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Wooden shipwrecks turn out to be thriving habitats for seafloor microbiomes

<p>The ocean floor is a graveyard to over three million shipwrecks, most of them made of wood. While they do alter the microbial habitat of the seafloor, new research has found that the impact is not all bad, and that they may even boost productivity.</p> <p>“Microbial communities are important to be aware of and understand because they provide early and clear evidence of how human activities change life in the ocean,” says author Dr Leila Hamdan of the University of Southern Mississippi, US.</p> <p>A study on the microbial life around two 19th-century shipwreck sites in the Gulf of Mexico investigates the diversity among these human-made habitats. Samples of biofilms were collected using pieces of pine and oak placed at the shipwreck, and up to 200 metres away from the shipwreck. After fourth months, microbes were measured using gene sequencing, including all bacteria, archaea and fungi</p> <p>“Ocean scientists have known that natural hard habitats, some of which have been present for hundreds to thousands of years, shape the biodiversity of life on the seafloor,” says Hamdan. “This work is the first to show that built habitats (places or things made or modified by humans) impact the films of microbes (biofilms) coating these surfaces as well. These biofilms are ultimately what enable hard habitats to transform into islands of biodiversity.”</p> <p>The results showed that bacteria preferred oak over pine, but that the type of wood had less impact on archaea or fungi diversity. Diversity also varied depending on the proximity to the wreck site, where surprisingly, the greatest diversity was not at the wreck site, but peaked at 125 metres away. The depth of the water, and proximity to a nutrient source like the Mississippi River delta, also played a part in the distribution of biofilms.</p> <p>Though this study informs on wooden shipwrecks and the impact on microbial diversity, there are also thousands of oil and gas platforms and oil pipelines in the Gulf of Mexico alone that warrant further research to understand their microbial impacts too.</p> <p>“While we are aware human impacts on the seabed are increasing through the multiple economic uses, scientific discovery is not keeping pace with how this shapes the biology and chemistry of natural undersea landscapes,” says Hamdan. “We hope this work will begin a dialogue that leads to research on how built habitats are already changing the deep sea.”</p> <p><strong><em>This article originally appeared on <a href="https://cosmosmagazine.com/science/biology/shipwrecks-habitats-microbiomes/" target="_blank" rel="noopener">cosmosmagazine.com</a> and was written by Qamariya Nasrullah.</em></strong></p>

Cruising

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Six million hectares of threatened species habitat up in smoke

<p>More than <a href="https://sydney.edu.au/news-opinion/news/2020/01/08/australian-bushfires-more-than-one-billion-animals-impacted.html">one billion mammals, birds, and reptiles</a> across eastern Australia are estimated to have been affected by the current fire catastrophe.</p> <p>Many animals and plants have been incinerated or suffocated by smoke and ash. Others may have escaped the blaze only to die of exhaustion or starvation, or be picked off by predators.</p> <p>But even these huge losses of individual animals and plants do not reveal the full scale of impact that the recent fires have had on biodiversity.</p> <p>Plants, <a href="https://theconversation.com/australias-bushfires-could-drive-more-than-700-animal-species-to-extinction-check-the-numbers-for-yourself-129773">invertebrates</a>, freshwater fish, and frogs have also been affected, and the impact of the fires is likely to be disproportionately greater for <a href="https://theconversation.com/a-season-in-hell-bushfires-push-at-least-20-threatened-species-closer-to-extinction-129533">threatened species</a>.</p> <p>To delve deeper into the conservation impact, we used publicly available satellite imagery to look at the burnt areas (up to January 7, 2020) and see how they overlapped with the approximate distributions of all the threatened animals and plants listed under the Environment Protection and Biodiversity Conservation Act.</p> <p>We restricted our analysis to the mediterranean and temperate zone of south-east and south-west Australia.</p> <p><strong>The bad news</strong></p> <p>We found that 99% of the area burned in the current fires contains potential habitat for at least one nationally listed threatened species. We conservatively estimate that six million hectares of threatened species habitat has been burned.</p> <p>Given that many fires are still burning and it is not yet clear how severe the burning has been in many areas, the number of species affected and the extent of the impact may yet change.</p> <p>What we do know is that these species are already on the brink of extinction due to other threats, such as <a href="https://theconversation.com/environment-laws-have-failed-to-tackle-the-extinction-emergency-heres-the-proof-122936">land clearing</a>, invasive species, climate change, disease, or previous fires.</p> <p>Approximately 70 nationally threatened species have had at least 50% of their range burnt, while nearly 160 threatened species have had more than 20% of their range burnt.</p> <p>More threatened plants have been affected than other groups: 209 threatened plant species have had more than 5% of their range burnt compared to 16 mammals, ten frogs, six birds, four reptiles, and four freshwater fish.</p> <p>Twenty-nine of the 30 species that have had more than 80% of their range burnt are plants. Several species have had their entire range consumed by the fires, such as the Mountain Trachymene, a <a href="http://www.environment.gov.au/biodiversity/threatened/species/pubs/9367-conservation-advice.pdf">fire-sensitive</a> plant found in only four locations in the South Eastern Highlands of NSW.</p> <p>Other species that have been severely impacted include the Kangaroo Island dunnart and the Kangaroo Island glossy black cockatoo. These species’ entire populations numbered only in the hundreds prior to these bushfires that have burned more than 50% of their habitat.</p> <p>Glossy black cockatoos have a highly specialised diet. They eat the seeds of the drooping sheoak <a href="https://ecos.csiro.au/glossy-black-cockatoos/">(<em>Allocasuarina verticillata</em>).</a> These trees may take anywhere from 10 to 50 years to recover enough to produce sufficient food for the black cockatoos.</p> <p>The populations of many species will need careful management and protection to give their habitats enough time to recover and re-supply critical resources.</p> <p>The figures above do not account for cumulative impacts of previous fires. For example, the critically endangered western ground parrot had around 6,000 hectares of potential habitat burnt in these fires, which exacerbates the impact of earlier extensive fires in 2015 and early 2019.</p> <p>Threatened species vary in their ability to cope with fire. For fire-sensitive species, almost every individual dies or is displaced. The long-term consequences are likely to be dire, particularly if vegetation composition is irrevocably changed by severe fire or the area is subject to repeat fires.</p> <p>More than 50% of the habitat of several species known to be susceptible to fire has been burnt – these include the long-footed potoroo and Littlejohn’s tree frog.</p> <p>Some species are likely to thrive after fire. Indeed, of the top 30 most impacted species on our list, almost 20% will likely flourish due to low competition in their burnt environments – these are all re-sprouting plants. Others will do well if they are not burnt again before they can set seed.</p> <p><strong>Rising from the ashes</strong></p> <p>For fire-sensitive threatened species, these fires could have substantially increased the probability of extinction by virtue of direct mortality in the fires or reducing the amount of suitable habitat. However, after the embers settle, with enough investment and conservation actions, guided by evidence-based science, it may be possible to help threatened species recover.</p> <p>Protection and conservation-focussed management of areas that have not burned will be the single most important action if threatened species are to have any chance of persistence and eventual recovery.</p> <p>Management of threatening processes (such as weeds, feral predators, <a href="https://theconversation.com/double-trouble-as-feral-horse-numbers-gallop-past-25-000-in-the-australian-alps-128852">introduced herbivores</a>, and habitat loss through logging or thinning) must occur not just at key sites, but across the landscapes they sit in. Maintaining only small pockets of habitat in a landscape of destruction will lock many species on the pathway to extinction.</p> <p>In some cases, rigorous post-fire restoration will be necessary to allow species to re-colonise burnt areas. This may include intensive weed control and assisted regeneration of threatened flora and specific food sources for fauna, installing nest boxes and artificial cover, or even targeted <a href="https://www.smh.com.au/environment/conservation/massive-food-drop-to-help-save-endangered-wallabies-in-fire-affected-areas-20200112-p53qss.html">supplementary feeding</a>.</p> <p>Unconventional recovery actions will be needed because this unique situation calls for outside-the-box thinking.</p> <p><strong>Playing the long game</strong></p> <p>These fires were made larger and more severe by <a href="http://www.bom.gov.au/climate/drought/">record hot, dry conditions</a>. Global temperatures have so far risen by approximately 1°C from pre-industrial levels.</p> <p><a href="https://climate.nasa.gov/news/2865/a-degree-of-concern-why-global-temperatures-matter/">Current projections indicate that we are on track for a 3°C increase.</a> What will that look like?</p> <p>We are in a moment of collective grief for what has been lost. A species lost is not just a word on a page, but an entire world of unique traits, behaviours, connections to other living things, and beauty.</p> <p>These losses do not need to be in vain. We have an opportunity to transform our collective grief into collective action.</p> <p>Australians are now personally experiencing climate impacts in an unprecedented way. We must use this moment to galvanise our leaders to act on climate change, here in Australia and on the world stage.</p> <p>The futures of our beloved plants and animals, and our own, depend on it.</p> <p><em>Written by Michelle Ward, Aaron Greenville, April Reside, Ayesha Tulloch, Brooke Williams, Emily Massingham, Helen Mayfield, Hugh Possingham, James Watson, Jim Radford and Laura Sonter. Republished with permission of <a href="https://theconversation.com/six-million-hectares-of-threatened-species-habitat-up-in-smoke-129438">The Conversation.</a></em></p>

Caring

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Threatened Australian wildlife at grave risk from habitat loss, study finds

<p>A new study shows that successive governments have failed to protect the habitat of our most endangered species. At present 90 per cent of the 120 most endangered animals have no safeguards in place to prevent the loss of their homes.</p> <p>Environmental groups have analysed the data and found that just 12 of the 120 most endangered animals in Australia have plans in place that limit the future loss of their natural habitats. This is despite the fact that habitat loss due to housing and mining is seen as the main threat to the majority of these endangered species.</p> <p>The report, compiled by the Australian Conservation Foundation, BirdLife Australia and Environmental Justice Australia, found that governments consistently avoid giving limits for habitat loss.</p> <p>James Trezise, policy coordinator for the Australian Conservation Foundation, said the report’s findings are “worrisome”.</p> <p>“Recovery plans can bind future decision making for governments,” he said. “We’ve seen examples where scientific advice has been given to governments on habitat loss, such as the swift parrot in Tasmania, and it has been ignored.</p> <p>“We know that land clearing is a key threat and recovery plans need to state unambiguously that the best bits of remaining bush should be left intact.”</p> <p>Even more evidence was found that the recommendations for protection of habitats are being ignored for specific at-risk species. Habitat loss is clearly outlined in the recovery plan for the endangered southern cassowary, however no action was taken to reduce the amount of land cleared. At the same time, threats to habitat loss are outlined in the recovery plan for the Carnaby’s black cockatoo, yet a focus on providing offsets for cleared land has in fact caused its numbers to decline, the report finds.</p> <p>With almost half of Australia’s forests having been cut down or severely disturbed since Europeans arrived, much of the natural habitats of a wide range of species have disappeared or been devastated.</p> <p>Australia is home to over 5 per cent of the world’s plant and animal species. Of these, 87 per cent are found nowhere else in the world.  It’s worth noting that Australia also has one of the worst extinction rates in the world, having lost 50 species in the past 200 years.</p> <p>At present the federal government lists 1,764 Australian species as being threatened to some degree.</p> <p>“Extinction is a choice,” said Samantha Vine, head of conservation at BirdLife Australia. “Where we’ve tried in the past, Australia has been remarkably successful at recovering threatened species. In many cases averting extinction has been straightforward and relatively inexpensive.</p> <p>“Securing and improving existing habitats for threatened species is one of the most powerful and cost effective conservation tools at our disposal.”</p> <p>A threatened species summit is being held by the federal government in coming weeks to discuss options for turning these statistics around. Topics of discussion for the government ministers and conservationists include the predation of mammals by feral cats.</p> <p>Gregory Andrews, the national threatened species commissioner, said the government is set to launch a threatened species strategy that will finally look at habitat loss and improving recovery plans.</p> <p>“Given the animals and plants at risk, and losses we have already endured, a strategic response is required,” he said.</p> <p>“And by working on the basis of science, focusing on practical action and partnering as broadly as possible, I’m confident that it’s possible.”</p> <p>Mr Trezise summed up the issues by saying: “Threatened species protection isn’t just about feral cats. It’s about a diverse range of pressures and the biggest threat is habitat clearance. We have a choice – we either accept that we put developments in less environmentally sensitive areas or we will have species go extinct.”</p> <p><strong>Related links:</strong></p> <p><span style="text-decoration: underline;"><em><a href="/news/news/2015/07/heart-disease-and-diabetes-danger/"><strong>Heart disease plus diabetes can knock more than 10 years off your life</strong></a></em></span></p> <p><span style="text-decoration: underline;"><em><a href="/news/news/2015/07/peanut-turtle-litter/"><strong>Turtle lives 20 years after being cut free from a six-pack ring</strong></a></em></span></p> <p><span style="text-decoration: underline;"><em><a href="/news/news/2015/07/baby-elephant-falls-in-well/"><strong>Mother elephant spends 11 hours trying to free baby from well</strong></a></em></span></p>

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