1~111111"III~Mlll"II' BACKGROUND
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A BOTANICAL SURVEY ALONG THE SOUTH ESK MAIN ROAD: STYNES BRIDGE TO THE ST. PAULS BRIDGE AT AVOCA A REPORT TO THE DEPARTMENT OF TRANSPORT AND WORKS: TRANSPORT INFRASTRUCTURE DIVISION MICHAEL ASKEY-DORAN JUNE 1993 . III~008717589 1~111111"III~mlll"II' BACKGROUND A botanical survey was carried out along the Esk Main Road between Stynes Creek Bridge and the St. Pauls River Bridge for the Department of Transport and Works: Transport Infrastructure Division. This section represents a distance of 3.97 km. AIMS The aim of this botanical survey was to provide an inventory of the plant species and communities occurring along this section of the Esk Main Road. An assessment of the conservation status and significance of those plant species and communities for both the roadside and adjacent land is made. Areas of high conservation value are identified and where necessary, suggestions on measures needed to ensure they are not adversely affected are made. Any ameliorative measures to encourage regrowth of native vegetation are considered. STUDY AREA The study area extends along a relatively flat section of road which dips at Jubilee lagoon and again at Stynes Creek at its western end. Vegetation in this area has largely been cleared leaving only a few, even aged eucalypts (Eucalyptus pauciflora and E. ovata) remaining. Regeneration of these species appears to be confined to the roadside verge. The broad flats have been largely converted to pasture which are used predominantly for grazing. The geology is variable, with alluvium of dominantly quartzose granule to cobble sized clasts predominating from just before the St. Pau1s River bridge to just past the turn off to Benham. Tertiary basalts occur along the St. Pauls River and a short distance past the bridge. From the pOint past Benham, the geology consists of alternating 'stretches of tertiary basalt and aeolian dune and sheet deposits. Soils of the area are stoney, reddish brown gradational soils on the lower plateaus and very dark grey clays with uniform texture and a high gravel content on the lower scarps and in the swales (Pinkard 1980). Mean monthly and yearly rainfall for selected stations: Jan Feb Mar Apr May .fun Jul Aug Sep Oct Nov Dec Year Fingal 58 44 82 68 99 86 101 89 76 72 80 79 934 Lewis Hill 40 41 52 57 58 65 60 60 53 56 53 58 653 Rossarden 40 51 67 77 105 92 88 103 85 69 67 51 895 METHODOLOGY Both sides of the existing road were surveyed on foot, covering an area from the edge of the pavement to 5 meters past the existing fenceline into the adjoining property. General species lists were made and these were used to derive communities. The native plant communities found in the survey area are shown on an accompanying base map (figure 1 ). Nomenclature follows Buchanan et at. (1989) except for Danthonia popinensis which follows Morris (1990). RESULTS Plant Species A total of 97 plant species were recorded for the survey area. Of these, 50 were native of which 5 are endemic to Tasmania. Only one of the native plant species found along this section of road is regarded as being at risk with regards to its conservation or reservation . status. This species, Danthonia popinensis has been recorded at only two other locations, Kempton - opposite Mood Food and near Conara. It is listed as U ue, being a species which is likely to become extinct if present land use changes and patterns and other causal factors of decline continue on both a national and state level and it is not known from any secure reserve (Kirkpatrick et al. 1991). Introduced plant species are the predominant flora of this road section in terms of cover, with grasses being the most dominant. In the majority of cases, native species are confined to a narrow grassy edge immediately adjacent to the fence line. This distribution results from both grading and mowing of the road strip. An exception to this can be found along the raised batters near the St. Pauls River bridge, where Pultenaea pedunculata, Hibbertia prostrata Danthonia popinensis, Danthonia carphoides var. angustior and Danthonia penicillata can be found. The·flora on the adjacent land is predominantly composed of introduced grasses and herbs. However, there are occasional patches of Kangaroo grass (Themeda australis) and funcus astreptus close to the fence line. Two poorly drained sites, one where the rail line crosses the road and the other at Stynes Creek bridge carry a number of native graminoides including funcus astreptus, sagg (Lomandra longifolia), tussock grass (Poa labillardieri), tall sedge (Carex appressa) and funcus procerus. There are individual specimens of snow gum (Eucalyptus pauciflora) and swamp gum (Eucalyptus ovata) present in the paddocks next to the fence line. Seedlings from these trees are common along the nearby roadside verge. Two small stands of silver wattle (Acacia dealbata) occur at either end of the road section. Plant Communities (1) Daetylis glomerata-Agrostis eapillaris-Plantago laneeolata introduced grassy verge and paddocks. This community is characterised by the presence of introduced species which dominate both in terms of numbers and cover. The grasses, cocksfoot (Dactylis glomerata), browntop (Agrostis eapillaris), and rough dogs tail (Cynosurus echinata) dominate in various proportions. In the areas of the verge which are mowed and graded, introduced herbs dominate, including narrow-leaf plantain (Plantago lanceolata), buck's-horn plantain (Plantago eoronopus), sheep's sorrel (Rumex acetosella) and wild carrot (Daueus carota). The native species in this community are largely confined to thefenceline which escapes regular mowing of the verge. Common dicotyledenous natives include common rice-flower (Pimelea humilis), peachberry (Lissanthe strigosa) and native geranium (Geranium solanderi). Native monocots found in this community include tussock grass (Poa labillardieri), kangaroo grass (Themeda triandra), Ehrharta stipoides, sagg (Lomandra longifolia) and funeus astreptus. Conservation status: low. (2) Daetylis glomerata-Poa labillardieri-Themeda triandra grassy verge. This community is similar to (1), however the native grass species, tussock grass (Poa labillardieri) and kangaroo grass (Themeda triandra) have significant covers. These two native species occur along with several introduced grasses including. cocksfoot (Dactylis glomerata), brown top (Agrostis capillaris) and rough dogstail (Cynosurus echinata). At one site near Jubilee Lagoon, sagg (Lomandra longifolia), Juncus astreptus and Isolepis nodosa occur in this community. Native herbs include buzzy (Acaena novae-zelandiae), common rice-flower (Pimelea humilis), common everlasting (Helichrysum apiculatum) and Asperula conferta. Introduced herbs dominate in the areas which have been mowed and graded and include narrow-leaf plantain (Plantago lanceolata), buck's-horn plantain (Plantago coronopus), wild carrot (Daucus carota) and sheep's sorrel (Rumex acetosella). Conservation status: locally: moderate statewide: low (3) Baumea rubiginosa-Juncus effusus-Poa labillardieri sedgeland. This community occurs in a poorly drained area on the southern side of the road at Jubilee Lagoon. It is characterised by the dominance of Baumea rubiginosa, tussock grass (Poa labillardieri) and Juncus effusus. Other species occurring in this community are predominantly introduced, and include cocksfoot (Dactylis glomerata), sheep's sorrel (Rumex acetosella), curled dock (Rumex crispus) and hyssop loosestrife (Lythrum hyssopifolium). Native species include knobby club-rush (Isolepis nodosa), variable sword edge (Lepidosperma laterale) and mat grass (Hemarthria uncinata). Conservation status: locally: moderate statewide: low (4) Pultenaea pedunculata-Hibbertia prostrata-Danthonia popinensis grassy shrubland. This community occurs on batters at the approach to the St. Pauls River bridge. It is characterised by the presence of two prostrate shrubs, matted bush-pea (Pultenaea pedunculata) and creeping guinea-flower (Hibbertia procumbens). Other native species include silver wattle (Acacia dealbata) juveniles, and monocots kangaroo grass (Themeda triandra), barbed spear-grass (Stipa semibarbata), sagg (Lomandra longifolia) and Lepidosperma inops. The presence of Danthonia popinensis marks this community as being one of high conservation value. Introduced plant species dominate this community as in the other communities. The most common grasses include cocksfoot (Dactylis glomerata) silver hair-grass (Aira caryophyllea), Juncus effusus, toad rush (Juncus bufonius), brown top (Agrostis capillaris) and quaking grass (Briza maxima). Introduced dicots include, narrow-leaf plantain (Plantago lanceolata), buck's-horn plantain (Plantago coronopus), rose hip (Rosa rubiginosa) and gorse (Ulex europaeus). Conservation status: extremely high. (5) Carex appressa-Juncus procera-Poa labillardieri sedgeland. This community can be found in a depression 2 meters below the level of the road at Stynes Creek bridge. It is dominated by tall sedge (Carex appressa), Juncus procerus and tussock grass (Foa labillardieri) and to a lesser extent, sagg (Lomandra longifolia). A number of introduced species occur in this community including, narrow-leaf plantain (Plantago lanceolata), cocksfoot (Dactylis glomerata), jointed rush (Juncus articulatus) and Polygonum arenastrum. Conservation status: locally: moderate statewide: low RECOMMENDATIONS Whilst there are no plant species or communities off significant conservation status along the greater part of this road, attempts should be made to limit destruction