The importance of long-term studies

By David Lindenmayer

There are many ways to study the environment. Long-term studies based on repeated measurements of the same entities is one of the most powerful. Most ecological research is short-term, but most key changes in the environment take place over prolonged periods. Long-term work is essential to document these changes. Scientists in the Conservation and Landscape Ecology Group at the Fenner School specialize in long-term empirical studies of biodiversity response in different kinds of landscapes – including those dominated by plantations, agriculture (where extensive revegetation efforts have taken place over the past 20 years) and national park management. The longest running study in the Conservation and Landscape Ecology Group was established in 1983 within the Victorian Central Highland’s spectacular montane ash forests – the tallest flowering plants on earth. Much of the ANU work in the Victorian forests has taken place in collaboration with State government agencies and community groups like Friends of the Leadbeater’s Possum, My Environment and Earthwatch.

There are many different aspects to the work in the Victorian forests. Research initially commenced as a detailed examination of the habitat requirements of arboreal marsupials, including the critically endangered Leadbeater’s Possum. However, the work quickly expanded to include long-term studies of populations of large, hollow-bearing trees that are the critical habitat components for Leadbeater’s Possum as well as nearly 40 other species of cavity-using species in montane ash forests. Other research focused on how disturbances such as logging and fire have influenced forest vertebrates and the habitats required by these animals. 

Many discoveries from research in montane ash forests were made only through long-term research. For example, repeated surveys of the condition of hollow-bearing trees have demonstrated that populations of these key habitat elements are declining rapidly. However, animals that depend on these trees have not declined at anything like the same rate. This has occurred because some species are able to adapt to changes in habitat by modifying their use of nesting sites in large old trees. Similarly, long-term work before and after catastrophic wildfires in 2009 has revealed a far greater sensitivity to fire among arboreal marsupials than expected – animals are now absent from many sites that were occupied by prior to the fire – even those subject to very low severity fire. 

2015 will be the 32nd year of almost continuous long-term research in the montane ash forests of the Central Highlands of Victoria. The expanding body of long-term work will undoubtedly include many exciting new scientific discoveries. Critically, the work is also significantly influencing policies, particularly those on forest restoration and the conservation of not only Leadbeater’s possum but also the Mountain Ash ecosystem per se.