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Small, local patches of habitat could be playing a much bigger role in conserving biodiversity than you think, according to new research.

Eastern rosella at Edithvale wetland [Credit Wayne Butterworth]

The global study just published in the Proceedings of the National Academy of Sciences looked at the conservation values of vegetation patches in 27 countries on four continents, and considered their size and distance to other habitat.

The results were surprising according to lead researcher Professor Brendan Wintle from Melbourne University.

"Compared to large and well connected habitat areas, small and isolated patches of habitat have generally been treated as not very important to conservation," said Professor Wintle. "What we have found, however, is that small and isolated habitat areas are very important to the survival of many rare and endangered species."

"The environment is suffering a death by a thousand cuts," Wintle continued. "We need to re-think vegetation management regulations and policies that allow small patches of vegetation to be destroyed."

Co-author Dr. Sam Veloz, Climate Adaptation Group Director at Point Blue Conservation Science, added "We have many existing processes in place to fund restoration or conservation activities that are largely focused on large patches of habitat. While it's important to continue these efforts, our paper emphasizes that small but important habitat patches should be included in an overall conservation portfolio."

An example from the paper explored suitable habitat for four songbird species in California and Oregon (the streaked horned lark, savannah sparrow, Western meadowlark and the Oregon vesper sparrow). Research showed that highly fragmented parts of the study areas for each species contain habitat patches of very high conservation value. And the four species studied have ranges primarily in those small, isolated patches.

Dr. Heini Kujala from the University of Melbourne, another co-author, said that once you start considering how much habitat is left for a species, small patches can be very valuable.

"Small habitat patches can sometimes be the last pieces of a once widespread habitat. For species that rely on this type of habitat that makes them very important," said Dr. Kujala.

"Definitely we are not saying that it is an improvement to cut up big habitat areas into smaller pieces, rather that many of the small pieces that we have left are really important for conservation."

The study's authors hope that the research will raise awareness among planners, land managers, scientists, and the community about the value of small vegetation patches.

Source: University of Melbourne [December 11, 2018]

A QUT-led collaboration with University of Adelaide reveals that Australia's pint-sized banded hare-wallaby is the closest living relative of the giant short-faced kangaroos which roamed the continent for millions of years, but died out about 40,000 years ago.

The diminutive banded hare-wallaby linked to the giant Sthenurinae kangaroos [Credit: Queensland University of Technology]

Published in Systematic Biology, the research involved the first near-complete mitochondrial (mt) genome sequencing from extinct Australian megafauna.

- DNA was sequenced from inner ear bones (petrous bones) of a 45,000-year-old giant short-faced kangaroo, Simosthenurus occidentalis, part of the Sthenurinae sub-family, found at Mt Cripps in Tasmania

- These are the longest DNA sequences ever recovered from Australia's extinct megafauna, with more than 16,000 base pairs of mtDNA, which is used to help understand evolutionary relationships

- The results support an evolutionary link between giant short-faced kangaroos (Sthenurinae) and the threatened banded hare-wallaby, Lagostrophus fasciatus

- The study also combined the DNA evidence with fossil and anatomical data to trace body size change over the evolutionary history of kangaroos and wallabies

The analysis was conducted by QUT evolutionary biologists Ph.D. researcher Manuela Cascini and Associate Professor Matthew Phillips, from the Science and Engineering Faculty, in collaboration with University of Adelaide's Professor Alan Cooper and Dr. Kieren Mitchell, who undertook the DNA sequencing at the Australian Centre for Ancient DNA.

Credit: Queensland University of Technology

Lead author Ms Cascini, a molecular biologist who moved from Italy to undertake her Ph.D. research with Associate Professor Phillips, said her project also involved analysis of mtDNA sequenced from the inner ear bones of another ancient extinct macropod that was found in Tasmania – the giant wallaby, Protemnodon anak, which weighed up to 150 kilograms.

Small fragments of ancient DNA sequenced from this giant wallaby species and from the giant short-faced kangaroo were first reported on by University of Adelaide scientists in 2015.

"Our analysis confirmed their conclusion that the giant wallabies are close relatives of the iconic living Macropus genus of kangaroos and wallabies," Ms Cascini said.

"However that earlier study provided insufficient DNA to confidently place the giant short-faced kangaroos on the evolutionary tree.

"We've now been able to show the strongest evidence yet that the closest living relative of these massive Sthenurinae kangaroos, which weighed up to about 240 kilograms, is the tiny, 2-kilogram banded hare-wallaby. These wallabies live in the wild only on islands off Western Australia and are classified as vulnerable."

Largest of the extinct giant short-faced kangaroos, Procoptodon goliah, featured on an Australia Post stamp  [Credit: Queensland University of Technology]

Associate Professor Phillips said the larger amount of mtDNA sequenced in this study by the University of Adelaide collaborators helped enable the strong finding on the banded hare-wallaby link.

"This is by far the most genetic data that anyone has extracted out of Australian megafauna, and it was taken from the petrous bones which are denser and often seem to hold DNA better," he said.
"You find a lot of ancient DNA studies of megafauna from permafrost in northern Europe and northern America because the cold helps preserve the DNA. But in Australia the hotter climate and older age of the megafauna is far less favourable for DNA preservation."

Dr. Mitchell said Tasmania's cooler climate and higher-altitude caves "make for much better DNA preservation than we find elsewhere in Australia, so we focused our hunt for high-quality megafaunal DNA there".

Associate Professor Phillips said other findings of the study on the evolution of kangaroos and wallabies (macropods) included:

- The macropod ancestors diverged from tree-living possums around 41 to 46 million years ago

- They remained small, in the 2-15 kg range, while Australia was more dominated by rainforest

- As the climate cooled and dried, and as the forests opened up over the past 10 million years, at least four different kangaroo lineages independently evolved to megafaunal size (more than 44 kg)

- This includes the short-faced kangaroos, the giant Protemnodon wallabies, and the living red and grey kangaroos.

Author: Rose Trapnell | Source: Queensland University of Technology [December 10, 2018]

The future of the world's coral reefs is uncertain, as the impact of global heating continues to escalate. However, according to a study published in Nature Climate Change, the response of the Great Barrier Reef to extreme temperatures in 2017 was markedly different to one year earlier, following two back-to-back bouts of coral bleaching. Remarkably, corals that bleached and survived 2016 were more resistant in 2017 to a recurrence of hot conditions.

Researchers found that the response of corals to heat stress during the second of two unprecedented back-to-back bleaching events on the Great Barrier Reef was markedly different from the first [Credit: Tane Sinclair-Taylor]

"Dead corals don't bleach for a second time. The north lost millions of heat-sensitive corals in 2016, and most of the survivors were the tougher species. As a result of bleaching, the mix of species is changing very rapidly," said lead author Prof Terry Hughes, Director of the Australian Research Council Centre of Excellence for Coral Reef Studies (Coral CoE), headquartered at James Cook University.

"We were astonished to find less bleaching in 2017, because the temperatures were even more extreme than the year before," he said.

The new research highlights the extent of damage, or "geographic footprint" of multiple coral bleaching events across the 2,300 km length of the world-heritage listed area.

The back-to-back heatwaves bring the total number of mass bleaching events on the Great Barrier Reef to four over the past two decades (in 1998, 2002, 2016 and 2017). The scientists found that only 7% of the Great Barrier Reef escaped bleaching entirely since 1998, and after the 2017 event, 61% of reefs have now been severely bleached at least once.

During an underwater survey, a researcher records the bleaching severity of a massive Porites coral colony on the Great Barrier Reef [Credit: Justin Marshall]

"We found, using the National Oceanic and Atmospheric Administration's (NOAA) satellite-based coral bleaching tools, that corals in the north of the Great Barrier Reef were exposed to the most heat stress in 2016. A year later, the central region saw the most prolonged heating," said co-author Dr Mark Eakin, from NOAA's Coral Reef Watch program, in Maryland, USA.

The southern third of the Great Barrier Reef was cooler in both years due to local weather conditions, and escaped with only minor bleaching.

"It's only a matter of time before we see another mass-bleaching event, triggered by the next marine heatwave, driven by global heating," said co-author Dr Andrew Hoey of Coral CoE at James Cook University. "One of the worst possible scenarios is we'll see these southern corals succumb to bleaching in the near future."

"The outcome in 2017 depended on the conditions experienced by the corals one year earlier. We called that 'ecological memory,' and show that these repeating events are now acting together in ways that we didn't expect," said Prof Hughes.

"We've never seen back-to-back mass coral bleaching before on the Great Barrier Reef, in two consecutive summers. The combined footprint has killed close to half of the corals on two-thirds of the world's largest reef system," said Dr Hoey.

"We need urgent global action on greenhouse emissions to save the world's coral reefs. Australia should be -- but regrettably isn't -- at the forefront of tackling global heating," said Prof Hughes.

Source: ARC Centre of Excellence in Coral Reef Studies [December 10, 2018]

Scientists are worried about the platypus, with a national risk assessment led by UNSW Professor Richard Kingsford suggesting declines of up to 30 percent.

A UNSW-led project has raised concerns about the decline of platypus populations [Credit: Taronga Zoo: G Anderson]

Mounting evidence that platypus populations are falling has concerned scientists who are nearing the end of a three-year national survey of the iconic species.

The UNSW-led Australian Research Council-funded project has compiled a comprehensive database of the distribution and abundance of the platypus over the last two centuries, combining this with data from systematic capture surveys to conduct a national risk assessment for the species.

"We have great concerns about the future survival of this unique species," says project leader Professor Richard Kingsford, director of the UNSW Centre for Ecosystem Science.