Badges of status and the cost of aggression

Summary The badges of status hypothesis suggests that frequency-dependent selection can maintain honest signalling of aggressiveness. Analysis of a simple ESS model reveals that this is only possible if aggressive individuals incur a cost independent of any particular fights they become involved in. Without such a cost, an honest population is vulnerable to invasion by a modest mutant bearing a dishonestly small badge. Analysis of a second model reveals that where individuals differ in their ability to bear the contest-independent cost of aggressiveness, badge size should reflect this ability. Under such circumstances, plumage badges which serve as honest status signals may have functional consequences beyond their role in settling contests. Thus females, when choosing a mate, could make good use of the information that plumage badges provide. Analysis of a third model shows that the existence of contest-independent benefits to badge size, such as increased mating success, is compatible with the maintenance of honest status signalling.Correspondence to: R.A. Johnstone     

A conceptual model of spatially heterogeneous nitrogen leaching from a welsh moorland catchment

Soil- and stream-water data from the Plynlimon research area, mid-Wales, have been used to develop a conceptual model of spatial variations in nitrogen (N) leaching within moorland catchments. Extensive peats, in both hilltop and valley locations, are considered near-complete sinks for inorganic N, but leach the most dissolved organic nitrogen (DON). Peaty mineral soils on hillslopes also retain inorganic N within upper organic horizons, but a proportion percolates into mineral horizons as nitrate (NO^? ₃), either through incomplete immobilisation in the organic layer, or in water bypassing the organic soil matrix via macropores. This NO^? ₃ reaches the stream where mineral soilwaters discharge (via matrix throughflow or pipeflow) directly to the drainage network, or via small N-enriched flush wetlands. NO^? ₃ in hillslope waters discharging into larger valley wetlands will be removed before reaching the stream. A concept of catchment ‘nitrate leaching zones’ is proposed, whereby most stream NO^? ₃ derives from localised areas of mineral soil hillslope draining directly to the stream; the extent of these zones within a catchment may thus determine its overall susceptibility to elevated surface water NO^? ₃ concentrations.     

Quality circle programmes: Volunteering for participation

Discriminant analysis was used to develop a profile of a typical Quality Circle Programme participant. Selected demographic, attitudinal, and behavioural characteristics were evaluated. Six characteristics significantly differentiated quality circle members from non-members, including educational level, tenure, job satisfaction, consideration, performance, and absenteeism. A profile of the typical circle member is described, and interpretations of the discriminant analysis are discussed.     

Dissolved inorganic nitrogen budget for a forested catchment at Beddgelert, North Wales

An input-output budget for dissolved inorganic-N in a small forested catchment in North Wales is presented. From 1982 to 1990, bulk precipitation inputs averaged 10.3 kg ha(-1) year(-1), whereas throughfall inputs in 1983-1984 were 20.3 kg ha(-1) year(-1). Streamwater outputs were consistently larger than bulk precipitation inputs, averaging 14.6 kg ha(-1) year(-1). Inorganic-N in the forest stream was predominantly nitrate and concentrations were substantially higher than in a nearby moorland stream. Both streams showed seasonal trends in nitrate concentration, with highest concentrations occurring in summer in the forest stream but in winter in the moorland stream. Nitrate concentration in the forest stream increased with increasing soil temperature up to approximately 7 degrees C and decreased at higher temperatures. Nitrification is thought to be responsible for nitrate production at temperatures both below and above 7 degrees C, but root uptake becomes significant only at the higher temperatures. In the forest, dry deposition and cloudwater inputs of inorganic-N are responsible for increased nitrogen fluxes in throughfall compared with wet deposition. Mineralization and nitrification in excess of plant needs causes the organic soil horizons to act as a net source of dissolved inorganic-N. Nitrogen transformations in the soil lead to soil acidification at a rate of 1.0 keq ha(-1) year(-1).     

Monitored natural attenuation forum: State of the practice—Highlights from a breakfast discussion

The Monitored Natural Attenuation (MNA) Forum is published as a column in each issue of Remediation. The format typically includes one or two questions related to MNA with responses from several MNA Panel members. This column highlights MNA topics discussed at a breakfast held in support of the MNA Forum. It includes thoughts from various MNA Panel members and other environmental professionals who attended the breakfast on the “state of the practice.” © 2005 Wiley Periodicals, Inc.     

Temporal trends (1990-2000) in the concentration of cadmium, lead and mercury in mosses across Europe

The European heavy metals in mosses survey provides data on the concentration of 10 heavy metals in naturally growing mosses. The survey has been repeated at five-yearly intervals and in this paper we report on the temporal trends in the concentration of cadmium, lead and mercury between 1990 and 2000. Metal- and country-specific temporal trends were observed. In general, the concentration of lead and cadmium in mosses decreased between 1990 and 2000; the decline was higher for lead than cadmium. For mercury not enough data were available to establish temporal trends between 1990 and 1995, but between 1995 and 2000 the mercury concentration in mosses did not change across Europe. The observed temporal trends for the concentrations in mosses were similar to the trends reported for the modelled total deposition of cadmium, lead and mercury in Europe.     

Quantitative tools for implementing the new definition of significant portion of the range in the U.S. Endangered Species Act

In 2014, the Fish and Wildlife Service (FWS) and National Marine Fisheries Service announced a new policy interpretation for the U.S. Endangered Species Act (ESA). According to the act, a species must be listed as threatened or endangered if it is determined to be threatened or endangered in a significant portion of its range (SPR). The 2014 policy seeks to provide consistency by establishing that a portion of the range should be considered significant if the associated individuals’ “removal would cause the entire species to become endangered or threatened.” We reviewed 20 quantitative techniques used to assess whether a portion of a species’ range is significant according to the new guidance. Our assessments are based on the 3R criteria—redundancy (i.e., buffering from catastrophe), resiliency (i.e., ability to withstand stochasticity), and representation (i.e., ability to evolve)—that the FWS uses to determine if a species merits listing. We identified data needs for each quantitative technique and considered which methods could be implemented given the data limitations typical of rare species. We also identified proxies for the 3Rs that may be used with limited data. To assess potential data availability, we evaluated 7 example species by accessing data in their species status assessments, which document all the information used during a listing decision. In all species, an SPR could be evaluated with at least one metric for each of the 3Rs robustly or with substantial assumptions. Resiliency assessments appeared most constrained by limited data, and many species lacked information on connectivity between subpopulations, genetic variation, and spatial variability in vital rates. These data gaps will likely make SPR assessments for species with complex life histories or that cross national boundaries difficult. Although we reviewed techniques for the ESA, other countries require identification of significant areas and could benefit from this research.     

Water quality assessment programs in Australia deciding what to measure,and how and where to use bioindicators

Effective water quality assessment programs require the formulation of common objectives between managers who are making decisions and scientists who are obtaining the information on which those decisions are to be made. The data collected must be apropriate for use in the decision making process. After the objectives have been formulated a number of testable hypotheses can be proposed and evaluated in terms of what information is required for decision making.From a management perspective it is important to know if an impact occurs and what management strategy to adopt to reduce or eliminate the impact. When bioaccumulators are used to indicate environmental quality the organisms proposed need to be fully evaluated before being used. Communities, which are often used to assess levels of impact, have the capacity to assimilate pollutants and they will function under pollutant stress. Thus managers need to make value judgements about when a community structure or function has shifted from acceptable to adverse. Bioassays in which the effects of pollutants on growth, biochemistry and behaviour are measured, give an indication of the sub-lethal effects of a pollutant, but it is difficult to set meaningful levels that are not to be exceeded for use by managers.Difficulties in using chemical and biological data mainly arise from a lack of appreciation of environmental heterogeneity. The data obtained must meet the needs for statistically testing hypotheses. Before programs can be designed to meet statistical needs the potential sources of variability must be considered. Once the minimum differences that are seen as important have been determined, the number of replicates needed can be calculated. Data verification is also needed, as if the validity of data is questioned, so will any decisions that have been made based on those data. Finally programs should be designed to minimize the sampling effort/cost to meet the objectives.     

Male morphology and behavior correlate with reproductive success in the American redstart (Setophaga ruticilla)

Summary In a population of American redstarts (Setophaga ruticilla), we determined whether a relationship exists between seasonal reproductive success (RS) and a variety of male and female morphological and behavioral characters including plumage and male song. Adult males differ dramatically in plumage from yearling males and also exhibit variable amounts of black on their breast (bib size). Adult males were more successful than yearlings in terms of the number of eggs laid by their females. Among adult males, those with smaller bibs (less black) had females that laid more eggs, and produced more hatchlings and more fledglings. We found no evidence to indicate that this result was a consequence of territory quality. We examined a number of features of song but none alone was a predictor of RS; however, one song feature (rare repeat song) correlated with bib size. When bib size and rare repeat song were analyzed simultaneously, both were found to relate to RS. No female features were predictors of RS, but females arriving earlier at the breeding site mated with males with smaller bibs. The evidence is consistent with the view that plumage of redstarts may be used as a basis for female choice. Offprint requests to: R.E. Lemon