Tag Archives: climate change

On The Trail Of Explosive Seaweed Blooms

You’ve probably heard of the Sargasso Sea – it is well-known for the floating seaweed called Sargassum that provides a habitat for baby sea turtles and many other sea critters. Floating in the Atlantic Ocean just off the east coast of North America, it’s also the region where the European and American eels mate, a process that scientists still don’t fully understand after centuries of research.

For the last 10 years, a phenomenon has occurred in the Atlantic where never-ending masses of Sargassum inundate beaches after uncharacteristically large blooms occurred. The Sargassum originates from the nutrient-poor waters of the North Equatorial Recirculation Region off the west coast of Africa and spreads throughout the Atlantic Ocean and adjacent ocean basins, affecting the Caribbean, states surrounding the Gulf of Mexico, South America and even Africa. Tom Theirlynck  is a marine biologist, currently working on his PhD at the Royal Netherlands Institute for Sea Research (NIOZ) and University of Amsterdam (IBED-FAME), and he as part of the Amaral-Zettler (NIOZ/UvA) research group is studying the excessive Sargassum blooms in detail. 

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Good News In Case The IPCC Report Got You Depressed

Image Credit: Charlie Marshall, CC BY 2.0, Image Cropped

Image Credit: Charlie Marshall, CC BY 2.0, Image Cropped

I’ve spent the last few days churning through the IPCC report and by jove, it is BLEAK. I’ll have a summary up soon in some format for those of you who find even the 42 page summary a bit daunting, but don’t look forward to it… But because it’s important to share hope and stories of real progress, I thought I’d churn through the news cycles and find some cases of things going well in the natural world.

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The Tug of War Between Climate Change and Habitat Destruction with Professor Francesca Verones

Image Credit: cunningschrisw, CC BY-SA 4.0, Image Cropped

While climate change often dominates news headlines, the fact remains that currently the majority of damage being done to the world’s ecosystems is a product of the way we use land. Major examples of land use change such as deforestation and cattle grazing do have impacts on the world’s climate of course, but they have numerous other very severe and more short-term impacts on the world’s biodiversity, as well as on human health.

Yet despite the fact that most species’ population declines and extinctions come down to the rapid degradation of their habitats, climate change remains the more ubiquitous of the two threats. With that in mind, I spoke to Professor Francesca Verones of the Norwegian University of Science and Technology earlier this year. Francesca’s work involves projecting the impact of human activity on the planet’s biodiversity, and we discussed why communicating the problems with land use change can be a challenge, and why changing our habits is hard, but necessary.

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Light My Fire: How Birds Respond to Extreme Climate in the Wake of Bushfire

Fire, drought and flooding rains: The effect of climatic extremes on bird species’ responses to time since fire (2021) Connell et al., Diversity and Distributions, https://doi.org/10.1111/ddi.13287

The Crux

Both bushfires and extreme climate events are capable of shaping not only habitats, but also the number of different species that inhabit them. Yet the interaction between these phenomena can be equally important. For instance, an extreme flood or drought could have a very different impacts on a forest depending on how recently that forest was burned by fire. If a fire tore through recently, an extended period of drought may finish off species already under stress, yet if there has been a longer period of time since the last fire, the ecosystem may be able to tolerate a drought.

Given that climate change is increasing the occurrence of both extreme climate events and bushfires, it’s better to start investigating the effects of these interactions sooner rather than later. This week’s authors looked at the interaction between the two phenomena in south-eastern Australia, an area whose wildlife has come under a lot of pressure recently.

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Bog Off! Why Is Peat Still Being Sold In Garden Composts?

A natural peatland in the North Yorkshire Dales, UK. Much of the UK’s peat is imported from Europe and Ireland. (Image Credit: Charlie Woodrow, CC by 2.0)

The COVID pandemic has disrupted all aspects of our lives, and forced many to pick up new hobbies to stay happy and occupied. Among these new hobbies is gardening, with stores across the UK seeing increasing demand for potted plants and horticultural products. But while gardening may seem like an eco-friendly past time, many of the products sold for home-use have multiple direct and indirect negative environmental effects, and among the worst of these is peat-rich composts. But what is peat? And why should you avoid gardening products that contain it?

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Can A Harsh Climate Create Stronger Interactions Between Species?

Bowler et al. (2020) Impacts of predator-mediated interactions along a climatic gradient on the population dynamics of an alpine bird. Proceedings of the Royal Society B, 287, https://doi.org/10.1098/rspb.2020.2653.

The Crux

Whether or not a species will survive in an area can usually be broken down into two broad categories: how suitable the environmental characteristics of that area are (temperature, elevation, rainfall), and how it interacts with the other species found nearby. Early ecological theory predicted that in harsh environments, how a species interacts with other species wouldn’t matter as much, and would only come into play when the area was easier for the species to inhabit.

Yet more modern work often contradicts this theory. For instance, the Alternative Prey Hypothesis (APH) suggests that in areas where there are relatively few species as a result of harsh climates, interactions between those few species will be relatively strong. For example, if a prey species declines one year, then its usual predator must find an alternative prey species. This creates an indirect interaction between the two prey species, which is particularly strong in harsh environments where there aren’t other species around.

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Can Pizza Affect A Bird’s Fishiness?

Fishiness of Piscine Birds Linked to Absence of Poisonous Fungi but not Pizza (2020) Stervander & Haelewaters, Oceanography and Fisheries, 12(5), DOI:10.19080/OFOAJ.2020.12.555850.

The Crux

One of the most worrying things about the global phenomena that is climate change is that we are so uncertain of its exact effects on our planet’s biodiversity. There are the more obvious questions that need to be asked, like how will warming temperatures affect species ranges, and will cold-tolerant species face significant population losses?

Yet there are other less obvious concerns out there which need to be tested. For instance, seeing as there are far more fish-like birds in Antarctica, do colder temperatures lead to birds being more fish-like? And will a warming climate therefore lead to a world devoid of fishy birds? This week’s researchers had a different theory, and used some interesting statistical techniques to test it out. The project was inspired by a particularly memorable pizza consumed by one of the researchers, in that it looked at “fishiness, birdiness, lack of fungal toxicity, and effects of prolonged heating”*.

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Out of Time

Phenological asynchrony: a ticking time-bomb for seemingly stable populations? (2020) Simmonds et al., Ecology Letters, https://doi.org/110.1111/ele.13603

Image Credit: Ian Kirk from Broadstone, CC BY 2.0, Image Cropped

The Crux

When we think of climate change we tend to think about extreme weather events and melting ice caps, but the way in which our environment is changing is giving the planet more than just unseasonal weather. Phenology (the timing of biological events in nature) dictates when an organism begins a given part of its life cycle, and changes in phenology are one of the most frequent responses to climate change. Take bees and flowers; bees feed on the flowers of certain plant species, and in turn spread the plants’ pollen for them. They both depend on the other being around at the same time, and if flowers bloomed too early, or if the bees came around before the flowers were “ready” for them, both parties would suffer.

Such a mismatch is known as an asynchrony, and it is hypothesized to cause population declines due to the harmful impacts on one or more of the interacting species involved (see another recent post to understand how the loss of one or more interactions can lead to cascading effects throughout a local community). While many theoretical models have investigated these processes, today’s authors wanted to combine such models with long-term data on the phenology and population size of great tits (Parus major). Great tits rely on a small period of insect abundance to feed their young, and as such the more closely they can match the needs of their young to the abundance of insect populations the more they will increase their fitness.

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Wilderness: A Place of Untouched Ecological Processes

Image Credit: European Wilderness Society, CC BY 4.0, Image Cropped

What comes to your mind when you think of Wilderness? Maybe it is a dense rainforest filled with a cacophony of bird calls, or plain filled with lagre grazing animals and free-roaming carnivores? They certainly qualify, but by definition, Wilderness is any area that hasn’t (or has only slightly) been modified by human activity in the past. This means that Wilderness areas can be incredibly diverse, from the aforementioned tropical forest to a murky swamp. These areas represent nature in its purest form, with the absence of human interventions allowing for dynamic, open-ended natural processes. These processes not only create marvelous landscapes and offer refuge for species, but also provide many benefits for humans.

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New Neighbors

Interspecific competition slows range expansion and shapes range boundaries (2020) Legault et al., Proceedings of the National Academy of Sciences, https://doi.org/10.1073/pnas.2009701117

Image Credit: CISRO, CC BY 3.0

The Crux

Climate change has resulted in multifarious changes in the natural world, not the least of which being where one can find a given species. Because areas are growing warmer, some species are shifting their habitats to stay within the type of environment that they like. The thing about shifting habitats though is that a species that shifts is likely to run into/need to compete with another species that is already there. Competition affects the growth and dispersal of organisms, so it follows that this should have an effect on the ability of a given species to shift or expand its range. However, most studies do not take competition into account when predicting range expansion.

A classic example in the scientific literature that did take competition into account was that of the gray squirrel invasion of Britain. Gray squirrels invaded and subsequently displaced the native red squirrels, but competition appeared to have no influence. Instead, a pathogen appeared to be the likely cause of the contraction of the red squirrel range. This example, however, comes from an observational study of a single replicate. Today’s authors instead conducted a manipulative lab experiment to test for the effects of competition on range expansion.

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