Rational decision processes and sex discrimination: Testing ‘rational’ bias theory

The extent to which sex discrimination is likely to occur as a consequence of manager-client relationships was examined in this test of rational bias theory. Results were gathered by means of a computerized survey technique. Findings indicated that discrimination is more likely to occur in relationships in which the client is relatively important to the manager, but less likely to occur, or be reversed, in the presence of conditions signaling that the client disapproves of discrimination. The findings partly supported the prediction that managers in relatively weaker positions more readily discriminate. The analysis offers theoretical and policy implications for future consideration.     

Landscape planning and the estate landscape

The country estate has a particular place in the English countryside and its contribution to the landscape scene is distinct and valuable. The paper describes an approach to planning a large country estate of parkland, woodland and estate villages in Cheshire. A Reconnaissance Survey led to the Outline Strategy for six ‘landscape types’ discovered on the estate. The Landscape Conservation Plan is described and the crucial importance of conservation measures is emphasised.     

Characterizing source-sink dynamics with genetic parentage assignments

Source-sink dynamics have been suggested to characterize the population structure of many species, but the prevalence of source-sink systems in nature is uncertain because of inherent challenges in estimating migration rates among populations. Migration rates are often difficult to estimate directly with demographic methods, and indirect genetic methods are subject to a variety of assumptions that are difficult to meet or to apply to evolutionary timescales. Furthermore, such methods cannot be rigorously applied to high-gene-flow species. Here, we employ genetic parentage assignments in conjunction with demographic simulations to infer the level of immigration into a putative sink population. We use individual-based demographic models to estimate expected distributions of parent-offspring dyads under competing sink and closed-population models. By comparing the actual number of parent-offspring dyads (identified from multilocus genetic profiles) in a random sample of individuals taken from a population to expectations under these two contrasting demographic models, it is possible to estimate the rate of immigration and test hypotheses related to the role of immigration on population processes on an ecological timescale. The difference in the expected number of parent-offspring dyads between the two population models was greatest when immigration into the sink population was high, indicating that unlike traditional population genetic inference models, the highest degree of statistical power is achieved for the approach presented here when migration rates are high. We used the proposed genetic parentage approach to demonstrate that a threatened population of Marbled Murrelets (Braclhyrarmphus marmotus) appears to be supplemented by a low level of immigration (approximately 2-6% annually) from other populations.     

Nitrate leaching and turf quality in established 'Floratam' St. Augustinegrass and 'Empire' zoysiagrass

The objectives of this research were to evaluate nitrate N (NO3-N) leaching and turf response to nitrogen rate (NR) and irrigation regime (IR) in 'Floratam' St. Augustinegrass ( [Walt.] Kuntze.) and 'Empire' zoysiagrass ( Steud). The research was conducted in Citra, FL, from 2005 through 2007. Nitrogen (N) was applied at annual rates of 32, 64, 128, and 196 kg ha?1 in 2005, and at 49, 196, 343, or 490 kg ha?1 in 2006 and 2007. Irrigation treatments consisted of 1.3 cm applied twice weekly or 2.6 cm applied once weekly. In general, NO?-N leaching was greater from zoysiagrass. In 2007, annual NO?-N leached varied due to the interaction of NR, IR, and grass. There was little association between NR and increased NO?-N leaching in St. Augustinegrass in any year. While St. Augustinegrass had no differences in NO?-N leached within NR due to IR, there were some differences in NO?-N leached from zoysiagrass at some N levels, with greater NO?-N leached from the more frequent irrigation regime. Turf quality (TQ) was generally above an acceptable level in St. Augustinegrass at all but the lowest NRs and at all NRs in zoysiagrass with the exception of the spring fertilizer cycle (SFC) in 2007, when high NR treatments resulted in disease. Maintenance of a healthy turfgrass cover is an important strategy for reducing potential nutrient movement from fertilizer application. The current recommended rates for St. Augustinegrass provide good turf cover and health, and result in minimal NO?-N leaching. Zoysiagrass N rates may need to be revised downward to reduce disease, improve turf cover, and reduce NO?-N leaching.     

Cooperative breeding in purple gallinules: the role of helpers in feeding chicks

Summary The participation of breeders and helpers in the feeding of 21 broods of chicks was studied in a population of cooperatively breeding purple gallinules (Porphyrula martinica). In the breeding group, all birds over the age of 2 months fed chicks. Female breeders fed chicks at the highest rate, followed by male breeders and adult helpers, old juvenile helpers, and young juvenile helpers. The amount of food breeders fed chicks was independent of the number of helpers in the breeding group. However, breeders made fewer feeding visits when they had helpers. Male and female breeders spent similar amounts of time feeding chicks. Helpers spent significantly less time feeding chicks than did breeders. As helpers grew older they fed chicks at a faster rate, made more feeding visits and spent more time feeding chicks. Analysis of variance was used to determine which variables explained the variation in the brood feeding rate (amount of food delivered to an entire brood during one observation). Age of chicks had a significant nonlinear effect, and size of brood and number of helpers had significant linear effects on the brood feeding rate. Chicks in groups with helpers received more food and were accompanied for longer periods of time than chicks in groups without helpers; either or both of these factors may have led to increased chick survival.     

Factors impacting on pharmaceutical leaching following sewage application to land

Sewage effluent application to land is a treatment technology that requires appropriate consideration of various design factors. Soil type, level of sewage pre-treatment and irrigation rate were assessed for their influence on the success of soil treatment in removing pharmaceuticals remaining after conventional sewage treatment. A large scale experimental site was built to assess treatment performance in a realistic environment. Of the factors investigated, soil type had the biggest impact on treatment performance. In particular, carbamazepine was very efficiently removed (>99%) when irrigated onto a volcanic sandy loam soil. This was in contrast to irrigation onto a sandy soil where no carbamazepine removal occurred after irrigation. Differences were likely caused by the presence of allophane in the volcanic soil which is able to accumulate a high level of organic matter. Carbamazepine apparent adsorption distribution coefficients (K(d)) for both soils when irrigated with treated sewage effluent were determined as 25 L kg(-1) for the volcanic soil and 0.08 L kg(-1) for the sandy soil. Overall, a volcanic soil was reasonably efficient in removing carbamazepine while soil type was not a major factor for caffeine removal. Removal of caffeine, however, was more efficient when a partially treated rather than fully treated effluent was applied. Based on the investigated pharmaceuticals and given an appropriate design, effluent irrigation onto land, in conjunction with conventional sewage treatment may be considered a beneficial treatment for pharmaceutical removal.     

A spatial analysis of phosphorus in the Mississippi river basin

Phosphorus (P) in rivers in the Mississippi River basin (MRB) contributes to hypoxia in the Gulf of Mexico and impairs local water quality. We analyzed the spatial pattern of P in the MRB to determine the counties with the greatest January to June P riverine yields and the most critical factors related to this P loss. Using a database of P inputs and landscape characteristics from 1997 through 2006 for each county in the MRB, we created regression models relating riverine total P (TP), dissolved reactive P (DRP), and particulate P (PP) yields for watersheds within the MRB to these factors. Riverine yields of P were estimated from the average concentration of each form of P during January to June for the 10-yr period, multiplied by the average daily flow, and then summed for the 6-mo period. The fraction of land planted in crops, human consumption of P, and precipitation were found to best predict TP yields with a spatial error regression model ( = 0.48, = 101). Dissolved reactive P yields were predicted by fertilizer P inputs, human consumption of P, and precipitation in a multiple regression model ( = 0.42, = 73), whereas PP yields were explained by crop fraction, human consumption of P, and soil bulk density in a spatial error regression model ( = 0.49, = 61). Overall, the Upper Midwest's Cornbelt region and lower Mississippi basin had the counties with the greatest P yields. These results help to point out specific areas where agricultural conservation practices that reduce losses to streams and rivers and point source P removal might limit the intensity or spatial occurrence of Gulf of Mexico hypoxia and improve local water quality.     

Indigenous Studies Speaks to Environmental Management

This article describes the increasing connections between the fields of Indigenous studies and environmental management and examines some of the ways that an Indigenous studies perspective can guide thinking about environmental management. Indigenous groups have been involved in the management of environmental and natural resources on their lands since time immemorial. Indigenous groups have also become increasingly involved in Western practices of environmental management with the advent of co-management institutions, subsistence boards, traditional ecological knowledge forums, and environmental issues affecting Indigenous resources. Thus, it is an important time for scholarship that explores how Indigenous groups are both shaping and being affected by processes of environmental management. This article summarizes key findings and themes from eight papers situated at the intersection of these two fields of study and identify means by which environmental managers can better accommodate Indigenous rights and perspectives. It is the authors’ hope that increased dialog between Indigenous studies and environmental management can contribute to the building of sustainable and socially just environmental management practices.