The link below is to an article that takes a look at a trek on Victoria’s ‘Fall Creek Circuit.’
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The link below is to an article that takes a look at the impact of the fashion industry on the environment.
Kerstin Jantke, University of Hamburg; Alienor Chauvenet, Griffith University; Hugh Possingham, The University of Queensland; James Allan, The University of Queensland; James Watson, The University of Queensland, and Kendall Jones, The University of Queensland
Australia has some of the most spectacular marine ecosystems on the planet – including, of course, the world-famous Great Barrier Reef. Many of these places are safe in protected areas, and support a myriad of leisure activities such as recreational fishing, diving and surfing. No wonder eight in ten Aussies live near the beach.
Yet threats to marine ecosystems are becoming more intense and widespread the world over. New maps show that only 13% of the oceans are still truly wild. Industrial fishing now covers an area four times that of agriculture, including the farthest reaches of international waters. Marine protected areas that restrict harmful activities are some of the last places where marine species can escape. They also support healthy fisheries and increase the ability of coral reefs to resist bleaching.
One hundred and ninety-six nations, including Australia, agreed to international conservation targets under the United Nations Convention on Biological Diversity. One target calls for nations to protect at least 10% of the world’s oceans. An important but often overlooked aspect of this target is the requirement to protect a portion of each of Earth’s unique marine ecosystems.
The world is on course to achieve the 10% target by 2020, with more than 7.5% of the ocean already protected. However, our research shows that many marine protected areas are located poorly, leaving many ecosystems underprotected or not protected at all.
What’s more, this inefficient placement of marine parks has an unnecessary impact on fishers. While marine reserves typically improve fisheries’ profitability in the long run, they need to be placed in the most effective locations.
We found that since 1982, the year nations first agreed on international conservation targets, an area of the ocean almost three times the size of Australia has been designated as protected areas in national waters. This is an impressive 20-fold increase on the amount of protection that was in place beforehand.
But when we looked at specific marine ecosystems, we found that half of them fall short of the target level of protection, and that ten ecosystems are entirely unprotected. For example, the Guinea Current off the tropical West African coast has no marine protected areas, and thus nowhere for its wildlife to exist free from human pressure. Other unprotected ecosystems include the Malvinas Current off the southeast coast of South America, Southeast Madagascar, and the North Pacific Transitional off Canada’s west coast.
Australia performs comparatively well, with more than 3 million square km of marine reserves covering 41% of its national waters. Australia’s Coral Sea Marine Park is one of the largest marine protected areas in the world, at 1 million km². However, a recent study by our research group found that several unique ecosystems in Australia’s northern and eastern waters are lacking protection.
Furthermore, the federal government’s plan to halve the area of strict “no-take” protection inside marine parks does not bode well for the future.
To assess the scope for improvement to the world’s marine parks, we predicted how the protected area network could have been expanded from 1982.
With a bit more strategic planning since 1982, the world would only need to conserve 10% of national waters to protect all marine ecosystems at the 10% level. If we had planned strategically from as recently as 2011, we would only need to conserve 13% of national waters. If we plan strategically from now on, we will need to protect more than 16% of national waters.
If nations had planned strategically since 1982, the world’s marine protected area network could be a third smaller than today, cost half as much, and still meet the international target of protecting 10% of every ecosystem. In other words, we could have much more comprehensive and less costly marine protection today if planning had been more strategic over the past few decades.
The lack of strategic planning in previous marine park expansions is a lost opportunity for conservation. We could have met international conservation targets long ago, with far lower costs to people – measured in terms of a short-term loss of fishing catch inside new protected areas.
This is not to discount the progress made in marine conservation over the past three decades. The massive increase of marine protected areas, from a few sites in 1982, to more than 3 million km² today, is one of Australia’s greatest conservation success stories. However, it is important to recognise where we could have done better, so we can improve in the future.
This is also not to discount protected areas. They are important but can be placed better. Furthermore, long-term increases in fish populations often outweigh the short-term cost to fisheries of no-take protected areas.
In 2020, nations will negotiate new conservation targets for 2020-30 at a UN summit in China. Targets are expected to increase above the current 10% of every nation’s marine area.
We urge governments to rigorously assess their progress towards conservation targets so far. When the targets increase, we suggest they take a tactical approach from the outset. This will deliver better outcomes for nature conservation, and have less short-term impact on the fishing industry.
Strategic planning is only one prerequisite for marine protected areas to effectively protect unique and threatened species, habitats and ecosystems. Governments also need to ensure protected areas are well funded and properly managed.
These steps will give protected areas the best shot at halting the threats driving species to extinction and ecosystems to collapse. It also means these incredible places will remain available for us and future generations to enjoy.
Kerstin Jantke, Postdoctoral Researcher on conservation biology, University of Hamburg; Alienor Chauvenet, Lecturer, Griffith University; Hugh Possingham, Professor, The University of Queensland; James Allan, Postdoctoral research fellow, School of Biological Sciences, The University of Queensland; James Watson, Professor, The University of Queensland, and Kendall Jones, PhD candidate, Geography, Planning and Environmental Management, The University of Queensland
Like something out of a zombie movie, species that were once thought extinct seem to be rising from the dead. Between February 21 and March 4 2019, three notable rediscoveries were announced – the Fernandina Island Galápagos tortoise (Chelonoidis phantasticus), which was last seen in 1906; Wallace’s giant bee (Megachile pluto), which had supposedly disappeared in 1980; and the Formosan clouded leopard (Neofelis nebulosa brachyura), which disappeared after the last sighting in 1983 and was officially declared extinct in 2013.
These rediscoveries suggest we may know very little about some of the world’s rarest species, but they also raise the question of how species are declared extinct in the first place. The IUCN Red List collates a global register of threatened species and measures their relative risks of extinction. The Red List has a set of criteria to determine the threat status of a species, which are only listed as “Extinct” when…
… there is no reasonable doubt that the last individual has died.
According to the Red List, this requires…
… exhaustive surveys in known and/or expected habitat, at appropriate times… throughout its historic range [which] have failed to record an individual. Surveys should be over a time frame appropriate to the taxon’s life cycle and life form.
Given all the evidence – or rather, lack of evidence – that’s needed, it’s surprising that any species is ever declared extinct. The criteria show that to understand whether a species is extinct, we need to know what it was doing in the past.
Sightings at a certain time and in a certain place make up our knowledge of a species’ survival, but when a species becomes rare, sightings are increasingly infrequent so that people start to wonder whether the species still exists.
People often use the time since the last sighting as a measure of likelihood when deciding if a species has died out, but the last sighting is rarely the last individual of the species or the actual date of extinction.
Instead, the species may persist for years without being seen, but the length of time since the last sighting strongly influences assumptions as to whether a species has gone extinct or not.
But what is a sighting? It can come in a variety of forms, from direct observation of a live individual in the flesh or in photographs, indirect evidence such as foot prints, scratches and faeces, and oral accounts from interviews with eyewitnesses.
But these different lines of evidence aren’t all worth the same – a bird in the hand is worth more than a roomful of recollections from people who saw it in the past. Trying to determine what are true sightings and what are false complicates the declaration of extinction.
The idea of a species being “rediscovered” can confuse things further. Rediscovery implies that something was lost or forgotten but the term often gives the impression that a species has returned from the dead – hence the term “lazarus species”. This misinterpretation of lost or forgotten species means the default assumption is extinction for any species that hasn’t been seen for a number of years.
So, what does this mean for the three recently “rediscovered” species?
While a living specimen of the Fernandina Island Galápagos tortoise had not been seen since 1906, indirect observations of tortoise faeces, footprints and tortoise-like bite marks out of prickly pear cacti had been made as recently as 2013.
The uncertainty around the quality of these later observations and the long time since the last living sighting probably contributed to it being declared “Critically Endangered (Possibly Extinct)” in 2015. In the natural world, a species is presumed extinct until proven living.
Wallace’s giant bee may not have been recorded in the last 38 years but it was never actually declared extinct according to the IUCN Red List. In fact, for many years it languished under the criteria of Data Deficient and was only recently assessed as Vulnerable.
So, while this is an exciting find for something that hadn’t been seen for so long, its rediscovery shows how little is known about many rare species in the wild, rather than how scarce they are.
The Formosan clouded leopard, meanwhile, was actually listed as Extinct. The last sighting of the species was in 1983, based on interviews with 70 hunters, and extensive camera trapping during the 2000s failed to detect its presence. It was officially declared extinct in 2013.
While the giant tortoise and bee were proclaimed alive after living specimens were found, the clouded leopard’s rediscovery is more uncertain. Based on sightings on two separate occasions by two sets of wildlife rangers, the evidence is compelling. But whether the Formosan Clouded Leopard has really risen from the dead will require considerably more effort to prove.
Few sights and sounds are as emblematic of the North American southwest as a defensive rattlesnake, reared up, buzzing, and ready to strike. The message is loud and clear, “Back off! If you don’t hurt me, I won’t hurt you.” Any intruders who fail to heed the warning can expect to fall victim to a venomous bite.
But the consequences of that bite are surprisingly unpredictable. Snake venoms are complex cocktails made up of dozens of individual toxins that attack different parts of the target’s body. The composition of these cocktails is highly variable, even within single species. Biologists have come to assume that most of this variation reflects adaptation to what prey the snakes eat in the wild. But our study of the Mohave rattlesnake (Crotalus scutulatus, also known as the Mojave rattlesnake) has uncovered an intriguing exception to this rule.
A 20-minute drive can take you from a population of this rattlesnake species with a highly lethal neurotoxic venom, causing paralysis and shock, to one with a haemotoxic venom, causing swelling, bruising, blistering and bleeding. The neurotoxic venom (known as venom A) can be more than ten times as lethal as the haemotoxic venom (venom B), at least to lab mice.
The Mohave rattlesnake is not alone in having different venoms like this – several other rattlesnake species display the same variation. But why do we see these differences? Snake venom evolved to subdue and kill prey. One venom may be better at killing one prey species, while another may be more toxic to different prey. Natural selection should favour different venoms in snakes eating different prey – it’s a classic example of evolution through natural selection.
This idea that snake venom varies due to adaptation to eating different prey has become widely accepted among herpetologists and toxinologists. Some have found correlations between venom and prey. Others have shown prey-specific lethality of venoms, or identified toxins fine-tuned for killing the snakes’ natural prey. The venom of some snakes even changes along with their diet as they grow.
We expected the Mohave rattlesnake to be a prime example of this phenomenon. The extreme differences in venom composition, toxicity and mode of action (whether it is neurotoxic or haemotoxic) seem an obvious target for natural selection for different prey. And yet, when we correlated differences in venom composition with regional diet, we were shocked to find there is no link.
In the absence of adaptation to local diet, we expected to see a connection between gene flow (transfer of genetic material between populations) and venom composition. Populations with ample gene flow would be expected to have more similar venoms than populations that are genetically less connected. But once again, we drew a blank – there is no link between gene flow and venom. This finding, together with the geographic segregation of the two populations with different venoms, suggests that instead there is strong local selection for venom type.
The next step in our research was to test for links between venom and the physical environment. Finally, we found some associations. The haemotoxic venom is found in rattlesnakes which live in an area which experiences warmer temperatures and more consistently low rainfall compared to where the rattlesnakes with the neurotoxic venom are found. But even this finding is deeply puzzling.
It has been suggested that, as well as killing prey, venom may also help digestion. Rattlesnakes eat large prey in one piece, and then have to digest it in a race against decay. A venom that starts predigesting the prey from the inside could help, especially in cooler climates where digestion is more difficult.
But the rattlesnakes with haemotoxic venom B, which better aids digestion, are found in warmer places, while snakes from cooler upland deserts invariably produce the non-digestive, neurotoxic venom A. Yet again, none of the conventional explanations make sense.
Clearly, the selective forces behind the extreme venom variation in the Mohave rattlesnake are complex and subtle. A link to diet may yet be found, perhaps through different kinds of venom resistance in key prey species, or prey dynamics affected by local climate. In any case, our results reopen the discussion on the drivers of venom composition, and caution against the simplistic assumption that all venom variation is driven by the species composition of regional diets.
From a human perspective, variation in venom composition is the bane of anyone working on snakebite treatments, or antidote development. It can lead to unexpected symptoms, and antivenoms may not work against some populations of a species they supposedly cover. Anyone living within the range of the Mohave rattlesnake can rest easy though – the available antivenoms cover both main venom types.
Globally, however, our study underlines the unpredictability of venom variation, and shows again that there are no shortcuts to understanding it. Those developing antivenoms need to identify regional venom variants and carry out extensive testing to ensure that their products are effective against all intended venoms.
Planning a trip to the tropics? You might end up bringing home more than just a tan and a towel.
Our latest research looked at mosquitoes that travel as secret stowaways on flights returning to Australia and New Zealand from popular holiday destinations.
We found mosquito stowaways mostly enter Australia from Southeast Asia, and enter New Zealand from the Pacific Islands. Worse still, most of these stowaways are resistant to a wide range of insecticides, and could spread disease and be difficult to control in their new homes.
Undetected insects and other small creatures are transported by accident when people travel, and can cause enormous damage when they invade new locations.
Of all stowaway species, few have been as destructive as mosquitoes. Over the past 500 years, mosquitoes such as the yellow fever mosquito (Aedes aegypti) and Asian tiger mosquito (Aedes albopictus) have spread throughout the world’s tropical and subtropical regions.
Dengue spread by Aedes aegypti mosquitoes now affects tens to hundreds of millions of people every year.
Explainer: what is dengue fever?
You probably won’t see Aedes mosquitoes buzzing about the cabin on your next inbound flight from the tropics. They are usually transported with cargo, either as adults or occasionally as eggs (that can hatch once in contact with water).
It only takes a few Aedes stowaways to start a new invasion. In Australia, they’ve been caught at international airports and seaports, and in recent years there has been a large increase in detections.
In our new paper, we set out to determine where stowaway Aedes aegypti collected in Australia and New Zealand were coming from. This hasn’t previously been possible.
Usually, mosquitoes are only collected after they have “disembarked” from their boat or plane. Government authorities monitor these stowaways by setting traps around airports or seaports that can capture adult mosquitoes. Using this method alone, they’re not able to tell which plane they came on.
But our approach added another layer: we looked at the DNA of collected mosquitoes. We knew from our previous work that the DNA from any two mosquitoes from the same location (such as Vietnam, for example) would be more similar than the DNA from two mosquitoes from different locations (such as Vietnam and Brazil).
So we built a DNA reference databank of Aedes aegypti collected from around the world, and compared the DNA of the Aedes aegypti stowaways to this reference databank. We could then work out whether a stowaway mosquito came from a particular location.
We identified the country of origin of most of the Aedes aegypti stowaways. The majority of these mosquitoes detected in Australia are likely to have come from flights originating in Bali.
Now we can work with these countries to build smarter systems for stopping the movement of stowaways.
As the project continues, we will keep adding new collections of Aedes aegypti to our reference databank. This will make it easier to identify the origin of future stowaways.
As Aedes aegypti has existed in Australia since the 19th century, the value of this research may seem hard to grasp. Why worry about invasions by a species that’s already here? There are two key reasons.
Currently, Aedes aegypti is only found in northern Australia. It is not found in any of Australia’s capital cities where the majority of Australians live. If Aedes aegypti established a population in a capital city, such as Brisbane, there would be more chance of the dengue virus being spread in Australia.
The other key reason is because of insecticide resistance. In places where people use lots of insecticide to control Aedes aegypti, the mosquitoes develop resistance to these chemicals. This resistance generally comes from one or more DNA mutations, which are passed from parents to their offspring.
Importantly, none of these mutations are currently found in Australian Aedes aegpyti. The danger is that mosquitoes from overseas could introduce these resistance mutations into Australian Aedes aegpyti populations. This would make it harder to control them with insecticides if there is a dengue outbreak in the future.
In our study, we found that every Aedes aegpyti stowaway that had come from overseas had at least one insecticide resistance mutation. Most mosquitoes had multiple mutations, which should make them resistant to multiple types of insecticides. Ironically, these include the same types of insecticides used on planes to stop the movement of stowaways.
We can now start tracking other stowaway species using the same methods. The Asian tiger mosquito (Aedes albopictus) hasn’t been found on mainland Australia, but has invaded the Torres Strait Islands and may reach the Cape York Peninsula soon.
Worse still, it is even better than Aedes aegypti at stowing away, as Aedes albopictus eggs can handle a wider range of temperatures.
A future invasion of Aedes albopictus could take place through an airport or seaport in any major Australian city. Although it is not as effective as Aedes aegypti at spreading dengue, this mosquito is aggressive and has a painful bite. This has given it the nickname “the barbecue stopper”.
Beyond mosquitoes, our DNA-based approach can also be applied to other pests. This should be particularly important for protecting Australia’s A$45 billion dollar agricultural export market as international movement of people and goods continues to increase.
Tom Schmidt, Research fellow, University of Melbourne; Andrew Weeks, Senior Research Fellow, University of Melbourne, and Ary Hoffmann, Professor, School of BioSciences and Bio21 Institute, University of Melbourne