Artificial Water Sources Research Articles

Surface water and energy budgets in the NCEP regional spectral model

Characteristics of the U.S. surface water and energy budgets in the National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) and the driving NCEP/NCAR (NCEPR) reanalysis are compared. The RSM is similar to the global spectral model (GSM) used in the reanalyses except that it has higher resolution over a limited area. There are, however, other important differences. Besides minor parameterization differences the RSM does not have an artificial water source to maintain the surface moisture (unlike the NCEPR), and the RSM surface water dries. Although the much larger wintertime surface water difference has only a small effect on the evaporation differences and other components of the wintertime water and energy cycles, summertime effects are greater. Relative to the NCEPR the RSM develops a consistent summertime pattern of decreased surface water, precipitation, evaporation, increased sensible heating, outgoing longwave radiation, incoming solar radiation and temperature over the western Mississippi River basin and the Gulf of Mexico, south and eastern coasts. Opposite features occur over the eastern Mississippi River basin and the U.S. West in the RSM. These hydrologically and energetically consistent RSM and NCEPR spatial differences extend to interannual variations in RSM water and energy budgets, which appear to be more strongly influenced by larger interannual surface water variations than might be discerned from the NCEPR.

Technology and Ecology in the Karoo: A Century of Windmills, Wire and Changing Farming Practice

Windmills and wire fencing entered the farming practices of the north-eastern Karoo in the final decades of the nineteenth century. A new grazing system came into being comprising artificial water sources and camps in which sheep and other livestock ranged freely. By the late 1920s this had displaced the old shepherding-plus-kraaling arrangements. At the time, the coming of the new methods was predicted to raise stocking rates, improve veld cover and lessen soil erosion. This paper asks what the ecological consequences have been when viewed historically. Information is drawn from available sources, and the replies are summarised of current farmers and other land resource managers in the Sneeuberg in response to questions about the impact of the camp system. Recent debates about alternative models of rangeland ecology are surveyed as an essential preliminary to the construction of historical hypotheses. Finally, more far-reaching and demanding questions on environmental change in the Karoo are posed for future research work.

Observations of Predator Activity at Wildlife Water Developments in Southern Arizona

Wildlife water developments have been constructed and maintained throughout the arid western United States to beneflt big game and upland gamebird populations. There is debate, however, over possible detriments to wildlife from artificial water sources in deserts and other arid environments. One concern is that water developments attract predators, which then impact the prey populations that these developments are intended to benefit. To examine the extent of predator activity around water developments, we examined 15 paired water and non-water (random) sites for sign (scats, tracks, visual observations, animal parts such as feathers and bones, and carcasses) of predators and prey. Predator sign was 7x greater around water sites than nonwater sites (P = 0.002). Coyote (Canis latrans Say) sign accounted for 79% of all predator sign and was 7x greater near water than away from water (P = 0.006). Amount of sign for all prey species combined was not different between paired sites (P = 0.6), but results for individual species and groups of species was variable; passerine and gallinaceous bird sign was greater around water sites (P = 0.008), ungulate sign was not different between water and non-water sites (P ? 0.20), and lagomorph sign was almost 2x greater away from water than near water (P = 0.05). Predators were probably attracted to wildlife water developments to drink rather than hunt; without water developments, predators may be even more concentrated around the fewer natural water sites.

Observations of predator activity at wildlife water developments in southern Arizona

Wildlife water developments have been constructed and maintained throughout the arid western United States to benefit big game and upland gamebird populations. There is debate, however, over possible detriments to wildlife from artificial water sources in deserts and other arid environments. One concern is that water developments attract predators, which then impact the prey populations that these developments are intended to benefit. To examine the extent of predator activity around water developments, we examined 15 paired water and non-water (random) sites for sign (scats, tracks, visual observations, animal parts such as feathers and bones, and carcasses) of predators and prey. Predator sign was 7x greater around water sites than non-water sites (P = 0.002). Coyote (Canis latrans Say) sign accounted for 79% of all predator sign and was 7x greater near water than away from water (P = 0.006). Amount of sign for all prey species combined was not different between paired sites (P = 0.6), but results for individual species and groups of species was variable; passerine and gallinaceous bird sign was greater around water sites (P = 0.008), ungulate sign was not different between water and non-water sites (P greater than or equal to 0.20), and lagomorph sign was almost 2x greater away from water than near water (P = 0.05). Predators were probably attracted to wildlife water developments to drink rather than hunt; without water developments, predators may be even more concentrated around the fewer natural water sites.

The Efficacy of Finlayson Troughs as a Means of Repelling Kangaroos From Water and Altering Grazing Pressure in Pastoral Areas.

We attempted to determine whether Finlayson troughs (a selective electric repellent device) would repel kangaroos (Macropus rufus and M. robustus) but still allow sheep to drink when access of kangaroos to artificial water sources was restricted on a large scale, and the effect that had on kangaroo populations. In late 1993 high percentages of kangaroos (over 80% of both species) were repelled from water sources fitted with Finlayson troughs when alternative water sources were available. However, when all water sources within a 100,000 ha area had activated Finlayson troughs or were fenced off, kangaroos found methods that enabled them to circumvent the Finlayson troughs within two weeks after activation of the troughs. The numbers which were able to obtain a drink increased greatly over this period. When used on a large scale, Finlayson troughs as used in this study were thus apparently ineffective in restricting the access of kangaroos to water. Aerial surveys and radio-tracking were used to determine the numbers and distribution of kangaroos over the whole area after activation of all the Finlayson troughs. There were no significant differences in kangaroo numbers between the treated area and a nearby control area which was devoid of Finlayson troughs. All 31 of the radio-collared kangaroos which could be located at the end of the trial remained within the areas they formerly occupied and the length of their movements did not increase.

Monosoonal precipitation responses of shrubs in a cold desert community on the Colorado Plateau.

South-eastern Utah forms a northern border for the region currently influenced by the Arizona monosoonal system, which feeds moisture and summer precipitation into western North America. One major consequence predicted by global climate change scenarios is an intensification of monosoonal (summer) precipitation in the aridland areas of the western United States. We examined the capacity of dominant perennial shrubs in a Colorado Plateau cold desert ecosystem of southern Utah, United States, to use summer moisture inputs. We simulated increases of 25 and 50 mm summer rain events on Atriplex canescens, Artemisia filifolia, Chrysothamnus nauseosus, Coleogyne ramosissima, and Vanclevea stylosa, in July and September with an isotopically enriched water (enriched in deuterium but not 18O). The uptake of this artificial water source was estimated by analyzing hydrogen and oxygen isotope ratios of stem water. The predawn and midday xylem water potentials and foliar carbon isotope discrimination were measured to estimate changes in water status and water-use efficiency. At. canescens and Ch. nauseosus showed little if any uptake of summer rains in either July or September. The predawn and midday xylem water potentials for control and treatment plants of these two species were not significantly different from each other. For A. filifolia and V. stylosa, up to 50% of xylem water was from the simulated summer rain, but the predawn and midday xylem water potentials were not significantly affected by the additional summer moisture input. In contrast, C. ramosissima showed significant uptake of the simulated summer rain (>50% of xylem water was from the artificial summer rain) and an increase in both predawn and midday water potentials. The percent uptake of simulated summer rain was greater when those rains were applied in September than in July, implying that high soil temperature in midsummer may in some way inhibit water uptake. Foliar carbon isotope discrimination increased significantly in the three shrubs taking up simulated summer rain, but pre-treatment differences in the absolute discrimination values were maintained among species. The ecological implications of our results are discussed in terms of the dynamics of this desert community in response to changes in the frequency and dependability of summer rains that might be associated with a northward shift in the Arizona monsoon boundary.

Wildlife observed in Kutse Game Reserve, Botswana, at pans with either artificial or natural water sources

African Journal of EcologyVolume 34, Issue 1 p. 70-74 Wildlife observed in Kutse Game Reserve, Botswana, at pans with either artificial or natural water sources Derek Hitchcock, Corresponding Author Derek Hitchcock Department of Integrative Biology, 2070 Valley Life Sciences Building, University of California at Berkeley, Berkeley, CA 94720, U.S.A.*12223 Echo Drive, Nevada City, CA 95959, U.S.A.Search for more papers by this author Derek Hitchcock, Corresponding Author Derek Hitchcock Department of Integrative Biology, 2070 Valley Life Sciences Building, University of California at Berkeley, Berkeley, CA 94720, U.S.A.*12223 Echo Drive, Nevada City, CA 95959, U.S.A.Search for more papers by this author First published: March 1996 https://doi.org/10.1111/j.1365-2028.1996.tb00596.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume34, Issue1March 1996Pages 70-74 RelatedInformation