Mainland New South Wales covers an area of about 800,000 square kilometres, extending over 12 degrees of longitude and 6 degrees of latitude. In broad terms, NSW encompasses four geographic zones – the coastal plains, the tablelands, western slopes and the western plains.
Apart from Antarctica, Australia is the world’s driest continent and climate is the major factor affecting the distribution of Australian birds; many species are adapted to this climate. Eastern Australia is especially well known for its seemingly unpredictable extremes in weather with floods or droughts a regular feature. For example, 1997 to 2006 was the driest period in NSW’s recorded history and was followed by a period of severe flooding.
Climatically, New South Wales lies within a temperate zone; however, very high temperatures occur in the far northwest and very cold temperatures on the Southern Highlands. The climate changes markedly east to west and this is evidenced by significant differences in vegetation. Average annual rainfall varies from greater than 2000 mm per annum in parts of eastern NSW to less than 200 mm in the far west. In part, the climatic variation occurs because of the presence of the Great Dividing Range, which runs the full length of NSW from north to south and is never more than 150kms from the coast; it rises abruptly from the coastal plain and much rain borne by onshore winds falls on the eastern escarpment. Thus, the coastal strip has good rainfall and being influenced by the warm waters of the adjacent Tasman Sea maintains relatively mild temperatures Winter snow falls, mostly in the Southern Alps (the far southern section of the Great Divide) and severe frosts can occur anywhere on the high country of the Great Divide. Beyond the Great Divide, rainfall decreases and temperature extremes occur. Most inland locations experience maximum summer temperatures above 30°C, and in the northwest may reach 50°C while winter frosts and temperatures below -5°C may occur in the Southern Alps and inland.
The Southern Oscillation and its impact on the region’s climate – Australian weather patterns are influenced by a phenomenon known as the Southern Oscillation (SO). The SO is a major air pressure shift occurring between the eastern Pacific and the western Pacific/Asian regions as a result of large-scale interactions between the ocean and the atmosphere and has a profound effect on climate variability, season to season and year to year. A sustained positive variation in the SO Index is known as a La Nina and a sustained strongly negative variation is called an El Nino. Such variations occur randomly. When negative variations occur there are widespread drought conditions; a La Nina may result in widespread heavy rain.
In addition to impacting land-based habitats, the Southern Oscillation influences oceanic circulation and productivity of the Tasman Sea.
The western Tasman Sea is dominated by the interplay between bodies of warm and cold water (Cooper, McAllan & Curtis 2014) and these result in great variability in the composition of the seabirds found through the year.
Regular seabird trips travel to the Continental Shelf and adjacent waters from Port Stephens (near Newcastle), Swansea (a suburb of Newcastle); Sydney, Wollongong and Eden (Far South Coast). An outcome of this activity is that most recent new vagrants to NSW have been seabirds. In addition, the topography of the waters of the mainland, coastal islands, the volcanic island of Lord Howe and its associated rock outcrops and reefs, and seamounts (undersea mountains) further modify oceanic waters so they contain high concentrations of food and larger numbers of seabird are often associated with these places.
The Great Dividing Range is both a climatic barrier and a distribution barrier for birds by separating the narrow and wetter coastal plain from the drier inland. A number of westward range offshoots of the Great Dividing Range (notably the Liverpool, Warrumbungle and Nandewar Ranges) extend the range of some coastal rainforest and forest dwelling species. The lowest section of the Great Dividing Range occurs in the Upper Hunter and, here, woodlands similar to those of the inland enable typically inland birds to move towards coastal areas.
Throughout the Divide, there are upland areas ranging from 300 metres to over 2,150 metres, these Tablelands comprise the New England Tableland, the Central Tablelands (Blue Mountains to Bathurst and Orange, Goulburn and Yass), the Monaro Tableland and the high plateaux of Kosciusko and Kiandra. Far from being level, their surface consists of a series of very broad, undulating valleys. They experience obvious altitudinal changes in climate, particularly cold winters and mild summers. Interspersed on the tablelands are open grass- or heath- lands. Previously, extensive temperate woodlands largely covered much of the tableland area as well as extending onto the riverine plains and the far western rangelands. Today, these woodlands have been extensively cleared and modified for agricultural pursuits, primarily sheep-wool production and cereal cropping. As one progresses west of the Divide, across the Western Slopes (similarly extensively cleared) the land flattens to dry plains and, here, the major rivers are important in determining bird distribution.
Further inland, the far western plains country may appear quite featureless to some travellers but there are numerous outcrops in the northern two thirds of the State and faulted and warped peneplains raise their heads abruptly near Broken Hill. These are the Barrier Ranges that at 390 – 480 metres practically tower above the surrounding plains. To the north the Grey Range, rising to between 260m and 330m, also stands above the plains landscape. These ranges and other outcrops introduce added diversity to the surrounding landscape.
Before the arrival of Europeans, the only substantial alterations to habitats were made by Aborigines, who manipulated the vegetation for thousands of years through the use of fire. Vegetation patterns were profoundly affected by this action. Europeans imposed more basic, permanent and rapid change to the vegetative cover. This change is still occurring through land clearing, use of European agricultural practices, the introduction of foreign plants and animals, and salinisation. Almost all of New South Wales has been modified to some extent; in particular, the understory has been eliminated or substantially reduced.
Forest & Woodlands
Australia is dominated by xerophytic (hard-leaved) plants, which have to contend with conditions which do not yield a generous supply of moisture to the plant. Here the vegetation mainly consists of eucalypts, acacias, geebungs, needlewood, allocasuarinas, quandong, spinifex, saltbush, bluebush, prickly wattle, etc.
Tall forests and woodlands are mostly confined to the higher rainfall areas of eastern New South Wales; while on the more easterly plains unless cleared open eucalypt woodland or woody shrubland are key habitats.
Tall forests may be rainforest or wet eucalypt types. Rainforest types, ranging from Sub-tropical to Cool Temperate, exist along the east coast of NSW. Where conditions are unsuitable for rainforests, wet eucalypt forest dominates this region. Temperate woodlands occurred in fertile rain shadows of coastal valleys, e.g. the Clarence, Hunter and Bega valleys and on the Cumberland Plain and on the western slopes and nearby plains. These savanna-type woodlands were described as park like by the early Europeans and are now the most extensively cleared vegetation communities across NSW because the areas are valued as important for wool, lamb and wheat production.
Mallee or Acacia Woodlands
Large tracts of mallee or acacia woodlands originally occupied parts of the semi-arid and arid parts of NSW, but much has been cleared. Areas of mallee, some of which are controlled by the NSW NP&WS still remain in the Western Division. Mallee is an important habitat for several rare birds (including Mallee-fowl, Regent Parrot, Scarlet-chested Parrot, Striated Grasswren, Shy Heathwren, Red-lored Whistler, Chestnut Quailthrush, Southern Scrub-robin and Black-eared Miner). In the northern parts of the semi-arid and arid western and central-western NSW mulga woodlands dominate.
Beyond to western slopes, the plains country begins. In the Northwest, the plains extend from the foothills of New England to the Darling or Barwon River, with practically negligible irregularities in their topography. Close in, Box, Ironbark or Cypress Pine woodlands are important; while to the west of these trees such as belah or brigalow often dominate sometimes interrupted by areas of eremophila, hopbush, cassia, wilga, or other large shrubs and, here and there, open grasslands varying from 100m to 20kms or more in extent occur. Examples are the Old Man, Tycannah, and Edgeroi Plains. On the far western plains, the vegetation usually consists of low saltbush, bluebush or prickly wattle shrublands, Mitchell grass plains or stony (gibber) plains. In southern inland NSW, the Riverina plain is a huge expanse of country mostly sparingly treed by only the Boree, Acacia pendulata.
The wetlands and rivers are important sites for waterbirds, waders and other birds reliant on such habitats but much of the coastal wetlands have been drained despite a growing appreciation of the importance of inland and coastal wetlands and the need to retain natural areas. In western NSW wetlands play an especially important role. The more permanent sites provide essential breeding sites of egrets, ibis and herons. Some of these, e.g. the Menidee Lakes, Lake Mulwala, are artificially filled as water storage basins. Others, e.g. Gingham Watercourses, Narran Lake, Macquarie Marshes those at the Lachlan/Murrumbidgee junction and the many billabongs along the Darling, Murrumbidgee and Murray are natural areas relying on regular floodwater. In the far northwest, most wetlands are ephemeral and some of the more extensive include Lake Wallace, Salt Lake, Cobham Lake, the Bulloo Overflow, the Cuttaburra channels, Yantabulla Swamps, Lake Bancannia, Lake Altiboulka, Mullawoolka Basin, Tonga Lake, Peery Lake.
Coastal wetlands tend to be dominated by sedge, phragmites and other emergent reeds, heath, paperbarks, mangroves, samphire, etc. Inland the vegetation is often Lignum, Cumbungi, Canegrass Nitre Goosefoot or River Cooba are important.
River Red Gums
The inland rivers, creeks, etc. of inland NSW are typically bordered by tall forests, and in Southern NSW towering majestically over the network of waterways, are River Red Gum forests. These are often forestry reserves, sometimes national parks, and may stretch for over 100,000 hectares. They are home to more than 150 species of birds. Ideal birding locations are to be found along the valleys of the Murray, Murrumbidgee and Lachlan rivers and are ideal places to get up close with the gums and their amazing bird life.
There are many great places for wildlife across the state but one of the best known birding locations is Everlasting Swamp [Map]
Major Source: Fatbirder
Map Source: Wiki Commons