Vegetation
The region's vegetation is predominantly Eucalyptus mallee over myrtaceous and proteaceous heath. Over 50% of the area is vegetated entirely by mallee, and a further 25% is mainly mallee but with patches of woodland; the latter vegetation occurs mainly on the calcareous soils to the east. The mallee consists of numerous Eucalyptus species, the most consistent being E. eremophila (Tall Sand Mallee). Seasonally wet and alluvial areas are vegetated by Melaleuca shrublands where fresh, and Tecticornia low shrublands where saline. There are also occasional thickets of Allocasuarina, especially on greenstone hills.
As of 2007, the Mallee region is known to contain 3443 indigenous vascular plant species, and a further 239 naturalised alien species. As with other regions in semi-arid areas of the South West, it exhibits high endemism, especially with respect to Eucalyptus and Acacia species. The endangered flora of the Mallee region consists of 55 species, with a further 325 species having been declared Priority Flora under the Department of Environment and Conservation's Declared Rare and Priority Flora List.
Species richness ranges from 17 to 48 species per 1000 m². The lowest species richness occurs in severe habitats such as alongside salt lakes, but also in the areas of highest soil nutrition, where dominant species suppress associated species. Conversely, the highest species richness occurs in soils with the lowest soil nutrition. Most species are killed by fire and regenerate from seed, suggesting that they have evolved in an environment in which fire is infrequent.
| Major Vegetation Group | Area before European settlement | Area circa 1997 |
|---|---|---|
| Cleared / modified native vegetation | - | 3,389,464 ha (45.8%) |
| Mallee woodlands and shrublands | 4,208,658 ha (56.9%) | 2,152,520 (29.1%) |
| Eucalyptus open woodlands | 1,860,688 ha (25.2%) | 896,404 (12.1%) |
| Eucalpt woodlands | 587,132 ha (7.9%) | 587,132 (7.9%) |
| Heath | 432,536 ha (5.8%) | 196,164 ha (2.7%) |
| Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes | 212,504 ha (2.9%) | 105,308 ha (1.4%) |
| Other shrublands | 58,628 ha (0.8%) | 53,316 ha (0.7%) |
| Chenopod shrub, samphire shrub and forblands | 22,652 ha (0.3%) | 5,516 ha (0.1%) |
| Eucalypt low open forest | 6,100 ha (0.1%) | 4,492 ha (0.1%) |
| Low closed forest and closed shrublands | 2,912 ha (0.0%) | 2,668 ha (0.0%) |
| Acacia shrublands | 1,352 ha (0.0%) | 1,348 ha (0.0%) |
| Other grasslands, herblands, sedgelands and rushlands | 820 ha (0.0%) | 364 ha (0.0%) |
| Casuarina forest and woodlands | 612 ha (0.0%) | 116 ha (0.0%) |
| Tussock grasslands | 28 ha (0.0%) | 4 ha (0.0%) |
| Melaleuca forest and woodlands | 12 ha (0.0%) | 4 ha (0.0%) |
Read more about this topic: Mallee (biogeographic Region)
Famous quotes containing the word vegetation:
“I would not have every man nor every part of a man cultivated, any more than I would have every acre of earth cultivated: part will be tillage, but the greater part will be meadow and forest, not only serving an immediate use, but preparing a mould against a distant future, by the annual decay of the vegetation which it supports.”
—Henry David Thoreau (1817–1862)
“We love to see any redness in the vegetation of the temperate zone. It is the color of colors. This plant speaks to our blood.... What a perfect maturity it arrives at! It is the emblem of a successful life concluded by a death not premature, which is an ornament to Nature. What if we were to mature as perfectly, root and branch, glowing in the midst of our decay, like the poke!”
—Henry David Thoreau (1817–1862)
“When the ground was partially bare of snow, and a few warm days had dried its surface somewhat, it was pleasant to compare the first tender signs of the infant year just peeping forth with the stately beauty of the withered vegetation which had withstood the winter ... decent weeds, at least, which widowed Nature wears.”
—Henry David Thoreau (1817–1862)