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David Lindenmayer, Australian National University; Martine Maron, The University of Queensland; Megan C Evans, The University of Queensland, and Philip Gibbons, Australian National University

It’s no secret that human development frequently comes at a cost to other creatures. As our urban footprint expands, native habitat contracts. To compensate for this, most Australian governments require developers to invest in biodiversity offsetting, where habitat is created or protected elsewhere to counterbalance the impact of construction.

Although biodiversity offsetting is frequently used in Australia – and is becoming increasingly popular around the world – we rarely know whether offsets are actually effective.

That’s why we spent four years monitoring the program designed to offset the environmental losses caused by widening the Hume Highway between Holbrook and Coolac, New South Wales. Our research has found it was completely ineffective.

Trading trees for boxes

The roadworks required the removal of large, old, hollow-bearing trees, which are critical nesting sites for many animals, including several threatened species. To compensate for these losses, the developer was required to install one nest box for every hollow that was lost – roughly 600 nest boxes were installed.

Many of the boxes were specifically designed for three threatened species: the squirrel glider, the superb parrot and the brown treecreeper. We monitored the offset for four years to see whether local wildlife used the nest boxes.

We found that the nest boxes were rarely used, with just seven records of the squirrel glider, two of the brown treecreeper, and none of the superb parrot. We often saw all three species in large old tree hollows in the area around the boxes we monitored.

Even more worryingly, almost 10% of the boxes collapsed, were stolen or otherwise rendered ineffective just four years after being installed. Perversely, we found that invasive species such as feral bees and black rats frequently occupied the nest boxes.

The offset clearly failed to deliver the environmental outcomes that were promised. Indeed, researchers have been concerned for some time now that offsetting can be misused and abused.

What can be done?

It’s worth noting that research supports using nest boxes as a habitat replacement. However, they may never be effective for species such as the superb parrot. It’s not quite clear why some animals use nest boxes and others don’t, but earlier monitoring projects in the same area found superb parrots consistently avoid them.

Still, concrete steps can – and should – be taken to improve similar offset programs.

First, the one-to-one ratio of nest boxes to tree hollows was inadequate; far more nest boxes needed to be installed to replace the natural hollows that were lost.

Second, nest boxes clearly cannot compensate for the many other key ecological values of large old trees (such as carbon storage, flowering pulses or foraging habitat). This suggests that more effort is needed at the beginning of a development proposal to avoid damaging environmental assets that are extremely difficult to replace – such as large old trees.There also was no requirement to regularly replace nest boxes as they degrade. It can take a hundred years or more for trees to develop natural hollows suitable for nesting wildlife. To truly offset their removal, thousands of boxes may be required over many decades.

Third, where it is simply impossible to protect key features of the environment during infrastructure development, more holistic strategies should be considered. For example, in the case of the woodlands around the Hume Highway, encouraging natural regeneration can help replace old trees.

Tree planting on farms can also make a significant contribution to biodiversity – and some of these may eventually become hollow-bearing trees. A combination of planting new trees and maintaining adequate artificial hollows while those trees mature might be a better approach.

Being accountable for failure

When an offset program fails, it’s unlikely anyone will be asked to rectify the situation. This is because developers are only required to initiate an offset, and are not responsible for their long-term outcomes.

In the case of the Hume Highway development, the conditions of approval specified that nest boxes were to be installed, but not that they be effective.

Despite the ecological failure of the offset (and over A$200,000 invested), the developer has met these legal obligations.

This distinction between offset compliance and offset effectiveness is a real problem. The Australian government has produced a draft policy of outcomes-based conditions, but using these conditions isn’t mandatory.

The poor results of the Hume Highway offset program are sobering. However, organisations like Roads and Maritime Services are to be commended for ensuring that monitoring was completed and for making the data available for public scrutiny – many agencies do not even do that.

Indeed, through monitoring and evaluation we can often learn more from failures than successes. There are salutary lessons here, critical to ensuring mistakes are not repeated.

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University; Martine Maron, ARC Future Fellow and Associate Professor of Environmental Management, The University of Queensland; Megan C Evans, Postdoctoral Research Fellow, Environmental Policy, The University of Queensland, and Philip Gibbons, Senior Lecturer, Australian National University

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

Nicki Shumway, Martine Maron and James Watson recently published a letter in Science on the health of the Great Barrier Reef:

The Great Barrier Reef was recently considered for a World Heritage ‘in danger’ listing, but was spared in 2015 by the development of the Reef 2050 Long Term Sustainability Plan. This plan includes targets to improve water quality and biodiversity in the Reef, which is considered in poor overall condition. A key criticism of the 2050 Plan by scientists was the lack of discussion and concrete action on the impacts of climate change to the Reef.  In addition, a key requirement by the World Heritage Committee was that the Plan be fully implemented and adequately funded, with a progress report submitted to the Committee by Dec. 1, 2016.

Unfortunately, the health and resilience of Great Barrier Reef has continued to deteriorate. Last year the largest bleaching event on record caused massive loss of coral cover, and again this year we are in the midst of another bleaching event – unprecedented for the Great Barrier Reef.

 The Reef is in poor condition, with current policy doing little to abate this decline. We wrote an article, published this month in Science about the inconsistent policies of the Queensland and Commonwealth governments, who on the one hand state their commitment to the integrity of the reef, and on the other, approve large coal mines in the same region. We suggest that an ‘in danger’ listing by UNESCO will be the wake-up call needed to prioritise this natural wonder over industrial development in the region.

 Read more here: Australia needs a wake-up call

Humans rely on things that come from nature – including clean air, water, food, and timber.  But how can we tell if these natural services that people rely on, are at risk of being lost, potentially permanently?

That is the focus of a new paper by an international team, led by Dr Martine Maron from The University of Queensland’s School of Earth and Environmental Sciences.

“There are many things that happen in nature that provide benefits to people, and we call these ecosystem services,” Dr Maron said.

“As well as natural goods, like seafood, crops, and timber, they can also include other things like the well-being benefits of spending time in a park or at the beach, protection from flooding and even regulation of the climate.

“Many of these things are essential to people, but until now, there hasn’t been a consistent way to look at whether different ecosystem services are under threat from growing human demand or unsustainable levels of use.

“We have developed a framework to identify services that at risk of being undersupplied or even of being lost entirely.  This allows time to either move towards more sustainable use, or to start planning for alternatives when we lose the ecosystem service.

“At its core, the framework is a method to analyse supply and demand, and the different things that affect them, like the condition of natural systems and whether demand by people is expected to change over time.

“For example, a fishery might have been able to supply demand until now, but as the local population grows, the whole ecosystem service can become under threat when demand exceeds supply.”

Dr Matthew Mitchell, a study co-author based at the University of British Columbia, said: “An example we often see in our cities is the loss of vegetation and its ability to intercept rainwater and reduce flooding.

“People continue to develop flood-prone areas while also clearing vegetation and building on upstream slopes, so floods are becoming more common and damaging.”

Dr Maron said the new framework could provide a basis for global, national and regional assessments of threat to ecosystem services, and accompany existing assessments of threat to species and ecosystems.

“As the need to prioritise investment in safeguarding ecosystem services becomes more urgent, a framework for assessing when and where ecosystem services are imperilled is timely,” she said.

The study, published in Trends in Ecology and Evolution, is supported by an Australian Research Council Discovery project grant.

It involves researchers from UQ; University of British Columbia, Canada; University College, London; University of New South Wales; NSW Office of Environment and Heritage; and the Wildlife Conservation Society, U.S.A.