Cocky count: how Perth’s ‘green’ growth plan could wipe out WA’s best-loved bird


Robert Davis, Edith Cowan University and Martine Maron, The University of Queensland

Carnaby’s black cockatoo lives only in southwestern Australia. Although a much-loved cultural icon, it is now facing a major threat to its persistence: urban growth. Will Western Australia’s favourite bird survive Perth’s expansion?

It is already listed as endangered under state and federal legislation. Historical land clearing has decimated Carnaby’s numbers, felling their breeding grounds and reducing their range. Today, the birds are thought to be using all of their remaining habitat, which is barely enough to sustain the population.

Current distribution range of Carnaby’s black cockatoos.
Joseph Forshaw/Wikimedia Commons, CC BY-SA

But there is a major new threat to this charismatic cockatoo. The new “Green Growth Plan” for Perth and the nearby Peel region could pave the way for the clearing of tens of thousands of hectares of important feeding and roosting habitat, in the name of urban development.

A rocky road ahead

State environment minister Albert Jacob has claimed that the Green Growth Plan is “the absolute best opportunity” for the cockatoo population’s long-term survival.

But under the current draft plan, which is open for public consultation until May 13, Carnaby’s will lose more than 50% of their remaining feeding habitat in the Perth-Peel region, with a proportionate decline possible if key food resources are lost.

Perth’s unique Banskia woodlands are the critical native feeding habitat for Carnaby’s Black-Cockatoo.
Robert Davis, Author provided

The Carnaby’s is already declining at an alarming rate, according to BirdLife Australia’s Great Cocky Count – one of the largest citizen science surveys of its kind in Australia.

The past six years of Great Cocky Counts suggest that the population has dropped by 15% each year. Without drastic action, the window of opportunity to save this population is rapidly closing.

Yet instead of addressing this decline, the Green Growth Plan is poised to lock in destruction of more than 30,000 hectares of Carnaby’s habitat, because the conservation measures it proposes are more than cancelled out by the loss of habitat in areas of prime habitat that are zoned for urban development.

New foods

In response to dwindling natural food sources, the adaptable Carnaby’s black cockatoos have been feeding on non-native pine plantations since the 1940s. These plantations have become even more important to the species as remaining native habitat continues to be cleared.

At their peak, Perth’s Gnangara pine plantation provided 23,000 ha of prime feeding and roosting habitat. One study found that the plantations support several thousand Carnaby’s black cockatoos from January to June each year, and more than half (59%) of the birds counted in the Perth region in 2014 were associated with Gnangara.

However, since 2004 these pines have been harvested without replacement. The plantations stand over an underground aquifer called the Gnangara Mound, one of Perth’s most important water resources. With Perth’s rainfall continuing to decline while the city’s water needs grow, the pines are no longer seen as a responsible use of water.

As removing the pines will increase recharge of the aquifer, the WA government has decided that the pines will have to go.

Even though the pines are not native, their loss will have a major impact on a species already imperilled by habitat loss. Many birds are likely to starve when the food source on which they have come to rely is taken away.

Why the Green Growth Plan doesn’t stack up

So what does the Green Growth Plan offer to protect the cockatoos in the face of the planned habitat loss? Unfortunately, not a lot.

In exchange for the loss of more than 14,000 ha of native habitat and 24,000 ha of pine forest in the Perth-Peel region, the plan proposes that 5,000 ha of pines should be replanted. But young pines take many years to produce the same amount of food as established trees, so there will be a time lag before the food source is even partly replaced.

The plan also proposes to increase the level of protection of more than 100,000 ha of existing feeding habitat. But of course, that habitat is already there, and is being used by the cockatoos. Most of it is also already protected to some degree, which raises questions about how much genuine benefit schemes like this really provide.

The bottom line is that less habitat cannot sustain the same number of cockatoos. They and other species that rely on Banksia woodlands of the Swan Coastal Plain have been suffering from Perth’s unchecked urbanisation for many decades.

For the Perth-Peel plan to truly be considered green, the needs of a growing city must be balanced fairly against preservation of our unique flora and fauna by prioritising habitat retention and looking to alternatives to the ongoing loss of critical habitat.

This article was co-authored by Tegan Douglas and Sam Vine of Birdlife Australia.

The Conversation

Robert Davis, Senior Lecturer in Vertebrate Biology, Edith Cowan University and Martine Maron, ARC Future Fellow and Associate Professor of Environmental Management, The University of Queensland

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

Banning fishing has helped parts of the Great Barrier Reef recover from damage


Camille Mellin, Australian Institute of Marine Science; Aaron MacNeil, Australian Institute of Marine Science, and Julian Caley, Australian Institute of Marine Science

The world’s coral reefs face unprecedented threats. Their survival depends on how well they can cope with a long list of pressures including fishing, storms, coral bleaching, outbreaks of coral predators and reduced water quality. Together, these disturbances have caused the Great Barrier Reef to lose half of its coral cover since 1985.

One often-used way of protecting marine ecosystems is to close parts of the ocean to fishing, in no-take marine reserves. From research, we know that by reducing fishing you end up with more and bigger fish (and other harvested species such as lobsters).

But other benefits of protection might be more surprising. In a new study, we show that no-take reserves helped the Great Barrier Reef’s corals to resist a range of disturbances, such as bleaching, disease and crown-of-thorns starfish, and to recover more quickly from damage.

More exposure, but better protection

Our study used observations between 1993 and 2013 of 34 types of coral and invertebrates and 215 fish species on 46 reefs spread across the Great Barrier Reef. Among the 46 study reefs, 26 were open to fishing and 20 were in no-take marine reserves.

During the study period, several occurrences of coral bleaching, coral disease, storms and outbreaks of crown-of-thorns starfish were recorded.

The total number of disturbances affecting our study reefs increased in recent years (2010-12), mostly due to severe storms affecting the central and southern sections of the Great Barrier Reef. Among our study reefs, those located inside no-take marine reserves were more exposed to disturbance than those outside no-take marine reserves.

Our study showed that, inside no-take marine reserves, the impact of disturbance was reduced by 38% for fish and by 25% for corals compared with unprotected reefs. This means that no-take marine reserves benefit not only fish but entire reef communities, including corals, and might help to slow down the rapid degradation of coral reefs.

Damaged coral reef around Lizard Island a few days after cyclone Ita.
Photo by Tom Bridge, http://www.tethys-images.com

Faster recovery

In addition to greater resistance, reef organisms recovered more quickly from disturbance inside no-take marine reserves. After each disturbance, we measured the time that both coral and fish communities took to return to their pre-disturbance state.

We found coral communities took the longest to recover after crown-of-thorns starfish outbreaks. Outside no-take marine reserves, it took on average nine years for these communities to recover. It took just over six years inside no-take marine reserves.

Although there is more work to be done, one reason that reefs inside no-take zones are able to cope better with disturbances is that they preserve and promote a wider range of important ecological functions. Where fishing reduces the numbers of some species outside protected areas, some of these functions could be lost.

Coral reef showing signs of recovery.
Photo copyright Tom Bridge/www.tethys-images.com

Knowledge for conservation

Marine reserves (including no-take zones) currently cover 3.4% of the world’s ocean, which is still well below the 10% target for 2020 recommended by the Convention on Biological Diversity. The slow progress towards this target is partly due to the perceived high costs of protection compared to true ecological benefits, which can be difficult to gauge. While some surprising benefits are beginning to be revealed in studies like ours, such benefits remain little understood.

Our results help to fill that gap by showing that no-take marine reserves can boost both the resistance and recovery of reef communities following disturbance. In ecology, resistance plus recovery equals resilience.

Our work suggests that the net benefit of no-take marine reserves is much greater than previously thought. No-take marine reserves host not only more and bigger fishes, but more resilient communities that might decline at slower rates.

These results reinforce the idea that no-take marine reserves should be widely implemented and supported as a means of maintaining the integrity of coral reefs globally.

Our conclusions also demonstrate that we need long-term monitoring programs which provide a unique opportunity to assess the sustained benefits of protection.

The Conversation

Camille Mellin, Research Scientist, Australian Institute of Marine Science; Aaron MacNeil, Senior Research Scientist, Australian Institute of Marine Science, and Julian Caley, Senior Principal Research Scientist, Australian Institute of Marine Science

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