suggested evc benchmarks for condition assessments

Transcription

1 j suggested evc benchmarks for condition assessments wet saltmarsh herbland Low herbland dominated by succulent to semi-succulent halophytes, occupying low-lying areas of coastal saltmarsh subject to regular inundation. Often very species-poor. Hemichroa pentandra Samolus repens Selliera radicans Triglochin striata Trailing Hemichroa Creeping Brookweed Shiny Swamp-mat Streaked Arrow-grass Wet Saltmarsh Herbland may be a naturally occurring EVC; or it may have established as a result of altered hydrological regimes, and represent the final degradation product of another system. How it is valued must depend on the context of the evaluation. This benchmark is appropriate for use wherever current ecological condition is to be assessed. If, however, an historic view of change is required, where regional changes over time must be included, some areas of Wet Saltmarsh Herbland should be assessed according to the benchmark of their former EVC (and thus down-scored). Medium to small succulent herbs 1 30 Medium to small creeping herbs 1 1 mangrove shrubland Shrubland to 4 m tall. Confined to protected low-energy coastal environments where there is sufficient shelter from strong wave action and currents to allow the accumulation of fine sediments, generally on mudflats within the tidal zone. appendix j: suggested evc benchmarks for condition assessments 507

2 Avicennia marina subsp. australasica Grey Mangrove None Mangroves 1 10 wet saltmarsh shrubland Shrubland to ~2 m dominated by halophytic species, occupying superficially well-drained and/or sandy areas within coastal saltmarsh subject to regular tidal inundation. Atriplex paludosa subsp. paludosa Suaeda australis Tecticornia arbuscula Marsh Saltbush Austral Seablite Shrubby Glasswort Annual weeds may not be apparent or their cover difficult to assess in late summer and autumn. Assessments should avoid this period. Medium to small succulent herbs 1 5 Medium to small Shrubs mangroves and coastal saltmarsh of victoria: distribution, condition, threats and management

3 coastal saline grassland Grassland dominated by rhizomatous grasses (at best development forming mounds), generally occurring towards upper zones of coastal saltmarsh, often in areas with some freshwater seepage. Distichlis distichophylla Sporobolus virginicus Australian Salt-grass Salt Couch (rarely, sandier sites) Critical life-form groupings and threshold values for determining if life form is substantially modified Creeping grasses 1 25 coastal dry saltmarsh Herbland to low shrubland of upper saltmarsh, generally in areas of low rainfall. Subject to relatively infrequent tidal inundation. Angianthus preissianus Disphyma crassifolium Frankenia pauciflora var. gunii Sarcocornia blackiana Salt Angianthus Rounded Noon-flower Southern Sea-heath Thick-head Glasswort appendix j: suggested evc benchmarks for condition assessments 509

4 Medium to small succulent herbs 2 25 Annual herbs (if assessing in spring) 1 1 coastal hypersaline saltmarsh Low shrubland dominated by succulent chenopods (or rarely Salt Lawrencia), occurring on heavier soils in hypersaline saltmarsh habitat above the zone influenced by regular tides. Frankenia pauciflora var. gunii Lawrencia squamata Tecticornia halocnemoides subsp. halocnemoides Tecticornia pergranulata subsp. pergranulata Southern Sea-heath Thorny Lawrencia Grey Glasswort Blackseed Glasswort Medium to small succulent herbs 1 5 Medium to small or prostrate shrubs 1 1 coastal tussock saltmarsh Saltmarsh dominated by robust tussocks to 2 m of either Gahnia filum or Austrostipa stipoides with a range of halophytic species at lower covers. Occupies less frequently inundated zones of coastal saltmarshes. G. filum is apparently dominant on heavier soils with a higher salt content, with A. stipoides occurring on peaty, sandy or shelly soils or where some leaching of salt occurs from the upper soil profile. 510 mangroves and coastal saltmarsh of victoria: distribution, condition, threats and management

5 Austrostipa stipoides Distichlis distichophylla Gahnia filum Prickly Spear-grass Australian Salt-grass Chaffy Saw-sedge Large graminoids 1 25 Medium to small herbs 2 1 saltmarsh-grass swamp Inundation-prone saltmarsh vegetation dominated by Australian Saltmarsh-grass Puccinellia stricta. Occupies very heavy, saline soils subject to intermittent inundation from freshwater inputs and prolonged dry periods with hypersaline conditions. Puccinellia stricta Wilsonia rotundifolia Australian Saltmarsh-grass Round-leaf Wilsonia Medium graminoids 1 25 Medium to small herbs 1 1 appendix j: suggested evc benchmarks for condition assessments 511

6 512 mangroves and coastal saltmarsh of victoria: distribution, condition, threats and management