Ecosystem diversity

Bega Valley

What the results tell us for Bega Valley

Sixty eight ecosystem types were identified in Bega Valley Shire, of which four (about 6%) were classed as highly dysfunctional (see Figure 1). When current pressures on ecosystems in Bega Valley Shire were taken into account, it was found that five ecosystems should be considered for immediate protection (if they are not already within the 32% that is under conservation), and for restoration. They are:

Legend No 24 — Coastal Swamp Oak-Swamp Melaleuca Wet Heath Swamp Forest
Legend No 53 — Riparian River Oak Acacia Shrub-Grass-Herb Forest
Legend No 54 — Bega Valley White Stringybark-Forest Red Gum Grass-Herb Dry Forest-Woodland
Legend No 73 — Eastern Tableland Snow Gum-Manna Gum Dry Shrub-Grass Forest
Legend No 189 — Coastal Alluvial Valley Floor Wetlands.

graph showing the number of ecosystems in each functional category - also listed in Table 1

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 21% of Bega Valley Shire has been cleared or modified (see Table 1), most of which has occurred in the coastal estuaries, wetlands, and valley floor ecosystems. 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 Bega Valley Shire is in the high end of the range of ecosystem diversity found in the entire Region. Overall, with fragmentation and clearing of the valley floors of Bega and Brogo Valleys, the current ecosystem diversity is estimated to be nearly 90% 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 Bega Valley Shire is further summarised in Table 1 below.

Table 1. Change in ecosystem diversity in Bega Valley
Ecosystems 1997				Pre-1750 area (ha)	Changed or modified since human settlement
Ecosystem functionality category	No.	Each category (%)	Extant (ha)	Pre-1750 area (ha)	Change (ha)	%
S Highly Dysfunctional	4	6%	9571	60 919	51 347	84%
R Moderately Dysfunctional	4	6%	7535	14 970	7435	50%
M Moderately Functional	9	13%	66 037	105 582	39 545	37%
I Functional	51	75%	410 644	442 447	31 803	7%
Total	68		493 787	623 918	130 130	21%

Table 2 shows all the ecosystems identified in Bega Valley Shire, listed according to the four functional categories in Table 1. The first four of these — the highly dysfunctional ecosystems — are mainly grassy, riparian, and fringe estuarine forest and non-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 and clearing over the last 100 years.

The four ecosystems assessed as highly dysfunctional covered about 61 000 hectares as functional ecosystems before European settlement. Today, the area in which these four ecosystems are functional is only 9500 hectares. That approximates to an 84% loss of functional habitat for 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, and longer term genetic diversity of higher trophic levels of insectivores, and carnivores.

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

In the Bemboka Creek corridor, Bega Valley has one of the more significant ecosystem remnants, comprising mainly ecosystem number 53, River Oak herb-grass forest, which functions as one of the most significant wildlife corridors in the central part of the Region. Elsewhere in the Region, remnant riparian communities are under threat because of weed invasion and habitat fragmentation, and loss of River Oak overstorey and replacement by introduced Willows.

The moderately functional and near natural ecosystems occur within 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.

Table 2. List of mapped ecosystems in Bega Valley Shire, sorted by level of functionality *
Map legend no.	Ecosystem description	Ecosystem function index	Pre-1750 area (ha)	1997 extant area (ha)	% cleared
54	Bega Valley White Stringybark-Forest Red Gum Grass-Herb Dry Forest-Woodland	S	49 825	5272	89%
189	Coastal Alluvial Valley Floor Wetlands	S	9421	3281	65%
73	Eastern Tableland Snow Gum-Manna Gum Dry Shrub-Grass Forest	S	1490	855	43%
53	Riparian River Oak Acacia Shrub-Grass-Herb Forest	S	183	164	11%
24	Coastal Swamp Oak- Swamp Melaleuca Wet Heath Swamp Forest	R	3012	925	69%
48	Coastal Lowlands Riparian Herb-Twiners-Grass Forest - various eucalypts	R	8743	4503	49%
28	Coastal Sands Bangalay-Old Man Banksia Shrub-Fern Forest	R	1022	604	41%
2223	Southern Coastal Hind Dune/Headland Scrub & Beach Strand Grassland	R	2194	1504	31%
49	Southern Hinterland RB Apple-River Peppermint Shrub-Herb-Grass Riparian Forest	M	56 938	21 803	62%
185	Mangrove Estuarine Low Forest	M	56	38	31%
64	Southern East Tableland Edge Mountain Gum-NL Peppermint Shrub-Grass Dry Forest	M	14 429	12 051	16%
68	North East Tablelands NL Peppermint-Manna Gum-Lomandra Shrub-Herb-Grass Dry Forest	M	3191	2666	16%
69	Eastern Tablelands Epacris-damp sedge Damp Heath	M	836	762	9%
55	Eastern Tableland Fern-Herb-Grass Moist Forest - E. fastigata	M	28 102	26 702	5%
50	Southern Escarpment RB Apple-Forest Red Gum Herb-Grass Dry Forest	M	1798	1784	1%
56	Tableland and Escarpment NL Peppermint-White Gum Moist Herb-Fern Grass Forest	M	211	210	0%
89	Eastern Tablelands Mountain Gum-Manna Gum Acacia-Herb-Grass Forest	M	21	21	0%
339	E39 Northern Riparian Scrub	I	711	443	38%
47	Southern Escarpment Herb - Grass Moist Forest - E. maidenii - E. globoidea	I	34 624	22 055	36%
330	E30 Wallagaraugh Dry Grass Forest	I	681	435	36%
328	E28 Wog Wog Dry Grass Forest	I	1304	922	29%
123	Montane Wet Heath/Bog - Hakea micrantha / Baeckea utilis	I	321	246	23%
364	E64 Saltmarsh	I	370	296	20%
338	E38 Southern Riparian Scrub	I	516	436	15%
331	E31 Hinterland Dry Grass Forest	I	29 833	25 917	13%
301	E1 Dry Rainforest	I	47	42	11%
18	Southern Coastal Hinterland Monkey Gum-Yellow Stringybark Moist Shrub-Vine-Grass Forest	I	22 487	20 399	9%
313	E13 Hinterland Wet Fern Forest	I	47 985	43 752	9%
329	E29 Nalbaugh Dry Grass Forest	I	606	556	8%
337	E37 Rough-barked Apple Coastal Dry Shrub Forest	I	16 151	15 147	6%
13	Rainshadow BL Stringybark-RB Apple Dry Shrub-Tussock-Grass Forest	I	8356	7844	6%
357	E57 Lowland Swamp	I	2010	1892	6%
35	South Coast and Byadbo Blue Acacia Shrublands	I	7171	6786	5%
2	Lowland Red Bloodwood-Turpentine Dry Shrub Forest	I	15 977	15 121	5%
6	Southern Coastal Lowlands Woollybutt Shrub-Tussock Grass Dry Forest	I	24 521	23 401	5%
314	E14 Hinterland Wet Shrub Forest	I	26 732	25 664	4%
58	Tableland and Escarpment Brown Barrel Wet Layered Shrub Forest	I	13 687	13 247	3%
355	E55 Coastal Lowland Heath	I	1676	1630	3%
342	E42 Messmate Stringybark Coastal Dry Shrub Forest	I	21 921	21 456	2%
349	E49 BL. Stringybark Coastal Dry Shrub Forest	I	31 974	31 481	2%
1	Southern Coastal Foothills Silvertop Ash Dry Shrub Forest	I	49 514	48 787	1%
19	Coastal Escarpment and Hinterland Y. Stringybark Dry Shrub-Fern Forest	I	23 706	23 417	1%
170	Southern Coastal Hinterland Backhousia Dry Gully RainForest	I	7410	7333	1%
8	Far Southern Silvertop Ash Coastal Shrub Dry Forest	I	4568	4525	1%
165	Southern Coastal Escarpment Cool-Warm Temperate RainForest	I	3601	3575	1%
312	E12 Mountain Wet Fern Forest	I	1863	1853	1%
138	Northern Plateau and Escarpment Silvertop Ash-Yertchuk Heath Shrub Dry Forest	I	22 917	22 792	1%
350	E50 Genoa Dry Shrub Forest	I	717	714	0%
309	E9 Shining Gum Mountain Wet Layered Forest	I	1510	1506	0%
10	Southern Coastal Lowlands White Stringybark-Woolybutt Shrub-Grass Dry Forest	I	1379	1377	0%
57	Southern Escarpment Monkey Gum-Brown Barrel Shrub-Fern-Herb Moist Forest	I	647	64	60%
164	Coastal Escarpment Cool Temperate RainForest	I	1031	1031	0%
356	E56 Swamp Heath	I	375	375	0%
7	Southern Coastal Hinterland BL Stringybark-Y. Stringybark Dry Shrub-Tussock-Grass Forest	I	4354	4353	0%
34	Deua Ecotonal Blackbutt Peppermint-Monkey Gum Shrub Forest	I	1211	1211	0%
59	Eastern Tableland and Escarpment NL Peppermint-Silvertop Ash Shrub-Fern Dry Forest	I	120	120	0%
61	Southern Escarpment White Ash Edge Moist Shrub Forest	I	1999	1999	0%
62	Southern Escarpment Edge WhiteAsh-Mountain Gum Moist Shrub-Fern Forest	I	1208	120	80%
135	Wadbilliga Plateau Moist Heath	I	1249	1249	0%
190	Rocky Outcrops	I	10	10	0%
302	E2 Myanba Eucalypt Fig Forest	I	333	333	0%
305	E5 Bunga Head Rainforest	I	7	7	0%
325	E25 Sandstone Dry Shrub Forest	I	113	113	0%
327	E27 Waalimma Dry Grass Forest	I	1324	1324	0%
343	E43 Mountain Gum Dry Shrub Forest	I	1020	1020	0%
351	E51 Kunzea Rocky Shrubland	I	51	51	0%
352	E52 Mountain Rock Shrubland	I	190	190	0%
354	E54 Mountain Nadgee Heath	I	359	359	0%
Totals	68		623 918	493 787

* 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
Map legend no.	Name of forest ecosystem	Level of pressure (1=low, 5=very high)	Primary process	Causes	Additional processes	Causes
54	Bega Valley White Stringybark-Forest Red Gum Grass-Herb Dry Forest-Woodland	5	Weed Invasion, Pasture Management	Agriculture	Tree Dieback	Ecosystem imbalance
189	Coastal Alluvial Valley Floor Wetlands	5	Patch Decline	Nutrient Enrichment	Weed Invasion	Perennial Pasture, Exotic Weeds
24	Coastal Swamp Oak- Swamp Melaleuca Wet Heath Swamp Forest	4	Patch Clearing	Housing, Hobby Farms	Nutrification	-
73	Eastern Tableland Snow Gum-Manna Gum Dry Shrub-Grass Forest	4	Clearing	Rough Grazing	Weed Invasion	Pasture & Weed Grasses
123	Montane Wet Heath/Bog - Hakea micrantha / Baeckea utilis	4	Patch Decline	-	Weed Invasion	Perennial Pasture, Exotic Weeds
10	Southern Coastal Lowlands White Stringybark-Woolybutt Shrub-Grass Dry Forest	3	Intensive Silviculture	Forestry	Clearing	-
28	Coastal Sands Bangalay-Old Man Banksia Shrub-Fern Forest	3	Patch Clearing	Housing, Hobby Farms	Urban Development	-
48	Coastal Lowlands Riparian Herb-Twiners-Grass Forest - various eucalypts	3	Riparian Patch Clearing	Hobby Farms, Housing	Weed Invasion	Livestock Grazing, Weeds
49	Southern Hinterland RB Apple-River Peppermint Shrub-Herb-Grass Riparian Forest	3	Clearing	Hobby Farms, Housing	Weed Invasion	Livestock Grazing, Weeds
50	Southern Escarpment RB Apple-Forest Red Gum Herb-Grass Dry Forest	3	Patch Clearing	Agriculture	-	-
53	Riparian River Oak Acacia Shrub-Grass-Herb Forest	3	Weed Invasion	Livestock Grazing outside of the ACT, Weeds	Nutrient Enrichment	Fertiliser, Livestock
56	Tableland and Escarpment NL Peppermint-White Gum Moist Herb-Fern Grass Forest	3	Patch Clearing	Agriculture, Hobby Farms	Weed Invasion	Livestock Grazing, Weeds
68	North East Tablelands NL Peppermint-Manna Gum-Lomandra Shrub-Herb-Grass Dry Forest	3	Clearing	Agriculture, Hobby Farms	Weed Invasion, Grazing	Livestock Grazing, Woody Weeds (willows)
69	Eastern Tablelands Epacris-damp sedge Damp Heath	3	Weed Invasion	Exotic Weeds	Nutrient Enrichment	Fertiliser, Livestock
185	Mangrove Estuarine Low Forest	3	Clearing	Urban Development	-	-
301	E1 Dry Rainforest	3	Drought Fire Regimes	All Tenures	-	-
302	E2 Myanba Eucalypt Fig Forest	3	Drought Fire Regimes	All Tenures	-	-
305	E5 Bunga Head Rainforest	3	Drought Fire Regimes	Reserve Management	-	-
364	E64 Saltmarsh	3	Nutrient Enrichment	Urban Development	-	-
2223	Southern Coastal Hind Dune/Headland Scrub & Beach Strand Grassland	3	Patch Decline	Coastal Development	-	-
1	Southern Coastal Foothills Silvertop Ash Dry Shrub Forest	2	Intensive Silviculture	Forestry	Frequent Fire Regimes	Fuel Management
2	Lowland Red Bloodwood-Turpentine Dry Shrub Forest	2	Patch Clearing	Housing, Hobby Farms	Frequent Fire Regimes	Fuel Management
6	Southern Coastal Lowlands Woollybutt Shrub-Tussock Grass Dry Forest	2	Intensive	SilvicultureForestry	-	-
7	Southern Coastal Hinterland BL Stringybark-Y. Stringybark Dry Shrub-Tussock-Grass Forest	2	Intensive Silviculture	Reserve Management	-	-
8	Far Southern Silvertop Ash Coastal Shrub Dry Forest	2	Intensive Silviculture	Forestry	-	-
18	Southern Coastal Hinterland Monkey Gum-Yellow Stringybark Moist Shrub-Vine-Grass Forest	2	Intensive Silviculture	Forestry	-	-
19	Coastal Escarpment and Hinterland Y. Stringybark Dry Shrub-Fern Forest	2	Intensive Silviculture	Forestry	-	-
34	Deua Ecotonal Blackbutt Peppermint-Monkey Gum Shrub Forest	2	Frequent Fire Regimes	Fuel Management	-	-
35	South Coast and Byadbo Blue Acacia Shrublands	2	Infrequent Fire Regimes	Fuel Management	-	-
55	Eastern Tableland Fern-Herb-Grass Moist Forest - E. fastigata	2	Intensive	SilvicultureForestry	-	-
57	Southern Escarpment Monkey Gum-Brown Barrel Shrub-Fern-Herb Moist Forest	2	Intensive Silviculture	Forestry	-	-
58	Tableland and Escarpment Brown Barrel Wet Layered Shrub Forest	2	Intensive Silviculture	Forestry outside of the ACT	-	-
59	Eastern Tableland and Escarpment NL Peppermint-Silvertop Ash Shrub-Fern Dry Forest	2	Frequent Fire Regimes	Fuel Management	Clearing	Agriculture, Hobby Farms
61	Southern Escarpment White Ash Edge Moist Shrub Forest	2	Infrequent Fire Regimes	Reserve Management	-	-
62	Southern Escarpment Edge WhiteAsh-Mountain Gum Moist Shrub-Fern Forest	2	Infrequent Fire Regimes	Reserve Management	-	-
64	Southern East Tableland Edge Mountain Gum-NL Peppermint Shrub-Grass Dry Forest	2	Fire Regimes	Reserve Management	-	-
89	Eastern Tablelands Mountain Gum-Manna Gum Acacia-Herb-Grass Forest	2	Patch Clearing	Rough Grazing for Livestock	Repeated Grazing, Weed Invasion	Introduced Livestock
135	Wadbilliga Plateau Moist Heath	2	Infrequent Fire Regimes	Reserve Management	-	-
138	Northern Plateau and Escarpment Silvertop Ash-Yertchuk Heath Shrub Dry Forest	2	Frequent Fire Regimes	Fuel Management	-	-
309	E9 Shining Gum Mountain Wet Layered Forest	2	Drought Fire Regimes	Reserve Management	-	-
312	E12 Mountain Wet Fern Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
313	E13 Hinterland Wet Fern Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
314	E14 Hinterland Wet Shrub Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
327	E27 Waalimma Dry Grass Forest	2	Intensive Silviculture	Forestry	-	-
328	E28 Wog Wog Dry Grass Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
329	E29 Nalbaugh Dry Grass Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
330	E30 Wallagaraugh Dry Grass Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
331	E31 Hinterland Dry Grass Forest	2	Intensive Silviculture	Forestry	Infrequent Fire Regimes	Reserve Management
337	E37 Rough-barked Apple Coastal Dry Shrub Forest	2	Intensive	Silviculture	ForestryInfrequent Fire Regimes	Reserve Management
342	E42 Messmate Stringybark Coastal Dry Shrub Forest	2	Intensive Silviculture	Forestry	-	-
343	E43 Mountain Gum Dry Shrub Forest	2	Intensive Silviculture	Forestry	-	-
349	E49 BL. Stringybark Coastal Dry Shrub Forest	2	Intensive Silviculture	Forestry	-	-
351	E51 Kunzea Rocky Shrubland	2	Infrequent Fire Regimes	Public Land Management	-	-
352	E52 Mountain Rock Shrubland	2	Infrequent Fire Regimes	Public Land Management	-	-
354	E54 Mountain Nadgee Heath	2	Infrequent Fire Regimes	Reserve Management	-	-
355	E55 Coastal Lowland Heath	2	Infrequent Fire Regimes	Reserve Management	-	-
356	E56 Swamp Heath	2	Infrequent Fire Regimes	Reserve Management	-	-
357	E57 Lowland Swamp	2	Infrequent Fire Regimes	Reserve Management	-	-
13	Rainshadow BL Stringybark-RB Apple Dry Shrub-Tussock-Grass Forest	1	Infrequent Fire Regimes	Reserve Management	-	-
47	Southern Escarpment Herb - Grass Moist Forest - E. maidenii - E. globoidea	1	Hillside Clearing	Hobby Farms, Housing	Fire Regimes	Reserve Management
164	Coastal Escarpment Cool Temperate RainForest	1	Drought Fire Regimes	Reserve Management	-	-
165	Southern Coastal Escarpment Cool-Warm Temperate RainForest	1	Drought Fire Regimes	Reserve Management	-	-
170	Southern Coastal Hinterland Backhousia Dry Gully RainForest	1	Drought Fire Regimes	Across all tenures	-	-
190	Rocky Outcrops	1	-	-	-	-
325	E25 Sandstone Dry Shrub Forest	1	Infrequent Fire Regimes	Reserve Management	Infrequent Fire Regimes	Reserve Management
338	E38 Southern Riparian Scrub	1	Weed Invasion	-	-	-
339	E39 Northern Riparian Scrub	1	Weed Invasion	Perennial Pasture, Exotic Weeds	Rough Grazing	Introduced Livestock
350	E50 Genoa Dry Shrub Forest	1	-	-	-	-

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

Legend No 24 - Coastal Swamp Oak- Swamp Melaleuca Wet Heath Swamp Forest
Legend No 54 - Bega Valley White Stringybark-Forest Red Gum Grass-Herb Dry Forest-Woodland
Legend No 73 - Eastern Tableland Snow Gum-Manna Gum Dry Shrub-Grass Forest
Legend No 123 - Montane Wet Heath/Bog - Hakea micrantha / Baeckea utilis
Legend No 189 - Coastal Alluvial Valley Floor Wetlands.

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 seven to 35, seven being the lowest risk indicator, and 35 being the highest. The processes are further explained in About the Data.

Within Bega Valley Shire, the results of this analysis have produced a list of ecosystems, which fall under all 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 five ecosystems which are potentially under very high overall threat in Bega Valley 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 2 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
Threat category	Number	% of total number of ecosystems
Very high	5	7%
High	10	15%
Moderate	41	60%
Little/no current overall threat	12	18%
Total Number	68	100%

Pending verification, the 10 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 41 ecosystems which fall under the 'moderate' category 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 12 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 responses in Table 5 are based on an index of potential overall threat which places Bega Valley 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 Bega Valley Shire
Legend no.	Ecosystem description	Ecosystem functionality	Level of pressure (1=low, 5=very high)	Combined pressure/ functionality	Management response
54	Bega Valley White Stringybark-Forest Red Gum Grass-Herb Dry Forest-Woodland	20	5	30	Immediate Protection-Restoration
189	Coastal Alluvial Valley Floor Wetlands	19	5	29	Immediate Protection-Restoration
73	Eastern Tableland Snow Gum-Manna Gum Dry Shrub-Grass Forest	19	4	27	Immediate Protection-Restoration
53	Riparian River Oak Acacia Shrub-Grass-Herb Forest	20	3	26	Immediate Protection-Restoration
24	Coastal Swamp Oak- Swamp Melaleuca Wet Heath Swamp Forest	18	4	26	Immediate Protection-Restoration
28	Coastal Sands Bangalay-Old Man Banksia Shrub-Fern Forest	17	3	23	Integrated Landscape Protection and Management
2223	Southern Coastal Hind Dune/Headland Scrub & Beach Strand Grassland	16	3	22	Integrated Landscape Protection and Management
48	Coastal Lowlands Riparian Herb-Twiners-Grass Forest - various eucalypts	15	3	21	Integrated Landscape Protection and Management
69	Eastern Tablelands Epacris-damp sedge Damp Heath	14	3	20	Integrated Landscape Protection and Management
50	Southern Escarpment RB Apple-Forest Red Gum Herb-Grass Dry Forest	14	3	20	Integrated Landscape Protection and Management
49	Southern Hinterland RB Apple-River Peppermint Shrub-Herb-Grass Riparian Forest	13	3	19	Integrated Landscape Protection and Management
68	North East Tablelands NL Peppermint-Manna Gum-Lomandra Shrub-Herb-Grass Dry Forest	12	3	18	Integrated Landscape Protection and Management
185	Mangrove Estuarine Low Forest	11	3	17	Monitor Ecological Function and Threats
56	Tableland and Escarpment NL Peppermint-White Gum Moist Herb-Fern Grass Forest	11	3	17	Monitor Ecological Function and Threats
123	Montane Wet Heath/Bog - Hakea micrantha / Baeckea utilis	8	4	16	Monitor Ecological Function and Threats
64	Southern East Tableland Edge Mountain Gum-NL Peppermint Shrub-Grass Dry Forest	11	2	15	Monitor Ecological Function and Threats
55	Eastern Tableland Fern-Herb-Grass Moist Forest - E. fastigata	11	2	15	Monitor Ecological Function and Threats
89	Eastern Tablelands Mountain Gum-Manna Gum Acacia-Herb-Grass Forest	11	2	15	Monitor Ecological Function and Threats
330	E30 Wallagaraugh Dry Grass Forest	10	2	14	Monitor Ecological Function and Threats
328	E28 Wog Wog Dry Grass Forest	10	2	14	Monitor Ecological Function and Threats
331	E31 Hinterland Dry Grass Forest	10	2	14	Monitor Ecological Function and Threats
329	E29 Nalbaugh Dry Grass Forest	10	2	14	Monitor Ecological Function and Threats
337	E37 Rough-barked Apple Coastal Dry Shrub Forest	10	2	14	Monitor Ecological Function and Threats
35	South Coast and Byadbo Blue Acacia Shrublands	10	2	14	Monitor Ecological Function and Threats
327	E27 Waalimma Dry Grass Forest	10	2	14	Monitor Ecological Function and Threats
364	E64 Saltmarsh	8	3	14	Monitor Ecological Function and Threats
10	Southern Coastal Lowlands White Stringybark-Woolybutt Shrub-Grass Dry Forest	8	3	14	Monitor Ecological Function and Threats
313	E13 Hinterland Wet Fern Forest	9	2	13	Monitor Ecological Function and Threats
314	E14 Hinterland Wet Shrub Forest	9	2	13	Monitor Ecological Function and Threats
342	E42 Messmate Stringybark Coastal Dry Shrub Forest	9	2	13	Monitor Ecological Function and Threats
349	E49 BL. Stringybark Coastal Dry Shrub Forest	9	2	13	Monitor Ecological Function and Threats
8	Far Southern Silvertop Ash Coastal Shrub Dry Forest	9	2	13	Monitor Ecological Function and Threats
312	E12 Mountain Wet Fern Forest	9	2	13	Monitor Ecological Function and Threats
138	Northern Plateau and Escarpment Silvertop Ash-Yertchuk Heath Shrub Dry Forest	9	2	13	Monitor Ecological Function and Threats
34	Deua Ecotonal Blackbutt Peppermint-Monkey Gum Shrub Forest	9	2	13	Monitor Ecological Function and Threats
59	Eastern Tableland and Escarpment NL Peppermint-Silvertop Ash Shrub-Fern Dry Forest	9	2	13	Monitor Ecological Function and Threats
61	Southern Escarpment White Ash Edge Moist Shrub Forest	9	2	13	Monitor Ecological Function and Threats
343	E43 Mountain Gum Dry Shrub Forest	9	2	13	Monitor Ecological Function and Threats
13	Rainshadow BL Stringybark-RB Apple Dry Shrub-Tussock-Grass Forest	10	1	12	Monitor Ecological Function and Threats
357	E57 Lowland Swamp	8	2	12	Monitor Ecological Function and Threats
6	Southern Coastal Lowlands Woollybutt Shrub-Tussock Grass Dry Forest	8	2	12	Monitor Ecological Function and Threats
355	E55 Coastal Lowland Heath	8	2	12	Monitor Ecological Function and Threats
1	Southern Coastal Foothills Silvertop Ash Dry Shrub Forest	8	2	12	Monitor Ecological Function and Threats
309	E9 Shining Gum Mountain Wet Layered Forest	8	2	12	Monitor Ecological Function and Threats
57	Southern Escarpment Monkey Gum-Brown Barrel Shrub-Fern-Herb Moist Forest	8	2	12	Monitor Ecological Function and Threats
356	E56 Swamp Heath	8	2	12	Monitor Ecological Function and Threats
7	Southern Coastal Hinterland BL Stringybark-Y. Stringybark Dry Shrub-Tussock-Grass Forest	8	2	12	Monitor Ecological Function and Threats
351	E51 Kunzea Rocky Shrubland	8	2	12	Monitor Ecological Function and Threats
352	E52 Mountain Rock Shrubland	8	2	12	Monitor Ecological Function and Threats
354	E54 Mountain Nadgee Heath	8	2	12	Monitor Ecological Function and Threats
301	E1 Dry Rainforest	6	3	12	Monitor Ecological Function and Threats
302	E2 Myanba Eucalypt Fig Forest	6	3	12	Monitor Ecological Function and Threats
305	E5 Bunga Head Rainforest	6	3	12	Monitor Ecological Function and Threats
339	E39 Northern Riparian Scrub	9	1	11	-
47	Southern Escarpment Herb - Grass Moist Forest - E. maidenii - E. globoidea	9	1	11	-
338	E38 Southern Riparian Scrub	9	1	11	-
350	E50 Genoa Dry Shrub Forest	9	1	11	-
325	E25 Sandstone Dry Shrub Forest	9	1	11	-
18	Southern Coastal Hinterland Monkey Gum-Yellow Stringybark Moist Shrub-Vine-Grass Forest	7	2	11	-
2	Lowland Red Bloodwood-Turpentine Dry Shrub Forest	7	2	11	-
58	Tableland and Escarpment Brown Barrel Wet Layered Shrub Forest	7	2	11	-
19	Coastal Escarpment and Hinterland Y. Stringybark Dry Shrub-Fern Forest	7	2	11	-
62	Southern Escarpment Edge WhiteAsh-Mountain Gum Moist Shrub-Fern Forest	7	2	11	-
135	Wadbilliga Plateau Moist Heath	7	2	11	-
170	Southern Coastal Hinterland Backhousia Dry Gully RainForest	8	1	10	-
165	Southern Coastal Escarpment Cool-Warm Temperate RainForest	6	1	8	-
164	Coastal Escarpment Cool Temperate RainForest	6	1	8	-
190	Rocky Outcrops	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.