WHO SHOULD MANAGE THE HIGH PLAINS AQUIFER? THE IRRIGATORS' PERSPECTIVE1

ABSTRACT: A state-local partnership exists in Colorado and Kansas with respect to management of the High Plains aquifer. This paper examines 330 irrigators' attitudes about the locus-of-control for different management activities in the High Plains-Ogallala region. Local control was preferred by most irrigators. The local district was most supported for 19 active management activities, whereas the state was favored for eight specific activities, primarily research efforts and water rights administration. Eight activities that had the potential for restricting water use were rejected in that irrigators indicated that no agency should be involved. Kansas and Colorado exhibited statistically significant preference differences for only five management options. A significantly higher percentage of those irrigators who preferred local control believed in sustainable management of the aquifer and aggressive groundwater management, and that their district served their interests.     

An evaluation of Washington's driving while intoxicated law: Effect on drunk driving recidivism

The 1980 Washington driving while intoxicated (DWI) law was evaluated to determine its impact on the subsequent driving behavior of persons convicted of DWI. The major provisions of this law were mandatory jail sentences for conviction of DWI and a change in the definition of DWI. The law made it illegal per se for a person to drive with a blood alcohol level of .10% or more. The law was intended to reduce the drunk driving and accidents of individuals convicted of DWI as well as deter such behavior among the general driving population. The study assessed the deterrence effect of the law on convicted DWI offenders. It was found that individuals convicted under the provisions of this law had higher accident rates and drunk driving recidivism rates than individuals convicted under the previous law. These increases suggest that mandatory jail sentences may fail to deter subsequent acts of drunk driving. It was concluded that alternative legal sanctions for DWI (such as license suspensions or revocations) may be sufficiently stringent to produce both general and specific deterrence of drunk driving.     

Magnetic particle technology in environmental remediation and wildlife rehabilitation

The use of magnetic particles in environmental remediation and wildlife rehabilitation is currently under investigation at Victoria University, in collaboration with the Phillip Island Research Centre, Victoria, Australia. Iron powder has been shown to be very effective for the magnetic cleansing of feathers and plumage and is almost ideal for this purpose, being non-toxic, a non-irritant and recyclable. Detailed investigations have demonstrated that by varying particle size, particle structure and surface texture, the efficacy of oil removal from feathers and plumage can be successfully manipulated. In this regard, it is possible to identify a grade of iron powder whereby, within experimental error, effectively 100% removal of a variety of fresh contaminants from different matrices, including feathers, can be achieved. Our investigations have been extended to the application of such particles to the successful removal of tarry and weathered/tarry contamination. The results of these investigations have indicated that, for such contaminants, removals ranging from 97–99% may be achieved. Magnetic particle technology may also be adapted for the screening of pre-conditioning agents that can further assist in the removal of tarry and weathered/tarry contamination from feathers. These investigations suggest that magnetic particles could have an important role to play in environmental remediation and wildlife rehabilitation as a clean and effective technology.     

Estimating Hydraulic Properties of Volcanic Aquifers Using Constant‐Rate and Variable‐Rate Aquifer Tests1

Abstract: In recent years the ground‐water demand of the population of the island of Maui, Hawaii, has significantly increased. To ensure prudent management of the ground‐water resources, an improved understanding of ground‐water flow systems is needed. At present, large‐scale estimations of aquifer properties are lacking for Maui. Seven analytical methods using constant‐rate and variable‐rate withdrawals for single wells provide an estimate of hydraulic conductivity and transmissivity for 103 wells in central Maui. Methods based on constant‐rate tests, although not widely used on Maui, offer reasonable estimates. Step‐drawdown tests, which are more abundantly used than other tests, provide similar estimates as constant‐rate tests. A numerical model validates the suitability of analytical solutions for step‐drawdown tests and additionally provides an estimate of storage parameters. The results show that hydraulic conductivity is log‐normally distributed and that for dike‐free volcanic rocks it ranges over several orders of magnitude from 1 to 2,500 m/d. The arithmetic mean, geometric mean, and median values of hydraulic conductivity are respectively 520, 280, and 370 m/d for basalt and 80, 50, and 30 m/d for sediment. A geostatistical approach using ordinary kriging yields a prediction of hydraulic conductivity on a larger scale. Overall, the results are in agreement with values published for other Hawaiian islands.     

A Systemic Approach to Scoping of Factors Influencing More Sustainable Land Use in Herefordshire

Defining and putting into practice sustainable land use is a complex, systemic problem. Systems models and techniques were used in a study of Herefordshire to clarify the situation and identify the potential for a more locally focused, learning-based approach to land use. Issues included: (i) uncertainty about the boundary of a 'system of sustainable Herefordshire land use'; (ii) the complexity of economic flows in the county and the absence of some critical data; (iii) the importance of the Herefordshire landscape to tourism and the role of agriculture as a determinant of the state of that landscape; (iv) weakness of the institutional linkage between tourism and agriculture; (v) the current lack of inclusion of many relevant stakeholders in concerted action. Factors favouring a learning approach included a strong local identity, local food-related developments, and educational initiatives. Barriers to such an approach included questions of power and landholding, government policies, and attitudes and skills within organizations. These findings are considered in relation to the wider debate over approaches to sustainability.     

Aposematism in a soft-bodied insect: a case for kin selection

Summary This paper describes the influence on predator behaviour, and the survival of an aposematic aphid, Aphis nerii, in comparison with a palatable, cryptic aphid, Acyrthosiphon pisum, when offered to two predators with different foraging tactics. The experiments were designed to test Fisher's (1930) suggestion that aposematism could evolve by kin selection, since aposematic animals often occur in aggregations of relatives. Initially, spiders (Zygiella x-notata) and birds (Parus major) killed high proportions of distasteful A. nerii (60% and 54% respectively). With experience, the predators killed and ate fewer A. nerii. The decreasing mortality of A. nerii after initial encounters with predators, coupled with its apparently obligate parthenogenesis, indicate that the evolution of aposematism in this soft-bodied insect is consistent with kin selection.     

Tributyltin in environmental samples from the Former Derecktor Shipyard, Coddington Cove, Newport RI

Tributyltin (TBT) was detected in all 24 surface sediment (top 2 cm) samples collected from Coddington Cove, Newport, RI. TBT surface sediment concentrations ranged from 32 to 372 ng Sn/g with a mean concentration of 146 ng Sn/g. Analyses of selected core sections detected TBT in at least the top 18 cm at all 7 stations where cores were collected. No consistent TBT concentration trends with depth for these cores suggest mixing is an important process in the sediment column. In one core (station 28), TBT was found in the 76-86 cm section at a concentration of 141 ng Sn/g; thus sediments are a significant sink for TBT. However, sediment mixing processes can enhance releases of bioavailable TBT. Mussels, clams and fish from Coddington Cove contain TBT at concentrations ranging from 9.2 to 977 ng Sn/g. TBT concentrations in lobsters were below the detection limit (<6 ng Sn/g). Based on available screening criteria, TBT concentrations in Coddington Cove sediment is likely to be having an adverse effect on the biota at some locations.     

Dietary antioxidants, lipid peroxidation and plumage colouration in nestling blue tits Cyanistes caeruleus

Carotenoid pigments are responsible for many of the red, yellow and orange plumage and integument traits seen in birds. One idea suggests that since carotenoids can act as antioxidants, carotenoid-mediated colouration may reveal an individual's ability to resist oxidative damage. In fact, there is currently very little information on the effects of most dietary-acquired antioxidants on oxidative stress in wild birds. Here, we assessed the impacts on oxidative damage, plasma antioxidants, growth and plumage colouration after supplementing nestling blue tits Cyanistes caeruleus with one of three diets; control, carotenoid treatment or α-tocopherol treatment. Oxidative damage was assessed by HPLC analysis of plasma levels of malondialdehyde (MDA), a by-product of lipid peroxidation. Contrary to predictions, we found no differences in oxidative damage, plumage colouration or growth rate between treatment groups. Although plasma lutein concentrations were significantly raised in carotenoid-fed chicks, α-tocopherol treatment had no effect on concentrations of plasma α-tocopherol compared with controls. Interestingly, we found that faster growing chicks had higher levels of oxidative damage than slower growing birds, independent of treatment, body mass and condition at fledging. Moreover, the chromatic signal of the chest plumage of birds was positively correlated with levels of MDA but not plasma antioxidant concentrations: more colourful nestlings had higher oxidative damage than less colourful individuals. Thus, increased carotenoid-mediated plumage does not reveal resistance to oxidative damage for nestling blue tits, but may indicate costs paid, in terms of oxidative damage. Our results indicate that the trade-offs between competing physiological systems for dietary antioxidants are likely to be complex in rapidly developing birds. Moreover, interpreting the biological relevance of different biomarkers of antioxidant status represents a challenge for evolutionary ecology.     

Shark-bitten vertebrate coprolites from the Miocene of Maryland

Coprolites (fossilized feces) preserve a wide range of biogenic components, from bacteria and spores to a variety of vertebrate tissues. Two coprolites from the Calvert Cliffs outcrop belt (Miocene-aged Chesapeake Group), MD, USA, preserve shark tooth impressions in the form of partial dental arcades. The specimens are the first known coprolites to preserve vertebrate tooth marks. They provide another example of trace fossils providing evidence of prehistoric animal behaviors that cannot be directly approached through the study of body fossils. Shark behaviors that could account for these impressions include: (1) aborted coprophagy, (2) benthic or nektonic exploration, or (3) predation.     

Chronosequence analysis of two enclosure management strategies in degraded rangeland of semi-arid Kenya

The establishment of enclosures has become an important measure to combat land degradation in many of the world's semi-arid rangelands. In view of the increased pressure exerted by this land reclamation strategy on the neighbouring agricultural lands, knowledge of the time required for restoring vegetation cover and soil health, and of the potential positive impact of an adapted management strategy, is highly required. This paper assesses the vegetation and soil rehabilitation in a 23-year chronosequence of two different enclosure management types. In the severely degraded, semi-arid Njemps Flats plain of the Lake Baringo Basin in Kenya communal enclosures characterised by high quality inputs and strict control, and private enclosures managed by individual farmers, were installed since the 1980s. Six communal enclosures (3–17 years since establishment) and six private enclosures (13–23 years since establishment) were selected. Vegetation cover was estimated along three 50 m transects set within each enclosure and in the adjacent open grazing area using the point-to-line transect method. Five 0.5 m² quadrats systematically placed alongside each transect were sampled for herbaceous standing biomass and topsoil physical, chemical and biological analyses. Grass cover and herbaceous biomass production proved to be the most responsive biotic parameters under both management types, whereas the recovery of the forbs was unsuccessful. Under communal management, the biomass production fully recovered up to its optimal level as recorded in the neighbouring nature reserves. Within private enclosures however, the adopted management strategies seriously restricted biomass production to a significantly lower level. Soil quality generally recovered more slowly with time. Significant improvements compared to the open rangeland were recorded in topsoil bulk density, organic C and total N stocks, and microbial biomass C and N stocks of the communal enclosures. Unlike the communal enclosures, only topsoil bulk density and the microbial biomass C stock showed a significant difference in the private enclosures. With respect to C and total N stocks, and the microbial biomass N a non-significant improving trend was recorded. The level of chemical and biological soil quality obtained under both management types is still low and draws the attention to the importance of careful monitoring of grazing and grass cutting activities under both enclosure management strategies. The chronosequences further highlight the potential of some well-managed private enclosures, whereas intrinsic soil properties such as high alkalinity, as well as changes in management, limit the rehabilitation of some other private as well as communal enclosures.