Host Specificity, Dispersion and Persistence Through Drought of Two Arid Zone Mistletoes

1988 ◽  
Vol 36 (3) ◽  
pp. 299 ◽  
Author(s):  
N Reid ◽  
RT Lange
Keyword(s):  
Host Specificity ◽  
Arid Zone ◽  
Age Distribution ◽  
South Australia ◽  
Severe Drought ◽  
Branch Diameter ◽  
Popu Lation ◽  
Canopy Volume ◽  
Canopy Size

In the Whyalla region of South Australia, the loranthaceous mistletoe Amyema quandang (Lindl.) Tiegh. is virtually host-specific to Acacia papyrocarpa Benth., whereas Lysiana exocarpi (Behr.) Tiegh. (Loranthaceae) frequently parasitises 12 species in seven families, and less commonly infects seven other species. Amyema quandang is contagiously distributed with respect to Acacia papyrocarpa, larger trees supporting higher numbers of mistletoes. Host branch diameter (HBD) is assumed to index the age of individual mistletoes of Amyema quandang since seedlings only establish on thin host branches. The age distribution of A. quandang is skewed towards young plants since almost half the population para- sitises host branches Ͱ4 15 mm in diameter, within the range infected by seedlings. HBD is correlated with canopy size and the number of haustorial branches. The proportion of reproductive mistletoes increases with HBD and hyperparasitic L. exocarpi are confined to older plants of A. quandang with HBD Ͱ5 31 mm. As a result of the severe drought in 1982, 25% of large plants of A. quandang lost one or two main haustorial branches and suffered reductions in canopy volume, but only 4% died; by contrast, 31% of large L. exocarpi died and a further 19% lost most of their foliage. In the A. quandang population as a whole, recruitment balanced mortality (19%) over a 40 month period, but in the L. exocarpi popu- lation recruitment compensated for only half the mortality. None of the xerophytic shrub and tree hosts of either mistletoe died.

The ecology of sympatric scincid lizards (Ctenotus) in arid South Australia

1998 ◽  
Vol 46 (6) ◽  
pp. 617 ◽  
Author(s):  
J. L. Read
Keyword(s):  
Home Range ◽  
Environmental Conditions ◽  
Plant Material ◽  
Reproductive Effort ◽  
Arid Zone ◽  
South Australia ◽  
Early Summer ◽  
Home Ranges ◽  
Local Species ◽  
Olympic Dam

Ctenotus skinks are the most diverse and abundant diurnal reptile genus at Olympic Dam, in the South Australian arid zone. The home range, demography, reproduction and diet of five syntopic Ctenotus species was studied over a 6-year period in chenopod shrubland. Longevity frequently exceeded three years in C. regius, four years in C. schomburgkii and five years in C. leonhardii, with a 7-year-old specimen of C. leonhardii being recorded. Females of most species tended to be larger and lived longer than males. Two eggs were typically laid by each species in early summer. Annual reproductive effort, particularly in C. leonhardii, varied considerably depending upon the prevailing environmental conditions. All local species apparently occupied home ranges, with maximum recapture radii in different species of 40–60 m. Ctenotus appear to be unspecialised insectivores, although plant material and lizards are sometimes eaten by the larger species.

Coordination between leaf, stem, and root hydraulics and gas exchange in three arid-zone angiosperms during severe drought and recovery

2018 ◽  
Vol 41 (12) ◽  
pp. 2869-2881 ◽  
Author(s):  
Danielle Creek ◽  
Chris J. Blackman ◽  
Timothy J. Brodribb ◽  
Brendan Choat ◽  
David T. Tissue
Keyword(s):  
Gas Exchange ◽  
Arid Zone ◽  
Severe Drought

Subaqueous speleothems from the Flinders Ranges, South Australia, as palaeohydrological archives for the arid zone

2021 ◽  
Author(s):  
Calla Gould-Whaley ◽  
Russell Drysdale ◽  
Jan-Hendrick May ◽  
John Hellstrom ◽  
Hai Cheng ◽  
...  
Keyword(s):  
Arid Zone ◽  
Regional Climate ◽  
South Australia ◽  
Middle Latitude ◽  
Water Levels ◽  
Human Migration ◽  
Dispersal Patterns ◽  
Groundwater Levels ◽  
Flinders Ranges ◽  
Ecosystem Changes

<p>Australia is the driest continent outside of Antarctica yet relatively little is known about its long-term moisture history. Many local palaeoclimate archives suffer preservation problems, particularly in the arid centre of the continent, where weathering and erosion leave behind an incomplete record. In an attempt to redress the paucity of arid-zone palaeoclimate records, we investigate ‘pendulites’, subaqueous speleothems that grow episodically according to fluctuations in local groundwater levels. At Mairs Cave (central Flinders Ranges, South Australia), pendulites have formed around stalactites. During the first sustained episode of drowning, the stalactite is veneered by subaqueous calcite, sealing it and preventing further stalactitic growth after water levels fall. Once sealed, the pendulites only record periods of persistent drowning, assumed to correspond to major pluvial episodes.</p><p>Age data from two pendulite samples collected from close to the ceiling where the highest water levels have reached reveal two main groundwater ‘high-stand’ phases centred on ~67 and ~48 ka, coincident with Southern Hemisphere summer insolation maxima. This suggests that precession-driven southward migration of the ITCZ resulted in regular and persistent incursions of tropical air masses to the central Flinders Ranges. Trace element, stable isotope and growth-rate changes reveal that these orbitally controlled growth intervals are superimposed by regional climate responses to Dansgaard-Oeschger and Heinrich events. The results from Mairs Cave shed new light on the moisture history of central Australia, in particular the competing influences of tropical and middle-latitude circulation systems. This provides a precisely dated regional palaeoclimate template for reconstructing ecosystem changes, understanding human migration/dispersal patterns of the first Australians, and the progressive demise of megafauna. We also highlight the utility of subaqueous speleothems more generally as important archives for investigating arid-zone palaeoclimate.</p>

Differential responses by sympatric macropodids to severe drought.

2004 ◽  
Vol 26 (2) ◽  
pp. 185
Author(s):  
PE Hornsby ◽  
EY Corlett
Keyword(s):  
South Australia ◽  
Severe Drought ◽  
The North ◽  
Flinders Ranges ◽  
Drought Conditions ◽  
Differential Responses ◽  
A Site ◽  
Significant Mortality

Responses to severe drought by two sympatric macropodids, the yellow-footed rock-wallaby (Petrogale xanthopus) and the euro (Macropus robustus erubescens) were examined at a site in the North Flinders Ranges of South Australia. The results indicate that the two species respond differentially to drought conditions. It was observed that small fluctuations occurred in the P. xanthopus population. In contrast, M. r. erubescens evidenced significant mortality, especially among larger animals.

Population Dynamics and Movement Patterns of Bolam's Mouse, Pseudomys bolami, at Roxby Downs, South Australia.

1998 ◽  
Vol 20 (3) ◽  
pp. 353
Author(s):  
K.E. Moseby ◽  
J.L. Read
Keyword(s):  
Arid Zone ◽  
Sand Dunes ◽  
South Australia ◽  
Breeding Strategy ◽  
Early Summer ◽  
Ecological Data ◽  
Winter Rainfall ◽  
Land Systems ◽  
Single Night ◽  
Time Of Year

Basic ecological data were collected on Bolam's mouse, Pseudomys bolami, during a six year trapping study at Roxby Downs in northern South Australia. Pseudomys bolami inhabited mixed arid land systems in the Roxby Downs area, sheltering in the longitudinal orange sand dunes but foraging at night principally on the adjacent chenopod swales. Distances of up to 334m were traversed in a single night and recapture rates were high within trapping sessions but low between sessions suggesting wide-ranging movements and short-term residency. Dietary observations imply an omnivorous diet. Whilst the closely related P. hermannsburgensis is regarded as having an opportunistic breeding strategy, P. bolami reproduced opportunistically but also regularly in spring and early summer. Different reproductive strategies may be influenced by the latitudinal distribution of P. bolami near the southern margin of the arid-zone, where rainfall can occur at any time of year but winter rainfall is more predictable. This contrasts with P. hermannsburgensis, which inhabits more northerly arid areas where rainfall is erratic and unpredictable. There was a 10 fold fluctuation in P. bolami captures over the trapping period with numbers of P. bolami and house mice, Mus domesticus peaking 12 months after above average rains during 1992. Rodent captures remained high for two years afterwards. Although P. bolami persisted throughout the study period, M. domesticus was only present when conditions were above average. Trap success of P. bolami or M. domesticus did not vary between the five sub habitats at the 1 ha study site. However, trap success of P. bolami was positively related to vegetation cover, particularly cover of low bluebush, Maireana astrotricha. Maireana astrotricha may be important in providing both food and cover for P. bolami, a scenario consistent with the utilisation of spinifex, Triodia spp. by P. hermannsburgensis in the northern arid-zone. Past over- grazing of chenopod shrublands may have reduced cover and contributed to the suggested decline in the distribution of P. bolami.

The decline of the Brushtail Possum, Trichosurus vulpecula (Kerr 1798), in arid Australia.

1992 ◽  
Vol 14 (2) ◽  
pp. 107 ◽  
Author(s):  
JA Kerle ◽  
JN Foulkes ◽  
RG Kimber ◽  
D Papenfus
Keyword(s):  
Surface Waters ◽  
Arid Zone ◽  
South Australia ◽  
Brushtail Possum ◽  
Protection Measures ◽  
European Settlement ◽  
Introduced Predators ◽  
Average Water ◽  
Cumulative Residual ◽  
Predator Pit

That the brushtail possum was once common and widespread in the arid zone is confirmed by a collation of historical information. Although possums were widespread, detailed records from the Northern Territory and South Australia show that they were most abundant in rocky ranges and outcrops and along watercourses. Possums are now rare in the arid zone. In considering the reasons for the decline of this apparently robust species we have further developed Morton's (1990) model for mammal decline in the arid zone. Our hypothesis is based on the premise that disturbance of refuge habitat patches critical for the survival of the species was occurring at the same time as the country was subjected to a below average water balance. During the period between 1920 and 1970 rainfall was either average or markedly below average with no exceptional rainfalls recorded. Analysis of the rainfall data using a cumulative residual mass curve suggests that sub-surface waters were probably not fully recharged, placing a natural stress on the refuge habitats. At the same time, possum populations were being affected by many disturbing factors introduced by European settlement. Once the populations were reduced, they fell into a 'predator- pit' through depredation by dingoes and introduced predators and were unable to increase in numbers even with the advent of improved conditions. In this paper we identify the need to accurately determine the refuge habitats of a species and then utilise tools such as the cumulative mass residual curve to predict when these habitats will be under most stress. Specific protection measures can then be developed in association with land managers in order to reduce disturbance at the most critical times.

Timing of breeding and female fecundity of the greater bilby (Macrotis lagotis) in the temperate zone of South Australia: implications for translocations of a previously widespread species

2019 ◽  
Vol 46 (5) ◽  
pp. 444 ◽  
Author(s):  
Karleah K. Berris ◽  
Steven J. B. Cooper ◽  
William G. Breed ◽  
Susan M. Carthew
Keyword(s):  
Litter Size ◽  
Reproductive Strategy ◽  
Arid Zone ◽  
South Australia ◽  
Reproductive Activity ◽  
Temperate Zone ◽  
Breeding Biology ◽  
Head Length ◽  
Widespread Species ◽  
Free Ranging

Context Many of Australia’s threatened mammals were once widespread across the continent and present in both arid, semiarid and temperate habitats. However, data on breeding biology can be lacking for some climatic regions due to local extinctions of populations. The breeding biology of the greater bilby (Macrotis lagotis) has previously only been studied in captive colonies or free-ranging arid zone populations. Between 1997 and 2005, captive-bred bilbies were released at two sites in temperate South Australia. These populations provided an opportunity to determine whether bilbies adopt a seasonal reproductive strategy in the temperate zone, where this species has not been present since the early 1900s. Aims To determine the season of births, litter size and female reproductive potential in two free-ranging populations of the bilby in the temperate zone of South Australia. Methods Bilbies were regularly cage-trapped at Venus Bay Conservation Park and Thistle Island between August 2007 and April 2010 to obtain data on reproductive activity in both populations. Key results Births of pouch young in both populations occurred in winter (June–August), spring and early summer, but not between February and mid-May. Males had a significantly smaller mean testes size relative to head length in late summer, when breeding activity ceased. Average litter size at pouch emergence was between 1.00 and 1.47 pouch young, with females producing up to three litters per annum. The mean head length of females that successfully raised twins was significantly larger than that of females who raised a single pouch young. Conclusions The seasonal breeding pattern observed in the present study differs from that of year-round reproductive activity in captivity and the arid zone. The present study suggests that female body size influences fecundity, and that releasing large females at the start of the breeding season in temperate areas may maximise the initial rate of increase of a translocated bilby population. Implications The present study suggests previously widespread species such as the bilby can adapt their reproductive strategy to suit local conditions. Cessation of breeding in autumn, as observed in this study, has also been observed in other bandicoot species in southern Australia.

Dark Island heath (Ninety-mile Plain, South Australia). V. The water relationships in heath vegetation and pastures on the Makin sand

1957 ◽  
Vol 5 (2) ◽  
pp. 151 ◽  
Author(s):  
RL Specht
Keyword(s):  
Soil Moisture ◽  
Balance Sheet ◽  
South Australia ◽  
Field Capacity ◽  
Severe Drought ◽  
Soil Moisture Storage ◽  
Drought Conditions ◽  
Moisture Storage ◽  
Medicago Sativa L ◽  
Soil Moisture Status

Heath vegetation shows a major flush of growth during the mediterraneantype summer season, a time when calculations of the soil moisture storage by the techniques of Thornthwaite (1948) or Prescott, Collins, and Shirpurkar (1952) indicate that severe drought conditions should oocur. Monthly observations on the moisture status of the Makin sand under heath vegetation and, for comparison, under various pastures are therefore recorded. The problems of obtaining an accurate water balance-sheet for such a heterogeneous vegetation as the heath are discussed. Difficulties in the use of the various techniques for measuring soil moisture in sand, which has a low pF of 1.85 at field capacity, are enumerated. The following relationships were found between the evapotranspiration index (Itr = Etr / Ew0.75) and the available water (W). These data were calculated for 6 ft of sand. (i) Heath vegetation (10–14 years old) log (2.4–Itr) = 0.420–0.0383 W (ii) Heath vegetation (burnt) log (2.4–Itr) = 0.461–0.0380 W (iii) Oenothera odorata Jacq. pasture log (2.4–Itr) = 0.395–0.0269 W (iv) Medicago sativa L. pasture log (2.4–Itr) = 0.390–0.0270 W (v) Ehrharta calycina Sm. pasture log (2.4–Itr) = 0.400–0.0339 W From these equations the mean monthly quantities of rainfall which may be stored in 6 ft of sand under the various treatments described were calculated. Drought conditions are shown to occur in December and January, but are relieved in the later months of summer. Even if the stored moisture below 8 ft is considered, the soil moisture status would be expected to be just sufficient to maintain the vegetation in a "dormant" state, and yet the major growth of the heath vegetation occurs at this time. The calculated mean annual values of Itr range from 0.53 to 0.60 for these perennial communities. Close approximations to the actual soil moisture status can be obtained by substituting these values for K in Prescott's formula for potential evaporation, i.e. Etr = K x Ew0.75. Supplementary data on transpiration, growth, and the root systems of the pastures are also included.

Dingo interactions with exotic mesopredators: spatiotemporal dynamics in an Australian arid-zone study

2015 ◽  
Vol 42 (6) ◽  
pp. 529 ◽  
Author(s):  
T. Schroeder ◽  
M. M. Lewis ◽  
A. D. Kilpatrick ◽  
K. E. Moseby
Keyword(s):  
Interaction Analysis ◽  
Arid Zone ◽  
Biological Control Agent ◽  
Spatial Scales ◽  
Habitat Preferences ◽  
South Australia ◽  
Control Agent ◽  
Dynamic Interaction ◽  
Home Ranges ◽  
Apex Predators

Context Apex predators occupy the top level of the trophic cascade and often perform regulatory functions in many ecosystems. Their removal has been shown to increase herbivore and mesopredator populations, and ultimately reduce species diversity. In Australia, it has been proposed that the apex predator, the dingo (Canis dingo), has the potential to act as a biological control agent for two introduced mesopredators, the red fox (Vulpes vulpes) and the feral cat (Felis catus). Understanding the mechanisms of interaction among the three species may assist in determining the effectiveness of the dingo as a control agent and the potential benefits to lower-order species. Aims To test the hypotheses that feral cats and foxes attempt to both temporally avoid dingoes and spatially avoid areas of high dingo use. Methods Static and dynamic interaction methodologies based on global positioning system (GPS) telemetry data were applied to test temporal and spatial interactions between the two mesopredators (n = 15) and a dingo pair (n = 2). The experimental behavioural study was conducted in a 37-km2 fenced enclosure located in arid South Australia. Key results The dynamic interaction analysis detected neither attraction nor avoidance between dingoes and cats or foxes at short temporal scales. There was no suggestion of delayed interactions, indicating that dingoes were not actively hunting mesopredators on the basis of olfactory signalling. However, static interaction analysis suggested that, although broad home ranges of cats and foxes overlapped with dingoes, core home ranges were mutually exclusive. This was despite similar habitat preferences among species. Conclusions We found that avoidance patterns were not apparent when testing interactions at short temporal intervals, but were manifested at larger spatial scales. Results support previous work that suggested that dingoes kill mesopredators opportunistically rather than through active hunting. Implications Core home ranges of dingoes may provide refuge areas for small mammals and reptiles, and ultimately benefit threatened prey species by creating mesopredator-free space. However, the potential high temporal variation in core home-range positioning and small size of mutually exclusive areas suggested that further work is required to determine whether these areas provide meaningful sanctuaries for threatened prey.

Population dynamics of an arid zone mistletoe (Amyema preissii, Loranthaceae) and its host Acacia victoriae (Mimosaceae)

2000 ◽  
Vol 48 (1) ◽  
pp. 45 ◽  
Author(s):  
Mark Stafford Smith ◽  
Nick Reid
Keyword(s):  
Temporal Dynamics ◽  
Arid Zone ◽  
Host Population ◽  
Double Infection ◽  
Establishment Success ◽  
Branch Diameter ◽  
Host Trees ◽  
Infected Tree ◽  
Spatial And Temporal Dynamics ◽  
Triple Infection

The principal host of the mistletoe, Amyema preissii, near Alice Springs is the short-lived, fast-growing tree, Acacia victoriae. In order to describe the dynamics of their interaction, the fate, size and phenology of mistletoes were monitored in natural host stands, infection experiments were conducted to determine establishment success and growth rates of seedlings, hosts were repeatedly disinfected in a 14.6-ha paddock surrounded by infected source trees, and mistletoe reinvasion of disinfected trees was monitored. In the unmanipulated population of A. victoriae, 46–54% of trees (> 2 m in height) were infected (5.8–6.7 mistletoes per infected tree). Establishment percentage of mistletoe seeds deployed on host branches varied between 11–24% after 12–23 months, and most naturally-dispersed seedlings established on branches ≤ 20 mm in diameter. Estimates of natural mistletoe dispersal to uninfected trees varied between 2 and 12 seeds per infected tree over periods of 8–23 months. Examination of young mistletoes showed that 24% of 122 clumps consisted of more than one mistletoe, with 27 occurrences of double infection and two occurrences of triple infection at the same point on the host branch. Mistletoes grew rapidly: in one sown cohort, plants achieved canopy diameters of 152–170 cm within 18–23 months, and half were flowering 15 months after germination. In unmanipulated populations, the largest mistletoes had a maximum canopy diameter of 250 cm and a maximum host branch diameter proximal to the haustorium of 100 mm, but modal sizes of these measures were 80–120 cm and < 10 mm, respectively. Turnover in the host population in the disinfection paddock was rapid: 60% of trees died between 1990 and 1995, mortality being balanced by recruitment. In unmanipulated stands of host trees, larger trees were more likely to be infected and supported larger numbers of mistletoes per tree than small trees. Once mistletoes had been removed from trees in the disinfection paddock, larger trees were still disproportionately infected by reinvading mistletoes and trees that had been infected previously were more likely to be reinfected. In order to fully describe the spatial and temporal dynamics of this host–mistletoe combination, further studies are needed of mistletoe persistence and mortality through time and annual seed production as a function of mistletoe size.

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