Deforestation on private land in Australia is at some of the highest rates in the world, despite ongoing conservation policies to prevent the practice that is devastating for biodiversity. Researchers from the Wilson Lab have conducted the first robust analysis of a policy’s ability to reduce deforestation of remnant trees in Queensland, amidst ongoing debate surrounding the policy’s effectiveness and concerns over its significant costs to local farmers and graziers. The study measured whether the controversial Vegetation Management Act 1999 (VMA) had successfully reduced deforestation of remnant trees in the Brigalow Belt South, a biodiversity hotspot in Queensland.

Lead author Blake Alexander Simmons, a PhD candidate in the Wilson Lab, said assessing policy is critical to understand its successes and failures. “Government conservation policies often lack thorough evaluation,” he said. “This can easily lead to an over-reliance on simple impact indicators, like the amount of remaining forest, and failure to recognise other determining factors like socio-economic change, climate conditions, and behaviour created by the policy itself.

“For example, the large decline in remnant vegetation clearing during 2006-2011 is often used as evidence for the effectiveness of the Vegetation Management Act. When we control for other influential factors, however, we see very minimal effectiveness of the policy during this period. This is likely due to the effects of the Millennium Drought, where landholders would not have been clearing vegetation even if the policy never existed.”

The researchers used a new application of robust causal impact techniques traditionally used for evaluating the effectiveness of social and biomedical programs, and more recently, some conservation interventions, like protected areas and payments for ecosystem services (PES) schemes. “We created two scenarios to develop an upper and lower bound of policy effectiveness. Under the most effective scenario, the VMA successfully saved over 19,000 ha of remnant trees, but this is amount is much smaller than many people expected. Under the least effective scenario, the VMA actually increased remnant tree clearing by 1,000 ha due to the effects of ‘panic clearing’.”

The researchers argue that the mechanisms through which the policy influences deforestation needs investigation. “The indirect effects of the VMA may be more powerful than its direct regulatory effects,” Simmons says. “Landholders appear to have redirected their clearing preferences toward unprotected trees, which is a positive outcome for the environment. If we want to protect Queensland landscapes, the government must promote this new behavioural norm while ensuring vegetation management policy effectively protects threatened trees.”

To find out more, access the article here: Effectiveness of regulatory policy in curbing deforestation in a biodiversity hotspot

Simmons, B. A., Wilson, K. A., Marcos-Martinez, R., Bryan, B. A., Holland, O., and Law, E. A. 2018. Effectiveness of regulatory policy in curbing deforestation in a biodiversity hotspot. Environmental Research Letters. 13: 124003. https://dx.doi.org/10.1088/1748-9326/aae7f9