Resources

Extensive land clearing is a major threat to biodiversity. Consequently, tree planting is a commonly used strategy to rapidly restore forest to degraded landscapes. However, its high cost prevents its use across the large areas needed to address the ongoing legacy of land clearing.

Tropical Ecosystems Hub researchers are responding to the need to find lower cost options to restore critical rainforest habitat without always undertaking a program of tree planting.

The team from Project 12.2: Harnessing Natural Regeneration for Cost-effective Rainforest Restoration are working to develop decision-support options to optimise regional investments using the most appropriate restoration method for any particular ecological and economic scenario.

This requires quantitative measurement of the pattern and speed at which rainforest regrowth occurs, so the project team has surveyed the vegetation structure and plant species diversity in a network of 29 sites that differ in their age of regrowth, across the Atherton Tablelands.

These field measurements are being combined with information about the age of regrowth and with similar data from a network of replanted sites, to compare the speed and success of unassisted regrowth with the outcomes of tree planting projects. The data will also enable the team to identify how much the outcomes vary among different sites, and will be combined with measurements of the sites’ other characteristics and surrounding vegetation to identify factors that may limit or accelerate regrowth.

In addition, the team has experimented with the use of woody debris in young restoration plantings to stimulate return of reptile diversity. They found that, after one year, the addition of woody debris increased the local abundance of reptiles and promoted colonization by at least one log specialist.

Another set of experimental trials has focused specifically on designing and testing management interventions which can overcome barriers to the regeneration of native rainforest trees within retired pasture. The early results have demonstrated that greater seedling recruitment can be promoted by grass suppression and provision of habitat structure to seed-dispersing birds. These results also show that some invasive non-native shrubs species (such as wild tobacco) can also facilitate the recruitment of rainforest seedlings. The team collated information from early intervention trials in tropical regions worldwide, which also show that management interventions to accelerate regrowth are most effective when a range of strategies are used in combination.

The knowledge gained from this work will help enable targeted restoration expenditure and the most effective allocation of investment. The project team will then apply this information at a landscape scale, to identify areas of highest potential for low-cost regrowth.

The Torres Strait is well known as a biological bridge, with many species moving between the islands and mainland Australia. Of global concern is the risk that emerging infectious diseases could have on human and wildlife health and that the Torres Strait could facilitate disease movement to the Australian mainland.

Tropical Ecosystems Hub researchers are working to improve methods of detecting and monitoring disease that will result in increased capacity to protect Torres Strait biodiversity and people from disease.

The team from Project 11.2: Improved Approaches for Detection of Disease and Prevention of Spread in Torres Strait are improving our understanding of the distribution of disease vectors across the Torres Strait and developing new surveillance methods for detecting disease vectors.

The challenge of managing disease outbreaks in frontier regions is early detection of new vectors and diseases, but the isolated nature of these remote regions is that standard surveillance approaches are not appropriate. Standard sampling of vectors requires vector-attractants are unavailable or difficult to transport, without great expense.

The project team trialed both a passive mosquito trap design that does not require batteries and a vector attractant that produces CO2 from yeast and sugar. The novel sampling method whilst capturing fewer mosquitoes than the standard traps and dry ice attractants, did capture the same types of mosquito species which importantly reveals what disease vectors are common in the landscape. Further, the new sampling method was found to be more robust and efficient in remote locations compared to standard BG traps capturing up to 14 times more mosquitoes in forest habitats.

Twenty species of mosquitos were identified from the 4,655 individuals captured across four islands in the Torres Strait: Saibai, Boigu, Kubin and Badu. In total, five times more mosquitoes were recorded in forest habitats compared to villages, with Saibai and Boigu Islands recording 4-5 times more mosquitoes than Kubin and Badu Islands during the sampling period.

With respect to the disease-vectoring potential of the sampled mosquitoes, the malaria-vector Anopheles spp. was recorded only on Saibia and Boigu islands, with proportional high numbers (45% of Boigu total) on Boigu during the sampling period. Dengue vector Aedes albopictus was recorded in all sampled villages and in the forest of Badu. The other dengue vector Aedes aegypti was only recorded on Boigu Island.

Information from the project will assist Biosecurity Queensland and the Australian Quarantine Inspection Service in devising environmental disease management interventions in Torres Strait. The project also serves to inform communities in Torres Strait of the diseases that can be transmitted by mosquitos.

Dr. Cathy Dichmont (CSIRO)

Shaping the future of the Great Barrier Reef is no easy task. The Reef catchment area covers almost 350,000 square kilometres. The region contributes $7 billion to the Australian economy annually, primarily through tourism, however farming, fishing and the research sectors are also important.

Future management decisions regarding the Reef need to strike the right balance between economic growth, environmental protection and community wellbeing. 

To ensure all voices are heard in the decision-making process, CSIRO and partners are creating a framework to empower local people to contribute to local management decisions through a case study in Mackay.

Community acceptance of decisions surrounding the Great Barrier Reef’s future is reliant on transparency and grassroots involvement. With this in mind, a ‘bottom-up’ framework has been developed by CSIRO to empower local community members to affect local decisions. Representatives from across the community are working collaboratively to determine key areas that will require future management decisions. 

To do this, the representatives prioritise management objectives from the most important to least important using a novel way to solicit information. The prioritisation framework gives Reef managers and decision makers vital information on what is important to each stakeholder group, what they all agree on and how willing they are to negotiate on each objective. Management decisions are then elicited from the community representatives and assessed against the ranked objectives to determine the likely impacts of each decision.

The framework was developed and tested in Mackay with a large group of stakeholders including local residents, farmers, fishers, tourism operators, community and environmental groups, plus decision makers across government.

The decision makers that will use the findings from the project to inform future strategies for Mackay include Mackay Regional Council, Queensland Government (fisheries and parks), the Ports Corporation and the Federal Government’s Great Barrier Reef Marine Park Authority.

With a focus on the coasts’ fisheries and biodiversity, six key topics were agreed on and explored by the group: mangroves, seagrasses, inshore corals, fisheries, urban development and ports.

The stakeholder group identified the economic, environmental and social pressures associated with each of these topics, and based on those threats, determined the best management action to address these pressures.

For example, the three most important objectives identified by the stakeholder group are “Reduce direct impacts of infrastructure and development”, “Reduce influx of pollutants” and “Increase compliance with environmental and resource use regulations”. The key actions to address these objectives therefore focused on cumulative impacts and measures to increase compliance to existing legislation through changes to existing practices and education campaigns. Based on the pressures and weighted objectives, the impacts of these management options could be quantitatively tested, determining the possible consequences, advantages and limitations of each decision.

Within six months the management framework will be finalised and demonstrated in Mackay. Once trialled and evaluated, we plan for this framework to be rolled out and customised across any coastal community in Australia.

For more information, contact Dr. Cathy Dichmont (cathy.dichmont@csiro.au)

E.T. da Silva, M.J. Devlin, J. G. Alvarez-Romero, A. Wenger & L. I.W. McKinna, Integration of satellite imagery and in-situ data for the identification of surface water quality conditions in the Great Barrier Reef.