Ecology of Small Mammals in Coastal Heathland at Anglesea, Victoria

1986 ◽  
Vol 13 (3) ◽  
pp. 397 ◽  
Author(s):  
BA Wilson ◽  
AR Bourne ◽  
RE Jessop

Aspects of ecology and reproduction of small mammals in a heathland community near Anglesea were investigated in the field by means of mark-recapture trapping. Population size, animal movements and reproductive state were estimated. The floristic and structural habitat preferences were also determined. The most common species were Antechinus stuartii, A. minimus maritimus, Sminthopsis leucopus, Rattus fuscipes assimilis and R. lutreolus. For Antechinus the populations were maximal throughout February-June (A. stuartii) and December-June (A. minimus) inclusive. A marked decline in numbers of Antechinus during late winter and early spring was associated with the total loss of males from the population. The maximal numbers of animals (per hectare) were 21 (A. stuartii), 14 (A. m. maritimus), 14 (R. f. assimilis) 7 (R. lutreolus), and 8 (S. leucopus). Young were born to A. m. maritimus during August, and 1 month later to A. stuartii. R. f. assimilis bred during late winter and spring, and S. leucopus from September to November. None of the species showed an overall preference for any floristic or structural vegetation type. This study confirms male 'die-off' in A. m. maritimus. The data also indicate that the difference in breeding times of A. m. maritimus between Anglesea and Dartmoor, Vic., is due to climatic or habitat differences rather than to sympatry with A. stuartii.

1984 ◽  
Vol 35 (5) ◽  
pp. 709 ◽  
Author(s):  
JR Donnelly

Weaning percentage and perinatal mortality of lambs born in late winter or early spring to Merino and Border Leicester x Merino ewes grazing at several stocking rates on lucerne or phalaris-clover pastures were measured over 2 years. Weaning percentages for mature crossbred ewes declined linearly from 136 lambs per 100 ewes joined when stocked at 9 ha-1 to 100 for those at 18 ha-1. For mature Merino ewes, the values were 109 and 70 respectively. Weaning percentages were similar on lucerne and phalaris pastures, although 8% more lambs were born to ewes grazing on phalaris; higher mortality in lambs born as multiples eliminated the difference. Death from exposure during the first 3 days of life was the most important cause of lamb losses. For lambs born as singles to Merino ewes the probability of death from exposure was up to 0.4, and reached 0.6 for lambs born as multiples. For single and multiple lambs born to crossbred ewes equivalent probabilities were 0.25 and 0.4 respectively. These probabilities were reduced if maternal weight was high at lambing, the reduction being of practical significance in very cold weather, particularly if the proportion of multiple births was high. Under mild conditions, where the probability of death from exposure was low, reductions in mortality from high ewe weight at lambing were of little consequence. Long-term weather records kept at the experimental site near Canberra show that a high risk of death in new-born lambs is likely from early June to mid-September. Throughout this period deaths from exposure could be expected to exceed 30% in lambs born as multiples to Merino ewes.


2021 ◽  
Author(s):  
Markus Jesswein ◽  
Heiko Bozem ◽  
Hans-Christoph Lachnitt ◽  
Peter Hoor ◽  
Thomas Wagenhäuser ◽  
...  

Abstract. Inorganic chlorine (Cly) is the sum of the degradation products of long-lived chlorinated source gases. These include the reservoir species (HCl and ClONO2) and active chlorine species (i.e. ClOx). The active chlorine species drive catalytic cycles that deplete ozone in the polar winter stratosphere. This work presents calculations of inorganic chlorine (Cly) derived from chlorinated source gas measurements on board the High Altitude and Long Range Research Aircraft (HALO) during the Southern hemisphere Transport, Dynamic and Chemistry (SouthTRAC) campaign in late winter and early spring 2019. Results are compared to Cly of the Northern Hemisphere derived from measurements of the POLSTRACC-GW-LCYCLE-SALSA (PGS) campaign in the Arctic winter of 2015/2016. A scaled correlation was used for PGS data, since not all source gases were measured. Cly from a scaled correlation was compared to directly determined Cly and agreed well. An air mass classification based on in situ N2O measurements allocates the measurements to the vortex, the vortex boundary region, and mid-latitudes. Although the Antarctic vortex was weakened in 2019 compared to previous years, Cly reached 1687 ± 20 ppt at 385 K, therefore up to around 50 % of total chlorine could be found in inorganic form inside the Antarctic vortex, whereas only 15 % of total chlorine could be found in inorganic form in the southern mid-latitudes. In contrast, only 40 % of total chlorine could be found in inorganic form in the Arctic vortex during PGS and roughly 20 % in the northern mid-latitudes. Differences inside the respective vortex reaches up to 565 ppt more Cly in the Antarctic vortex 2019 than in the Arctic vortex 2016 (at comparable distance to the local tropopause). As far as is known, this is the first comparison of inorganic chlorine within the respective polar vortex. Based on the results of these two campaigns, the difference of Cly inside the respective vortex is significant and larger than reported inter annual variations.


1996 ◽  
Vol 23 (2) ◽  
pp. 237 ◽  
Author(s):  
PE Cowan ◽  
RE Brockie ◽  
GD Ward ◽  
MG Efford

Long-distance movements of juvenile male and female brushtail possums (Trichosurus vulpecula) at a farmland site, Hawke's Bay, New Zealand, were studied by radio-tracking. About 20% of radio-tagged possums dispersed more than 2 km, moving up to 11.5 km from their natal area, most in a north-easterly direction. The proportion of males that dispersed was higher than that of females, but the difference was not statistically significant. All juveniles dispersing did so before they were one year old. The bimodal timing of dispersal in summer and late winter to early spring reflected an underlying similar pattern of breeding. Most possums made several moves before settling. A higher proportion of possums dispersed from the lowdensity area of pastoral and cropping land than from the higher-density areas of swamp and willows. A few dispersal records of ear-tagged animals were also obtained; most records were of males from the area of pastoral and cropping land, and movements ranged from 3 to 25 km.


2009 ◽  
Vol 36 (6) ◽  
pp. 528 ◽  
Author(s):  
Sally Fenner ◽  
Gerhard Körtner ◽  
Karl Vernes

More than most other animal control techniques, toxic baiting is fraught with the potential impact on non-target species. In the present study, we investigated the effect of aerial baiting with 1080 to control wild dogs in north-eastern New South Wales (NSW), Australia, on populations of southern bush rats (Rattus fuscipes assimilis) and brown antechinus (Antechinus stuartii), using a controlled experiment. Six populations, three each within widely spaced baited and unbaited trapping grids, were monitored before and after bait laying. To develop capture–mark–recapture indices, separate 4-day trapping surveys were undertaken twice before and twice after meat baits (250 g containing 6 mg sodium fluoroacetate, 1080) were delivered from a helicopter at 40 baits per kilometre. To assess non-fatal bait consumption, all baits contained rhodamine B (RhB), which gets incorporated into the vibrissae of animals that have ingested this marker. Neither mammal population decreased in size after baiting, nor was there any increase in population turnover rates or changes in the movement patterns of either species. Furthermore, no trapped animal tested positive for RhB, suggesting that these small mammals rarely consume meat baits, and that, at the population level, the impact of baiting on them was likely negligible. It is therefore unlikely that the current practise of aerial baiting in NSW, although effective in reducing dog activity, threatens populations of these two common species and perhaps small mammals in general.


1987 ◽  
Vol 14 (2) ◽  
pp. 163 ◽  
Author(s):  
D. Lunney ◽  
B. Cullis ◽  
P. Eby

This study of the effects of logging on small mammals in Mumbulla State Forest on the south coast of New South Wales included the effects of a fire in November 1980 and a drought throughout the study period from June 1980 to June 1983. Rattus fuscipes was sensitive to change: logging had a significant impact on its numbers, response to ground cover, and recapture rate; fire had a more severe effect, and drought retarded the post-fire recovery of the population. The three species of dasyurid marsupials differed markedly in their response to ground cover, canopy cover, logging and fire. Antechinus stuartii was distributed evenly through all habitats and was not affected by logging, but fire had an immediate and adverse effect which was sustained by the intense drought. A. swainsonii markedly preferred the regenerating forest, and was not seen again after the fire, the failure of the population being attributed to its dependence on dense ground cover. Sminthopsis leucopus was found in low numbers, appeared to prefer forest with sparse ground cover, and showed no immediate response to logging or fire; its disappearance by the third year post-fire suggests that regenerating forest is inimical to the survival of this species. Mus musculus showed no response to logging. In the first year following the fire its numbers were still very low, but in the next year there was a short-lived plague which coincided with the only respite in the 3-year drought and, importantly, occurred in the intensely burnt parts of the forest. The options for managing this forest for the conservation of small mammals include minimising fire, retaining unlogged forest, extending the time over which alternate coupes are logged and minimising disturbance from heavy machinery.


Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.


1959 ◽  
Vol 37 (4) ◽  
pp. 419-428 ◽  
Author(s):  
William S. Hoar ◽  
G. Beth Robertson

Goldfish maintained under controlled photoperiods for 6 weeks or longer were relatively more resistant to a sudden elevation in temperature when the daily photoperiods had been long (16 hours) and relatively more resistant to sudden chilling when they had been short (8 hours). The magnitude of the effect varied with the season. Thyroid activity was slightly greater in fish maintained under the shorter photoperiods. The longer photoperiods stimulated more rapid growth of ovaries during late winter and early spring. The endocrine system is considered a link in the chain of events regulating seasonal variations in resistance to sudden temperature change.


1963 ◽  
Vol 14 (6) ◽  
pp. 778 ◽  
Author(s):  
DE Harrison

During the late winter and early spring of 1960, and again to a lesser extent in 1961 and 1962, many lettuce crops in the Murray Valley area of north-western Victoria were seriously affected by a disease characterized by blackening, dry rotting, and collapse of the affected leaves. The incidence of disease varied from about 10% up to practically complete destruction of some plantings. A yellow bacterium was consistently isolated from affected plants and proved to be pathogenic to lettuce. Laboratory studies have shown that the organism agrees closely with the recorded description of Xanthomonas vitians (Brown) Dowson, which has not, apparently, been previously studied in Australia.


2014 ◽  
Vol 104 (5) ◽  
pp. 576-585 ◽  
Author(s):  
C. Monzo ◽  
J.A. Qureshi ◽  
P.A. Stansly

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of ‘huanglongbing’ (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.


1997 ◽  
Vol 24 (6) ◽  
pp. 737 ◽  
Author(s):  
Ross L. Goldingay ◽  
Robert J. Whelan

The distribution and abundance of small terrestrial mammals were assessed in forest adjacent to powerline easements at three different sites in New South Wales. At each site, four transects of 300 m length extended into the forest from the edge of the easement. The abundances of two native species (Antechinus stuartii, Rattus fuscipes) did not differ significantly with distance from the easement but abundances differed markedly among sites. Mammals were captured in only one easement where dense vegetation was present. Feral carnivores, which may mediate edge effects on small mammals, were surveyed by using hair-sampling tubes. Cats and dogs were detected only 50–200 m inside the forest. Foxes were not detected by hair-tubes but were observed on two easements. These results suggest that powerline easements may not create edge effects in eucalypt forest for some native mammal species, although further studies are needed to determine the generality of this conclusion. We recommend that easement management should be more benign to native mammals, given the ubiquity of this form of habitat fragmentation. Promotion of dense vegetative cover and habitat linkages within easements could achieve this.


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