Section a obbens p65

Vegetation, flora and recommendations for conservation

management of Jingaring Nature Reserve: A “botanical gem”

in the Western Australian wheat-belt.

F J Obbens, R W Davis & L W Sage

Western Australian Herbarium, Department of Conservation and Land Management,

Locked Bag 104, Bentley Delivery Centre WA 6983

 

(received February 1999, accepted December 2000)

Abstract

The significance of larger remnants at retaining local bio-diversity in an essentially cleared and fragmented

agricultural landscape is generally accepted, but small intact remnants also contribute significantly to overall

bio-diversity. This was highlighted by our comprehensive survey  of vascular flora of Jingaring Nature Reserve,

which included every season over a two-year period. The exceptionally diverse flora of this relatively undis-

turbed wheatbelt remnant identified six distinct communities encompassing heaths and woodlands. Over 260

vascular species were recorded, including two rare, five priority and a number of species of special interest from

51 families. Weeds accounted for 27 species, but the extent of invasion is relatively low. The known limit of many

species’ distributions occur near or at the reserve and this may be an evolutionary artefact of significant impor-

tance. Higher species diversity per unit area was recorded compared to other unpublished surveys of larger areas

around this district.

Several management issues are of concern for Jingaring Nature Reserve including protection of rare and

priority flora, weed invasion, fire management and damage caused by unauthorised access. Eradication of

rabbits and localised weed control around rabbit warrens in the reserve should result in regeneration of these

areas.

Keywords: vegetation, flora, Jingaring Nature Reserve, wheat-belt, remnant vegetation.

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Journal of the Royal Society of Western Australia, 84 (2), June 2001

54

Methods

The vegetation communities of Jingaring Nature Re-

serve were interpreted from a 1996 aerial photograph and

confirmed in the field during 1999. Classification of these

vegetation communities is based on Muir (1977b). This

classification assesses vegetation structure by taking meas-

ures of lifeform/height class and canopy cover/density

class to produce a vegetation type. For example, trees 15-

30 m with a 10-30% canopy cover were designated

woodlands, while the same trees with a canopy cover of 2-

10% would be designated as open woodlands. To a

significant extent this classification also reflects species

compositional differences. Additionally, brief investiga-

tions were made of the soils in each vegetation community.

This included taking soil samples (~3 cm depth) to nomi-

nally assess soil texture and colour.

The flora survey and collections were accomplished

by walking along transects (spaced 150 m apart) which

spanned the full width of the reserve in a north-south

orientation. The first transect began at approximately 50

m in from the reserve’s south-west corner, in the vicinity

of Sandplain Creek. Every vegetation type was traversed

several times using this technique. This transect survey

was undertaken during late spring 1998, but various addi-

tional surveys were also carried out during mid autumn,

early and late winter, early and mid spring, and early

summer over 1998 and 1999. On these occasions a tech-

nique known as ‘randomized stratified walk’ (Hopper et

al. 1997) was employed. As the name suggests, this method

involves specimen collections via random walks in each

habitat type. The purpose of this intensive surveying was

to obtain a good flowering specimen of each species and

to compile a more complete vascular flora list (i.e. as a

benchmark survey).

The authors identified most specimens with some as-

sistance from specialist staff of the WA Herbarium. All

specimens were submitted for incorporation at the WA

Herbarium. Species names follow WACENSUS (WA Her-

barium census of Western Australian vascular plants),

while conservation status of species is according to De-

partment of Conservation and Land Management’s