Conserving Whole Ecosystems

This is the text of a brochure available from Friends of Grasslands.  Contact Us for printed copies.

Introduction

A key aim of Friends of Grasslands (FoG) is to encourage conservation of our natural ecosystems, particularly those under most threat such as natural temperate grasslands, grassy woodlands and grassy forests (grassy ecosystems) and many of our wetland systems.

The term ‘ecosystem’ is a relatively new term and is not widely understood. A simple definition of an ecosystem, and there are many available, is “a group of organisms, their environment, and their inter-relationships.”

A natural grassland ecosystem, for example, includes the organisms (grasses and other plants, fauna, fungi, small organisms, etc.) physical environments (soils, landforms, water, and climate), and their inter-relationships (photosynthesis and decomposition, food chains, water and nutrient cycles), all of which are part of a grassland ecosystem.

An ecosystem approach to conservation therefore is a holistic approach to conservation, and managing a patch of grassland or woodland for example requires keeping in mind all the elements of the ecosystem.

A patch as an example of an ecosystem

Often when faced with the complexity of an ecosystem people feel bewildered – natural temperate grasslands alone have over five hundred plant species, not to mention fungi, lichens, and numerous animals including insects.

To start to understand ecology it is useful to think of a favourite patch. If the patch covers several types of vegetation, it is better to take one part of it – a grassland for example.

You might think about a patch of grassland and ask:

If you have thought about these questions, then ask – why is it so. Why does the patch exist in this way? How does it differ from other patches? Why are there subtle mosaics? What eats what? Why has native vegetation resisted/not resisted weed invasion?

You might also ask: how is the patch classified as an ecosystem, and what other patches are similar to it and why? You are well on the way to understanding an ecosystem approach to conservation.

You might also ponder: what management is undertaken here in terms of grazing, weeding, and restoration, and what management would maintain it in its current condition or in an improved condition.     

Vegetation communities as proxies for ecosystems

Most ecosystems are defined by reference to plant communities (a group of plants living together in a particular region). It is no coincidence that plants form communities, as each plant species in a community is adapted to grow in a particular physical environment that may be described by its altitude, landscape, soils, climate, availability of water, etc.

While many classifications of vegetation communities have been published, their authors often take different approaches, in part reflecting the fact that vegetation patterns are highly complex and the change from one pattern to another is subtle. Therefore there is a degree of judgement and arbitrariness in any attempt to describe the different vegetation communities.  

To describe a group of ecosystems we have taken the Southern Tablelands of NSW, including the ACT. What follows is neither a comprehensive nor a definitive classification of ecosystems in the Southern Tablelands region, but it is hoped that it will encourage readers to develop their own understanding of ecosystems. 

The description of ecosystems described below draws heavily on three authors: Costin, Keith, and Falding. Costin’s publication, even though published fifty years ago, is a must read for anyone who seriously wants to understand the vegetation of the Southern Tablelands. Keith provides an easy-to-read and simple account of vegetation communities of NSW. Falding maps the different vegetation communities and illustrates how government planning can ensure that we retain what is left of our depleted ecosystems. Each publication (see references below) is worth serious study. There are many more excellent references. The description below also relies heavily on some unpublished research being undertaken by Environment ACT on the vegetation communities of the ACT.

Alpine and Southern Highlands Bioregions

The Southern Tablelands includes alpine, sub-alpine, montane, and lowland areas. The alpine and sub-alpine are generally grouped together and described as the alpine bioregion, while montane and lowland areas are considered as part of the Southern Highlands bioregion.

Fortunately the alpine bioregion is largely protected in national parks, although particular land uses, and plant and animal introductions remain significant threats.

The alpine (above the tree line) areas contain a number of important vegetation communities which include:

These are important ecosystems, dear to the hearts of many FoG members for many reasons, including their natural beauty and spectacular flower displays. From a grassy-ecosystem perspective, they are important because:

The non-alpine communities include: grassland, woodland, open forest, tall wet forest, heath and shrub land, and wetlands.     

Natural grassland

Natural grasslands are essentially treeless areas dominated by native grasses, often with patches or sprinklings of wildflowers.

Grasslands may in turn be divided into a number of distinct communities, and those most familiar to FoG members would be: alpine, temperate and montane, maritime, and riverine plain grassland.

The temperate and montane grassland are the most familiar, and can be divided into three communities, largely dependent on landscape and water considerations:

Each of these grasslands is quite distinct with a separate suite of plants. Dry grasslands are the most plant species diverse and colourful.

Alpine grasslands are in the higher areas of the Southern Tablelands and intergrade with alpine herb lands. Maritime grasslands exist along the eastern seaboard and are either dominated by kangaroo grass where soils are better, or spinifex grass on sandy soils. The riverine plain grasslands refer to those found in the Riverina around Hay.

Grassy woodland

There are several major grassy woodland communities in the Southern Tablelands: box, snow gum, and alpine woodlands, as well as two riparian grassy woodland communities.

Box woodland in the ACT is referred to as yellow box-red gum grassy woodland, named after the two large tall trees, yellow box (Eucalyptus melliodora) and Blakely’s red gum (E. blakelyi) that dominate it. North of the ACT these trees are joined by another co-dominant, white box (E. albens), and the combined community is simply referred to as box woodland. White box do not appear to occur naturally in the ACT. In the south west of the Southern Tablelands white box mix with white cypress pine to form a tall woodland community. 

Snow gum woodland occurs in the colder parts of the region where yellow box and red gum generally will not grow, e.g., snow gum sometimes grows on basalt soils, and yellow box and red gum do not. Snow gum woodland may consist of white sally snow gum (E. pauciflora), black sally (E. stellulata) which prefers more moist soils, and a number of other trees, e.g., candlebark (E. rubida) being common. Each of these tree species may be found in other communities. Sub-alpine woodlands are dominated by another snow gum (E. niphophylla).

Two distinct riparian woodlands exist: ribbon gum (E. viminalis) riparian woodland, and river she-oak (Casuarina cunninghamiana) riparian woodland.

Because of the ways in which these communities are managed they often consist largely of old and widely spaced trees with an understorey dominated by grasses and, if in good condition, many wildflowers, often similar to those found in grassland. Patches of shrub occur in some places. If woodlands are allowed to regenerate, new trees are often closely spaced and may shade out the grasses.

Dry forest

Traditionally, woodlands have been differentiated from forests by the percentage of the ground shaded by trees when the sun is directly overhead. However, the distinction is often not helpful in deciding whether some vegetation should be called a woodland or forest, so readers should not be too concerned with distinguishing woodland from open forest.

In the Southern Tablelands there is no accepted view of what dry forest communities exist. A number of trees are often referred to in describing forest communities. These are: apple box (E. bridgesiana), broad-leaved peppermint (E. dives), red stringybark (E. macrorhyncha), scribbly gum (E. rossii), black cypress pine (Callitris endlicheri).

Dry forests may be dominated at ground level by shrubs or grasses.

Tall wet forests

Different classifications come up with between two and four groupings of tall wet forest communities in the Southern Tablelands. These are described by reference to the main trees that dominate them: alpine ash (E. delegatensis) which requires deep soil, mountain gum (E. dalrympleana) which can grow on shallow soil, brown barrel (E. fastigata), which also requires deep soil, and narrow-leaf peppermint (E. robertsonii) which requires somewhat deeper soils.

These communities rely on higher rainfall along the base of the alpine chain and the escarpment that divides the coast from the Southern Tablelands.     

Other communities

There are a number of non-alpine heath and shrub lands. Many fringe rivers and may be dominated by epacrids, kunzea, and tee-tree. One fairly widespread community is dominated by Casuarina nana.

There are many varied types of wetlands including vegetation communities which are in permanent bodies of water (including fens, and valley and suspended bogs), and ephemeral lakes and other areas which sometimes lie below water.

In the Southern Tablelands, there are occurrences of relic or isolated populations of trees (often mallee) that could be considered as separate vegetation communities.

Decline of our ecosystems

The following table shows how ecosystems in the Southern Tablelands have fared since settlement, and reveals sharp declines in all ecosystems.

The second column shows the proportion of the region occupied by each broad ecosystem at the time of settlement, the third column shows the proportion of the region now occupied by each broad ecosystem, and the last column what proportion of each broad ecosystem now remains. 

 For example, grasslands have declined from eleven percent of the region to one percent, i.e. now only nine percent of their original area remains. The percentage may be a little higher if one includes grasslands in the grassland woodland mosaic. In reality, the story is much worse, as grassland remnants remaining in relatively good condition is less than three percent.

 

% in 1788

% now

% left

Grassland

11

1

9

Grassland-woodland mosaic

11

3

27

Box woodland

23

9

39

Dry forest

38

21

55

Wet forest

14

12

86

Riparian

1

0.5

50

Other

1

51

-

 

What is being done?

If our vegetation is in such a parlous state, what is being done, and what can community groups do?

Mapping

Vegetation mapping of what was present and its current retention is being undertaken. FoG has been an active contributor to this through its plant surveys, advice to government, and advocacy.

Listing

Many grassy ecosystem communities and related species are being listed under threatened species legislation at commonwealth, state, and territory level. Again groups like FoG have been playing their part.  

Recovery plans

There is a legislative requirement that recovery plans be developed for listed communities and species. This has been happening apace, and in the ACT there are some very good examples of grassland and woodland strategies.

Protection and management

Much is occurring to protect endangered communities and species through either reserve or off-reserve arrangements, which manage for conservation, but more needs to be done.

On-ground work and restoration

FoG’s vision is that we return as much of our landscape as possible to what it was in 1788, i.e., recovery our grassy and other ecosystem vegetation. This makes much sense as these ecosystems are the most sustainable, ecological functional, and climate change adaptable. The priorities are best management for high quantity remnant vegetation, reconnecting this vegetation, and restoring degraded land wherever possible to its original native vegetation. This is slowly beginning to happen.

Education & advocacy

FoG and many like minded groups are starting to target broader and broader groups at all ages with good material and likewise to work effectively with decision makers.

Native vegetation legislation

The commonwealth and all mainland states have enacted legislation to stop native vegetation clearing. While it has many weaknesses, it is important that it be allowed for work to protect our most precious assets.

Some concluding remarks

The concept of ‘ecosystem’ is powerful analytic tool, but the classification of ecosystems remains very fluid.

It should be remembered that ‘ecosystem’ is a conceptualism of our vegetation which is very subtle. We also need to consider the mosaic of ecosystems, i.e., how various ecosystems communities merge into one another, and how many animals move between different vegetation communities.

The boundary between two vegetation communities, the ecotone, is itself worthy of study for its habitat and ecosystem function characteristics. Other subtleties e.g. rocky outcrops, aspect, seepage, and disturbance, can have important effects on plant and animal species.

Useful literature

Martin Falding A planning framework for natural ecosystems of the ACT and NSW Southern Tablelands, NSW National Parks and Wildlife Service, Hurstville, NSW, 2002. ISBN 0-646-41930-7.

Alex B Costin A Study of the ecosystems of the Monaro region of New South Wales with special reference to soil erosion, Government Printer 1954.

David Keith Ocean shores to desert dunes, the native vegetation of New South Wales and the ACT, NSW National Parks and Wildlife Service, 2004. ISBN 0 7313 6780 4.

Environment ACT Woodlands for wildlife, ACT lowland woodland strategy, Action Plan No. 27.  2004 ISBN: 0 6 642 60259 X.

Environment ACT A vision splendid of the grassy plains extended, ACT lowland native grassland conservation strategy, Action Plan No. 28. ISBN: 0 642 60338 3.

To contact FoG: Contact Us