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

2005 ◽  
Vol 53 (4) ◽  
pp. 283 ◽  
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.

DEVELOPING AGE-SIZE RELATIONSHIPS FOR LONG LIVED TREE SPECIES

2014 ◽  
Vol 22 (02) ◽  
pp. 309-326
Author(s):  
JOHN BOLAND ◽  
RUSSELL SINCLAIR
Keyword(s):  
Tree Rings ◽  
Tree Species ◽  
South Australia ◽  
Arid Areas ◽  
Mature Trees ◽  
Similar Nature ◽  
Annual Cycles ◽  
Acacia Aneura ◽  
Permanent Quadrats ◽  
Semi Arid

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.

Long-term effects of warren ripping for rabbit control in semi-arid South Australia.

1991 ◽  
Vol 13 (2) ◽  
pp. 96 ◽  
Author(s):  
GJ Mutze
Keyword(s):  
South Australia ◽  
Cost Effective ◽  
Long Term Effects ◽  
Short Term ◽  
Long Term Effect ◽  
Perennial Shrubs ◽  
Control Work ◽  
Semi Arid

Warren ripping and poisoning were used to control rabbits on the flood-out plain of a major creek system on Manunda Station, a sheep-grazing property near Yunta in semi-arid South Australia. Rabbit numbers were initially reduced by >99 per cent, as indicated by the number of active entrances remaining in rabbit warrens. After nearly 10 years without follow-up control work, ripped warrens had only two per cent of the pre-control number of active entrances. Poisoning effectively reduced rabbit numbers in the short-term, but had no long-term effect on the number of active entrances, either in ripped or unripped warrens. Perennial shrubs regenerated on and around ripped warrens. Warren ripping on this part of Manunda is a cost-effective management option.

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

2004 ◽  
Vol 26 (1) ◽  
pp. 111 ◽  
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.

Small-scale resource heterogeneity in semi-arid landscapes

1994 ◽  
Vol 1 (3) ◽  
pp. 201 ◽  
Author(s):  
David J. Tongway ◽  
John A. Ludwig
Keyword(s):  
Grazing Pressure ◽  
Arid Ecosystems ◽  
Small Scale ◽  
Patchy Distribution ◽  
Landscape Degradation ◽  
Term Change ◽  
Regulation Mechanisms ◽  
Acacia Aneura ◽  
Semi Arid

Patchy distribution of plant populations is a hallmark of arid and semi-arid ecosystems. This has been attributed to the patchy distribution of scarce or limiting resources across the landscape and within the soil itself. Behind these descriptive properties are a range of processes which are the causal mechanisms of resource allocation, conservation and utilization within the landscape. Terrain-controlled mechanisms have been previously described in respect of groved mulga (Acacia aneura) communities. This paper describes a set of resource regulation mechanisms which are largely controlled by plants and plant communities and which are effective at fine scales. The actual mechanisms are inferred from field observations, and validated by looking for the net effects of defined processes acting over time. Plant-mediated resource control is inherently more sensitive to grazing pressure than terrain-controlled processes, because herbivores are able to quickly and drastically alter the density and basal cover of plants, and so change the effectiveness of the control processes. This may lead to a long-term change in system function. This paper examines the generality of these propositions in a series of contrasting landscape types, and proposes a framework by which landscape degradation can be assessed by examining the modes of basic resource regulation.

Estimation of the Density of Feral Goats in Part of Arid South Australia by means of the Peterson Estimate

1984 ◽  
Vol 11 (1) ◽  
pp. 93 ◽  
Author(s):  
RP Henzell ◽  
PI McCloud
Keyword(s):  
South Australia ◽  
Grazing Pressure ◽  
Sheep Grazing ◽  
Long Term Effects ◽  
Arid Rangeland

The density of feral goats in about 234 km2 of arid rangeland used for sheep grazing in South Australia was estimated by means of a mark-resight technique. Marking and subsequent resighting were done at watering points. The Petersen estimate was 4.4 goats per square kilometre; adjustment to allow for nonrandom behaviour raised this estimate to 5.0 km-1. Maximum allowable sheep density is 12 km-2. The goat density we observed imposes an added burden on the vegetation. The densities of red and western grey kangaroos, when added together, approximate that of the goats. Rabbits are virtually absent. The long-term effects of the total grazing pressure on the vegetation cannot be predicted in detail but will probably be deleterious.

Insights into recharge processes and speleothem proxy archives from long-term monitoring networks of cave drip water hydrology

2020 ◽  
Author(s):  
Andy Baker ◽  
Pauline Treble ◽  
Andreas Hartmann ◽  
Mark Cuthbert ◽  
Monika Markowska ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotope Composition ◽  
Monitoring Networks ◽  
Rainfall Events ◽  
Drip Water ◽  
Antecedent Conditions ◽  
Hydrological Variability ◽  
Cave Drip Water ◽  
Semi Arid

&lt;p&gt;Since 2010 we have established cave drip water hydrological monitoring networks in four contrasting climate zones (Mediterranean, montane, semi-arid and sub-tropical) across continental Australia. Deploying over one hundred automated drip loggers, we combine these long-term monitoring datasets with climate and water isotope data, lidar mapping, electrical resistivity imaging and karst hydrological modelling to provide insights into recharge processes and the impact of hydrological variability on speleothem proxy archives.&lt;/p&gt;&lt;p&gt;We identify increases in drip discharge and compare the timing of those events to antecedent climate conditions (rainfall, evapotranspiration). We find rainfall recharge thresholds vary with climate. At our montane site, recharge occurs after 13 to 31 mm rainfall events, depending on antecedent conditions. At the semi-arid site, recharge occurs after 40 mm rainfall events, and at our sub-tropical sites, recharge occurs following all instances where &gt; 93 mm / week of precipitation occurs, with lower precipitation thresholds (down to 33 mm / week) possible depending on antecedent conditions and at sites with limited vegetation cover. We use these recharge thresholds to constrain simple soil moisture balance models to better understand soil and karst storage volumes. Combined with electrical resistivity imaging, we can relate recharge to the caves to subsurface water flow paths and karst water stores.&lt;/p&gt;&lt;p&gt;At our montane and Mediterranean climate sites, relatively consistent drip water isotopic composition confirms the presence of well-mixed water stores. This allows us to quantify the extent of speleothem oxygen isotope variability due to fractionation associated with changes in drip rate. We identify significant differences in long-term mean drip rates between different drip sites within a cave, and significant differences in event-based drip rate responses within a cave. Drip hydrological variability helps explain the within-cave variability of speleothem oxygen isotope composition observed at both sites, and helps identify the primary drip water oxygen isotope signal.&lt;/p&gt;&lt;p&gt;At our semi-arid site, drip water isotopic composition is dominated by epikarst evaporation and our drip water monitoring demonstrates that recharge events are infrequent (~1.6 per year). Using both observational and modelling data, we quantify the relative importance of evaporative fractionation in the epikarst and fractionation during calcite precipitation. Using modern speleothem samples, we demonstrate that the oxygen isotope signal in this water limited environment reflects the balance between the oxygen isotope composition of recharge and its subsequent fractionation in the soil, epikarst and cave.&lt;/p&gt;

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

scholarly journals CD34+ human marrow cells that express low levels of Kit protein are enriched for long-term marrow-engrafting cells

Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4136-4142 ◽  
Author(s):  
I Kawashima ◽  
ED Zanjani ◽  
G Almaida-Porada ◽  
AW Flake ◽  
H Zeng ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Marrow Cell ◽  
In Utero ◽  
Fetal Sheep ◽  
Hematopoietic Stem ◽  
Show Evidence ◽  
Marrow Cells

Using in utero transplantation into fetal sheep, we examined the capability of human bone marrow CD34+ cells fractionated based on Kit protein expression to provide long-term in vivo engraftment. Twelve hundred to 5,000 CD34+ Kit-, CD34+ Kit(low), and CD34+ Kit(high) cells were injected into a total of 14 preimmune fetal sheep recipients using the amniotic bubble technique. Six fetuses were killed in utero 1.5 months after bone marrow cell transplantation. Two fetuses receiving CD34+ Kit(low) cells showed signs of engraftment according to analysis of CD45+ cells in their bone marrow cells and karyotype studies of the colonies grown in methylcellulose culture. In contrast, two fetuses receiving CD34+ Kit(high) cells and two fetuses receiving CD34+ Kit- cells failed to show evidence of significant engraftment. Two fetuses were absorbed. A total of six fetuses receiving different cell populations were allowed to proceed to term, and the newborn sheep were serially examined for the presence of chimerism. Again, only the two sheep receiving CD34+ Kit(low) cells exhibited signs of engraftment upon serial examination. Earlier in studies of murine hematopoiesis, we have shown stage-specific changes in Kit expression by the progenitors. The studies of human cells reported here are in agreement with observations in mice, and indicate that human hematopoietic stem cells are enriched in the Kit(low) population.

Studies on the control of water-dropwort (Oenanthe pimpinelloides) in South Australia

1995 ◽  
Vol 35 (4) ◽  
pp. 483
Author(s):  
GJ Mitchell ◽  
RJ Carter ◽  
SR Chinner
Keyword(s):  
Stem Elongation ◽  
South Australia ◽  
Perennial Herb ◽  
Metsulfuron Methyl ◽  
Rate Of Spread ◽  
Herbicide Treatments ◽  
Direct Drilling ◽  
Water Dropwort

Water-dropwort (Oenanthe pimpinelloides L.), a tuberous perennial herb, is currently known in South Australia from only a single locality in the Mount Lofty Ranges. There is little information on water-dropwort control, and 2 experiments were conducted to assess the effects of sowing pasture, with or without presowing herbicides, on the control of this weed. Phalaris (Phalaris aquatica L.) and perennial clovers were successfully introduced into infested pastures by direct drilling in autumn. Water-dropwort regenerated from seed more densely in unsown plots than plots of established perennial pasture, suggesting that upgrading pastures may be a strategy to reduce the rate of spread by seed of this weed. A range of herbicide treatments applied to waterdropwort at the stem elongation stage in spring before autumn sowing of pastures provided effective shortterm control. The best short-term control was provided by glyphosate at 1440 g a.i./ha; metsulfuron methyl at 6, 12, and 36 g a.i./ha; and metsulfuron methyl at 12 g a.i./ha tank-mixed with glyphosate or 2,4-D amine at 720 or 1000 g a.i./ha, respectively. These treatments, and chlorsulfuron at 21 g a.i./ha, also significantly (P<0.05) reduced water-dropwort abundance (relative to untreated areas) for up to 18 months after sowing and initially improved the density of sown pasture species, but these improvements were not evident 14 months after resowing. Although prior season herbicide treatments controlled water-dropwort in newly sown pastures, 2 separate applications of herbicides, in May and October, gave no better control of water-dropwort than a single herbicide application in spring. Water-dropwort infestations do not appear to prevent successful direct drilling of phalaris and perennial clovers. Although pasture renovation did not provide long-term suppression of water-dropwort, the maintenance of vigorous pastures may reduce the rate of population growth from seedlings of this weed. Recropping restrictions may limit the role of chlorsulfuron for water-dropwort control in pasture renovation situations.

scholarly journals Trends in the Frequency of Intense Precipitation Events in Southern and Southeastern Brazil during 1960–2004

2011 ◽  
Vol 24 (7) ◽  
pp. 1913-1921 ◽  
Author(s):  
Mateus da Silva Teixeira ◽  
Prakki Satyamurty
Keyword(s):  
Extreme Rainfall ◽  
Southeastern Brazil ◽  
Extreme Rainfall Event ◽  
Southern Brazil ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Annual Frequency ◽  
Long Term Trends ◽  
Increasing Trends

Abstract A new approach to define heavy and extreme rainfall events based on cluster analysis and area-average rainfall series is presented. The annual frequency of the heavy and extreme rainfall events is obtained for the southeastern and southern Brazil regions. In the 1960–2004 period, 510 (98) and 466 (77) heavy (extreme) rainfall events are identified in the two regions. Monthly distributions of the events closely follow the monthly climatological rainfall in the two regions. In both regions, annual heavy and extreme rainfall event frequencies present increasing trends in the 45-yr period. However, only in southern Brazil is the trend statistically significant. Although longer time series are necessary to ensure the existence of long-term trends, the positive trends are somewhat alarming since they indicate that climate changes, in terms of rainfall regimes, are possibly under way in Brazil.

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