scholarly journals Aridity and land use negatively influencea dominant species' upper critical thermal limits

PeerJ ◽  
2019 ◽  
Vol 6 ◽  
pp. e6252 ◽  
Author(s):  
Nigel R. Andrew ◽  
Cara Miller ◽  
Graham Hall ◽  
Zac Hemmings ◽  
Ian Oliver

Understanding the physiological tolerances of ectotherms, such as thermal limits, is important in predicting biotic responses to climate change. However, it is even more important to examine these impacts alongside those from other landscape changes: such as the reduction of native vegetation cover, landscape fragmentation and changes in land use intensity (LUI). Here, we integrate the observed thermal limits of the dominant and ubiquitous meat antIridomyrmex purpureusacross climate (aridity), land cover and land use gradients spanning 270 km in length and 840 m in altitude across northern New South Wales, Australia. Meat ants were chosen for study as they are ecosystem engineers and changes in their populations may result in a cascade of changes in the populations of other species. When we assessed critical thermal maximum temperatures (CTmax) of meat ants in relation to the environmental gradients we found little influence of climate (aridity) but that CTmaxdecreased as LUI increased. We found no overall correlation between CTmaxand CTmin. We did however find that tolerance to warming was lower for ants sampled from more arid locations. Our findings suggest that as LUI and aridification increase, the physiological resilience ofI. purpureuswill decline. A reduction in physiological resilience may lead to a reduction in the ecosystem service provision that these populations provide throughout their distribution.

1979 ◽  
Vol 1 (4) ◽  
pp. 260 ◽  
Author(s):  
RW Condon

This article describes how land settlement policies over a period of 100 years and shrub regeneration in parts of the poplar box (Eucalyptus populnea) lands in New South Wales have had and will continue to have a major influence on the economics of grazing properties in the region. Choise of animals offers few options, but there are many methods of improving productivity which may be applicable to a particular property; their feasibility is being tested in a pilot rehabilitation scheme which is described. Choice of animals offers few options, but there are many methods of improving productivity which may be applicable to a particular property; their feasibility is being tested in a pilot rehabilitation scheme which is described.


1980 ◽  
Vol 2 (1) ◽  
pp. 31 ◽  
Author(s):  
EJ Weston ◽  
DF Thompson ◽  
BJ Scott

Poplar box (Eucalyptus populnee) woodlands mainly occuron duplex, clay and red earth soils between the 300 mm and 750 mm rainfall isohyets. The poplar box lands have been occupied for from 100 to 150 years and have been modified extensively through tree felling, ringbarking, clearing, cultivation, burning and grazing by domestic livestock. The current land use is described for six vegetation groups which together comprise the poplar box lands. The eastern areas of the poplar box lands are mainly used for intensive agriculture based on wheat. barley and grain sorghum, with small areas sown to c~ops of high water demand. Mixed farming involves dairying (in Queensland) and fat lambs (in New South Wales) and broad-acre cereal and fodder cropping. Sheep and cattle grazing replace intensive crop production as the rainfall decreases. In all areas used for cropping the stability and fertility of the soil are of paramount importance in maintainihg production. The use of woodlands in areas of lower rainfall can lead to deterioration of the resource and to the encroachment of woody native species into the grazing lands. Because cropping is unreliable the opportunity to use cultivation to control woody regrowth is reduced. In central areas much of the land can be sown to improved pastures, but in western areas diversification is limited by the low rainfall and land use is restricted to grazing, initially only by sheep but now by sheep and cattle. Particularly in western New South Wales the increase in unpalatable shrubs and the decrease in available forage has resulted in low stocking rates, and high grazing pressure, making reclamation and pasture improvement difficult. In consequence many enterprises are becoming uneconomic.


1971 ◽  
Vol 19 (2) ◽  
pp. 177 ◽  
Author(s):  
MMH Wallace ◽  
JA Mahon

The lucerne flea, S. viridis, is restricted to the southern parts of Australia and, apart from a few isolated occurrences in eastern New South Wales, occurs only in areas with an essentially Mediterranean-type climate. The northern inland limit to its distribution agrees closely with the 250-mm isohyet for the growing season of May-October inclusive. The eastern limit to distribution in New South Wales and Victoria agrees with a December-March isohyet of 225 mm. Areas east of this line receive predominantly summer rainfall, and the pastures contain a high proportion of perennial plants which probably do not provide the nutritional stimulus for the development of aestivating diapause eggs in S. viridis essential for oversummering. The predatory mite B. lapidaria requires slightly moister conditions than S. viridis and the limit of its inland distribution agrees reasonably well with the 260-mm isohyet for the May-October period. Low temperatures (mean maximum < 17.5'C) also seem necessary during this period. The eastern distribution limits in Victoria are similar to those of S. viridis.


1999 ◽  
Vol 30 (1) ◽  
pp. 51-73 ◽  
Author(s):  
R. J. HAWORTH ◽  
S. J. GALE ◽  
S. A. SHORT ◽  
H. HEIJNIS

Rural Society ◽  
2011 ◽  
Vol 20 (3) ◽  
pp. 266-279 ◽  
Author(s):  
Alex Baumber ◽  
John Merson ◽  
Peter Ampt ◽  
Mark Diesendorf

Soil Research ◽  
2005 ◽  
Vol 43 (1) ◽  
pp. 21 ◽  
Author(s):  
Rick Young ◽  
Brian R Wilson ◽  
Malem McLeod ◽  
Clair Alston

The organic carbon stock in biomass and soil profiles sampled from nearby paddocks with different land-use histories was estimated at 7 sites in the upper Liverpool Plains catchment and the Manilla district of north-western New South Wales, Australia. The distribution of soil carbon concentrations over a depth of 2 m was significantly affected by site and land use. Continuous cultivation and cropping over ≥20 years significantly depleted carbon concentrations compared with grassy woodlands in the surface 0.20 m at all sites and to a depth of 0.60 m at 3 sites. Depth of sampling (0–0.20 v. 0–1.0 m) significantly affected the differences between land uses at most sites regarding estimates of the stock of soil carbon. These results show that differences in soil carbon concentrations and stock size do not remain constant with depth between contrasting land uses. However, comparisons between land uses of the total amount of carbon stored were dominated by the number of trees per ha and the size of the trees in grassy woodlands. The implications of these results for carbon accounting are discussed.


2009 ◽  
Vol 15 (1) ◽  
pp. 76
Author(s):  
Hannah Nicholas

Comprising the proceedings and plenary session of the forum ?Animals of arid Australia: out on their own?? held in Mosman, New South Wales in 2004, this publication consists of 17 papers that bring together a range of themes on the fauna and land use of Australia?s arid zone. The authors encompass various disciplines and backgrounds, and a wide range of skills.


2001 ◽  
Vol 23 (1) ◽  
pp. 44 ◽  
Author(s):  
Daniel Lunney

Twenty-four mammal species – predominantly the medium-sized, ground-dwelling mammals with a dependence on grass/herbs and seeds – disappeared forever from the landscape of the Western Division of New South Wales in a period of 60 years from first settlement in 1841. The present study examines the causes of this extinction episode by constructing a picture of the changing landscape from the historical record and interpreting the findings ecologically. The conclusions point to an extinction process that can be largely attributed to the impact of sheep, an impact that was exacerbated in the scarce and fragile refuges of the flat landscape in times of intense and frequent drought. This conclusion differs from those of many others, particularly Kerin in the Western Lands Review, who pointed to "the impact of feral animals, rather than overgrazing" as the cause of mammal extinctions, and Morton, who considered that the rabbit was "principally (although not entirely)" responsible for mammal extinctions in the rangelands. The rabbit plague in the Western Division from the early 1880s and the influx of foxes in the last years of the 19th century expedited the local demise of some species and even delivered the final blow to surviving remnant populations of a few species of native mammals but they were not the primary agent of extinction. Historical accounts give prominence to the rapidly growing wool industry in the 19th century. From its dominant position as an export commodity, wool became the chief means of the successful spread of colonial settlement. By 1853 there were about 300,000 sheep based at the southern end of the Darling on the watered frontages, which were all taken up by 1858. The west of the Darling was largely occupied by sheep farmers between 1859 and 1876. The history of settlement around Menindee from 1841 can be read as a devastating critique of the failure to realise that the west could not sustain a pattern of land use imposed on it from another world. The deterioration of the pastoral landscape was such that by the late 1880s the "walls of the pastoral fortresses... were beginning to crumble of their own accord, as the foundations on which they were built — the physical environment — altered under stresses...". The sequence of occupation and land use in the Western Division and the timing of the loss of native mammal species allows the conclusion to be drawn that it was sheep, and the way the land was managed for the export wool industry, that drove so many of the mammal species to extinction. The impact of ever-increasing millions of sheep on all frontages, through all the refuges, and across all the landscape by the mid 1880s is the primary cause of the greatest period of mammal extinction in Australia in modern times.


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