DEVELOPING AGE-SIZE RELATIONSHIPS FOR LONG LIVED TREE SPECIES

Calculating the age of trees is often desirable in vegetation studies, but is sometimes difficult. In arid areas in particular, tree rings may not be annual, and growth may be related more to rainfall than annual cycles. A relationship between age and trunk circumference was developed for two species, Acacia aneura and Myoporum platycarpum, based on measurements of trees of known age (<80 years) growing on permanent quadrats on the Koonamore Reserve, in semi-arid South Australia. Extrapolation beyond the known ages was made by finding the maximum girth of mature trees in a larger population and using this to estimate an asymptote to which the curve is constrained to approach. We envisage that the techniques developed here could be applied to other species of a similar nature, those for which there is no relationship between number of tree rings and age.

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Long-term changes in vegetation, gradual and episodic, on the TGB Osborn Vegetation Reserve, Koonamore, South Australia (1926 - 2002)

Australian Journal of Botany ◽

10.1071/bt04144 ◽

2005 ◽

Vol 53 (4) ◽

pp. 283 ◽

Cited By ~ 29

Author(s):

Russell Sinclair

Keyword(s):

Gradual Increase ◽

South Australia ◽

Gradual Change ◽

Sheep Grazing ◽

Rainfall Events ◽

Show Evidence ◽

Acacia Aneura ◽

Permanent Quadrats ◽

Semi Arid

The TGB Osborn Vegetation Reserve at Koonamore, South Australia, is a 390-ha exclosure in semi-arid chenopod shrubland. The area was heavily overgrazed in 1925 when it was fenced to exclude sheep. Permanent quadrats and photopoints have been maintained to the present. Feral rabbits were sometimes numerous until the mid-1970s but have since been controlled. The records represent 50 years without sheep grazing, followed by 26 years without either sheep or rabbits. Dramatic seedling establishment events have occurred since 1978 for the following species: Acacia aneura Benth., Myoporum platycarpum R.Br., Senna artemesioides subsp. coriacea Randell, S. artemesioides subsp. petiolaris Randell, Acacia burkittii Benth., Dodonaea attenuata A.Cunn., Eremophila longifolia (R.Br.) F.Muell., E. sturtii R.Br. and Maireana pyramidata (Benth.) Paul G.Wilson. However, the chenopod shrubs Atriplex vesicaria Benth. and A. stipitata Benth. increased earlier and did not respond in the same way to episodic rainfall events or rabbit control. Numbers of Alectryon oleifolius (Desf.) S.T.Reynolds and Casuarina pauper F.Muell. ex L.A.S.Johnson have remained almost unchanged, whereas Maireana sedifolia (F.Muell.) Paul G.Wilson and M. astrotricha (L.Johnson) Paul G.Wilson have shown a very gradual increase over time. The data show evidence for both episodic and gradual change among different species.

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Blade ploughs as an alternative to tined rippers for rabbit warren destruction in semi-arid areas.

The Rangeland Journal ◽

10.1071/rj9890040 ◽

1989 ◽

Vol 11 (1) ◽

pp. 40

Author(s):

LP Hunt

Keyword(s):

South Australia ◽

Arid Areas ◽

The Difference ◽

The Cost ◽

Semi Arid

A tractor-mounted blade plough was used to control rabbits in semi-arid South Australia by destroying their warrens. This implement was compared with a conventional two-tine ripper on the basis of effectiveness and cost. The blade plough was slightly less effective (overall mean 88% warrens destroyed) than the ripper (91% destroyed) three weeks after treatment but this difference was not significant. Warrens treated with the blade plough also had a slightly higher rate of reopening although the difference between treatments was not significant until 54 weeks after treatment. The blade plough was significantly faster in destroying warrens (mean 6.93 min cf. 9.88 min) despite frequent bogging of the tractor. The choice of a more suitable tractor should overcome this problem. Costs were similar but a small saving can be made by using a blade plough if a suitable tractor is already owned by the landholder. Including one follow-up treatment the cost of destruction per warren was $2.30 with the blade plough compared with $2.61 for the ripper. For properties where stock numbers are restricted, the return on an investment in rabbit control was estimated to be 13% per annum for the blade plough and 12% per annum for the ripper. Where stock numbers can be increased returns should be greater.

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Persistence of dead trees and fallen timber in the arid zone: 76 years of data from the T.G.B. Osborn Vegetation Reserve, Koonamore, South Australia

The Rangeland Journal ◽

10.1071/rj04008 ◽

2004 ◽

Vol 26 (1) ◽

pp. 111 ◽

Cited By ~ 10

Author(s):

R. Sinclair

Keyword(s):

Temperate Forests ◽

Arid Zone ◽

South Australia ◽

Dead Trees ◽

Standing Dead ◽

Acacia Aneura ◽

Permanent Quadrats

Very little information is available about how long dead trees remain standing, or fallen logs persist, in the Australian arid zone. Data on dead timber longevity were extracted from records of both permanent quadrats and photopoints on the T.G.B. Osborn Vegetation Reserve on Koonamore Station, South Australia. Two species were examined, Acacia aneura (mulga) and Myoporum platycarpum (false sandalwood, sugarwood). Some individuals of mulga are capable of standing dead for over 75 years, while dead M. platycarpum may stand for over 60 years. Dead Myoporum trees remained standing for an average of 31.2 � 5.7 years, fallen trunks persisted for 38.4 � 3.7 years. Standing dead A. aneura persisted on average for 40.0 � 3.7 years, fallen trunks for 22.4� 6.3 years. These figures are almost certainly underestimates. The reasons why are discussed and some comparisons made with temperate forests and tropical mangroves.

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The 1920S Drought Recorded by Tree Rings and Historical Documents in the Semi-Arid and Arid Areas of Northern China

Climatic Change ◽

10.1007/s10584-006-9082-x ◽

2006 ◽

Vol 79 (3-4) ◽

pp. 403-432 ◽

Cited By ~ 150

Author(s):

Eryuan Liang ◽

Xiaohong Liu ◽

Yujiang Yuan ◽

Ningsheng Qin ◽

Xiuqi Fang ◽

...

Keyword(s):

Tree Rings ◽

Northern China ◽

Historical Documents ◽

Arid Areas ◽

Semi Arid

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Long-Distance Movements of Feral Cats in Semi-Arid South Australia and Implications for Conservation Management

Animals ◽

10.3390/ani11113125 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3125

Author(s):

Jeroen Jansen ◽

Hugh McGregor ◽

Geoff Axford ◽

Abbey T. Dean ◽

Sebastien Comte ◽

...

Keyword(s):

Large Scale ◽

Control Strategies ◽

South Australia ◽

Arid Areas ◽

Long Distance ◽

Feral Cats ◽

Control Programs ◽

Movement Data ◽

Study Sites ◽

Semi Arid

Movements that extend beyond the usual space use of an animal have been documented in a range of species and are particularly prevalent in arid areas. We present long-distance movement data on five feral cats (Felis catus) GPS/VHF-collared during two different research projects in arid and semi-arid Australia. We compare these movements with data from other feral cat studies. Over a study period of three months in the Ikara-Flinders Ranges National Park, 4 out of 19 collared cats moved to sites that were 31, 41, 53 and 86 km away. Three of the cats were males, one female; their weight was between 2.1 and 4.1 kg. Two of the cats returned to the area of capture after three and six weeks. During the other study at Arid Recovery, one collared male cat (2.5 kg) was relocated after two years at a distance of 369 km from the area of collar deployment to the relocation area. The movements occurred following three years of record low rainfall. Our results build on the knowledge base of long-distance movements of feral cats reported at arid study sites and support the assertion that landscape-scale cat control programs in arid and semi-arid areas need to be of a sufficiently large scale to avoid rapid reinvasion and to effectively reduce cat density. Locally, cat control strategies need to be adjusted to improve coverage of areas highly used by cats to increase the efficiency of control operations.

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