Remnant Native Vegetation Investigation Discussion Paper

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4.2 Comparison of bioregions 4.2.1 EXTENT OF REMNANT NATIVE VEGETATION The main determinant of both ecosystem health and ecological connectivity of a landscape is the extent of remnant native vegetation. Graph 1 shows that the proportion of native vegetation remaining in the fragmented parts of Victoria’s bioregions varies greatly – from less than 16% of the Victorian Volcanic Plain, to more than 93% in the Highlands – Far East. In fragmented landscapes overall, 31.6% of the state’s original extent of native vegetation remains. This graph provides the basis for sorting the bioregions into the following three main groups: most cleared, moderately cleared, and least cleared bioregions. Graph 1 Proportion of native vegetation in fragmented landscapes in each bioregion Notes: 1. See appendix 3 for a comparative tabulation of bioregion statistics. 2. Particularly in more extensively cleared bioregions, the amount of remnant native vegetation reported here is higher than previous estimates - see section 3.1.1 for a full explanation of this change. Most cleared bioregions With the exception of the Strzelecki Ranges (which has an unusual land-use history, as described on page 77), the ten most cleared bioregions all have relatively fl at terrain and fertile soils, and less than 40% of their original extent of native vegetation remaining. As a result, habitat loss and isolation of remnants are almost certainly the major cause of biodiversity loss in these landscapes. These bioregions are of highest relevance for the Remnant Native Vegetation Investigation: Victorian Volcanic Plain Wimmera Warrnambool Plain Murray Mallee Victorian Riverina Gippsland Plain Dundas Tablelands Strzelecki Ranges Otway Plain Murray Fans Graph 2 shows that all these bioregions have proportionately few or no adjoining largely-intact landscapes. In addition, several of these bioregions are among the largest in Victoria – collectively the Murray Mallee, Victorian Volcanic Plain, Wimmera and Victorian Riverina account for half of the statewide area of fragmented landscapes. % MOST CLEARED MODERATELY CLEARED LEAST CLEARED 100 80 60 40 20 0 Victorian Volcanic Plain Wimmera Warrnambool Plain Murray Mallee Victorian Riverina Gippsland Plain Dundas Tablelands Strzelecki Ranges Otway Plain Murray Fans Central Victorian Uplands Glenelg Plain Northern Inland Slopes Goldfields Lowan Mallee Highlands – Southern Fall East Gippsland Lowlands Monaro Tablelands East Gippsland Uplands Bridgewater Highlands – Northern Fall Otway Ranges Greater Grampians Robinvale Plains Victorian Alps Murray Scroll Belt Wilsons Promontory Highlands – Far East Bioregions 46
Moderately cleared bioregions Bioregions with 40-70% remnant native vegetation in their fragmented landscapes are characteristically foothills or less fertile fl atter country. Although not as fragmented as the preceding bioregions, these moderately cleared bioregions are still a major focus for the Remnant Native Vegetation Investigation: Central Victorian Uplands* Glenelg Plain Northern Inland Slopes* Goldfields* Lowan Mallee Highlands – Southern Fall East Gippsland Lowlands Monaro Tablelands East Gippsland Uplands Bridgewater Highlands – Northern Fall As shown in Graph 2, the bioregions in this group are generally in the middle range of sizes spanned by Victorian bioregions. Four bioregions – Lowan Mallee, East Gippsland Lowlands, East Gippsland Uplands and Highlands – Northern Fall – have extensive adjoining largely-intact landscapes which ameliorate some of the effects of fragmentation in their fragmented landscapes. See comments in section 4.2.2 below about the extent of remaining native vegetation in the three asterisked (*) bioregions. Least cleared bioregions Even in their fragmented landscapes, the remaining seven bioregions have large extents of their original extent of native vegetation remaining – between 76% and 94%. While there may be particular characteristics (such as vegetation condition) or smaller more fragmented localities which are relevant to the Remnant Native Vegetation Investigation, generally these bioregions are not the focus of the investigation: Otway Ranges Greater Grampians Robinvale Plains Victorian Alps Murray Scroll Belt Wilsons Promontory Highlands – Far East The bioregions in this group are generally small, even allowing for the proportionately extensive largely-intact landscapes in most of them (Graph 2). Graph 2 More cleared bioregions tend to be larger • Total area of largely-intact landscapes • Total area of fragmented landscapes Area (’000 ha) MOST CLEARED MODERATELY CLEARED LEAST CLEARED 3,000 2,500 2,000 1,500 1,000 500 0 Victorian Volcanic Plain Wimmera Warrnambool Plain Murray Mallee Victorian Riverina Gippsland Plain Dundas Tablelands Strzelecki Ranges Otway Plain Murray Fans Central Victorian Uplands Glenelg Plain Northern Inland Slopes Goldfields Lowan Mallee Highlands – Southern Fall East Gippsland Lowlands Monaro Tablelands East Gippsland Uplands Bridgewater Highlands – Northern Fall Otway Ranges Greater Grampians Robinvale Plains Victorian Alps Murray Scroll Belt Wilsons Promontory Highlands – Far East Bioregions 47
Page 1 and 2: Remnant Native Vegetation Investiga
Page 3 and 4: Remnant Native Vegetation Investiga
Page 5 and 6: Council members (left to right): Ia
Page 7 and 8: Gippsland Plain 72 Dundas Tableland
Page 9 and 10: LANDSCAPE ECOLOGY AND LANDSCAPE CHA
Page 11: PATTERNS, IMPACTS AND THREATS The d
Page 14 and 15: 1.1 Background to the investigation
Page 16 and 17: 1.3 Terms of reference for the inve
Page 18 and 19: 1.6 The investigation process The p
Page 20 and 21: 1.8 Community views During the prep
Page 22 and 23: Framework Attendees at the regional
Page 24 and 25: Modifi cation of the landscape by h
Page 26 and 27: McIntyre and Hobbs (1999) conceptua
Page 28 and 29: The ability of a species to dispers
Page 30 and 31: 2.3 Climate change 2.3.1 MAGNITUDE
Page 33 and 34: 3 STATEWIDE MODELLING OF NATIVE VEG
Page 35 and 36: 3.1 Vegetation modelling 3.1.2 VEGE
Page 37 and 38: Table 3.2 Extent of terrestrial pub
Page 39 and 40: 3.3 Statistical analysis of GIS mod
Page 41 and 42: 3.4 Connectivity modelling Understa
Page 43 and 44: Brown treecreeper Climacteris picum
Page 45 and 46: Mallee ningaui Ningaui yvonneae The
Page 47 and 48: 4 CHARACTERISATION OF VICTORIA’S
Page 49: Table 4.1 Statewide summary of nati
Page 53 and 54: Graph 3 More cleared bioregions ten
Page 55 and 56: Graph 5 The condition of native veg
Page 57 and 58: Graph 7 In fragmented landscapes, t
Page 59: GROUPS AND BIOREGIONS Least cleared
Page 62 and 63: Biogeographical regions or bioregio
Page 64 and 65: 5.2 Site condition and landscape co
Page 66 and 67: VICTORIAN VOLCANIC PLAIN KEY FINDIN
Page 68 and 69: WIMMERA KEY FINDINGS TOTAL BIOREGIO
Page 70 and 71: WARRNAMBOOL PLAIN TOTAL BIOREGION 2
Page 72 and 73: MURRAY MALLEE KEY FINDINGS TOTAL BI
Page 74 and 75: VICTORIAN RIVERINA KEY FINDINGS TOT
Page 76 and 77: GIPPSLAND PLAIN KEY FINDINGS The Gi
Page 78 and 79: DUNDAS TABLELANDS KEY FINDINGS TOTA
Page 80 and 81: STRZELECKI RANGES TOTAL BIOREGION 3
Page 82 and 83: OTWAY PLAIN TOTAL BIOREGION 237,190
Page 84 and 85: MURRAY FANS TOTAL BIOREGION 435,153
Page 86 and 87: CENTRAL VICTORIAN UPLANDS KEY FINDI
Page 88 and 89: GLENELG PLAIN KEY FINDINGS The Glen
Page 90 and 91: NORTHERN INLAND SLOPES KEY FINDINGS
Page 92 and 93: GOLDFIELDS KEY FINDINGS TOTAL BIORE
Page 94 and 95: LOWAN MALLEE KEY FINDINGS Due to th
Page 96 and 97: HIGHLANDS - SOUTHERN FALL KEY FINDI
Page 98 and 99: EAST GIPPSLAND LOWLANDS KEY FINDING
Page 100 and 101:
MONARO TABLELANDS KEY FINDINGS The
Page 102 and 103:
EAST GIPPSLAND UPLANDS KEY FINDINGS
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BRIDGEWATER KEY FINDINGS TOTAL BIOR
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HIGHLANDS - NORTHERN FALL KEY FINDI
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OTWAY RANGES KEY FINDINGS TOTAL BIO
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GREATER GRAMPIANS KEY FINDINGS TOTA
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ROBINVALE PLAINS KEY FINDINGS TOTAL
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VICTORIAN ALPS KEY FINDINGS TOTAL B
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MURRAY SCROLL BELT KEY FINDINGS TOT
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WILSONS PROMONTORY KEY FINDINGS The
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HIGHLANDS - FAR EAST KEY FINDINGS T
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6 LANDSCAPE PATTERNS, IMPACTS AND T
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6.2 Impacts of landscape change on
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DECLINE OF NATIVE GRASSLANDS AND TH
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6.3 Current and future threats The
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6.3.4 CHANGES IN THE MATRIX Althoug
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THE VALUE OF SCATTERED TREES AND SM
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The preceding chapters have highlig
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7.1 Clarity of terminology and obje
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7.3.3 PRIORITISING PATCHES OF HIGH
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7.3.6 DIFFERENT APPROACH FOR WETLAN
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Within any landscape, other things
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7.3.17 EXPLAINING THE BASIS OF POLI
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(single-species perspective) 2) of
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REFERENCES 1 Steffen, W., Burbidge,
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APPENDIX 1 ADVISORY GROUPS Communit
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Patch metrics Patch metrics aim to
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APPENDIX 3 SUMMARY STATISTICS FOR E
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Living Links Southeast Metropolitan
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APPENDIX 5 QUESTIONS THAT MAY COMPL
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