Indicator: Ecosystem diversity

| Indicator description | Complete list of Indicators |

What the results tell us for Tumut

| Analysis techniques |

For maps showing Tumut ecosystems in 1750 and in 1997, Contact us for details of the full report for the Australian Capital Region (available only on CD-ROM).

Thirty-nine ecosystem types were identified in Tumut Shire, of which 10 (about 26%) were classed as highly dysfunctional (see Figure 1). When current pressures on ecosystems in Tumut Shire were taken into account, it was found that 12 ecosystems should be considered for immediate protection (if they are not already within the 35% of Tumut Shire that is under conservation) and for restoration. Those 12 ecosystems are:

• Legend No 43 - Western Slopes River Red Gum Riparian Moist Sedge Woodland
• Legend No 76 - Central Tablelands Candlebark-Snow Gum Grass Grass-Shrub Dry Forest
• Legend No 94 - Tableland Black Sallee Dry Herb-Grassy Woodland
• Legend No 116 - Western Slopes Blakely's Red Gum Herb-Grassy Woodland
• Legend No 117 - Western Slopes White Box Dry Grass Woodland
• Legend No 119 - Central Tablelands Candlebark-Snow Gum Grass Grass-Shrub Dry Forest
• Legend No 120 - Western Slopes Red Stringybark-White Box Dry Shrub-Herb-Grassy Forest
• Legend No 146 - Tableland Black Sallee Dry Herb-Grassy Woodland
• Legend No 148 - Tableland Swamp Tussock Grass-Carex Grassland /Sedgeland/ Open Woodland
• Legend No 154 - Tablelands Apple Box Dry Grassy Woodland
• Legend No 160 - Central Highlands Blakelys Red Gum-Yellow Box Dry Grass Woodland
• Legend No 161 - Tablelands and Slopes Yellow Box Dry Herb-Grassy Woodland

Figure 1. Number of ecosystems in each functional category

The assessment of ecosystem functionality in this Report was based on data from the Southern and Eden Forest Regional Forest Assessment Project. The ecosystems and subsequent analysis require on-ground verification and this should happen as the indicator is developed (see About the Data).

About 50% of Tumut Shire has been cleared or modified (see Table 1), most of which has occurred in the grassy ecosystems in the South-East Highlands bioregion. This is also where most of the highly dysfunctional ecosystems are found.

Ecosystem diversity in each Government area was compared across the Region. Historically and currently, the ecosystem diversity in Tumut Shire is in the middle to high range of ecosystem diversity found in the entire Region. Overall, with modification and clearing of the valleys and ridges of the western parts of the Cooma-Monaro Plains and forest edges, the current ecosystem diversity is estimated to be about two fifths (40%) of that of historical conditions. Comparative results are discussed further in the results for the Region.

The historical and current condition of ecosystem diversity in Tumut Shire is further summarised below.

Table 2 shows all the ecosystems identified in Tumut Shire, listed according to the four functional categories in Table 1. The first 10 of these - the highly dysfunctional ecosystems - are mainly grasslands and grassy forest ecosystems.

These ecosystems have reached this condition because of their presence in heavily modified landscapes, and their extensive habitat fragmentation. They have lost their usual complement of functional groups, such as ground dwelling marsupials, birds, and possibly fungi and invertebrates. In the case of the grassy woodlands, habitat complexity in most cases has been reduced to a grassy understorey with scattered shrubs, as a result of intensive grazing over the last 100 years.

The 10 ecosystems assessed as highly dysfunctional once covered around 74 000 hectares as functional ecosystems before European settlement. Today, the area in which these 10 ecosystems are functional is only about 6300 hectares. That approximates to a 91% loss of functional habitat within these ecosystems (see Figure 2). This contrasts with a recommended 30% reduction in area of vegetation cover relative to historic extent of ecosystems (Smith et. al., 2000). Such significant levels of habitat reduction indicate that the present habitat is insufficient to maintain historic levels of all functional groups in these ecosystems.

Figure 2. Change in the area of each ecosystem functional category

The moderately functional and near natural ecosystems occur National Parks and Wildlife Service reserves and State Forests. The ecosystems here have had minimal change to their ecosystem function and habitat complexity. These are well conserved, being contained within the boundaries of the South-East Forests National Park.

* see data details in About the data, S =highly dysfunctional ecosystems, R = moderately dysfunctional, M = somewhat functional, I = functional

Ecosystems and their pressures

Table 3 shows the threatening processes, assessed at a regional level as part of the Regional Forests Assessment process, which are most likely to be exerted on each of the ecosystems. Therefore they may not be relevant in every instance, and on-ground verification for each Government area would be desirable.

Table 3. Threatening processes, sorted by level of pressure

Legend Number	Name of Ecosystem Type	Level of Threat (1=Low, 5=Very High)	Primary Process	Causes	Additional Processes	Causes
43	Western Slopes River Red Gum Riparian Moist Sedge Woodland	5	Clearing	Fuelwood, Intensive Cropping	Weed Invasion, Grazing	Livestock Management, Weeds
116	Western Slopes Blakely's Red Gum Herb/Grass Woodland	5	Patch Decline	Tree Dieback	Weed Invasion	Perennial Pasture, Exotic Weeds
117	Western Slopes White Box Dry Grass Woodland	5	Paddock Tree Removal	Fuel Wood Collection	Weed Invasion	Perennial Pasture, Exotic Weeds
148	Tableland Swamp Tussock Grass-Carex Grassland-Sedgeland / Open Woodland	5	Patch Decline, Weed Invasion	Rough Grazing	Weed Invasion	Perennial Pasture, Exotic Weeds
154	Tablelands Apple Box Dry Grassy Woodland	5	Remnant Patch Clearing /Modification	Roadside & Travelling Stock Reserve Management, Paddock Improvement	Weed Invasion	Perennial Pasture, Exotic Weeds
160	Central Highlands Blakelys Red Gum-Yellow Box Dry Grass Woodland	5	Patch Decline	Tree Dieback	Weed Invasion	Perennial Pasture, Exotic Weeds
161	Tablelands and Slopes Yellow Box Dry Herb/Grass Woodland	5	Clearing	Fuelwood collection, Intensive Cropping, Urban/Rural Housing	Weed Invasion	Perennial Pasture, Exotic Weeds
93	Western Tablelands Western Peppermint Herb/Grass Dry Forest	4	Clearing	Pine Plantations	Repeated Grazing, Weed Invasion (St Johns Wort)	Introduced Livestock
94	South West Slopes Red Stringybark-Apple Box Acacia Dry Herb/Grass Forest	4	Clearing	Pine Plantations	Repeated Grazing, Weed Invasion (St Johns Wort)	Introduced Livestock
119	Western Tablelands Red Box-Red Stringybark Dry Shrub/Grass Forest	4	Clearing	Pine Plantations	Rough Grazing	Introduced Livestock
120	Western Slopes Red Stringybark-White Box Shrub/Herb/Grass Dry Forest	4	Patch Decline	Fuel Wood Collection	Rough Grazing	Introduced Livestock
146	Tableland Black Sallee Dry Herb-Grassy Woodland	4	Patch Decline, Weed Invasion	Rough Grazing	Patch Clearing	Hobby Farms
71	Western Tableland Red Stringybark Ti-tree Dry Shrubby Forest	3	Clearing	Rough Grazing	-	-
76	Central Tablelands Candlebark-Snow Gum Grass Grass-Shrub Dry Forest	3	Clearing	Rough Grazing, changed fire regimes, Hobby Farms outside of ACT	Weed Invasion	Pasture & Weed Grasses
104	Tablelands Western Peppermint-Mountain Gum Acacia/Herb/Grass Forest	3	Intensive Silviculture	Forestry	-	-
114	Tablelands Red Stringybark-Scribbly Gum Dry Shrub/Tussock Grass Forest	3	Clearing	Hobby Farms	Rough Grazing	Introduced Livestock
121	Western Slopes Red Stringybark-Red Box Grass/Herb Dry Forest	3	Clearing	-	-	-
124	Western Montane Snow Gum-Black Sallee Wet Heath/Herb Grass Woodland	3	Weed Invasion	Rough Grazing	Patch Decline, Weed Invasion	Pine Plantation
129133	Alpine Wet Herbfield & Sub-alpine Wet Herb/Grassland/Bog	3	Patch Decline	Global Warming	-	-
38	Tableland Calytrix-Red Box Dry Heath Shrub/Herb/Grass Woodland	2	Grazing	Livestock	-	-
58	Tableland and Escarpment Brown Barrel Wet Layered Shrub Forest	2	Intensive Silviculture	Forestry outside of the ACT	-	-
86	Western Montane Alpine Ash-Snow Gum Pepper Bush Moist Shrub Forest	2	Infrequent Fire Regimes	Drought	-	-
87	Western Escarpment Alpine Ash-Mountain Gum Moist Shrub/Herb/Grass Forest	2	Oldgrowth Loss	Infrequent fire Regimes	-	-
89	Eastern Tablelands Mountain Gum-Manna Gum Acacia/Herb/Grass Forest	2	Patch Clearing	Rough Grazing for Livestock	Repeated Grazing, Weed Invasion	Introduced Livestock
91	Burrinjuck Apple Box-Blue Gum-Silver Wattle Dry Herb/Grass Forest	2	Frequent Fire Regimes	Fuel Management	Repeated Grazing, Weed Invasion	Introduced Livestock
101	Bago Montane Mountain Gum-Snow Gum Hop Bush Dry Shrub/Herb/Grass Forest	2	Intensive Silviculture	Forestry	Grazing	Livestock
103	Western Montane BL Peppermint-Mountain Gum-Peppermint Dry Fern/Grass Forest	2	Infrequent Fire Regimes	Reserve Management	-	-
108	Western Tablelands Red Stringybark-BL Peppermint Dry Herb/Grass Forest	2	Intensive Silviculture	Forestry	Grazing	Introduced Livestock
118	Western Slopes Red Ironbark-Red Box Dry Grass Forest	2	Patch Decline	Fuel Wood Collection	Weed Invasion	Perennial Pasture, Exotic Weeds
128	Sub-alpine Snow Gum Dry Shrub/Herb Woodland	2	Infrequent Fire Regimes	Reserve Management	-	-
130	Sub-alpine Snow Gum Shrub/Grass Woodland	2	Infrequent Fire Regimes	Reserve Management	-	-
131	Sub-alpine Herbfield	2	Infrequent Fire Regimes	Reserve Management	-	-
36	Montane / Sub-Alpine Dry Rocky Shrubland	1	Infrequent Fire Regimes	Reserve Management	-	-
82	Western Montane Manna Gum-Western Peppermint Cassinia Fern/Herb Forest	1	Weed Invasion	Woody Weeds, Exotic Grasses	Rutting	Feral Pigs
97	Montane Mountain Gum-Snow-Gum Silver Wattle Dry Shrub/Herb/Grass Forest	1	Rutting	Feral Pigs	Infrequent Fire Regimes	Reserve Management
98	Western Montane Snow Gum-Mountain Gum Moist Shrub Forest	1	Rutting	Feral Pigs	Infrequent Fire Regimes	Reserve Management
99	Montane Snow Gum Dry Shrub/Herb/Grass Forest	1	Rutting	Feral Pigs	Infrequent Fire Regimes	Reserve Management
106	Montane Western NL Peppermint-Mountain Gum Dry Shrub-Tussock Forest	1	Infrequent Fire Regimes	Drought	-	-
190	Rocky Outcrops	1	-	-	-	-

The most significant ecosystems under threat in the Tumut Shire are those with pressure levels of 4 and 5, identified within Table 3. Ecosystems that fall into this category include:

• Legend No 43 - Western Slopes River Red Gum Riparian Moist Sedge Woodland
• Legend No 93 - Western Tablelands Western Peppermint Herb/Grass Dry Forest
• Legend No 94 - South West Slopes Red Stringybark-Apple Box Acacia Dry Herb/Grass Forest
• Legend No 116 - Western Slopes Blakely's Red Gum Herb/Grass Woodland
• Legend No 117 - Western Slopes White Box Dry Grass Woodland
• Legend No 119 - Western Tablelands Red Box-Red Stringybark Dry Shrub/Grass Forest
• Legend No 120 - Western Slopes Red Stringybark-White Box Shrub/Herb/Grass Dry Forest
• Legend No 146 - Tableland Black Sallee Dry Herb-Grassy Woodland
• Legend No 148 - Tableland Swamp Tussock Grass-Carex Grassland-Sedgeland / Open Woodland
• Legend No 154 - Tablelands Apple Box Dry Grassy Woodland
• Legend No 160 - Central Highlands Blakelys Red Gum-Yellow Box Dry Grass Woodland
• Legend No 161 - Tablelands and Slopes Yellow Box Dry Herb/Grass Woodland

Suggested management response

The extent to which an ecosystem is considered to be potentially threatened overall has been derived by analysing its current condition based on clearing or modification over time (the ecosystem functionality index), plus the (assumed) current pressures on it (level of pressure index). The combined index produces a range of values from 7 to 35, 7 being the lowest risk indicator, and 35 being the highest. The processes are further explained in About the Data.

Within Tumut Shire, the results of this analysis have produced a list of ecosystems, which fall under four broad categories of action that apply across the Region. Those four broad actions associated with overall levels of threat are:

• 'Immediate Protection and Restoration' is recommended for those ecosystems with a potential overall threat value between 25 and 35 (very high)
• 'Integrated Landscape Protection and Management' is recommended for those ecosystems with a potential overall threat value between 18 and 24 (high)
• 'Monitor Condition and Pressures' is recommended for those ecosystems with a potential overall threat value between 12 and 17 (moderate)
• No immediate action is recommended for those ecosystems with a potential overall threat value of 11 and below (little/no current overall threat).

Table 4 shows that there are 12 ecosystems which are potentially under very high overall threat in Tumut Shire, and which may require immediate landscape protection and restoration. Actions which need to be implemented are:

• The ecosystems need to be validated with field verification of the current regional vegetation map.
• The regional vegetation map should then be updated to reflect any errors in mapping before a landscape audit.
• A landscape audit of the shape, size, configuration of ecosystem patches should be developed to assist with landscape planning and ecological restoration actions.
• This should be followed up with a list of management actions that will restore the ecological integrity and health of most vegetation patches greater than two hectares that could form part of a conservation management network. The threshold area of two hectares is presently recognised in the 1997 Native Vegetation Conservation Act of New South Wales as being the minimum patch size for protection and restoration of native vegetation. Current scientific studies have shown that a minimum patch size to maintain the range of natural bird species is between 10 and 25 hectares.

Table 4. Number of ecosystems in overall threat categories.

Category	Number of Ecosystems	% of Total Number of Ecosystems
Very high	12	31%
High	4	10%
Moderate	17	44%
Little/no current overall threat	6	15%
Total Number	39	100%

Pending verification, the four ecosystems considered to be subject to high overall threat would attract a proposed management response of 'Integrated Landscape Protection'. This suggests that the planning and management actions should limit the further fragmentation and loss of structural and species diversity from rural/residential subdivision, grazing, and patch clearing. Where possible, ecological pressures on these ecosystems should be stabilised to levels that ensure long-term conservation of ecological integrity and health of the remaining remnant patches.

The 17 ecosystems which fall under the 'moderate' category would attract a proposed management response of 'Monitor Ecological Function and Threats'. This suggests that the pressures on these ecosystems should be monitored, and in some cases acted on, if unacceptable changes to ecosystem characteristics and ecological processes occur.

Finally, the six remaining ecosystems are considered to be subject to little-no current overall threat. They require limited management in a landscape management context, although some of the local threats to ecosystem function should be monitored.

The suggested management response in Table 5 is based on an index of potential overall threat which places Yass Shire into a regional context when considering suggested management actions for conservation of ecosystem diversity.

Table 5. Suggested management responses for each ecosystem type in Tumut shire council.

Legend Number	Name of Ecosystem Type	Ecosystem Functionality Index	Level of Pressure (1=Low, 5=Very High)	Combined Pressure / Functionality Index	Management Response
43	Tablelands and Slopes Yellow Box Dry Herb-Grassy Woodland	25	5	35	Immediate Protection-Restoration
116	Tableland Swamp Tussock Grass-Carex Grassland /Sedgeland/ Open Woodland	22	5	32	Immediate Protection-Restoration
160	Tablelands Apple Box Dry Grassy Woodland	22	5	32	Immediate Protection-Restoration
161	Western Slopes River Red Gum Riparian Moist Sedge Woodland	22	5	32	Immediate Protection-Restoration
154	Estuaries/Water Bodies	21	5	31	Immediate Protection-Restoration
117	Central Highlands Blakelys Red Gum-Yellow Box Dry Grass Woodland	19	5	29	Immediate Protection-Restoration
148	Western Slopes Red Ironbark-Red Box Dry Grass Forest	19	5	29	Immediate Protection-Restoration
146	Western Slopes Blakely's Red Gum Herb-Grassy Woodland	20	4	28	Immediate Protection-Restoration
120	Western Slopes White Box Dry Grass Woodland	19	4	27	Immediate Protection-Restoration
94	Tableland Black Sallee Dry Herb-Grassy Woodland	18	4	26	Immediate Protection-Restoration
119	Central Tablelands Candlebark-Snow Gum Grass Grass-Shrub Dry Forest	18	4	26	Immediate Protection-Restoration
76	Western Slopes Red Stringybark-White Box Dry Shrub-Herb-Grassy Forest	19	3	25	Immediate Protection-Restoration
93	Western Tablelands Red Box-Red Stringybark Dry Shrub/Grass Forest	14	4	22	Integrated Landscape Protection and Management
118	South West Slopes Red Stringybark-Apple Box Acacia Dry Herb-Grassy Forest	17	2	21	Integrated Landscape Protection and Management
71	Western Montane Snow Gum-Black Sallee Wet Heath-Herb-Grassy Woodland	13	3	19	Integrated Landscape Protection and Management
114	Western Montane Manna Gum-Western Peppermint Cassinia Fern-Herb Forest	13	3	19	Integrated Landscape Protection and Management
38	Western Montane BL Peppermint-Mountain Gum-Peppermint Dry Fern-Grassy Forest	13	2	17	Monitor Ecological Function and Threats
108	Tablelands Red Stringybark-Scribbly Gum Dry Shrub-Tussock Grass Forest	13	2	17	Monitor Ecological Function and Threats
104	Western Slopes Red Stringybark-Red Box Grass/Herb Dry Forest	11	3	17	Monitor Ecological Function and Threats
124	Burrinjuck Apple Box-Blue Gum-Silver Wattle Dry Herb-Grass Forest	11	3	17	Monitor Ecological Function and Threats
103	Western Tablelands Western Peppermint Herb-Grassy Dry Forest	12	2	16	Monitor Ecological Function and Threats
121	Tablelands Western Peppermint-Mountain Gum Acacia-Herb-Grassy Forest	10	3	16	Monitor Ecological Function and Threats
82	Western Tableland Dry Shrubland - E. macrorhyncha/Leptospermum brevipes	13	1	15	Monitor Ecological Function and Threats
89	Rocky Outcrops	11	2	15	Monitor Ecological Function and Threats
101	Tableland Calytrix-Red Box Dry Heath Shrub-Herb-Grass Woodland	11	2	15	Monitor Ecological Function and Threats
128	Western Tablelands Red Stringybark-BL Peppermint Dry Herb-Grassy Forest	11	2	15	Monitor Ecological Function and Threats
91	Sub-alpine Herbfield	10	2	14	Monitor Ecological Function and Threats
129133	Western Escarpment Alpine Ash-Mountain Gum Moist Shrub-Herb-Grass Forest	8	3	14	Monitor Ecological Function and Threats
86	Sub-alpine Snow Gum Shrub/Grass Woodland	9	2	13	Monitor Ecological Function and Threats
87	Montane Mountain Gum-Snow Gum Silver Wattle Dry Shrub-Herb-Grass Forest	9	2	13	Monitor Ecological Function and Threats
130	Western Montane Snow Gum-Mountain Gum Moist Shrub Forest	9	2	13	Monitor Ecological Function and Threats
36	Montane - Sub-Alpine Dry Rocky Shrubland	10	1	12	Monitor Ecological Function and Threats
131	Bago Montane Mountain Gum-Snow Gum Hop Bush Dry Shrub-Herb-Grassy Forest	8	2	12	Monitor Ecological Function and Threats
97	Central Tableland-ACT Montane Mountain Gum-BL Peppermint Dry Shrub Forest	9	1	11	-
98	Alpine Wet Herbfield-Sub-alpine Wet Herb/Grassland/Bog	9	1	11	-
99	Western Montane Alpine Ash-Snow Gum Pepper Bush Moist Shrub Forest	9	1	11	-
106	Sub-alpine Snow Gum Dry Shrub-Herb Woodland	9	1	11	-
58	Eastern Tablelands Mountain Gum-Manna Gum Acacia-Herb-Grass Forest	7	2	11	-
190	Montane Snow Gum Dry Shrub-Herb-Grass Forest	5	1	7	-

About the data (analysis techniques)

Dataset and description – forest ecosystems layer

Regional vegetation maps of south-eastern New South Wales were prepared as part of the Comprehensive Regional Assessments of forests in New South Wales between 1997 and 2000. The Comprehensive Regional Assessments covered the Southern and South-East Forests, which fall into the Australian Capital Region.

The Comprehensive Regional Assessments were designed to provide a scientific basis for creating a 'Comprehensive, Adequate and Representative' system of conservation on public land, and at the same time set up systems of ecologically sustainable forest management on all public land tenures. The derivation and mapping of forest ecosystems was identified as a major source of information to assess the conservation adequacy of forests in the Southern Regional Forest Agreement. Based on the Joint ANZECC/MCFFA National Forest Policy Statement Implementation Sub-committee (JANIS) criteria (JANIS 1997), forest and non-forest ecosystems were meant to act as broad surrogates for the range of biodiversity within the Southern Comprehensive Regional Assessment Region. To meet the JANIS criteria, the classification and mapping of forest and non-forest ecosystems were designed to meet the following criteria, namely that the ecosystems:

• could represent the full range of biodiversity
• be defined in terms of floristic composition in relation to substrate and position within the landscape
• be recognisable in the field
• be mapped at a practicable scale of at least 1:100,000
• have their pre-1750 distribution modelled or mapped (JANIS, 1997).

The project objective was to prepare maps of pre-1750 and extant forest ecosystems for the Southern Comprehensive Regional Assessment Region to assess the adequacy of conservation of forest ecosystems across both public and private tenures.

The region was divided into three sub-regions to facilitate the mapping of vegetation as well as conform to regions to be negotiated in the Regional Forest Agreement negotiations. These regions became known as the South Coast, Western and Northern sub-regions.

Forest ecosystem classification and mapping in the Southern Comprehensive Regional Assessment Region followed a hybrid mapping approach using conventional aerial photo-interpretation, expert field knowledge, field survey data and computer modelling systems. The mapping of extant vegetation involved, firstly, derivation of an ecosystem classification from PATN (software program) analysis using vascular plant cover abundance data; and secondly assignment of Aerial Photo Interpretation mapping polygons to classified forest ecosystem types on extant forest land. Some modelling of Aerial Photo Interpretation polygons occurred where it was difficult to separate two vegetation types in the same polygon using aerial photo-interpretation.

The mapping of pre-1750 vegetation on cleared land involved expert allocation of soil landscape units to classified forest ecosystem types, using expert knowledge and classified site data, assigned to forest ecosystem types. Generalised Additive Modelling supported the mapping of pre-1750 vegetation by establishing possible relationships between the various forest ecosystems and environmental variables, such as terrain and soils.

The ecosystems in the Australian Capital Region are based on extensive survey plot data across Southern and Eden Regional Forest Assessment regions, involving over 5000 field samples, collated and analysed as part of the vegetation mapping project. This project produced vegetation types that were meant to act as broad surrogates for ecosystems in the Southern Forests Region, acting as a broad filter for the range of biodiversity in the Region. These vegetation types were mapped across most of the Australian Capital Region with the exception of the western local government areas of Young, Boorowa and Harden.

The mapped layers cover the pre-1750 and 1997 (extant) areas of all the identified ecosystems in the Australian Capital Region. Approximately 185 ecosystems were preliminarily identified across the Southern Forests Region.

Data details

• Absolute figures may not be 100% accurate due to mapping techniques.
• Scale of data is 1:25000
• Minimum patch size for forested areas (with a cover of more than 10%) was 10 hectares, down to two hectares for non-forested areas. Some ecosystems are known to occur only in small patches and are too small to map. As a result there will be many parts of Government areas that have some tree cover which is not included in the data.
• The complete list of ecosystems in the Australian Capital Region, habitat and their occurrence in biogeographic regions is tabulated in results for Ecosystem diversity for the Region. Click on the dropdown menu at the top of this page.
• Dataset currency — Beginning date: 1997 ; Ending date: 2000
• Dataset status — Complete ; Maintenance and update frequency: Further validation is required
• Access — Stored data format and available types: Arcview grid
• The current custodian of the data is National Parks and Wildlife Service of New South Wales.
  Contact details: Lyn Finch, National Parks and Wildlife Service, Southern Directorate.

Analysis techniques

The analysis in this indicator is a new method of understanding and managing ecosystem diversity in the Australian Capital Region. Ecosystem condition and the processes of change are analysed together, to produce an overall assessment of threat, leading to different levels of suggested management response. Our expert Reference Group considers the approach to be a very significant step towards a more comprehensive understanding of biodiversity in our Region. However, we have not yet had the opportunity to fully verify every aspect of the analysis for each Government area, and suggest that this should be done before the next comprehensive State of the Environment Report is due.

The term 'ecosystem' is used here to describe identifiable units of the natural landscape. The basis of ecosystem classification relates to a region-wide classification of vascular plant data into vegetation units, which were intended as broad surrogates for ecosystems. Over 5000 vegetation plots have been classified into over 200 terrestrial and aquatic ecosystems. Data on vascular plants have been used to classify ecosystems in the Region for the following reasons:

• information on vascular plants is available across the Region and can be readily collected in a consistent repeatable manner
• information on animal data is inconsistent, uneven in spread, and sometimes non-existent because of the high level of local extinctions caused by human activity and introductions of pest animals to natural ecosystems in this Region, and because of the difficulty and expense of surveys
• the data on vascular plants can be classified using rigorous, transparent, and repeatable classification algorithms and checked more easily on maps and in the field
• the classified vegetation units have definite relationships to the physiography and lithology of landscape units found throughout the Region.

The relationship between vegetation types and ecosystem diversity is explained in the Indicator Description.

Terms used

Ecosystem functionality index

Functionality of an ecosystem refers to the intactness of all the parts, both biotic and abiotic, relative to the known original conditions of that ecosystem. A functional ecosystem has the full range of functional groups, such as vascular and non-vascular plants, herbivores, insectivores, frugivores, and carnivores, which make up a diverse range of interactions and relationships in that ecosystem. Functionality of ecosystems is a key element for understanding current ecosystem diversity. A functionality index is used to describe the current ecosystem function of each ecosystem identified in the Regional Forest Assessment data, relative to the original historical conditions found in that ecosystem.

The approach used here is to derive a functionality index that integrates key elements of ecosystem functionality. This index is an additive index, which summarises the extent of ecosystem functionality in terms of five criteria. Of necessity, subjective judgments are involved, although the process is clearly defined. The criteria are:

• 'landscape integrity' refers to whether an ecosystem falls into a heavily modified landscape, which would be ranked as a 5, on a scale of 1 to 5. If an ecosystem falls within a natural matrix of ecosystems with little overall modification, it would be ranked as a 1 in a scale of 1 to 5.
• 'extent of habitat fragmentation' refers to the comparative size of current patch size relative to historical conditions. A highly fragmented ecosystem with predominantly small patch sizes would be ranked as a 5, on a scale of 1 to 5. If an ecosystem occurs in large unfragmented patches or relatively intact lineal patches, it would be ranked as a 1, on a scale of 1 to 5.
• 'proportion of native species present' – if an ecosystem had a high proportion of exotic species present in most of its patches, it would be ranked as a 5, on a scale of 1 to 5. If an ecosystem had negligible exotic species present in most of its patches, it would be ranked as a 1, on a scale of 1 to 5.
• 'current habitat complexity' refers to the micro-habitat of an ecosystem, relative to historical conditions. Some ecosystems are inherently more variable and have more layers and places for plants or animals to find resources or shelter. An ecosystem with a high habitat complexity would be ranked as 1, on a scale of 1 to 5. An ecosystem with few layers and few micro-habitats for species would be ranked as a 5, on a scale of 1 to 5.
• 'presence or absence of key functional groups' – if most of the functional groups are present within an ecosystem, it would be ranked as a 1, on scale of 1 to 5. If an ecosystem has lost some key functional groups, which affects ecological processes within an ecosystem, it would be ranked as a 5, on a scale of 1 to 5.

Table 6 shows how the five criteria are assessed to create the four categories of ecosystem functionality. Although not all information may be known in detail about each criteria that make up the functionality index, this method provides an explicit approach to assessing ecosystem functionality.

Table 6. Ecosystem functionality assessment criteria

Category of functionality	Landscape integrity	Degree of fragmentation	Exotic species present	Habitat complexity	Functional groups present	Cut-off points
Highly dysfunctional (S)	Very low (5)	Very high (5)	Many (5)	Very low (5)	Few (5)	19–25
Moderately dysfunctional (R)	Low	High	Some	Low	Some	15–18
Moderately functional (M)	Moderate	Moderate	Few	Moderate	Some-most	11–17
Functional (I)	High (1)	Little (1)	Hardly any (1)	High (1)	Most (1)	0–10

Ecosystem diversity index

An ecosystem diversity index is used here to standardise the number of ecosystems found in each local government area, using a logarithmic function. This mathematical function has been used extensively in calculating a species diversity index for different regions to enable more direct comparisons of regional species diversity.

• Ecosystem diversity index is calculated using the formula:
  ED = Pre-1750 area/(log10 (number of ecosystems)).
• This index produces a weighted area diversity index so diferent size areas can be compared on the same basis.
• There are 194 forest and non-forest ecosystems in the Capital Region. This estimate does not include human modified ecosystems in the Region nor possible ecosystems that may be found in the Shires of Harden, Boorowa and Young.
• The estimates for ecosystem diversity indices for Boorowa, Harden and Young are estimates only. No ecosystem classification similar to the rest of the Region is available.

Level of pressure index

The level of pressure is an index describing the current level at which threatening processes are impacting on ecosystems in the Australian Capital Region. The term encapsulates two key factors:

• the degree to which a threatening process or processes are impacting on an ecosystem as a proportion of the total number of remnant patches
• the time-scale over which a threatening process or a combination of processes is impacting on an ecosystem.

Table 7 illustrates some of the potential combinations that give an index of pressure impacting on a given ecosystem.

Table 7. The ecosystem pressure index

Proportion of remnant patches under pressure (%)	Potential time lag before change occurs	Pressure Index
81–100	Immediate and ongoing	5
61–80	1–2 years	4
41–60	3–5 years	3
21–40	5–10 years	2
0–20	More than 10 years	1

Numbers and percentages in tables are rounded to the nearest whole number.

EcoGIS undertook interpretation of ecosystem functionality under contract to the Commissioner for the Environment, ACT.

References

Gellie, N.J.H., Gilmour, P.G., Doherty, M. and Thomas, V. (in prep.) Vegetation of the Southern Forests Region, paper to be published in Cunninghamia, Journal of Plant Ecology, Royal Botanic Gardens Sydney.

JANIS 1997, Nationally Agreed Criteria for the Establishment of a Comprehensive, Adequate and Representative Reserve System for Forests in Australia, Joint ANZECC/MCFFA National Forest Policy Statement Implementation Sub-committee, Commonwealth of Australia.

Smith, P.L., Wilson, B., Nadolny, C. and Lang, D. (2000) The Ecological Role of the Native Vegetation of New South Wales, Background Paper No.2, Native Vegetation Advisory Council of NSW.

Description: What does 'ecosystem diversity' measure?

Which data are collected?

• extent, type and condition of vegetation available as habitat for native plants, animals and micro-organisms (terrestrial and aquatic) for each biogeographic subregion

Why do we report this indicator?

The diversity of vegetation types in our landscapes are often closely tied to the range of ecosystems - the variety of habitats, biotic communities and ecological processes - that are available for native plants, animals and microorganisms to live in. Vegetation types are also usually the most obvious parts of terrestrial ecosystems, so many ecosystems are described in terms of their dominant plants (e.g. grasslands, Yellow Box-Red Gum woodland).

Ecosystems can be separate from each other, but more often they overlap or they can become less clearly defined at their edges. The term habitat describes the place or type of site in an ecosystem within which an organism normally occurs.

Changes to vegetation diversity can result from natural evolutionary changes, as well as from human activities such as clearing, pollution, harvesting of native species, recreational activities.

Vegetation diversity is important to State of the Environment reporting because it indicates the condition of the natural environment, the extent to which human activities have impacted on the natural ecosystems, and how well these impacts have been moderated through management.