Traplining by purple-throated carib hummingbirds: behavioral responses to competition and nectar availability

We examined the effects of nectar availability and competition on foraging preferences and revisit intervals of traplining female purple-throated caribs hummingbirds (Eulampis jugularis) to Heliconia patches shared by two individuals or visited solely by one individual. Birds at both shared and solitary patches preferred multiflowered to single-flowered inflorescences, but the magnitude of this preference depended on food availability and competition. During a year of low flower availability, females visited multiflowered inflorescences more frequently than single-flowered inflorescences only when nectar availability was experimentally enhanced; similarly, females at shared patches exhibited a significant preference for multiflowered inflorescences only after experimental increases in nectar availability. Experimental manipulations of nectar availability also had different effects on revisit intervals of birds at shared vs solitary patches. Birds at shared patches responded to patch-wide increases in nectar rewards by increasing the duration of their visit intervals, whereas birds at solitary patches did not. In contrast, birds at solitary patches responded to abrupt losses of nectar at flowers (simulating competition) by decreasing the duration of their visit intervals, whereas a bird at a shared patch did not alter its return interval. The contrasting results between shared vs solitary patches suggest that future studies of traplining behavior should incorporate levels of competition into their design.     

Influence of sewage inputs and fish farm effluents on dissolved nitrogen species in a chalk river

Nitrate, ammonium and dissolved organic nitrogen (DON) concentrations were measured in the lower reaches of the River Test in Hampshire to assess the impact of two effluent point sources. An 18-month survey from July 2001 to December 2002 was carried out at locations above and below fish farm inputs and a sewage effluent outfall. The concentration of nitrate exceeded 400 μM at the four sites on all sample dates. A consistent increase in ammonium concentration was measured downstream of the fish farm, but not the sewage effluent input. DON samples collected downstream of the fish farm did not show a consistent increase in concentration, compared with the upstream sampling location, whereas the sewage effluent input at Romsey was a point source of DON to the River Test with a mean increase of 15 μM. Nitrate was the major component of dissolved nitrogen in this aquifer-fed chalk-bed river system, with up to 10% being DON and ammonium comprising <1%.     

Estimating the Density of Honeybee Colonies across Their Natural Range to Fill the Gap in Pollinator Decline Censuses

Abstract: Although pollinator declines are a global biodiversity threat, the demography of the western honeybee (Apis mellifera) has not been considered by conservationists because it is biased by the activity of beekeepers. To fill this gap in pollinator decline censuses and to provide a broad picture of the current status of honeybees across their natural range, we used microsatellite genetic markers to estimate colony densities and genetic diversity at different locations in Europe, Africa, and central Asia that had different patterns of land use. Genetic diversity and colony densities were highest in South Africa and lowest in Northern Europe and were correlated with mean annual temperature. Confounding factors not related to climate, however, are also likely to influence genetic diversity and colony densities in honeybee populations. Land use showed a significantly negative influence over genetic diversity and the density of honeybee colonies over all sampling locations. In Europe honeybees sampled in nature reserves had genetic diversity and colony densities similar to those sampled in agricultural landscapes, which suggests that the former are not wild but may have come from managed hives. Other results also support this idea: putative wild bees were rare in our European samples, and the mean estimated density of honeybee colonies on the continent closely resembled the reported mean number of managed hives. Current densities of European honeybee populations are in the same range as those found in the adverse climatic conditions of the Kalahari and Saharan deserts, which suggests that beekeeping activities do not compensate for the loss of wild colonies. Our findings highlight the importance of reconsidering the conservation status of honeybees in Europe and of regarding beekeeping not only as a profitable business for producing honey, but also as an essential component of biodiversity conservation.     

The Identification of Atmospheric Nitric Oxide by a Spectroscopic Scan

Lines of the 1-0 band of NO near 5.3 jum have been observed in spectra of approximately 500 m of ground-level air at Columbus, Ohio, on several occasions between October 1970 and January 1971. The estimated NO abundances lie between 0.0 and 0.08 ppm with uncertainties of ±0.01 ppm.     

Relocation attitudes and adjustment: A longitudinal study

This study identified correlates of attitude toward an impending employer-initiated relocation, then followed up by predicting post-transfer attitude and adjustment difficulty in the same sample. Predictors suggested by past research on mobility attitudes (i.e. demographic characteristics and attributes of the pre-move location) were less important in explaining pre-move attitude toward the transfer than were expected attributes of the new location. After the move, experienced aspects of the new location such as role ambiguity, degree of advancement, and community and job satisfaction were the strongest predictors of overall post-move attitude and adjustment difficulty. In many cases, pre-move expectations about attributes of the new location were not related to affect or adjustment after the move, suggesting that pre-move expectations may have been inaccurate. Implications for theory, research, and organizational practice are discussed.     

Disease Surveillance and Control After a Flood: Khartoum, Sudan, 1988

Following a flood in Khartoum, Sudan, emergency disease surveillance was implemented to monitor the health status of the population. Simple, symptom-oriented case definitions for diarrheal disease, measles, respiratory disease, malaria, and jaundice were included on the report form used to collect daily counts of outpatients in a sample of both temporary and permanent clinics located in areas of the city most affected by the flood. Data collected from major teaching hospitals allowed comparison of pre- and post-disaster levels of morbidity and mortality. In addition, special surveys collected information unobtainable from health facilities. Sentinel clinic surveillance data indicated that diarrheal disease accounted for the greatest number of clinic visits, while malaria was the second most common reason for seeking medical attention. Malaria blood smear surveys showed that the parasitemia prevalence ranged from 11% to 19% in the general population and from 21% to 46% among febrile clinic patients. Hospital admission data demonstrated an increase in morbidity from diarrhea and malaria in August 1988, when compared to previous months and August of the previous year, although it is uncertain whether this increase was due to the flood. Nutrition surveys demonstrated that 23% of young children were moderately or severely undernourished, with substantial variation by area of the city. No major outbreaks of communicable disease were detected in the 4 weeks after the flood. Disease surveillance provided data useful in identifying public health problems, setting priorities, targeting interventions and controlling rumors. Disease control measures taken by the Ministry of Health included provision of potable water, standardization of medical care, and distribution of immunizations, oral rehydration salts, and vitamin supplements to children.     

Petrographic and spectroscopic characterization of phosphate-stabilized mine tailings from Leadville,Colorado

The use of soluble PO4(3-) and lime as a heavy metal chemical stabilization agent was evaluated for mine tailings from Leadville, Colorado. The tailings are from piles associated with the Wolftone and Maid of Erin mines; ore material that was originally mined around 1900, reprocessed in the 1940s, and now requires stabilization. The dominant minerals in the tailings are galena (PbS), cerrusite (PbCO3), pyromorphite (Pb5(PO4)3Cl), plumbojarosite (Pb0.5Fe3(SO4)2(OH)6), and chalcophanites ((Pb,Fe,Zn,Mn)Mn2O5 x 2H2O). The tailings were treated with soluble PO4(3-) and lime to convert soluble heavy metals (principally Pb, Zn, Cu, Cd) into insoluble metal phosphate precipitates. The treatment process caused bulk mineralogical transformations as well as the formation of a reaction rind around the particles dominated by Ca and P. Within the mineral grains, Fe-Pb phosphosulfates, Fe-Pb sulfates (plumbojarosite), and galena convert to Fe-Ca-Pb hydroxides. The Mn-Pb hydroxides and Mn-(+/-Fe)-Pb hydroxides (chalcophanites) undergo chemical alteration throughout the grains during treatment. Bulk and surface spectroscopies showed that the insoluble reaction products in the rind are tertiary metal phosphate (e.g. (Cu,Ca2)(PO4)2) and apatite (e.g. Pb5(PO4)3Cl) family minerals. pH-dependent leaching (pH 4,6,8) showed that the treatment was able to reduce equilibrium concentrations by factors of 3 to 150 for many metals; particularly Pb2+, Zn2+, Cd2+, and Cu2+. Geochemical thermodynamic equilibrium modeling showed that apatite family and tertiary metal phosphate phases act as controlling solids for the equilibrium concentrations of Ca2+, PO4(3-) Pb2+, Zn2+, Cd2+, and Cu2+ in the leachates during pH-dependent leaching. Both end members and ideal solid solutions were seen to be controlling solids.     

Scarcity and conflict,key problems in water management: a Mexican case study

Water scarcity has become a key issue in water management. There are two contrasting positions regarding scarcity as a source of conflict or cooperation. Accordingly, it is worth exploring what exactly are the conditions that make water scarcity a source of conflict or cooperation. The history of water conflicts has shown that people are more likely to kill around a water hole than when conflicts grow into national or international issues. This suggests that there may be an inverse relationship between the level of violence and the scale at which the water conflict takes place. A common problem in environmental management has been the lack of effective mechanisms to handle conflict. In the majority of these cases, the main shortcoming was an inability of the parties to identify their differences. Therefore, this research explores the idea that understanding the causes of conflict from the outset, followed by an evaluation, at the local scale, of the conditions, is a necessary precondition to finding appropriate and sustainable solutions. With this background in mind, the objective of this paper is to employ a conflict assessment process in order to explore to the extent to which a collaborative dialogue among stakeholders can be an appropriate approach to conflict resolution. A case study in Mexico is employed as a testing ground.