Marine Impacts 

Although climate change predictions for the marine environment are attenuated compared to the terrestrial realm, there is still generally a poor understanding of its implications for the marine biota. The adaptability of marine species to temperature, salinity and substrata changes resulting from climate forcing need to be examined in conjunction with other drivers of population change such as fishing exploitation, coastal development and other forms of habitat degradation. Future impacts are being quantified and modelled to provide well-supported predictions of marine system health across Australia.

Density regulation as a major determinant of population persistence: advancing empirical and theoretical approaches to conserve biodiversity

Without efficient application of limited conservation resources, more species will go extinct and invasive species will continue to proliferate. With a better understanding of extinction processes, a higher benefit:cost ratio will ensure better outcomes for biodiversity. We will directly address:

• the sustainable use of Australia's biodiversity by providing evidence-based support for minimum viable population size targets to avoid extinction;
• responding to climate change by determining the species- and environmentally specific contexts leading to elevated risks of extinction; and
• protecting Australia from invasive diseases and pests by determining density targets that maximise eradication success. 

We will compile and analyse a large database of long-term time series abundance data from thousands of species to determine how density-dependent processes modify predictions of extinction risk. Outcomes include:

• predictions of the evidence, strength and form of classic and inverse density dependence;
• determining how these are modified by life history and environmental context; and
• a concrete basis for estimating wildlife population sizes that maximise persistence (threatened species) or eradication potential (invasive species).

The results will be a significant contribution to the application of extinction theory to applied conservation at a time of crisis in global biodiversity.

Project team
Corey Bradshaw, Franck Courchamp (Université Paris-Sud), Navjot Sodhi (National University of Singapore)

Funding
ARC Discovery

Estimating fishing-related mortality and designing sustainable management protocols for shark fisheries in Northern Australia

Sharks are extremely valuable economically, with the landed catch in the Northern Territory alone exceeding $10 million in 2004. The increasing world demand for high-quality protein will necessitate appropriate management so that over-exploitation does not occur as it has in most other shark fisheries worldwide. The proposed project will provide key information that will direct careful and informed management decisions well into the future. The added benefit of collecting information on the rarer and more susceptible non-target species caught in this fishery will ensure that any negative impacts are reduced. The project will also provide information on the potential impact of illegal fishing by neighbouring countries to our north. 

Our research aims to:

• implement an intensive tagging study to estimate fishing-related and natural mortality of two commercially important species--the black-tip (Carcharhinus tilstoni) and spot-tail (C. sorrah) sharks;
• develop a series of mathematical models incorporating mortality estimates to evaluate fishing mortality rates and susceptibility of populations of these sharks under current and alternative future management arrangements; and
• prescribe new and additional monitoring protocols and management arrangements leading to better spatial and temporal management of shark fisheries in northern Australia.

Project team
Corey Bradshaw, Mark Meekan (Australian Institute of Marine Science)

Funding
ARC Linkage

Forecasting change in subtidal habitats: connecting local pollution with global climate in temperate Australia.

This project explores the potential consequences of climate change on the marine ecology of temperate coasts. It tests the effects of forecasted environments (global and local) on rocky subtidal communities among contrasting localities of species composition and physical conditions. These tests redress criticism of Australia's current narrow focus on testing local and contemporary environmental conditions, and the indeterminate outcomes they may cause management in the face of climate shift.

The current narrow focus of management on local and contemporary environmental conditions (e.g. water quality) has indeterminate outcomes in the face of climate change. This proposal seeks to forecast marine habitats under realistic scenarios of climate change and continuing local population growth and activity. This information provides managers with information needed to understand the consequences of current policy and debates about its improvement.

Project team
Sean Connell; Bayden Russell; CF Gurgel

Funding
ARC Linkage

Local and regional investigations into perturbations of marine habitat

Surprising changes to coastal ecology are forecast as increasing physical stresses (e.g. nutrient and sediment runoff) initiate changes to habitat. Lack of information about perturbations remains a major gap in marine ecology and coastal management. Multifactorial experiments will examine perturbations to one of temperate Australia's most widespread subtidal habitats (kelp forests) to test predictions derived from ecological theory. Tests focus on models about abrupt switches of habitat to contrasting states and responses among regions bearing striking differences in consumer control. These trans-Australian tests may change the way we view one of the world's most extensive temperate coastlines.

Project team
Sean Connell

Funding
ARC Linkage