Correlations between Human Collecting and Intertidal Mollusc Populations on Rocky Shores

We tested whether the population structures of intertidal molluscs varied with the activity of human collectors in northern Port Phillip Bay, Victora, Australia. We examined eight sites, two of which had been protected for around 70 years by the area being used as a rifle range with the other six being visited frequently by human. The shores were examined in two different years, and in 1991 we counted humans and recorded their activities. At heavily visited shores, almost half of the people seen were simply walking, while 25% were actively collecting, despite regulations prohibiting the collection of intertidal gastritis. The remaining people were fishing or skydiving. At the protected shores, we observed only one collector and a handful of walkers over more than 20 observation periods, including weekdays, normal weekends, and holiday weekends. In 1989 and 1991, we compared size distributions of seven intertidal species between sites in the two categories. Four mollify species are taken for food and bait; the remaining three served as “controls”. The size distributions and abundance of noncarbonated species (alicized napalm, Leaderless viola, and emization ebonies) did not differ between visited and protected sites in either year, although most species did vary between individual sites. In contrast, three of the four collected species, alicize trampoliners, Austrocochlea constricta, and Nerita atramentosa, were significantly larger at the protected sites, and N. atramentosa was markedly less abundant at heavily visited sites. The fourth collected species, Turbo undulatus, has a distribution extending into the subtidal zone, and it is possible that intertidal populations ate replenished from deeper water. The changes in mean size of molluscs are well within the range reported from South America and South Africa under subsistence fishing, and they demonstrate that at least close to major urban centers, human recreational activities can have substantial effects in developed countries.     

Individualism-collectivism as an individual difference predictor of organizational citizenship behavior

Though it appears intuitively appealing that individual differences should be related to a person's decision to perform citizenship behaviors, the search for such individual differences has yet to yield clear results. In this study, data were collected to assess the extent of a relationship between individualism–collectivism as a within culture individual difference and self-reports of organizational citizenship behaviors. Results suggest that if an individual holds collectivistic values or norms, he/she would be more likely to perform citizenship behaviors. In addition, this relationship was found to be robust to common method effects and to the effect of the relationship between procedural justice and OCB. Implications for the way collectivistic tendencies within cultures may be used in organizations are discussed.     

ASSESSMENT OF SAMPLING ERROR ASSOCIATED WITH SOIL MOISTURE ESTIMATION DESIGNS1

A spectral formalism was developed and applied to quantify the sampling errors due to spatial and/or temporal gaps in soil moisture measurements. A design filter was developed to compute the sampling errors for discrete measurements in space and time. This filter has as its advantage a general form applicable to various types of sampling design. The lack of temporal measurements of the two‐dimensional soil moisture field made it difficult to compute the spectra directly from observed records. Therefore, the wave number frequency spectra of soil moisture data derived from stochastic models of rainfall and soil moisture were used. Parameters for both models were estimated using data from the Southern Great Plains Hydrology Experiment (SGP97) and the Oklahoma Mesonet. The estimated sampling error of the spatial average soil moisture measurement by airborne L‐band microwave remote sensing during the SGP97 hydrology experiment is estimated to be 2.4 percent. Under the same climate conditions and soil properties as the SGP97 experiment, equally spaced ground probe networks at intervals of 25 and 50 km are expected to have about 16 percent and 27 percent sampling error, respectively. Satellite designs with temporal gaps of two and three days are expected to have about 6 percent and 9 percent sampling errors, respectively.     

Automatic Calibration of Hydrologic Models With Multi‐Objective Evolutionary Algorithm and Pareto Optimization1

Abstract: In optimization problems with at least two conflicting objectives, a set of solutions rather than a unique one exists because of the trade‐offs between these objectives. A Pareto optimal solution set is achieved when a solution cannot be improved upon without degrading at least one of its objective criteria. This study investigated the application of multi‐objective evolutionary algorithm (MOEA) and Pareto ordering optimization in the automatic calibration of the Soil and Water Assessment Tool (SWAT), a process‐based, semi‐distributed, and continuous hydrologic model. The nondominated sorting genetic algorithm II (NSGA‐II), a fast and recent MOEA, and SWAT were called in FORTRAN from a parallel genetic algorithm library (PGAPACK) to determine the Pareto optimal set. A total of 139 parameter values were simultaneously and explicitly optimized in the calibration. The calibrated SWAT model simulated well the daily streamflow of the Calapooia watershed for a 3‐year period. The daily Nash‐Sutcliffe coefficients were 0.86 at calibration and 0.81 at validation. Automatic multi‐objective calibration of a complex watershed model was successfully implemented using Pareto ordering and MOEA. Future studies include simultaneous automatic calibration of water quality and quantity parameters and the application of Pareto optimization in decision and policy‐making problems related to conflicting objectives of economics and environmental quality.     

Communally breeding bats use physiological and behavioural adjustments to optimise daily energy expenditure

Small endotherms must change roosting and thermoregulatory behaviour in response to changes in ambient conditions if they are to achieve positive energy balance. In social species, for example many bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, and also by social thermoregulation. Direct measurements of daily fluctuations in metabolic rates in response to ambient and behavioural variables in the field have not been technologically feasible until recently. During different reproductive periods, we investigated the relationships between ambient temperature, group size and energy expenditure in wild maternity colonies of Bechstein’s bats (Myotis bechsteinii). Bats used behavioural and physiological adjustments to regulate energy expenditure. Whether bats maintained normothermia or used torpor, the number of bats in the roosts as well changed with reproductive status and ambient temperature. During pregnancy and lactation, bats remained mostly normothermic and daily group sizes were relatively large, presumably to participate in the energetic benefits of social thermoregulation. In contrast, smaller groups were formed on days when bats used torpor, which occurred mostly during the post-lactation period. Thus, we were able to demonstrate on wild animals under natural conditions the significance of behavioural and physiological flexibility for optimal thermoregulatory behaviour in small endotherms.     

Out of Africa: Fossils shed light on the origin of the hoatzin,an iconic Neotropic bird

We describe the earliest fossils of the enigmatic avian taxon Opisthocomiformes (hoatzins) from the Oligo-Miocene (22–24 mya) of Brazil. The bones, a humerus, scapula and coracoid, closely resemble those of the extant hoatzin, Opisthocomus hoazin. The very similar osteology of the pectoral girdle in the new Brazilian fossil compared to the extant O. hoazin, in which it reflects peculiar feeding adaptations, may indicate that hoatzins had already evolved their highly specialized feeding behavior by the mid-Cenozoic. We further show that Namibiavis senutae from the early Miocene of Namibia is another, previously misclassified representative of Opisthocomiformes, which documents that the extant Neotropic distribution of hoatzins is relictual. Because of the weak flight capabilities of hoatzins, their occurrence on both sides of the South Atlantic is of particular biogeographic interest. We detail that this distribution pattern is best explained by dispersal from Africa to South America, and that Opisthocomiformes provide the first example of transatlantic rafting among birds.     

Dissolution kinetics of high explosives particles in a saturated sandy soil

Solid phase high explosive (HE) residues from munitions detonation may be a persistent source of soil and groundwater contamination at military training ranges. Saturated soil column tests were conducted to observe the dissolution behavior of individual components (RDX, HMX, and TNT) from two HE formulations (Comp B and C4). HE particles dissolved readily, with higher velocities yielding higher dissolution rates, higher mass transfer coefficients, and lower effluent concentrations. Effluent concentrations were below solubility limits for all components at superficial velocities of 10-50 cm day(-1). Under continuous flow at 50 cm day(-1), RDX dissolution rates from Comp B and C4 were 34.6 and 97.6 microg h(-1) cm(-2) (based on initial RDX surface area), respectively, significantly lower than previously reported dissolution rates. Cycling between flow and no-flow conditions had a small effect on the dissolution rates and effluent concentrations; however, TNT dissolution from Comp B was enhanced under intermittent-flow conditions. A model that includes advection, dispersion, and film transfer resistance was developed to estimate the steady-state effluent concentrations.