Population Ecology of Mesembriomys-Gouldii (Rodentia, Muridae) in the Wet-Dry Tropics of the Northern-Territory

1987 ◽  
Vol 14 (3) ◽  
pp. 293 ◽  
Author(s):  
GR Friend
Keyword(s):  
Climatic Variability ◽  
Food Resource ◽  
Northern Territory ◽  
Population Increase ◽  
Reproductive Pattern ◽  
Mammal Species ◽  
Young Females ◽  
Dry Tropics ◽  
Open Forest ◽  
General Decline

A population of the black-footed tree-rat Mesembriomys gouldii was studied between September 1980 and January 1983 in tropical open-forest in the Northern Territory. Twenty-four males and 32 females were captured over 2900 wire-cage trap-nights. Abundance peaked in May-June and October-November of each year, reflecting increased trappability of adults and/or influxes of immature animals following breeding pulses in an otherwise non-seasonal reproductive pattern. There was a marked increase in population during 1981, followed by a general decline to very low numbers during 1982. Females outnumbered males throughout most of the study, and particularly between March and July each year when more young females than males entered the trappable population. Marked seasonal differences in composition, transiency and trappability were apparent between the male and female populations, suggesting a relatively non-social behavioural pattern. The preference shown by M. gouldii for relatively stable, structurally diverse open-forest areas, which are characterised by shrubs and trees with conspicuous and/or fleshy fruits, accords with the limited data on diet. It is further suggested that a geographically but not temporally restricted food resource may explain the patchy distribution and non-seasonal breeding pattern recorded for this species. Climatic variability (particularly rainfall), through its influence on plant phenology and food availability, may strongly influence demographic changes, however, and was deemed responsible for both the population increase in 1981 and the subsequent marked decline during 1982. Long-term studies are needed in the wet-dry tropics to clarify the relationship between many such mammal species and their environment.

Distribution of mammals in monsoon rainforests of the Northern Territory

1992 ◽  
Vol 19 (3) ◽  
pp. 295 ◽  
Author(s):  
KA Menkhorst ◽  
JCZ Woinarski
Keyword(s):  
Native Species ◽  
Environmental Gradient ◽  
Northern Territory ◽  
Species Variation ◽  
Mammal Species ◽  
Moisture Condition ◽  
Mammal Fauna ◽  
Open Forest ◽  
Historical Processes ◽  
Monsoon Rainforest

The mammal fauna of 50 patches of monsoon rainforest in the Northern Territory, Australia, was surveyed. No mammal species is restricted to this habitat, and most of the region's marnmal fauna uses it at least occasionally. Mammal species composition within monsoon rainforests undergoes substantial variation along an extensive environmental gradient reflecting moisture condition and rockiness. For most mammal species, variation in abundance among patches was related more to the position of the patch on this environmental gradient than to patch size or extent of disturbance. Disturbance was positively correlated with the richness and abundance in quadrats of three taxonomic groupingsrodents, 'other' native species, and all native species (other than bats)-and negatively correlated with richness and abundance of macropods. Compared with surrounding (open forest and savanna woodland) vegetation, monsoon rainforests have few grazing herbivores and small granivorous rodents, but more species that eat fleshy fruits and seeds from woody plants. The mammal fauna of monsoon rainforests in the Northern Territory is similar to that of monsoon rainforests of the Kimberley (to the west) but unlike that of wet tropical rainforests in Cape York (to the east). These differences, and the current impoverishment of the mammal fauna of the Northern Territory monsoon rainforest, are attributable to historical processes and the current small area of this highly fragmented monsoon rainforest estate. Three bat species may be important for pollination and dispersal of monsoon rainforest plants.

Some Aspects of the Ecology of the Mammal Fauna of the Jabiluka Area. Northern Territory

1984 ◽  
Vol 11 (2) ◽  
pp. 207 ◽  
Author(s):  
JA Kerle ◽  
MA Burgman
Keyword(s):  
Success Rate ◽  
Fire History ◽  
Northern Territory ◽  
Fire Occurrence ◽  
Edaphic Factors ◽  
Mammal Species ◽  
Site Preferences ◽  
Mammal Fauna ◽  
Open Forest ◽  
Riparian Woodland

On the Pancontinental Jabiluka exploration lease, between July 1979 and September 1981, mammals of 30 native and five introduced species were recorded, with an overall trap success rate of 5% and an average of 1.9 sightings per spotlight-hour. Three major groups of mammal species corresponded to the primary groupings of vegetation in the study area: riparian woodland, dryland woodland and open forest, and sandstone. This last group was subdivided into three on site preferences. Two ungrouped species were found in a variety of habitats. The distribution of mammals was very patchy, and their abundance varied seasonally. This may result from rainfall patterns, fire occurrence and fire history, as well as from landform and edaphic factors. The species responded to the variation in environment and the consequent mosaic of habitats by three strategies: by rapid response to changes in microhabitat through increased dispersion or moving to more favourable habitats, by restriction to stable habitats, or by adaptation to a variety of habitats.

Habitat relationships for two poorly known mammal species Pseudomys calabyi and Sminlhopsis sp. from the wet-dry tropics of the Northern Territory.

1992 ◽  
Vol 15 (1) ◽  
pp. 47
Author(s):  
J.C.Z. Woinarski
Keyword(s):  
National Park ◽  
Northern Territory ◽  
Stage Iii ◽  
Vertebrate Species ◽  
Land Area ◽  
Mammal Species ◽  
Dry Tropics ◽  
Species Pairs ◽  
Arnhem Land

Most records of Sminthopsis sp. and all records of Pseudomys calabyi are from gravelly hills with Eucalyplus dichromophloia and E. tintinnans woodland in Stage III of Kakadu National Park, Northern Territory. This habitat is distinct from that used by other small dasyurids and pseudomyine rodents of this region. For P. calabyi it may offer the attraction of prolonged availability of fallen grass seeds. Both taxa have vicariants in the Kimberley, a pattern resembling that for many vertebrate species pairs of the more isolated sandstone massifs of the Kimberley and Arnhem Land area.

An attempt to determine the size of the Common Barn-owl’s (Tyto alba) hunting area based on its prey composition

2021 ◽  
pp. 175815592110660
Author(s):  
Jenő J Purger ◽  
Dávid Szép
Keyword(s):  
Functional Groups ◽  
Small Mammals ◽  
Small Mammal ◽  
Barn Owl ◽  
Tyto Alba ◽  
Mammal Species ◽  
Open Forest ◽  
Prey Composition ◽  
Small Mammal Species ◽  
Owl Pellets

The relative abundance of small mammal species detected from Common Barn-owl pellets reflects the landscape structure and habitat pattern of the owl’s hunting area, but it is also affected by the size of the collected pellet sample and the size of the supposed hunting area. The questions arise: how many pellets should be collected and analyzed as well as how large hunting area should be taken into consideration in order to reach the best correspondence between the owl’s prey composition and the distribution of habitats preferred by small mammals preyed in supposed hunting areas? For this study, we collected 1045 Common Barn-owl pellets in a village in southern Hungary. All detected small mammal species were classified into functional groups (guilds) preferring urban, open, forest and wetland habitats. The proportion of functional groups was compared to the proportion of these habitats around the pellet collection site within circles of one, two, and three km radius. Saturation curves showed that at least 300 pellets or ca. 600 mammalian remains are required for the detection of the 19 small mammal species. The share of small mammals detected in the prey and their functional groups according to their habitat preference showed an increasing consistency with the distribution of real habitats in the potential hunting area of a radius of 3 km around the owl’s breeding or resting place.

Shelter selection by a small mammal community in the wet-dry tropics of Australia.

1989 ◽  
Vol 12 (2) ◽  
pp. 55
Author(s):  
R.W. Braithwaite
Keyword(s):  
Habitat Selection ◽  
Small Mammal ◽  
Tree Species ◽  
Average Distance ◽  
Small Species ◽  
Dry Tropics ◽  
Open Forest ◽  
Shelter Selection ◽  
Small Mammal Community ◽  
The Mean

The location of shelter used by nine species of small mammals released after capture during a mark-recapture study in tropical woodland and open forest was recorded whenever possible. A quantitative profile of such post-release behaviour by different species permits its incorporation into analyses of habitat selection. Characteristics of post-release behaviour also provide clues about the nature of predation pressure on various species. Arboreal species tended to select tree species with boles having camouflage potential. Small species used small holes. Scansorial species used the greatest range of sheltering sites. Average distance moved to shelter was inversely related to the mean density of a species.

Evaluation of risks for two native mammal species from feral cat baiting in monsoonal tropical northern Australia

2018 ◽  
Vol 45 (6) ◽  
pp. 518 ◽  
Author(s):  
Jaime Heiniger ◽  
Skye F. Cameron ◽  
Graeme Gillespie
Keyword(s):  
Rhodamine B ◽  
Native Species ◽  
Field Trials ◽  
Camera Traps ◽  
Northern Australia ◽  
Target Species ◽  
Mammal Species ◽  
Feral Cat ◽  
Feral Cats ◽  
Dry Tropics

Context Feral cats are a significant threat to native wildlife and broad-scale control is required to reduce their impacts. Two toxic baits developed for feral cats, Curiosity® and Hisstory®, have been designed to reduce the risk of baiting to certain non-target species. These baits involve encapsulating the toxin within a hard-shelled delivery vehicle (HSDV) and placing it within a meat attractant. Native animals that chew their food more thoroughly are predicted to avoid poisoning by eating around the HSDV. This prediction has not been tested on wild native mammals in the monsoonal wet–dry tropics of the Northern Territory. Aim The aim of this research was to determine whether northern quolls (Dasyurus hallucatus) and northern brown bandicoots (Isoodon macrourus) would take feral cat baits and ingest the HSDV under natural conditions on Groote Eylandt. Methods We hand-deployed 120 non-toxic baits with a HSDV that contained a biomarker, Rhodamine B, which stains animal whiskers when ingested. The species responsible for bait removal was determined with camera traps, and HSDV ingestion was measured by evaluating Rhodamine B in whiskers removed from animals trapped after baiting. Key results During field trials, 95% of baits were removed within 5 days. Using camera-trap images, we identified the species responsible for taking baits on 65 occasions. All 65 confirmed takes were by native species, with northern quolls taking 42 baits and northern brown bandicoots taking 17. No quolls and only one bandicoot ingested the HSDV. Conclusion The use of the HSDV reduces the potential for quolls and bandicoots to ingest a toxin when they consume feral cat baits. However, high bait uptake by non-target species may reduce the efficacy of cat baiting in some areas. Implications The present study highlighted that in the monsoonal wet–dry tropics, encapsulated baits are likely to minimise poisoning risk to certain native species that would otherwise eat meat baits. However, further research may be required to evaluate risks to other non-target species. Given the threat to biodiversity from feral cats, we see it as critical to continue testing Hisstory® and Curiosity® in live-baiting trials in northern Australia.

Relative abundance of the central rock-rat, the desert mouse and the fat-tailed pseudantechinus at Ormiston Gorge in the West MacDonnell Ranges National Park, Northern Territory

2013 ◽  
Vol 35 (2) ◽  
pp. 144 ◽  
Author(s):  
G. P. Edwards
Keyword(s):  
Population Ecology ◽  
Relative Abundance ◽  
National Park ◽  
Northern Territory ◽  
Mammal Species ◽  
The West

This study examines the relative abundance of two species of sympatric rodent, the desert mouse (Pseudomys desertor) and the central rock-rat (Zyzomys pedunculatus), and a sympatric dasyurid (Pseudantechinus macdonnellensis) in relation to rainfall in the West Macdonnell Ranges National Park, Northern Territory, over a 6-year period. Seventeen trapping sessions were conducted between July 2000 and September 2006. All three species showed spikes in abundance during 2001 and 2002, which were very wet years, and then declined as rainfall diminished. Z. pedunculatus was not trapped at the sites beyond June 2002 while P. desertor was not trapped beyond September 2002. P. macdonnellensis was trapped in low numbers between September 2002 and February 2005 but was not trapped subsequently. Rainfall and the abundance of all three mammal species were clearly correlated. However, the patterns of abundance were subtly different. Z. pedunculatus exhibited three distinct peaks in abundance during the study (July 2000, April 2001 and March 2002), P. desertor exhibited two distinct peaks (July 2001 and June 2002) while. P. macdonnellensis exhibited only one peak in abundance (March 2002). The results of this study provide more evidence that populations of both arid Australian rodents and some dasyurids are influenced by rainfall. The study also provides some insights into the population ecology of the poorly known and threatened central rock-rat.

Distributional patterning of mammals on the Wessel and English Company Islands, Arnhem Land, Northern Territory, Australia

1999 ◽  
Vol 47 (1) ◽  
pp. 87 ◽  
Author(s):  
J. C. Z. Woinarski ◽  
C. Palmer ◽  
A. Fisher ◽  
K. Brennan ◽  
R. Southgate ◽  
...  
Keyword(s):  
Species Richness ◽  
Rattus Rattus ◽  
Northern Territory ◽  
Capra Hircus ◽  
Individual Species ◽  
Suitable Habitat ◽  
Sampling Effort ◽  
Mammal Species ◽  
Island Size ◽  
Arnhem Land

Eighteen non-marine mammal species (including seven species of bats) were recorded from a total of 49 islands in the Wessel and English Company island chains off north-eastern Arnhem Land, Northern Territory. Most individual species were restricted to, or had higher incidence on, larger islands, and species richness as a whole increased as island size increased. The most notable exception was the semi-aquatic Hydromys chrysogaster, which occurred relatively equitably across island sizes; this species, two bat species and the macropod Petrogale brachyotis were recorded from islands smaller than 10 ha. However, the variation between islands in the number of native terrestrial mammal species was not best predicted by island size, but rather by a combination of sampling effort and altitude (which explained 64% of the deviance in species richness), or altitude and distance to larger land mass (explaining 63% of deviance). Richness–area patterns for individual islands in these chains were reasonably consistent with those of other islands sampled in northern Australia. However, the fauna of the Wessel and English Company groups as a whole was less rich than that of the Pellew and Kimberley islands, and individual islands appeared to have lower species richness than comparable mainland areas. Species that were notably absent or that were recorded from relatively few islands include large macropods, Tachyglossus aculeatus, Antechinus bellus, Phascogale tapoatafa, Sminthopsis spp., Mesembriomys gouldii, Rattus colletti, Leggadina lakedownensis and Pseudomys calabyi. Some of these species may be absent through lack of suitable habitat; others have presumably disappeared since isolation, possibly due to Aboriginal hunting. Richness at the quadrat (50 × 50 m) scale was generally very low. Habitat relationships are described for the 7 species recorded from more than 5 quadrats. At a quadrat-scale, the richness of native mammals was greater on islands larger than 1000 ha than on islands smaller than 1000 ha. Quadrat-scale species richness varied significantly among the islands sampled by the most quadrats (even when the comparison was restricted to either of the two most extensive vegetation types), but this variation was not closely related to either area or altitude. The two most frequently recorded species, the rodents Melomys burtoni and Zyzomys argurus, showed distinct habitat segregation on islands where both were present, but tended to expand their habitat range on islands where only one of the species occurred. The most notable conservation feature of the mammal fauna of the Wessel and English Company Islands is the occurrence of the golden bandicoot, Isoodon auratus, a vulnerable species apparently now extinct on the Northern Territory mainland. Four feral animal species (Rattus rattus, Canis familiaris, Bubalus bubalis and Capra hircus) were recorded from a total of 6 islands.

Sediment fluxes and sinks for Magela Creek, Northern Territory, Australia

2018 ◽  
Vol 69 (7) ◽  
pp. 1018 ◽  
Author(s):  
Wayne D. Erskine ◽  
M. J. Saynor ◽  
J. M. Boyden ◽  
K. G. Evans
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Northern Territory ◽  
Bed Load ◽  
Sediment Yields ◽  
Sediment Fluxes ◽  
Erosion Rates ◽  
Dry Tropics ◽  
The World ◽  
Total Sediment

Sediment fluxes and sinks based on total sediment load for Magela Creek in the Australian wet–dry tropics have been constructed from detailed measurements of stream suspended sediment (turbidity and suspended sand) and bed load for the 10-year period, 2001–2002 to 2010–2011. This work shows that the sediment trap efficiency of the vegetated wetlands on lower Magela is high at ~89.5%. Sediment fluxes are the lowest in the world because of low soil erosion rates and because upstream floodplains and downstream wetlands trap and store sediment. Bedload yields are less than suspended sediment yields, but the amount of silt and clay is much less than the amount of sand (suspended sand and bedload). All sand is stored upstream of the East Alligator River. Downstream connectivity of sediment movement does not occur. Therefore, sediment moves discontinuously from the upper to the lower catchment.

scholarly journals Evidence that population increase and range expansion by Eurasian Sparrowhawks has impacted avian prey populations

2018 ◽  
Author(s):  
Christopher Paul Bell
Keyword(s):  
Range Expansion ◽  
Census Data ◽  
Prey Species ◽  
Site Occupancy ◽  
Population Increase ◽  
Substantial Impact ◽  
Bird Populations ◽  
General Decline ◽  
The Impact ◽  
Prey Populations

AbstractThe role of increased predator numbers in the general decline of bird populations in the late 20th century remains controversial, particularly in the case of the Eurasian Sparrowhawk, for which there are contradictory results concerning its effect on the abundance of potential prey species. Previous studies of breeding season census data for Sparrowhawks and prey species in Britain have measured predator abundance either as raw presence-absence data or as an estimate derived from spatially explicit modelling, and have found little evidence of association between predator and prey populations. Here, a predator index derived from site-level binary logistic modelling was used in a regression analysis of breeding census data on 42 prey species, with significant effects emerging in 27 species (16 positive, 11 negative). The frequency of significant positive associations may indicate the tracking of prey abundance by Sparrowhawks, which would tend to cancel out any negative predation effect on prey populations, rendering it difficult to detect using census data. If so, the negative effects that have emerged for some species may underestimate the impact of increased Sparrowhawk numbers on the prey populations concerned. Nevertheless, estimates of the effect on national populations of prey species, obtained by combining effect sizes with a measure of the increase in site occupancy by the predator, suggest the possibility of a substantial impact. It cannot, therefore, be ruled out that the increase in abundance and range expansion of Sparrowhawks made a significant contribution to contemporaneous declines in the populations of many of its prey species.

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