Climate change is killing off Earth’s little creatures



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A jumping spider, which uses sharp eyesight to hunt its prey.
ThomasShahan.com/Flickr, CC BY-SA

Bill Laurance, James Cook University

Climate change gets blamed for a lot of things these days: inundating small islands, fueling catastrophic fires, amping-up hurricanes and smashing Arctic sea ice.

But a global review of insect research has found another casualty: 40% of insect species are declining and a third are endangered. It confirms what many have been suspecting: in Australia and around the world, arthropods – which include insects, spiders, centipedes and the like — appear to be in trouble.




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Curious Kids: why do spiders have hairy legs?


The global review comes hard on the heels of research published in the Proceedings of the National Academy of Sciences USA that suggests a potent link between intensifying heat waves and stunning declines in the abundance of arthropods.

If that study’s findings are broadly valid – something still far from certain – it has chilling implications for global biodiversity.

Our natural world depends on arthropods.
Steve Raubenstine/Pixabay

Arthropod Armageddon

In the mid-1970s, researchers on the Caribbean island of Puerto Rico conducted a large-scale study to measure the total biomass (living mass) of insects and other arthropods in the island’s intact rainforests, using sweep nets and sticky-traps.

Four decades later, another research team returned to the island and repeated the study using identical methods and the same locations. To their surprise, they found that arthropod biomass was just one-eighth to one-sixtieth of that in the 1970s – a shocking collapse overall.

And the carnage didn’t end there. The team found that a bevy of arthropod-eating lizards, birds and frogs had fallen sharply in abundance as well.

Insects are crucial in food webs for species such as this hummingbird.
Pixabay

In the minds of many ecologists, a widespread collapse of arthropods could be downright apocalyptic. Arthropods pollinate some of our most important food crops and thousands of wild plant species, disperse seeds, recycle nutrients and form key links in food chains that sustain entire webs of life.

This ecological ubiquity arises because arthropods are so abundant and diverse, comprising at least two-thirds of all known species on Earth. In the 1940s, evolutionary biologist J. B. S. Haldane quipped that “God has an inordinate fondness for beetles.” Humans might think we rule the world, but the planet really belongs to arthropods.

Killer heat waves

The researchers who documented the arthropod collapse in Puerto Rico considered a variety of possible causes, including pesticides and habitat disruption. But the evidence kept pointing to another driver: rising temperatures.

Weather stations in Puerto Rico indicate that temperatures there have risen progressively in the past several decades – by 2℃ on average.

But the researchers are far less worried about a gradual increase in temperature than the intensification of heat waves—which have risen markedly in Puerto Rico. This is because nearly all living species have thresholds of temperature tolerance.

For example, research in Australia has shown that at 41℃, flying foxes become badly heat-stressed, struggling to find shade and flapping their wings desperately to stay cool.

But nudge the thermometer up just one more degree, to 42℃, and the bats suddenly die.

In November, heat waves that peaked above 42℃ in north Queensland killed off almost a third of the region’s Spectacled Flying Foxes. The ground beneath bat colonies was littered with tens of thousands of dead animals. Dedicated animal carers could only save a small fraction of the dying bats.

Bats die en-masse during a recent heatwave.

The El Niño connection

El Niño events – fluctuations in Pacific sea-surface temperatures that drive multi-year variations in weather across large swaths of the planet – are also part of this story. New research appears to be resolving longstanding uncertainties about El Niños and global warming.

Recent studies published in Nature and Geophysical Research Letters suggest global warming will in fact intensify El Niños – causing affected areas to suffer even more intensively from droughts and heat waves.

And this ties back to Puerto Rico, because the researchers there believe a series of unusually intense El Niño heatwaves were the cause the arthropod Armageddon. If they’re right then global warming was the gun, but El Niño pulled the trigger.

Beyond heat waves

Puerto Rico is certainly not the only place on Earth that has suffered severe declines in arthropods. Robust studies in Europe, North America, Australia and other locales have revealed big arthropod declines as well.

And while climatic factors have contributed to some of these declines, it’s clear that many other environmental changes, such as habitat disruption, pesticides, introduced pathogens and light pollution, are also taking heavy tolls.

Monarch butterflies are declining in the USA and Mexico, probably from habitat disruption.
Pixabay

So, at a planetary scale, arthropods are suffering from a wide variety of environmental insults. There’s no single reason why their populations are collapsing.




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Climate change: effect on sperm could hold key to species extinction


The bottom line is: we’re changing our world in many different ways at once. And the myriad little creatures that play so many critical roles in the fabric of life are struggling to survive the onslaught.The Conversation

Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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A numbers game: killing rabbits to conserve native mammals



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Controlling rabbit populations has a key role in conserving Australia’s native plants and animals
William Booth

Euan Ritchie, Deakin University; Damien Fordham, University of Adelaide, and Miguel Lurgi, Centre national de la recherche scientifique (CNRS)

Invasive species have a devastating effect on biodiversity. In Australia, introduced red foxes and feral cats have been implicated in the majority of the extinctions of the native mammal fauna, which has been decimated since European arrival.

But there’s a herbivore that also causes eco-catastrophe. Rabbits both compete with native animals for food and shelter and act as easy prey for abundant populations of cats and foxes. By over-grazing vegetation and reducing habitat complexity, they make hunting easier for introduced predators.




Read more:
Invasive predators are eating the world’s animals to extinction – and the worst is close to home


Food webs are complex. Because of this, once an invasive species is embedded in a food web, simply eradicating them without considering the potential knock-on effects to other species they interact with, could cause unintended and undesirable consequences. We modelled different rates of rabbit population reduction to assess what level of control might be best for aiding the conservation of native mammals and not causing negative outcomes.

Rabbit numbers boom and crash

Rabbits, famously, reproduce rapidly and can cope with a relatively high predation rate. This can cause “hyper-predation”, where rabbit-inflated cat and fox populations indirectly increase the predation pressure on native mammals. This is especially so when rabbit populations intermittently crash due to, for example, extreme environmental events (like severe and prolonged droughts) or disease. This causes predators to switch their diet and eat more native mammals.

Threatened species such as the greater bilby are likely to benefit from rabbit control.
Jasmine Vink

This logically suggests that reducing rabbit numbers might thus help reduce cat and fox populations, by removing their abundant prey. Collectively this should benefit native plants and animals, including many threatened mammal species. However, ecosystem and pest management is a complex game.

When controlling rabbits we need to look beyond one or two species. We should consider the potential consequences for the entire ecological community, which ultimately depend on how changes in one species percolate through the network of ecological interactions between them.

Our new research, recently published in the Journal of Applied Ecology, set out to examine these questions in more detail. We consider other key players in Australia’s arid regions, such as kangaroos and dingoes, when looking at the effects of rabbit control on small native mammals. Our aim was to provide a better understanding of how changes in rabbit populations might affect other species via the food web.

We developed a multi-species ecological network model to describe and quantify how changing rabbit abundance can affect species on different feeding levels. In addition to rabbits, small native mammals, and mesopredators (cats and foxes), our model also considers apex predators (dingo) and large herbivores (kangaroo) as part of the Australian arid food web. This model allowed us to examine changes in predator-prey interactions (including potential prey switching and hyper-predation) and how these could affect the survival of native prey through time.

Our model of an Australian arid ecosystem food web.
Author provided

We found that removing rabbits at rates between 30-40% appeared to benefit small mammals. This is approximately the rate at which rabbits are currently managed in Australia using biocontrol agents (introduced diseases).

Rabbit control in Australia typically involves a “press and pulse” approach. Rabbit populations are suppressed via biocontrol (press) and periods of warren destruction and poisoning (pulse). Finding that reducing rabbit populations by around 40% seems most beneficial to small mammals is important, as it informs how and when we combine these strategies.

The 40% rate corresponds well with the disease-induced (press) mortality rate in rabbit populations due to rabbit haemorrhagic disease and myxomatosis. These are the primary biocontrol agents used in arid Australia to control rabbit populations.

Our study supports rabbit-reduction strategies that involve sustained “press” control, that kill a moderate portion of a rabbit population, with less frequent removal at higher proportions of the population.

To effectively manage invasive species, it’s important to focus on entire communities. Targeting single species might not be enough – every animal exists within a complex web of interactions.




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Mourn our lost mammals, while helping the survivors battle back


There has been much focus by the current government on controlling feral cats, as a way to conserve many of Australia’s unique and threatened mammal species.

The ConversationHowever, more focus could be devoted to protecting habitat cover and complexity, by reducing the land clearing and over-grazing that makes hunting easier. We can also manage rabbits sensibly to reduce competition for resources, and indirectly control cats and foxes.

Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University; Damien Fordham, , University of Adelaide, and Miguel Lurgi, Postdoctoral research fellow, Centre national de la recherche scientifique (CNRS)

This article was originally published on The Conversation. Read the original article.

The new international whaling resolution will do little to stop Japan killing whales


Indi Hodgson-Johnston, University of Tasmania

Australia and New Zealand were claiming a conservation success this week, when their resolution against lethal “scientific” whaling was adopted at the International Whaling Commission’s biennial meeting in Slovenia. But in reality the non-binding decision will do little to stop Japan’s whaling program.

This resolution aims to tighten the loophole that allows nations to catch whales under the guise of scientific whaling. It provides for greater oversight of the currently self-assessed special permits for lethal scientific whale research.

After the disappointment of failing to establish a South Atlantic whale sanctuary, the anti-whaling bloc of nations at the IWC meeting have hailed the latest resolution, with Australia’s environment minister Josh Frydenberg describing the decision as “a big win”.

Where next for Japanese whaling?

Japan conducts its whaling under a self-issued permit, under Article VIII of the International Convention for the Regulation of Whaling. This article allows a country to grant its nationals special licence “to kill, take and treat whales for purposes of scientific research subject to such restrictions as to number and subject to such other conditions as the Contracting Government thinks fit”.

In 2014 the International Court of Justice ruled Japan’s JARPA II whaling program illegal on the basis that it was “not for the purposes of scientific research” and therefore in breach of Article VIII. But crucially it did not ban all future scientific whaling activities by Japan.

After the decision, Japan created a new research programme called NEWREP-A (New Scientific Whale Research Program in the Antarctic Ocean), which purported to have different scientific methods to its predecessor.

As Japan no longer recognises the jurisdiction of the International Court of Justice regarding “living resources of the sea”, arguments on adherence to the broader principle laid down in the decision would possibly be in vain.

A new tack

This brings us back to the new resolution, which was brought to the IWC by Australia, New Zealand and other anti-whaling nations in a bid to make it harder for nations such as Japan to issue themselves with special permits for scientific whaling.

The underlying principle is Australia’s repeated assertion that “lethal scientific research is simply not necessary”.

Japan’s new NEWREP-A program included the killing of 333 minke whales in the 2015-16 season, and the IWC’s Scientific Committee was powerless to prevent Japan from proceeding, given that the conditions of special permits are currently self-assessed and can proceed without scientific endorsement from the committee.

The new resolution establishes a Working Group under the Convention, which will consider the Scientific Committee’s recommendations in relation to all special permits. It also gives a greater role to the Commission in the process of issuing special permits.

The aim is to apply much greater scrutiny to the granting of special permits, rather than allowing nations simply to award them to themselves. Plans for special permits are requested to be submitted to the new working group at least six months in advance of the Scientific Committee’s meeting, alongside the data used to back up a country’s claims to be running a scientific whaling program. These data will be evaluated both during the program’s development, and during ongoing and final reviews.

These inquiries into the special permit will then be presented to the IWC itself, which will form its own official view on the proposed whaling program and publish its findings.

Overall, the resolution gives the Commission a much greater role in deciding whether a given nation should be allowed to kill whales. But resolutions are not legally binding, and there is no function to penalise those who do not follow them.

Non-binding resolutions

In response to the new resolution, Japan’s Commissioner to the IWC said that Japan “will abide by the Convention itself”. This implies that Japan will continue to apply its own interpretation of the Convention, and will not follow the extra steps outlined in the new resolution.

So despite the new emphasis on applying scientific scrutiny to whaling permits, at a higher level than before within the IWC’s structure, this actually doesn’t mean much in practical terms for Japan. The reality is that Japan will continue to act independently of IWC advice due to its view on what Article VIII means.

As a result, Japan is unlikely to stop killing whales any time soon, despite the efforts of Australia, New Zealand and other anti-whaling nations to shut the program down.

The Conversation

Indi Hodgson-Johnston, Antarctic Law and Policy Researcher, PhD Candidate, University of Tasmania

This article was originally published on The Conversation. Read the original article.

Zimbabwe Charges Another Man Over Cecil the Lion Killing


TIME

Zimbabwe has charged another man in relation to Cecil the Lion’s killing, but it’s not the American dentist who shot the animal last month.

Prosecutors accused farmer Honest Ndlovu on Tuesday of allowing Walter Palmer to hunt on his land without the proper approval, the Associated Press reports. “Both the professional hunter and land owner had no permit or quota to justify the offtake of the lion and therefore are liable for the illegal hunt,” the Zimbabwe Parks and Wildlife Management Authority said in a previous statement.

Ndlovu, who faces a $400 fine or a year in prison according to his attorney, is out on bail. He is the second man to be charged after Theo Bronkhorst, who pleaded not guilty to “failing to prevent an illegal hunt” in late July. Zimbabwe authorities say Bronkhorst lured Cecil the Lion out of his home in a national park and onto…

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A plague of hornets in China is killing people and eating bees


Grist

asian-giant-hornet-image

If you’ve always wanted to visit China, this … this might not be the best time. Thanks to climate change, massive numbers of Asian giant hornets (which are the size of your thumb) have been rolling through Shaanxi Province, eating honeybees, and stinging humans to death. And they could be coming to your area next.

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USA: Cats are Killing Machines


The link below is to an article that reports on the incredible number of wildlife deaths attributed to domestic cats.

For more visit:
http://news.mongabay.com/2013/0130-killer-kittens.html

Article: Climate Change Killing our Coral Reefs


The link below is to an article reporting on the threat to Coral Reefs from climate change – in short, climate change is killing coral reefs around the world.

For more visit:
http://news.mongabay.com/2012/0710-hance-coral-reefs-climate-statment.html