Botanic Gardens Trust, Sydney, Australia

Woodland ecology

The science of ecology is about understanding the interactions of living organisms with each other and with their environment. The woodland at the Australian Botanic Garden, Mount Annan is a remnant of western Sydney’s Cumberland Plain Woodland, part of a larger class of woodlands known as grassy woodlands, because of the predominance of grasses and herbs in their understories. For example you may have heard of the related Grassy White Box woodlands of the NSW western slopes. These, and other grassy woodlands, have environmental features, particularly the presence of clay soils, and sometimes many plant species in common. In contrast our nearby Sydney sandstone woodlands, such as in Royal National Park and the Blue Mountains, are shrubby woodlands; they have a predominance of shrubby species and very few species in common with Cumberland Plain Woodland, despite their proximity and similar rainfall. They are confined to low nutrient sandy soils.

As ecological scientists we’ve spent years trying to understand the ecology and interactions of species in our woodland, so that we can manage it to ensure that all the native species continue to survive. We’ve only scratched the surface, but would like to share what we’ve learnt so far, so that you can appreciate not only the woodland at the Australian Botanic Garden, but also the remnants of woodland that are elsewhere in western Sydney, and which may not be being treated as well. While other sites will have many species in common, most will have particular features that make each site special in its own way. We can’t tell you exactly what to do at your site, as ecological conditions and management issues may be different, but search our web pages here for information and ideas on a complex and fascinating subject.

How do woodlands function?

Identifying the individual species and knowing the names of woodland plant species is only the beginning. Ecology is about discovering many interesting natural history facts. To understand how the woodland functions we need to look at the life histories of individual woodland species and how they interact with each other.

What are the life cycles of the plants and how long do they live. When do new plants germinate? What conditions favour some species but hinder others?

In a sense we want to try to take the woodland system apart, look at the individual components and the species ecology, and then put them back together to try to understand how they interrelate with each other through their community ecology.

Taking our woodland system apart

A good way to look at the ecology of individual species is in terms of cycles, processes and impacting events. Begin with the stages in the life cycle of the plant: adult - flower - fruit - seed - germination - establishment - juvenile - adult.

To this we add the processes that are part of the life cycle - pollination, seed dispersal and predation - as well as ongoing processes such as seasonality and aging. We need to look at some of the interactions with other factors such as plant /animal interactions and weather conditions.

We then add some impacting events that may affect a plant during its life - fire, drought, plagues, disease etc.

Quite complicated isn’t it! And remember we are considering this in relation to only one plant species. In the woodland at the Australian Botanic Garden there are about 130 native plant species and up to 80 exotic species all vying for a place.

Putting our woodland together

Finally we need to know how these factors all work together i.e. how the plant community functions holistically. We need to know its condition or health and whether there are exotic species and what their impact is. Taken together, this information will provide a sound basis for understanding and predicting how the woodland functions through time and space.

We provide a summary of the key ecological features we have identified in the woodland at the Australian Botanic Garden. Many of these points are relevant to a wide range of grassy woodland communities. Management decisions that are required to ensure that the biodiversity and ecological processes are maintained can then be evaluated.

Ecology of Cumberland Plain Woodland
 Ecologists at work

Brunoniella australis flower

Usnea sp

Pollination of Rhodanthe anthemoides

Ecological burning