Future Reduction (future + reduction)

Distribution by Scientific Domains

Selected Abstracts

Assessing the results of scenarios of climate and land use changes on the hydrology of an Italian catchment: modelling study

Daniela R. D'Agostino
Abstract Hydrological models are recognized as valid scientific tools to study water quantity and quality and provide support for the integrated management and planning of water resources at different scales. In common with many catchments in the Mediterranean, the study catchment has many problems such as the increasing gap between water demand and supply, water quality deterioration, scarcity of available data, lack of measurements and specific information. The application of hydrological models to investigate hydrological processes in this type of catchments is of particular relevance for water planning strategies to address the possible impact of climate and land use changes on water resources. The distributed catchment scale model (DiCaSM) was selected to study the impact of climate and land use changes on the hydrological cycle and the water balance components in the Apulia region, southern Italy, specifically in the Candelaro catchment (1780 km2). The results obtained from this investigation proved the ability of DiCaSM to quantify the different components of the catchment water balance and to successfully simulate the stream flows. In addition, the model was run with the climate change scenarios for southern Italy, i.e. reduced winter rainfall by 5,10%, reduced summer rainfall by 15,20%, winter temperature rise by 125,15 C and summer temperature rise by 15,175 C. The results indicated that by 2050, groundwater recharge in the Candelaro catchment would decrease by 21,31% and stream flows by 16,23%. The model results also showed that the projected durum wheat yield up to 2050 is likely to decrease between 22% and 104% due to the future reduction in rainfall and increase in temperature. In the current study, the reliability of the DiCaSM was assessed when applied to the Candelaro catchment; those parameters that may cause uncertainty in model output were investigated using a generalized likelihood uncertainty estimation (GLUE) methodology. The results showed that DiCaSM provided a small level of uncertainty and subsequently, a higher confidence level. Copyright 2010 John Wiley & Sons, Ltd. [source]

The Origins of the British Commonwealth Strategic Reserve: The UK Proposal to Revitalise ANZAM and the increased Australian Defence Commitment to Malaya

Hiroyuki Umetsu
At the end of 1952 the UK proposed to revitalise the ANZAM arrangement by concentrating it more closely on the defence of British interests in Malaya. Hitherto ANZAM had focused almost completely upon planning for the wartime defence of sea communications in the Southwest Pacific. This article explains why the UK sought to revitalise ANZAM, and why Australia accepted the British proposal. The British proposal arose from the adoption by the UK of a strategy of nuclear deterrence which led it to project both a future reduction of British conventional forces available for overseas commitments, and a greater reliance upon Commonwealth partners for the protection of British interests in Malaya. It also represented an attempt to reduce the value of the ANZUS security treaty, signed in early September 1951. Australia accepted the British proposal that Commonwealth partners should shoulder a heavier burden in Malaya as a way of preserving the value of ANZUS and of adjusting to the future reduction of the British military presence in Asia. [source]

Stocking piscivores to improve fishing and water clarity: a synthesis of the Lake Mendota biomanipulation project

R. C. Lathrop
SUMMARYY 1.,A total of 2.7 106 walleye fingerlings and 1.7 105 northern pike fingerlings were stocked during 1987,99 in eutrophic Lake Mendota. The objectives of the biomanipulation were to improve sport fishing and to increase piscivory to levels that would reduce planktivore biomass, increase Daphnia grazing and ultimately reduce algal densities in the lake. The combined biomass of the two piscivore species in the lake increased rapidly from < 1 kg ha,1 and stabilised at 4,6 kg ha,1 throughout the evaluation period. 2.,Restrictive harvest regulations (i.e. increase in minimum size limit and reduction in bag limit) were implemented in 1988 to protect the stocked piscivores. Further restrictions were added in 1991 and 1996 for walleye and northern pike, respectively. These restrictions were essential because fishing pressure on both species (especially walleye) increased dramatically during biomanipulation. 3.,Commencing in 1987 with a massive natural die-off of cisco and declining yellow perch populations, total planktivore biomass dropped from about 300,600 kg ha,1 prior to the die-off and the fish stocking, to about 20,40 kg ha,1 in subsequent years. These low planktivore biomasses lasted until a resurgence in the perch population in 1999. 4.,During the period prior to biomanipulation when cisco were very abundant, the dominant Daphnia species was the smaller-bodied D. galeata mendotae, which usually reached a biomass maximum in June and then crashed shortly thereafter. Beginning in 1988, the larger-bodied D. pulicaria dominated, with relatively high biomasses occurring earlier in the spring and lasting well past mid-summer of many years. 5.,In many years dominated by D. pulicaria, Secchi disc readings were greater during the spring and summer months when compared with years dominated by D. galeata mendotae. During the biomanipulation evaluation period, phosphorus (P) levels also changed dramatically thus complicating our analysis. Earlier research on Lake Mendota had shown that Daphnia grazing increased summer Secchi disc readings, but P concentrations linked to agricultural and urban runoff and to climate-controlled internal mixing processes were also important factors affecting summer readings. 6.,The Lake Mendota biomanipulation project has been a success given that high densities of the large-bodied D. pulicaria have continued to dominate for over a decade, and the diversity of fishing opportunities have improved for walleye, northern pike and, more recently, yellow perch. 7.,Massive stocking coupled with very restrictive fishing regulations produced moderate increases in piscivore densities. Larger increases could be realised by more drastic restrictions on sport fishing, but these regulations would be very controversial to anglers. 8.,If the lake's food web remains in a favourable biomanipulation state (i.e. high herbivory), further improvements in water clarity are possible with future reductions in P loadings from a recently initiated non-point pollution abatement programme in the lake's drainage basin. [source]

Quantifying the grazing impacts associated with different herbivores on rangelands

Summary 1Rangelands, produced by grazing herbivores, are important for a variety of agricultural, hunting, recreation and conservation objectives world-wide. Typically, there is little quantitative evidence regarding the magnitude of the grazing impact of different herbivores on rangeland habitats to inform their management. 2We quantified the grazing and trampling impact of sheep, cattle, red deer Cervus elaphus, rabbits Oryctolagus cuniculus, mountain hares Lepus timidus and red grouse Lagopus lagopus on open-hill habitats in 11 areas of upland Scotland. The degradation of heather in upland Scotland Calluna vulgaris -dominated habitats, of conservation significance at a European scale, has been attributed, anecdotally, to increasing sheep and red deer populations. 3Field indicators of habitat condition were used to generate a five-point scale of impact in vegetation polygons of seven habitats. The presence of each herbivore species was attributed on the basis of ,signs' of occupancy. A Bayesian regression model was used to analyse the association of herbivore species with grazing impact on plant communities, controlling for environmental attributes. 4Overall the presence of sheep was associated with the largest increase (7/11 areas) in grazing and trampling impact of all herbivores. Cattle had the second largest impact but generally this was restricted to fewer areas and habitats than sheep. In contrast, impacts associated with wild herbivores tended to be small and only significant locally. 5Although red deer presence was associated with a significantly lower impact than sheep, this impact increased with increasing deer density at both land-ownership and regional scales. For sheep there was little or no evidence of density dependence. 6Synthesis and applications. The higher impact associated with sheep presence probably reflects their greater aggregation because of their limited ranging behaviour, exacerbated by sheep being herded in places convenient for land managers. Consequently, future reductions in sheep numbers as a result of reform of European Union farming policies may limit the extent of their impact, but not necessarily the local magnitude. However, reductions in sheep stocks may lead to increases in deer densities, with greater impact, particularly in heather-dominated habitats. Where habitat conservation is a priority this may well require a reduction in deer numbers. [source]