Biodiversity Assessment Technical Report


Review of existing site-based data



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7.2 Review of existing site-based data


The data review process involves assessment of existing databases to determine the adequacy of existing site-based biological data for use in subsequent analyses. The outputs of the review can be used to identify priority areas and data gaps to be filled through future survey work. The data review relies on expert knowledge and professional judgment.
The distribution of survey sites where adequate data on fish and aquatic macroinvertebrates is shown in Map 11.

7.2.1 Fish


Intensive inventory surveys of fish assemblages in the Central Highlands have been primarily conducted by the Department of Natural Resources and Environment (NRE). Some investigations which incidentally recorded fish species, were conducted by other government agencies, universities or private individuals.

Pre - 1990 fish surveys

Very few historical records (pre - 1970) exist for the Central Highlands region, and prior to 1970, records were sporadic, consisting of observations of individual species from only a few locations. The first survey of fish assemblages was undertaken in 1973 at seven sites on the La Trobe River (Tunbridge 1974). Between 1973 and 1990, a total of 11 recognised major surveys occurred in the area contributing 164 new sites (Table 7.4), exclusive of resampled sites.


Five of these surveys were fisheries orientated, targeting larger, recreational species and using techniques (e.g. netting with large mesh sizes) not designed to capture all fish species. These types of surveys are referred to in this report as “partial surveys”. Consequently, smaller fish species were not sampled by these surveys, and they were generally conducted in the larger reaches of the main rivers in lowland to foothill areas only.
Table 7.4: Major surveys conducted for freshwater fish in the Central Highlands prior to 1989.

Date

Area surveyed

Sites surveyed

Source

1973

La Trobe catchment

7

Tunbridge 1974

1973-1974

Yarra River and tributaries

38

Jackson et al. 1980

1975

Bunyip catchment

15

Barclay 1975

1975

Thomson River

10

Tunbridge *

1978-1984

Goulburn, La Trobe and Bunyip catchments

24

Baxter 1985 *

1984

Plenty River system

9

Closs 1984

1985

Bunyip catchment

10

Koehn 1986b

1987

Goulburn catchment

8

Baxter at al 1988 *

1988

Goulburn and La Trobe catchments

7

Baxter at al 1989 *

1988

La Trobe catchment

7

Hall 1989

1988

Plenty River system

23

McKenzie et al. 1989

1989

Goulburn, La Trobe and Yarra catchments

6

Baxter et al. 1990 *

Note: * indicates fisheries surveys.
All sampling of fish in the region has been sporadic pre-1990 and non-systematic. Information obtained from successive surveys has not necessarily been complementary, resulting in significant gaps in the knowledge of species distributions in the region, and within particular river systems.

Post - 1990 fish surveys

Since 1990, survey intensity and coordination has improved for the region, mainly due to intensive sampling of specific areas, with 282 new sites (exclusive of resampled sites) being assessed in major surveys. Further, the majority of surveys used techniques which potentially sampled the entire community rather than just selected species (e.g. electrofishing - termed “full” surveys), and were also conducted in foothill to upland areas in many of the smaller streams. Much useful information was collected by Peter Unmack from 70 sites across the region (Table 7.5) though unfortunately nearly all of these collections are rated as a partial survey as the equipment used would generally not have sampled all species present (eg. seine net, dipnet, and angling).


Both Raadik (unpublished data) and Saddlier (unpublished data) have intensively surveyed a total of 144 sites across the region (Table 7.5), concentrating on the smaller fish species and sampling in foothill and upland areas for specific projects, some of which is reported in Koehn et al (1991). Many of these sites were surveyed for the nationally threatened Barred Galaxias (Galaxias fuscus), as were the 13 sites sampled by Shirley (1991). Koehn et al. (1991) also details various miscellaneous surveys conducted in the region. No systematic survey of the aquatic habitat across this region has been undertaken, with most information being derived from specific intensive surveys for specific projects.
Table 7.5: Major surveys conducted for freshwater fish in the Central Highlands since 1990.


Date

Area surveyed

Sites surveyed

Source

1990

Goulburn catchment

5

Koehn 1990

1990

Yarra catchment

9

Baxter et al. 1991 *

1990-1994

Goulburn, Bunyip and Yarra catchments

70

Unmack

1990-1996

Goulburn, Thomson, Latrobe, Bunyip and Yarra catchments

58

Raadik

1990-1996

Goulburn, Thomson, La Trobe, Bunyip and Yarra catchments

76

Saddlier

1990-1991

Goulburn, La Trobe and Yarra catchments

51

Koehn et al. 1991

1991

Goulburn and Yarra catchments

13

Shirley 1991

Note: * indicates fisheries surveys.
The number of freshwater survey sites in the Central Highlands is 572, with 264 located north of the divide in the Goulburn River catchment and 308 in the four catchments to the south (Table 7.6). Of these, 400 sites are considered to be fully surveyed (full coverage of species diversity) which provide adequate data quality, 145 north of the GDR and 255 in the south.
There is generally wide spatial coverage of the aquatic habitat across the Region, though many survey sites fall into `hot spot’ areas where survey intensity has been very high in a few areas due to specific projects such as the Barred Galaxias project (see earlier). Consequently, there is a very extensive knowledge of fish from only a few areas within the Region.
Table 7.6: Summary of information on fish survey sites in the Central Highlands from 1973-1994.


Land tenure

State forest

Private land and other Public land

Conservation reserves




Survey Type

Catchment



Full

Partial

Full

Partial

Full

Partial

Total

Goulburn

91

50

38

48

16

21

264

Thomson

6

1

3

2

2

0

14

La Trobe

32

3

11

2

1

0

49

Bunyip

7

0

22

4

11

1

45

Yarra

46

7

90

17

27

13

200

Sub total

182

61

164

73

57

35




Total sites

243

237

92

572

% of total

42.5

41.4

16.1




Notes: Full - all fish species recorded; Partial - only larger, recreational species collected.
By comparison, Jackson and Davies (1983) surveyed 115 sites in the Grampians region, in an area approximately 15% the size of the Central Highlands, and Cadwallader (1979) surveyed 60 sites in one river system (Seven Creeks). It is considered that these scales of intensity are required to give excellent survey coverage. If the Central Highlands were to be surveyed with the same intensity to that conducted in the Grampians, approximately another 360 sites would be required, and more importantly, these sites would need to be more spatially orientated than previous ones to provide better coverage. Table 7.6 shows that survey sites have been concentrated in State forest, other public land and private land, with significantly less sites sampled in conservation reserves The current number of quality sites (400) comprises some 52% of the coverage required if survey intensity in this region were to match the two surveys described above.
Some 92 sites (16.1%) have been located in areas set aside for conservation purposes, 237 (41.4%) were located in private land and other areas of public land (eg. licensed stream frontages). Two hundred and forty three sites (42.5%) have been located in State Forest and many of these have been surveyed since 1990, or were surveyed approximately 15 to 25 years ago.

7.2.2 Aquatic macroinvertebrate fauna


Inventory surveys of aquatic macroinvertebrates in the Central Highlands have been primarily conducted by a number of Government Departments and Monash University. Some investigations which incidentally recorded invertebrate species (e.g. as part of taxonomic studies) have been conducted by universities or private individuals.

Pre-1990 macroinvertebrate surveys

Department of Water Resources (1989) recorded 131 sites where aquatic macroinvertebrate surveys have been conducted in the Central Highlands prior to 1990 (Table 7.7). These were sampled as part of several studies, primarily investigating the impact of human disturbance on stream systems, but included 13 graduate and post-graduate projects at Monash University. Studies associated with the construction of the Thomson Dam (Malipatil and Blyth 1982; Doeg et al. 1987; Marchant 1989), eductor dredging in the Goulburn Rivers (Doeg 1987) and the release of the former State Electricity Commission cooling waters into the Latrobe River (Metzeling et al. 1984; Marchant et al. 1984) were all conducted by the Museum of Victoria. The impact of the construction of Blue Rock Dam was conducted by the EPA (Chessman et al. 1982) and the effect of mercury contamination was studied in the upper Goulburn River through Rusden College (Ealey et al. 1983).


The Yarra catchment has been the most extensively surveyed with 45 sites sampled prior to 1990. Of these, 12 sites were part of Monash University graduate and post-graduate projects, but the remaining 33 sites were part of a more extensive monitoring program (Campbell et al. 1982; Pettigrove 1985).
Unfortunately, a variety of different survey techniques was employed in each of these studies. As these often used different sampling methods and regimes, data comparisons between these surveys should be treated with caution.
Table 7.7: Major surveys conducted for aquatic macroinvertebrates in the Central Highlands prior to 1990.


Date

Catchment

Sites surveyed

Institutions responsible

1975-1980

Goulburn

27

Monash University, Museum of Victoria

1979-1981

Thomson

7

Museum of Victoria

1979-1984

Latrobe

21

Museum of Victoria, EPA, Monash University

1975-1982

Bunyip

21

Monash University, Rusden College, Dandenong Valley Authority

1976-1986

Yarra

45

Ministry for Conservation, Monash University, Rural Water Commission



Post-1990 macroinvertebrate surveys

Since 1990, various surveys have continued in some catchments. A number of graduate and post-graduate projects at Monash University have continued, primarily in the upper Goulburn River catchment (Taggerty, Steavensons and Acheron Rivers), while a few studies have been conducted in the Yarra catchment (Saddlier and Doeg 1996). No new major surveys have been conducted in the Latrobe, Thomson or Bunyip catchments.


As part of the Monitoring River Health Initiative (MRHI), 40 sites are currently being monitored in the Central Highlands region (L. Metzeling, EPA, pers. comm. - Table 7.8). An additional 47 sites have also been sampled in the urban sections of the Yarra River. Melbourne Water also conducts an extensive community based monitoring program for aquatic macroinvertebrates in the Yarra River.
Table 7.8: Number of sites sampled as part of the MRHI after 1990 in each catchment in the Central Highlands.


Catchment

Number of sites

Goulburn

6

Thomson

2

Latrobe

13

Bunyip

4

Yarra

15

There has been no comprehensive or systematic study of the aquatic macroinvertebrate fauna of the entire Central Highlands Region. Numerous individual studies have been conducted for specific purposes. The recent introduction of 40 sites surveyed under the MRHI program will provide some baseline data for the region. The data from these are being used to construct a national predictive model, allowing the invertebrate fauna to be predicted on the basis of the river characteristics (e.g. water quality, altitude, bed structure). However, an overall survey intensity at a greater density than 40 sites in the Central Highlands will be required. The number of additional sites required for accurate localised modelling cannot be estimated, but a further 50 sites in the Central Highlands would contribute significantly to the input of suitable models.





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