Comparison of the Sensitivity of Landscape-fire-succession Models to Variation in Terrain, Fuel Pattern, Climate and Weather   总被引：1，自引：0，他引：1  

Geoffrey J. Cary  Robert E. Keane  Robert H. Gardner  Sandra Lavorel  Mike D. Flannigan  Ian D. Davies  Chao Li  James M. Lenihan  T. Scott Rupp  Florent Mouillot 《Landscape Ecology》2006,21(1):121-137

The purpose of this study was to compare the sensitivity of modelled area burned to environmental factors across a range of independently-developed landscape-fire-succession models. The sensitivity of area burned to variation in four factors, namely terrain (flat, undulating and mountainous), fuel pattern (finely and coarsely clumped), climate (observed, warmer & wetter, and warmer & drier) and weather (year-to-year variability) was determined for four existing landscape-fire-succession models (EMBYR, FIRESCAPE, LANDSUM and SEM-LAND) and a new model implemented in the LAMOS modelling shell (LAMOS(DS)). Sensitivity was measured as the variance in area burned explained by each of the four factors, and all of the interactions amongst them, in a standard generalised linear modelling analysis. Modelled area burned was most sensitive to climate and variation in weather, with four models sensitive to each of these factors and three models sensitive to their interaction. Models generally exhibited a trend of increasing area burned from observed, through warmer and wetter, to warmer and drier climates with a 23-fold increase in area burned, on average, from the observed to the warmer, drier climate. Area burned was sensitive to terrain for FIRESCAPE and fuel pattern for EMBYR. These results demonstrate that the models are generally more sensitive to variation in climate and weather as compared with terrain complexity and fuel pattern, although the sensitivity to these latter factors in a small number of models demonstrates the importance of representing key processes. The models that represented fire ignition and spread in a relatively complex fashion were more sensitive to changes in all four factors because they explicitly simulate the processes that link these factors to area burned. The US Government's and the Canadian Government's right to retain a non-exclusive, royalty-free license is acknowledged  相似文献   

Are hedgerows effective corridors between fragments of woodland habitat? An evidence-based approach   总被引：1，自引：1，他引：1  

Zoe G. Davies  Andrew S. Pullin 《Landscape Ecology》2007,22(3):333-351

Anthropogenic modification of the countryside has resulted in much of the landscape consisting of fragments of once continuous habitat. Increasing habitat connectivity at the landscape-scale has a vital role to play in the conservation of species restricted to such remnant patches, especially as species may attempt to track zones of habitat that satisfy their niche requirements as the climate changes. Conservation policies and management strategies frequently advocate corridor creation as one approach to restore connectivity and to facilitate species movements through the landscape. Here we examine the utility of hedgerows as corridors between woodland habitat patches using rigorous systematic review methodology. Systematic searching yielded 26 studies which satisfied the review inclusion criteria. The empirical evidence currently available is insufficient to evaluate the effectiveness of hedgerow corridors as a conservation tool to promote the population viability of woodland fauna. However, the studies did provide anecdotal evidence of positive local population effects and indicated that some species use hedgerows as movement conduits. More replicated and controlled field investigations or long-term monitoring are required in order to allow practitioners and policy makers to make better informed decisions about hedgerow corridor creation and preservation. The benefits of such corridors in regard to increasing habitat connectivity remain equivocal, and the role of corridors in mitigating the effects of climate change at the landscape-scale is even less well understood.  相似文献   

THE YIELDS AND COMPOSITION OF LUCERNE, GRASS AND CLOVER UNDER DIFFERENT SYSTEMS OF MANAGEMENT     

W. Ellis  Davies 《Grass and Forage Science》1964,19(2):263-270

The mean yields of 4 varieties of lucerne were compared under 5 methods of growing: broadcast with and without grass; drills 2 ft apart; alternate lucerne/grass drills 1 ft apart; spaced plants. One cut was harvested in the sowing year and 3 cuts a year for the next 3 years.
The alternate lucerne/grass drills yielded 20% less dry matter than the comparable broadcast plots. Broadcasting and sowing in alternate drills had the same effect on the pattern of lucerne/grass competition. The meadow fescue companion produced its highest yield at the first cut and there was a marked drop during each year and from year to year. There was little evidence of nitrogen transfer from the lucerne to the grass.  相似文献   

Book review     

Bryan Davies 《Soil Use and Management》2008,24(3):325-325

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The human stress response to surgical trauma and anaesthesia     

C A Davies 《Equine veterinary journal》1990,22(5):304-305

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Selection of Swaledale sheep of reduced susceptibility to experimental scrapie   总被引：1，自引：0，他引：1  

D C Davies  R H Kimberlin 《The Veterinary record》1985,116(8):211-214

A flock of 294 Swaledale sheep was injected with brain tissue from different sources so as to include strains of natural scrapie currently affecting the Swaledale breed. Discounting intercurrent deaths, 85 per cent of the flock developed clinical scrapie within an observation period of 2557 days (seven years). Scrapie cases fell into distinct early and late groups, occurring at (mean +/- sem) 287 +/- 7 days and 1207 +/- 38 days after injection, respectively. Breeding groups were formed from the survivors after the early cases had occurred and successive lamb crops were produced. Two groups of progeny and two groups of controls were injected with scrapie. The incidence of scrapie in the progeny (27 per cent) was much lower than in the controls (64 per cent). The incidence in the progeny was also assessed in relation to the response of their parents: it was high (about 40 per cent) when one or both parents developed late scrapie but otherwise very low (about 5 per cent). Hence the progeny of surviving parents had a greatly reduced susceptibility to the strains of scrapie used. Seventy-two of these selected progeny formed a nucleus flock which is being bred at Redesdale. The next stage of the experiment is to assess the effect of selected rams in recorded flocks with a high incidence of natural scrapie.  相似文献   

THE POTENTIAL OF LOTUS spp. FOR HILL LAND IN WALES     

W. Ellis  Davies 《Grass and Forage Science》1969,24(3):264-270

Thirty-four introductions of Lotus corniculatus and L. uliginosus , obtained from Europe, North America and New Zealand, were grown in plots with Aberystwyth S23 ryegrass at three centres in Wales (230–400 m a. s. 1.) to assess their potential as legumes for poor acid hill soils. The control white clover varieties were generally successful in these difficult conditions, whereas all the Lotus introductions were poor in two experiments and in the third experiment gave way to volunteer white clover by the third harvest year. These results indicate that none of the numerous Lotus varieties tested would be a useful addition to pasture seeds mixtures for hill lands in Wales.  相似文献   

LAND RESTORATION WITH PULVERIZED FUEL ASH     

E. W. F. Gillham  W. Morley  Davies 《Grass and Forage Science》1972,27(1):13-15

This paper describes experiments carried out with different depths of topsoil and methods of cultivation on an ash lagoon at Besthorpe, near Newark. Good yields of grass were obtained even on bare ash with suitable rates of fertilizer application. In the conditions existing at Besthorpe, the optimum depth of soil appeared to be three in. (7.62 cm), but the depth of cultivation (three in. (7.62 cm) or twelve in. (30.48 cm), die latter resulting in mixtures of soil and ash, had no significant effect. B uptake by the growing plants was markedly lower in the third year of the experiment but, apart from its possible effect on yield, it produced no ill effects.  相似文献   

Cellular morphology of Clostridium spiroforme   总被引：1，自引：0，他引：1  

S P Borriello  H A Davies  R J Carman 《Veterinary microbiology》1986,11(1-2):191-195

The helically-coiled bacterium, Clostridium spiroforme, has been shown to consist of an ordered aggregation of numerous individual semi-circular cells joined end to end.  相似文献   

O-serotyping of Yersinia ruckeri with special emphasis on European isolates.     

R L Davies 《Veterinary microbiology》1990,22(4):299-307

Yersinia ruckeri is the aetiological agent of enteric redmouth disease (ERM), an acute to chronic bacteraemic infection of salmonid fish. The O-serotypes of 127 isolates of Y. ruckeri obtained from Europe (96 isolates), North America (23 isolates), Australia (six isolates) and South Africa (two isolates), as well as four reference strains, were determined by slide agglutination test and microplate agglutination assay. A serotyping scheme is proposed based on heat-stable O-antigens; the serotypes were designated O1, O2, O5, O6 and O7. The proposed scheme is compared to serotyping schemes described by other authors. All five O-serotypes were present in both Europe and North America, whereas only serotype O1 isolates were identified in Australia and South Africa. These findings suggest that European and North American populations of Y. ruckeri are interrelated, thus supporting previous evidence which suggests that the organism was introduced into Europe from North America by the importation of asymptomatic infected carrier fish. Conversely, the results suggest that Australia and South Africa are more isolated from the dissemination of Y. ruckeri. Serotypes O5, O6 and O7 have not previously been recognized in Europe and these findings will have important implications on the diagnosis of ERM and on the vaccination of fish against this disease. It is suggested that the Australian isolate previously described as serotype III is a rough-type mutant and that other isolates described in the literature as serotype III have been incorrectly serotyped and are, in fact, serotype O1. To avoid further confusion it is suggested that the scheme described here be adopted for serological studies of Y. ruckeri.  相似文献