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Tropical Ecosystems Hub researchers have drawn chilling conclusions for the future of specialist rainforest vertebrate species in the Wet Tropics region in a changing climate.

In its fifth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC AR5) adopted four Representative Concentration Pathways (RCPs) for estimating the trajectory of greenhouse gas concentration in the atmosphere. The four pathways, RCP 2.6, RCP 4.5, RCP 6 and RCP 8.5, are effectively measures of the extent to which the Earth’s energy budget will be out of balance in the year 2100 relative to pre-industrial values.

The team from Project 3.1 Rainforest Biodiversity have concluded that, under a low emission scenario (RCP 4.5), about 10% of endemic rainforest vertebrates in the Wet Tropics are expected to be critically endangered by 2085. However, under a high emission scenario (RCP 8.5), similar to what we are currently tracking, nearly 60% of these species will be critically endangered.

Whilst the big challenge is to reduce global greenhouse gas emissions, the challenge for local land use managers and planners is to determine which areas provide refuge for species in a changing environment to maximise conservation of biodiversity.

Identifying areas with high species richness, species turnover or species endemism is an important first step in determining likely refugia both now and in the future. By using conservation prioritisation software, the team ensure that the areas of highest priority incorporate complementarity across both species and sites.

The project team’s analysis included 202 species across taxonomic groupings of birds, reptiles, amphibians and mammals from the Centre for Tropical Biodiversity and Climate Change long term monitoring database. The team assessed climate change impacts on individual species and biodiversity as a whole against the RCP emission scenarios for decadal time steps from present to 2085.

The modelling produced a suite of predictive metrics for use in understanding future impacts on species distributions and the ecology of the animals of the Wet Tropics. The project team focused on two variables from the models, “change in abundance” and level of future “habitat fragmentation”.

The results largely paint a grim picture for the survival of the endemic vertebrates of the rainforests of North Queensland if global greenhouse gas emissions continue to rise rapidly.

The results indicate that, with the “business-as-usual” worst-case scenario (RCP 8.5), great losses in species are predicted to occur by 2085. Coupled with these predicted losses in vertebrate populations in the future, results indicate that populations will be highly fragmented.

Mitigating greenhouse gas emissions and increasing carbon sequestration on a global scale is necessary to avert the worst of the scenarios modelled under IPCC AR5. However, the results of the current research emphasise the importance of identifying local, critical climate change refugia early and maintaining or enhancing connectivity between sites in anticipation of future climate scenarios.

To this end, the Queensland government is now using the methodology developed through this research to identify climate change refugia in the Wet Tropics region with the intention of purchasing land where necessary.

Managers of the Great Barrier Reef’s 900 islands face difficult decisions when it comes to investing in conservation management. So where should they invest limited resources to achieve the best outcomes for management problems?

These conservation decisions must be made in the face of spatially heterogeneous and dynamic threats, including invasive plants and animals and inappropriate fire regimes, and within a constrained budget. NERP Tropical Ecosystems Hub researchers from James Cook University are assembling a decision-making framework for such a purpose.

Project 9.3 works closely with GBRMPA and the Queensland Government to develop a cost-effective approach to prioritising management actions across GBR islands. More specifically, the project’s goal is to maximize conservation outcomes defined by specific objectives for diverse natural features, including native plant and animal species, vegetation assemblages and breeding aggregations.

A decision-support tool with GIS capability will help managers to identify management priorities within and between islands. The project will deliver results that are useful to a range of stakeholder organisations, including state and Australian government bodies, the tourism sector, and conservation planners and managers.

The project covers both Queensland and Commonwealth Islands in the southern sector of the GBR from Mackay to Bundaberg. This region was chosen based on the national and international significance of these islands in relation to vulnerable and endangered species, tourism value, and the likely threats presented by expanding industrial development.

For the initial development of the decision-support tool, 13 islands have been chosen as a representative sample of the southern GBR islands. These islands differ in size, geomorphology, species assemblages, regional ecosystems, threats and commercial and recreational uses. As a result, the selected islands encapsulate the varied challenges for management.

After the initial number of islands has been enlarged, the main project outputs will be:

1. A compilation of all available data, including quantified expert judgements on islands to set parameters for key variables to be used in the management prioritization.
2. A novel, cost-effective, transparent, and accountable approach to prioritizing management actions for multiple objectives across islands, designed and understood by GBR managers.
3. An interactive, spatially explicit decision-support tool for day-to-day use that will allow managers to identify action-specific management priorities within and between islands.

Amelia Wenger, JCU

For more information, contact Amelia Wenger at: amelia.wenger@my.jcu.edu.au

Project 9.3: Prioritising management actions for Great Barrier Reef islands

Marine Environmental Research

Miller, I., Cheal, A.J., Emslie, M.J., Logan, M., Sweatman, H. (2012) Ongoing effects of no-take marine reserves on commercially exploited coral trout populations on the Great Barrier Reef. Marine Environmental Research. 79, 167-170 [doi:10.1016/j.marenvres.2012.05.008].

* Funded by AIMS