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.
Flora: York Herbarium
The jarrah and marri forest occupies the highest rainfall area in the western part of the York Shire. With the decline in rainfall in a northerly and easterly direction this forest grades into a series of open woodlands of jarrah, wandoo and powderbark, and marri and wandoo. Marri shows a preference for the more sandy soils, while wandoo occurs on more clayey soils.
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 tree species found in the area include:
- Jarrah (Eucalyptus marginata)
- Wandoo (Eucalyptus wandoo)
- Powderbark Wandoo (Eucalyptus accedens)
- York Gum (Eucalyptus loxophleba)
- Salmon Gum (Eucalyptus salmonophloia)
- Red Morrel (Eucalyptus longicornis)
- Brown Mallet (Eucalyptus astringens)
- Marri (Corymbia calophylla)
- Sheoak (Allocasuarina spp.)
- Tea-tree (Melaleuca spp.)
- Banksia spp.
As well as a vast array of understory shrubs, herbs and climbers
Many Priority Flora, including Priority 4 flora from, among others, the Hibbertia, Acacia, Hemiandra, Darwinia, Caladenia, Cyanicula and Stylidium genera are also found in the Shire of York.
Fauna: The fauna of the York Shire is a diverse collection of wildlife. Mammals, birds and reptiles inhabiting the area include Echidna, Western grey kangaroo, Western brush wallaby, Euro, Dunnart, Western pygmy-possum, Brush-tail possum, White-striped mastiff-bat, Rakali, Great egret, Grey teal, Pacific black duck, Sacred kingfisher, White faced heron, Little pied cormorant, Barking gecko and Oblong turtle to name a few.
Detailed fauna surveys have also recorded a total of 24 lizard, 7 snake and 7 frog species as well as 95 bird species.