Changes in abundance and reproductive activity of small arid-zone murid rodents on an active cattle station in central Australia

2017 ◽  
Vol 44 (1) ◽  
pp. 22 ◽  
Author(s):  
W. G. Breed ◽  
C. M. Leigh ◽  
M. F. Breed
Keyword(s):  
Natural Environment ◽  
Arid Zone ◽  
Sand Dunes ◽  
Early Summer ◽  
High Abundance ◽  
Population Cycle ◽  
Similar Species ◽  
Population Abundance ◽  
Negative Consequences ◽  
Central Australia

Context Boom and bust population cycles are characteristic of many arid-zone rodents, but it is unknown to what extent these dynamics might be influenced by the presence of invasive rodents, such as the house mouse (Mus musculus) in Australia. Aim To determine whether the presence of M. musculus can have negative consequences on the population abundance and reproduction of two old Australian endemic rodents (the spinifex hopping mouse, Notomys alexis, and sandy inland mouse, Pseudomys hermannsburgensis). Methods The study took place on the sand dunes of a cattle station in central Australia. Population abundance was estimated as the number of individuals caught in small mammal traps, and female reproductive condition by external examination and, in a few cases, euthanasia and inspection of the reproductive tract. Key results Two synchronous periods of high abundance of N. alexis and M. musculus occurred several months after significant rainfall events, whereas the abundance of P. hermannsburgensis was consistently low. No reproduction took place in N. alexis or M. musculus when populations had reached high abundance. During low-rainfall periods, M. musculus was not detected on the sand dunes, and the two endemic species were sparsely distributed, with reproduction occasionally being evident. Conclusions During dry periods, M. musculus contracted back to refuges around the homestead and, after significant rainfall, it expanded onto the sand dunes and became abundant at the same time as did N. alexis. In contrast, and unlike in areas where M. musculus was generally rare, P. hermannsburgensis always remained at a low abundance. These patterns suggest that in areas of the natural environment close to human-modified sites, populations of at least one species of an old endemic rodent are supressed by the presence of M. musculus. Reproduction did not occur in the old endemics at times of high M. musculus abundance, but did take place in spring/early summer, even in some dry years. Implications The spread of M. musculus into the Australian arid zone may have had negative impacts on the population dynamics of P. hermannsburgensis. These findings suggest that the presence of human settlements has resulted in refuges for house mice, which periodically spread out into the natural environment during ‘boom’ times and adversely affect the natural population cycle of ecologically similar species such as P. hermannsburgensis.

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.

Population dynamics of three species of dasyurid marsupials in arid central Australia: a 10-year study

2001 ◽  
Vol 28 (5) ◽  
pp. 493 ◽  
Author(s):  
Christopher R. Dickman ◽  
Adele S. Haythornthwaite ◽  
Gayle H. McNaught ◽  
Paul S. Mahon ◽  
Bobby Tamayo ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Life Histories ◽  
Arid Zone ◽  
Early Spring ◽  
Early Summer ◽  
Late Winter ◽  
Sand Ridge ◽  
Red Foxes ◽  
Central Australia ◽  
Simpson Desert

This study investigated the population dynamics of three species of dasyurid marsupials in sand ridge habitat of the Simpson Desert, western Queensland, over a 10-year period between March 1990 and December 1999. The lesser hairy-footed dunnart (Sminthopsis youngsoni), was captured most consistently over the period of study, followed by the wongai ningaui (Ningaui ridei), and the mulgara (Dasycercus cristicauda). Rates of recapture were low (4.5–22.2%), probably because individuals of each species are very mobile. All species bred in late winter or early spring when animals were aged at least 8–10 months, and independent juveniles first appeared usually in summer. S. youngsoni reared a second litter in late spring or early summer in 3 of the 10 years studied, when the availability of food was likely to have been high; neither N. ridei nor D. cristicauda were known to attempt a second litter within a season. To explore factors that might influence population dynamics, we compared capture rates of each species with measures of rainfall, temperature, vegetation cover, abundance of predators [feral cats (Felis catus), red foxes (Vulpes vulpes), and goannas (Varanus spp.)], dragons, other dasyurids and indices of food abundance. The abundance of S. youngsoni appeared to depend primarily on the cover of spinifex 7–9 months earlier, that of D. cristicauda was related most strongly to rainfall 7–9 months earlier, while that of N. ridei was related to minimum temperature lagged by 1–3 months. While the dynamics of other arid-zone mammals are driven demonstrably by interactions between rainfall, resource availability and predation, our findings suggest that dasyurids have limited flexibility in their life histories and are influenced more subtly and by factors such as facilitation that are just beginning to become apparent.

scholarly journals A Study of Desertification Using Remote Sensing Techniques in Basra Governorate, South Iraq

2021 ◽  
pp. 912-926
Author(s):  
Fadel Abbas Zwain ◽  
Thair Thamer Al-Samarrai ◽  
Younus I. Al-Saady
Keyword(s):  
Remote Sensing ◽  
Land Degradation ◽  
Land Surface ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Arid Zone ◽  
Sand Dunes ◽  
Risk Index ◽  
Anthropogenic Factors ◽  
Landsat Images

Iraq territory as a whole and south of Iraq in particular encountered rapid desertification and signs of severe land degradation in the last decades. Both natural and anthropogenic factors are responsible for the extent of desertification. Remote sensing data and image analysis tools were employed to identify, detect, and monitor desertification in Basra governorate. Different remote sensing indicators and image indices were applied in order to better identify the desertification development in the study area, including the Normalized difference vegetation index (NDVI), Normalized Difference Water Index (NDWI), Salinity index (SI), Top Soil Grain Size Index (GSI) , Land Surface Temperature (LST) , Land Surface Soil Moisture (LSM), and Land Degradation Risk Index (LDI) which was used for the assessment of degradation severity .Three Landsat images, acquired in 1973, 1993, and 2013, were used to evaluate the potential of using remote sensing analysis in desertification monitoring. The approach applied in this study for evaluating this phenomenon was proven to be an effective tool for the recognition of areas at risk of desertification. The results indicated that the arid zone of Basra governorate encounters substantial changes in the environment, such as decreasing surface water, degradation of agricultural lands (as palm orchards and crops), and deterioration of marshlands. Additional changes include increased salinization with the creeping of sand dunes to agricultural areas, as well as the impacts of oil fields and other facilities.

scholarly journals Comparison of population densities of selected bird species breeding in main urban habitats in southwestern Poland

Biologija ◽  
2020 ◽  
Vol 66 (3) ◽  
Author(s):  
Grzegorz Kopij
Keyword(s):  
Bird Species ◽  
Mapping Method ◽  
Residential Area ◽  
Early Summer ◽  
Similar Species ◽  
Pica Pica ◽  
Residential Areas ◽  
Urban Habitats ◽  
Corvus Cornix ◽  
Reverse Situation

A simplified version of the territory mapping method was used. Four counts were conducted in a fragment of the city of Wrocław in the spring and early summer 2010. Two main urban habitats were distinguished: a densely built-up area with block buildings and a residential area with flat houses. In total, 44 bird species were recorded as breeding in the whole study area. Five species nested in a density higher than 10 pairs per 100 ha each: Columba palumbus, Pica pica, Streptopelia decaocto, Sylvia atricapilla, and Turdus merula. Whereas in the densely built-up areas Columba palumbus and Streptopelia decaocto were equally common, in the residential area Streptopelia decaocto was almost three times more common than Columba palumbus. Pica pica was about three times more common than Corvus cornix both in the builtup areas and in the residential areas. Although densely built-up areas and residential areas have a similar species composition, many species breed in different densities. This is probably due to a different structure of vegetation. While tall trees are relatively common and shrubs rare in the densely built-up areas, the reverse situation prevails in residential areas.

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.

Pleistocene settlement in the Australian arid zone: occupation of an inland riverine landscape in the central Australian ranges

Antiquity ◽  
1998 ◽  
Vol 72 (275) ◽  
pp. 34-45 ◽  
Author(s):  
Peter B. Thorley
Keyword(s):  
Environmental Change ◽  
Arid Zone ◽  
River Catchment ◽  
Central Australia

Recent excavations at the Kulpi Mara Rockshelter in the Palmer River catchment of central Australia have produced radiocarbon determinations spanning an archaeological sequence of 30,000 years. These results enable re-assessment of models addressing the how, where and when of arid zone colonisation, and human adjustments to environmental change in the later Pleistocene. Whilst the evidence supports early occupation of the central arid zone during wetter conditions, doubts are raised about the continuity of occupation during the height of glacial aridity.

Zooplankton diversity and assemblages in arid zone rivers of the Lake Eyre Basin, Australia

2006 ◽  
Vol 57 (1) ◽  
pp. 49 ◽  
Author(s):  
Russell J. Shiel ◽  
Justin F. Costelloe ◽  
Julian R. W. Reid ◽  
Peter Hudson ◽  
Joan Powling
Keyword(s):  
Seasonal Changes ◽  
Arid Zone ◽  
Early Summer ◽  
Taxon Richness ◽  
Ecosystem Structure ◽  
Regression Analyses ◽  
Flood Events ◽  
Assemblage Composition ◽  
Boom And Bust ◽  
Three Rivers

The responses of zooplankton assemblages in arid zone rivers to seasonal changes, flow events, drying and water quality changes are fundamental to our understanding of these unregulated rivers. For three years the zooplankton and littoral microfauna in three rivers in the Lake Eyre Basin were studied. A diverse assemblage was discovered with a total of 398 identifiable taxa being recorded, consisting of 72 protist, 227 rotifer and 93 microcrustacean taxa. Zooplankton diversity was highest in a boom phase during, or in the summer following, a large flood. The rotifer assemblage dominated during, or soon after, periods of flow. However, during the winter and early summer, there was a decline in rotifer taxon richness and abundance accompanied by an increase in microcrustacean taxon richness and abundance. The winter samples occurred during the recession of a large flood and the early summer samples during periods of no flow. These changes suggested the involvement of a strong annual cycle of ecosystem structure evident within the longer term patterns of boom and bust driven by the timing and size of flood events. Multivariate and regression analyses found that salinity was a significant and independent driver of assemblage composition.

Rediscovery of Senecio reitzianus (Asteraceae), a species believed to be possibly extinct, on Santa Catarina Island, southern Brazil

Phytotaxa ◽  
2017 ◽  
Vol 291 (3) ◽  
pp. 183
Author(s):  
LUÍS ADRIANO FUNEZ ◽  
GUSTAVO HASSEMER ◽  
JOÃO PAULO RAMOS FERREIRA
Keyword(s):  
Sand Dunes ◽  
Conservation Status ◽  
Field Work ◽  
Detailed Account ◽  
Type Locality ◽  
Similar Species ◽  
Southern Brazil ◽  
Species Extinction ◽  
Santa Catarina ◽  
Data Deficient

Senecio reitzianus was described from sand dunes in Lagoa da Conceição (Florianópolis, Santa Catarina state, southern Brazil). The species remained to be known only from the type. Almost seventy years later, we discovered a population of this species in Costão do Santinho, about 20 km from the type locality. A detailed account of this population is provided and its conservation status is assessed. We also present photographs of this species from the wild and also of the holotype, as well as a new description and comparisons with similar species in the genus. Our results reinforce the urgent need of further field work, especially on data-deficient species, in order to have a chance to prevent the species extinction.

scholarly journals Impact of Armed Conflicts on the State of Ecological Security

2020 ◽  
Vol 6 (1) ◽  
pp. 32-39
Author(s):  
Adam Paweł Olechowski
Keyword(s):  
Natural Environment ◽  
Armed Conflict ◽  
Large Scale ◽  
Environmental Problems ◽  
Armed Conflicts ◽  
Ecological Security ◽  
Negative Consequences ◽  
Military Operations ◽  
Military Conflicts ◽  
Humanitarian Crises

Abstract Contemporary armed conflicts, although not as global in scope as the two world wars in the 20th century, create serious threats in many dimensions. One of the areas of their influence is the natural environment. In fact every armed conflict, also one that takes place in a relatively small territory, causes a number of negative consequences in the natural environment. These, in turn, may have further consequences. Apart from the damage caused by military operations, accompanying phenomena appear on a large scale. In recent years, a series of armed conflicts in Africa and West Asia resulted in huge migrations of millions of people. In addition to the resulting humanitarian crises, large-scale environmental problems are observed. Thus, it clearly shows that even potentially minor military conflicts can lead to serious disturbances of the natural environment. The author shows the various consequences of armed conflicts for the natural environment over the last half century.

Sign in / Sign up

Export Citation Format

Share Document