It was once endowed with abundant sources of fresh water and a rich variety of ecosystems. European settlement began as early as the 1830’s and today little remains of its natural vegetation except in the Wandoo National Park in the west. Loss of habitat results not only in loss of flora and fauna, including the invertebrates and soil fauna, but also in the degradation of water quality.
The Western Australian government had made little effort to plan and manage the scale of land clearance and it was not until the late twentieth century that the Department of Conservation and Land Management was created and promptly adopted five relatively small areas of remnant bush for conservation in the shire. Sadly this did not include the Avon River and its riparian vegetation.
In 1990 local townsfolk came together to lobby the Western Australian government to take responsibility for the Avon River. Thus was born the River Conservation Society Inc. At the same time the Society began a careful survey of all aspects of river management and began the process of fencing out exotic species from the Avon River and its tributaries.
Work began on restoring the river banks and establishing a revegetation strip 30 meters wide on both banks for the entire length of the Avon River within the shire. This revegetation ‘superhighway’ is linked by winter streams to the granite and gravel hilltops unsuitable for cultivation. This strategy of revegetating the waterways was adopted by the new Avon River Management Authority and later by other shires.
The management of the river itself is of major concern. The society persuaded the Waterways Commission to excavate several of the silted up permanent pools on the Avon, including Gwambygine Pool south of York. In 1996 – 1998 the society carried out the first ever biological survey of an inland permanent pool. This pool has become the baseline against which the condition of other pools are measured for depth, water quality and aquatic flora and fauna.
The society cares for ten of the crown reserves located within the shire of York. The intention is to preserve these last remnants of bush for future generations to enjoy and to prevent them being used for purposes that will degrade or destroy their habitat.
Flora and Fauna
The climate of the Shire of York is characterised by hot dry summers and mild wet winters. The summers are occasionally relieved by short periods of heavy rain of tropical cyclonic origin. The mean monthly maximum and minimum temperatures in summer are 34°C and 16°C respectively, while in winter they are 18°C and 5°C respectively.
In the York region the seasonality, variability and gradient of rainfall from west to east are significant factors in the determination of vegetation types and their distribution. These factors interact with geology, geomorphology and soils to determine the vegetation patterns across the shire.
The eastern half of the York area is dominated by York gum woodland. Most of this country owes its character to the relatively fertile red loam soils and a surface of gentle relief. This has led to a unique situation in which York gum is no longer confined to the soils of the lower slopes, but may occur as the sole species forming woodland over the whole landscape. Its usual associate, wandoo, is confined to less basic rocks. In the northern part of this association salmon gum shares dominance with the York gum, while in the eastern parts wandoo becomes reinstated as a co-dominant.
Extensive sandplains occur near the eastern boundary of the York Shire. These are for the most part on higher ground consisting mainly of yellow, earthy sands. The original vegetation was scrub-heath or banksia low woodland. Along major drainage lines yellow, alkaline loams support tea-tree and samphire on extensive salt flats.
Some of the species found in the area include Jarrah (Eucalyptus marginata), marri (E. calophylla), wandoo (E.wandoo), tea-tree (Melaleuca spp.), Banksia spp., powderbark (E. accedens), heath, York gum (E. loxophleba), sheoak (Allocasuarina spp.), Salmon gum (E.salmonophloia), morrell (E. longicornis), mallet (E. astringens), samphire (Halosacrcia spp.).
Detailed fauna surveys have also recorded a total of 24 lizard, 7 snake and 7 frog species including 95 bird species.