their current habitat, making it unfavorable, begin to move to another location. This allows them to track favorable environmental conditions and possibly mitigate any negative effects of climate change.

Sounds easy, right? Just pack it all up and move when things get hard? Well, for some organisms it may be that simple (looking at you, birds), but for others (like trees) it is significantly harder to do so. Trees (and other plants) are limited in that they depend on other organisms or things like wind to help disperse their seeds. Making things even more difficult are plant species that depend on specific pollinators, and in order for a successful range shift to happen trees AND their pollinators have to make the move. Today’s authors wanted to study how relationships between trees and their pollinators changed at the leading edge of a range shift, allowing them to understand how and why trees succeed during a range shift.

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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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Tim Robertson: The World of Ecological Data

Image Credit: GBIF, CC BY 4.0, Image Cropped

When I was a child, I’d often study books of Australian birds and mammals, rifling through the pages to see which species lived nearby. My source of information were the maps printed next to photos of the species, distribution maps showing the extent of the species range. These days, many of these species ranges are declining. Or at least, many ecologists believe they are. One of the problems with knowing exactly where species exist or how they are faring is a lack of data. The more data we have, the more precise an idea we get of the future of the species. Some data is difficult to collect, but yet more data has been collected, and is simply inaccessible.

At the Living Norway seminar earlier this month I sat down with Tim Robertson, Head of Informatics and the Global Biodiversity Information Facility. GBIF is an international network that works to solve this data problem worldwide, both by making collected data accessible and by helping everyday people to collect scientific data. I spoke with Tim about the journey from a species observation to a species distribution map, the role of GBIF, and the future of data collection.

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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), 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.

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Why are animals where they are?

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.

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Johanna Schmitt: Climate Change and Plant Life

We sometimes ignore the effects of climate change on plant life, but the potential severity of these effects isn’t something that should be ignored for long (Image Credit: Pisauikan, Pixabay licence, Image Cropped)

From the California wildfires to the recent strikes across Australian primary schools, climate change is a topic that only seems to grow in its ubiquity. Yet whilst humans are increasingly focused on more obvious repercussions, such as extreme weather events, animal extinctions and shifting coastlines, we sometimes forget that climate change will have severe repercussions for plant life as well.

I spoke to Professor Johanna Schmitt of the University of California earlier this year to discuss some of those repercussions. Johanna’s team is working to determine how well certain plant species will be able to adapt in the face of rapid climate change.

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Victory May Not Guarantee Survival in Species Conflicts

Spreading of the Australian yabby has led to decreases in other local species. But what happens when these species meet?
Spreading of the Australian yabby has led to decreases in other local species. But what happens when these species meet? (Image Credit: Daiju Azuma, CC BY-SA 2.5, Image Cropped)
Insight into invasion: Interactions between a critically endangered and invasive cray fish (2018) Lopez et al., Austral Ecology, doi:10.1111/aec.12654

The Crux

When we talk about invasive species, often the first thing that pops into our minds are things like feral cats, wild pigs, vicious newcomers that wipe out species or transform vast areas. But often what we focus on less are species which arrive and simply outcompete the locals.

The yabby (Cherax destructor) is one such invader. An Australian species, it has been introduced to new waterways through the country and is now threatening other species, including the Falls Spiny Crayfish (Euastacus dharawalus) in eastern New South Wales, Australia. The introduction of the yabby has resulted in a decreasing habitat range for the crayfish, but what sort of mechanisms are causing this? This experiment aimed to document interactions between the two species.

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