Achieving international biodiversity targets: learning from local norms, values and actions regarding migratory waterfowl management in Kazakhstan (2022) Jones et al., Journal of Applied Ecology, https://doi.org/10.1111/1365-2664.14198
The Crux
Some species that we consider local treasures have ranges that extend over vaste swathes of the planet, and some of these make use of those entire ranges. This is probably most obvious in bird species. Some of the locals that have been popping up in my neighbourhood as spring kicks off have been spending the winter on the other half of the planet, and have made use of countless other locations on their journeys between the two endpoints.
This makes conservation a headache. Just because a species is beloved and protected at one end of its range doesn’t mean it’s afforded the same luxury at another end. Even if the species is internationally recognised as threatened, that doesn’t mean every location it visits will respect – or even be aware – of this status. That means that to protect migratory species, we need to figure out the most important parts of their ranges, and work with the people who live there to ensure the birds persist. Today’s paper is an investigation into how effective this sort of work could prove in the future.
Image Credit: Sharkcrew, CC BY-SA 4.0, Image Cropped
In February 2022, a British swimmer was killed by a great white shark(Carcharadon carcharias) near Sydney, Australia. Unsurprisingly, this gained significant media attention. State authorities launched a search for the culprit, with the aim of culling/relocating it away from people. This plan would seem, on the surface, to make perfect sense – shark ate human, make it go away. Yet this logic is largely based on a widespread misconception, and an outdated theory that science has long since abandoned.
Original Fin
If we go back a little further in the history of shark-human interactions, we come toJuly 1916. Over twelve summer days, the coast of New Jersey was the site of five incidents, four of them fatal. This story itself you may not know, but the film (and book) it is often widely cited as inspiring you certainly will: Jaws.
The evocative taglines and reused assets of the Jaws posters (Image Credit: Universal Pictures)
Less prominent in popular culture, but similarly inspired by this event, was the “rogue shark” theory. Popularised by Australian surgeon Dr Victor Copplesonbetween the 1930s and 1950s, it suggests “the guilt, not of many sharks, but of one shark”. It was built on the widespread concept of sharks as “man-eaters”, which dates at least as far back as the mid-1800s. Coppleson believed that the majority of sharks behaved “normally”, while “rogue” sharks were “vicious”, and “patrol a certain area…for long periods”. Such a shark, he further stated, “must be hunted until it is destroyed”.
You may note that this theory seems remarkably similar to the plot and characterisation of Jaws, painting a picture of a villain intent on the destruction of human life. But one is a classic of creature-feature cinema, and the other is supposed to be a serious scientific theory. And therein lies the – rather glaring – problem.
Innocent Until Proven Gillty
Map showing the timeline and locations of the Jersey Shore attacks. 3 of the 5 attacks occurred in Matawan Creek (Image Credit: Kmusser, CC BY-SA 3.0)
In terms of evidence, perhaps the easiest place to start is with the events that inspired the whole idea. The five incidents occurred within twelve days, progressing northwards up the coast of New Jersey. A short time frame, and a (relatively) localised area. This led some scientists to conclude that this was likely the work of one individual, conducting a tour of violence up the coast. If a decent defence lawyer had been present, however, I suspect he would have called this evidence circumstantial at best.
A juvenile great white was also caught in the area around this time with human remains in its gut. So now there’s some hard evidence, supporting a perception of the crimes and the culprit. Except, perhaps not.
Three of the incidents occurred in brackish water– the domain, more typically, of the bull shark – and two in oceanic water. This could suggest at least two individual sharks, of separate species, were involved in the incidents. This, obviously, does not completely invalidate the theory, and remains a matter of some (rather futile, over a century later) debate.
Great White Lie
According to George Buress, of the International Shark Attack File (ISAF), there are only two or three cases in the past three centuries where it is thought likely that an individual shark has been responsible for multiple incidents. Only one of these is backed up by reasonable proof, and the ‘multiple’ attacks in this incident took place over 5 minutes, not the sort of days or weeks timeframe the rogue shark theory was associated with. This leads us to alternative, and in many cases more logical and better supported, theories as to why these incidents occur.
Perhaps most obvious and self-explanatory, a considerable proportion of shark attacks (35% of confirmed shark-human interactions in 2021) areconsidered “provoked” by the ISAF. If someone starts prodding at a shark, no-one should be surprised if they get bitten. However, the simple unprovoked/provoked dichotomy widely used by the ISAF and elsewhere isn’t always particularly satisfactory. We do not understand enough about shark behaviour to draw a clear line under what counts as provocation. Would a shark perhaps view a person swimming too close, or above it, as a threat?
Numerous other theories have been proposed, and in 2014 John West, curator of the Australian Shark Attack File, summarised these in a single paper. He suggested that all the theories could generally fit into three broad categories; a) hunger, b) curiosity and c) aggression.
Most such theories are difficult to properly study and empirically assess, for obvious ethical reasons. However, much of the support for these theories comes from taking what we do know about shark behaviour and ecology, and the context of specific incidents, and drawing more informed conclusions from there.
For example, the majority of “unprovoked” incidents are classed by the ISAF as “hit-and-run” attacks. Many of these incidents occur in turbid, murky water, such as surf zones. In these conditions, it is easy to see how erratic splashing, shiny and reflective accessories, and contrasting colours could lead a shark to mistake a person for a more typical prey animal. These incidents also rarely involve repeat bites, with sharks typically moving on rapidly after finding the target not to their tastes.
We’re going to need a bigger theory…
In conclusion, understanding what leads to shark-human interactions, in order to better understand shark behaviour and reduce such incidents, requires proper investigation of the complex contextual factors surrounding such occurrences.
Scientific consensus, however, seems to be made up, at least regarding “rogue” sharks. Jaws was never intended to be a documentary, and we should stop treating it like one. The idea of the “rogue” shark, and language like it and “man-eater”, promote an unsubstantiated, malicious, criminalised perception of shark behaviour. This perception remains widespread, politicised and influential, despite simply not being backed up by the evidence.
The reality is that shark “attacks” remain incredibly rare, at an average of roughly 72 “unprovoked” incidents, and five fatalities, worldwide per year since 2016. For comparison, over one year between 2017 and 2018, 218 sharks were killed in culling and defence programs in Queensland, Australia, alone! While improvements have been made, sharks need us to change the way we view and discuss them, as our history together makes it abundantly clear that we are a far greater threat to the existence of sharks than they are to any single one of us.
Ben Bluck is a soon-to-be PhD student at the University of Southampton. He is broadly interested in almost everything to do with behavioural ecology and marine biology, especially sharks. You can find him being inactive on Twitter here (@anendemicshrub).
Let’s face it, IPCC reports are never a fun read. They’re a damming assessment of our ability to take care of the only planet we’ve got. Piecing through them to find the key takeaways is likewise a tough task, but since the final report (for this round) has now been submitted, I thought I’d reflect on what I’ve learned going through each step of the report over the last year.
The urgency behind the most recent IPCC report has thankfully garnered it a lot of attention worldwide*. It’s a report that was very frank in its desperation for people to take this threat as seriously as possible. Yet both this report and the one that hit us in February also made mention of one other key factor that has been swept under the rug – the ability of functioning ecosystems to both mediate and mitigate the impact of climate change.
Alongside a wealth of other benefits we gain from biodiversity, ecosystems play vital roles in helping us withstand the rigours of climate change. Wetlands and rivers protect us from increased flooding. Forests help mitigate extreme heat waves. Peatlands, mires, and permafrost are all crucial carbon sinks. Yet as species disappear, these ecosystems deteriorate, as pieces of the complicated web that they’re made up of disappear. It’s why the concept of mass extinction is so frightening.
But what is mass extinction? We often hear about the concept of a mass extinction, and the question of whether we’re currently in the sixth mass extinction is constantly thrown around. So let’s have a quick look at exactly what extinction itself means, what a mass extinction is, and why it’s increasingly obvious that we’re in one.
The Sumatran tiger, which is different from other subspecies of tiger for reasons (Image Credit: Bernard Spragg, CC0 1.0)
We’re only 3 months in, but 2022 has been a hell of a year for species-related controversy. Grolar and pizzly bears have come roaring into public consciousness, researchers proclaimed that the T-Rex we know and love is actually three different species, and soon-to-be minted Doctor Yi-Kai Tea has been sinking and raising some truly glorious fish species like nobody’s business (we call this taxonomic ha-wrasse-ment).
With the classification calamities flying thick and fast, it’s easy to wonder exactly what it is about naming a species that is so damn hard. So let’s have a quick runthrough of what a species is, why taxonomy is so damn complicated, and why it even matters.
Over the last two years, I had the chance to spend over 100 days at sea on board the German research vessel Sonne, transversing the Atlantic and examining all sorts of fascinating deep-sea animals. On these trips, the scientists were joined by someone whose goal it is to bring the science to the people: Solvin Zankl, who has been a professional wildlife photographer for over 20 years.
When the deep-sea nets reach the surface, the biologists start stressing, frantically ensuring the catch is properly documented and preserved. This is when Solvin’s smorgasbord starts, as he calmly looks through the catch and picks out the more interesting specimens, some of which he knows and some of which he has never seen before. Then he slowly maneuvers his small canisters of cold water into the cold room to spend the next hours meticulously portraying each animal.
Since I believe his job is an absolute dream job for many biologists, I asked him a few questions on how he got into this profession and what some of the challenges are.
Invasive alien species as an environmental stressor and its effects on coping style in a native competitor, the Eurasian red squirrel(2022) Santicchia et al., Hormons and Behaviour, https://doi.org/10.1016/j.yhbeh.2022.105127
The Crux
We know that human activities can cause enormous stress for local species, and the introduction of invasive species is one of the most harmful stressors on a global basis. We know that new, harmful species can cause local extinctions, but how does their introduction affect the locals on a behavioural level?
Grey squirrels were introduced to Europe last century and have been spreading since, displacing the native red squirrels and wiping them out in many areas. This week’s authors wanted to know exactly how red squirrels’ behaviour changed when the grey squirrels were introduced, by looking in detail at the behaviour of red squirrles in both invaded and non-invaded areas, and seeing if they could see evidence of these changes in the expression of hormones (more on this in Did You Know).
Co-existence concerns between predators and humans are spreading like climate-induced wildfires across the UK and EU, with recent headlines repeating stories of culls, conflicts, and illegal hunts; causing frustration and worry among ecologists and wildlife enthusiasts. Let’s review some of the recent controversial acts and policies surrounding predator persecution, and have a deeper look at the continuing war on wildlife and disputes between people and predators.
The koala being added to the threatened species list, plus the ridiculously warm winter weather that some of the Northern Hemisphere has been experiencing, have really struck home how much damage rampant deforestation and fossil fuel use are doing over this past week. But as always, its important to remember that across some fronts progress is being made. Whether it’s the gradual transition to more sustainable energy use many countries are showing, or heroic conservation efforts by people from every corner of the world, these successes should be spotlighted once in a while! So here’s a dose of optimism.
Mini-acoustic sensors reveal occupancy and threats to koalas Phascolarctos cinereus in private native forests(2021) Law et al., Journal of Applied Ecology, https://doi.org/10.1111/1365-2664.14099
The Crux
Forests that lie on privately owned land make up a huge percentage of Australia’s native forests – over 23%. That’s 164 million hectares, a massive swathe of territory for Australia’s amazing endemic species to call home.
The problem is that because it’s private, it’s often difficult to survey. Which means there’s a huge chunk of an ecosystem that we have very little knowledge about. Sometimes this frustrates, but other times it breeds novel approaches to conservation.
This week’s authors wanted to survey native Australian forests, with one species in mind – the charismatic and oft-threatened koala. They took an approach which brought land-owners on board, and sent them audio recording equipment to register the presence of koalas, in an effort to figure out how many koalas made use of private forests.
What They Did
Spread across Australia’s privately owned forests, the researchers found just under a million hectares worth of land that they estimated to be suitable for koalas. They contacted the owners of said land and explained the project and its significance. Once the owners understood the concept and the work involved, they were sent ‘Audiomoths’ – small recording devices that can be attached to trees in koala habitat and record male koalas bellows during mating season (September to December).
Recording koala bellows isn’t that straightforward though, and many recordings had to be removed from the final results as heavy wind and rain made it difficult to determine what was making what noise.
Once koalas were identified, their presence was modelled against a range of different human impacts, including nearby roads and land clearance, and environmental variables like extent of vegetation and local fire severity.
Did You Know: Koala Extinction
Koalas are notoriously picky eaters, and many people know that they will only eat eucalyptus leaves. Yet it goes further, with some koalas only eating leaves from certain species of eucalyptus tree, having grown so accustomed to these species that their gut bacteria can’t tolerate anything else. It means that relocating koalas can be almost impossible, and that preserving their natural habitat is of the utmost importance (and benefits a huge range of other species).
The survey resulted in almost 10,000 hours of recordings across 128 properties and three years. Over 1,600 bellows were recorded across 41% of all the sites surveyed.
The only variables which had an affect on koala presence were the proximity of sealed (paved) roads and the vegetation cover. The closer by a sealed road was, the less likely koalas were to show up. Heavily forested areas were also less likely to house koalas, whereas forest that was more fragmented by grassland and open woodland were better suited for them.
Problems
The study mentions early on that there are often differences between private and public forest, yet there’s no comparison here between the two. Using Audiomoths in public nature reserves would have made for a great comparison, particularly to check whether the environmental and human variables affected koalas in the same way. However the constraints here are financial ones, and I think the authors would agree that it’s more interesting the double the data for this particular experiment rather than double the Audiomoth budget and make a comparative study.
So What?
The environmental results here aren’t particularly interesting – koala’s habitat preferences are relatively well studied. What is a real positive is the success of the technique used, that of bringing private landowners on side and getting a wealth of data in return. An added bonus of a project like that is that as well as collecting data, you get the opportunity to share scientific knowledge and teach a group of the public about local wildlife.
Dr. Sam Perrin is a freshwater ecologist who completed his PhD at the Norwegian University of Science and Technology and is currently working as a climate data analyst at Ducky AS. You can read more about his research and the rest of the Ecology for the Masses writers here, see more of his work at Ecology for the Masses here, or follow him on Twitter here.
Ecology for the Masses 