Blog on Forest Health

By Leonie Valentine

As the new fauna postdoc within the Centre, my research will be looking at the role of fauna in maintaining ecosystem health.  Sounds intriguing, doesn’t it?  I’ve been pondering just how I will tackle this broad idea over the last couple of months.    In one of the first meetings I attended, I asked what were the Centre’s “Big Picture Questions”.  As the Centre’s vision for research is to ensure healthy woodland and forest ecosystems, the following big picture questions were suggested: How do woodland systems work when they are healthy? What happens when they go wrong? How do we fix it?

So, how do fauna relate to these questions?  Fauna are a very important component of ecosystems.  For example, fauna are often pollinators of plant species, and the abundance and species of herbivores can change plant species richness as well as ecosystem processes.  Fauna are often used to monitor the ‘health’ of an ecosystem. For instance, the health of freshwater systems is often measured by the number and diversity of native and non-native invertebrate fauna and fish.

The impact of ecosystem processes, such as fire, can also alter the “ecosystem health” of a forest or woodland.  Some recent work I’ve been doing this year with the Department of Environment and Conservation has examined the productivity (in terms of fruit produced) of Banksia attenuata and B. menziesii in different time-since-last-fire habitat.  What does this have to do with fauna I hear you say??  Well, Carnaby’s Black-Cockatoo is an endangered cockatoo that feeds on Banksia of the Swan Coastal Plain, and the loss of food resources has been attributed to their decline.   By examining the productivity of Banksias in different fire-aged habitat, we can provide information to land managers on the range of fire-free intervals that will result in the greatest amount of food resources for Carnaby’s.

For my future work with the Centre, I’m particularly interested in how predation affects fauna assemblages.  Carnivores can regulate the population abundance of other fauna, and without native predators, or with the introduction of non-native predators, changes to the ecosystem health can occur.  For example, when wolves became extinct in Yellowstone National Park, their prey (elk) altered their browsing behaviour to an extent that nearly led to the localised extinction of two cottonwood tree species.   In a move towards restoring the ecology of this ecosystem, wolves have been reintroduced into Yellowstone National Park.  In SWWA, introduced foxes have been implicated in the dramatic decline of numerous native mammals.  I’d like to look at how the loss of native mammals from SWWA may have impacted ecosystem health. In addition, I’m interested in examining how the removal of foxes may change native faunal assemblages, as well as the impact of other meso-predators on fauna in declining and healthy woodlands.

Of course, there are many other projects that I’d like to look at too! In order to answer the Big Picture Questions there are a number of issues that researchers in the Centre need to understand.  Ideally, we need to know how faunal assemblages are composed and operate in health ecosystems, what happens to the fauna when the ecosystem health declines, and how fauna can contribute towards fixing a declining ecosystem.  Looks like we’ve got our work cut out for us!