Landscape-level influences of terrestrial snake occupancy within the southeastern United States

Habitat loss and degradation are thought to be the primary drivers of species extirpations, but for many species we have little information regarding specific habitats that influence occupancy. Snakes are of conservation concern throughout North America, but effective management and conservation are hindered by a lack of basic natural history information and the small number of large-scale studies designed to assess general population trends. To address this information gap, we compiled detection/nondetection data for 13 large terrestrial species from 449 traps located across the southeastern United States, and we characterized the land cover surrounding each trap at multiple spatial scales (250-, 500-, and 1000-m buffers). We used occupancy modeling, while accounting for heterogeneity in detection probability, to identify habitat variables that were influential in determining the presence of a particular species. We evaluated 12 competing models for each species, representing various hypotheses pertaining to important habitat features for terrestrial snakes. Overall, considerable interspecific variation existed in important habitat variables and relevant spatial scales. For example, kingsnakes (Lampropeltis getula) were negatively associated with evergreen forests, whereas Louisiana pinesnake (Pituophis ruthveni) occupancy increased with increasing coverage of this forest type. Some species were positively associated with grassland and scrub/shrub (e.g., Slowinski's cornsnake, Elaphe slowinskii) whereas others, (e.g., copperhead, Agkistrodon contortrix, and eastern diamond-backed rattlesnake, Crotalus adamanteus) were positively associated with forested habitats. Although the species that we studied may persist in varied landscapes other than those we identified as important, our data were collected in relatively undeveloped areas. Thus, our findings may be relevant when generating conservation plans or restoration goals. Maintaining or restoring landscapes that are most consistent with the ancestral habitat preferences of terrestrial snake assemblages will require a diverse habitat matrix over large spatial scales.     

Dynamics of pheromone production and communication in the mountain pine beetle, Dendroctonus ponderosae Hopkins, and the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae)

Summary. The mountain pine beetle, Dendroctonus ponderosae Hopkins, and the pine engraver, Ips pini (Say), often co-exist in lodgepole pine, Pinus contorta var. latifolia Engelmann. Intra- and interspecific semiochemical communication occurs in both species and their complete semiochemical repertoire and precise dynamics of pheromone production have not been elucidated. Porapak-Q extracts of captured volatiles from beetles of each species aerated at different attack phases (freshly emerged, pioneer sex alone in the log and both sexes paired in new galleries), followed by gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectroscopic analyses identified 17 compounds (seven compounds common to both species, six present in D. ponderosae and four present in I. pini) that excited the antennae of either or both species. Seven compounds for D. ponderosae and nine for I. pini had not been assessed for behavioural activity. In field trapping experiments, 2-phenylethanol produced by both species inhibited the response of D. ponderosae to its aggregation pheromones. exo- and endo-Brevicomin produced by D. ponderosae significantly decreased the response of I. pini to its aggregation pheromone ipsdienol. Nonanal, a ubiquitous compound found in the volatiles of lodgepole pine, various nonhosts and in both beetle species deterred the response of I. pini to ipsdienol. The occurrence of cis-verbenol, trans-verbenol and verbenone in emergent I. pini, and verbenone and 2-phenylethanol in emergent D. ponderosae suggests that these compounds may inhibit aggregation and induce dispersal following emergence. Termination of aggregation in D. ponderosae appears to depend on the production of frontalin in combination with changes in the relative ratios of verbenone, exo-brevicomin, trans-verbenol and 2-phenylethanol. In I. pini, the cessation of ipsdienol production by males is probably the main factor in terminating aggregation. Received 16 November 1999; accepted 7 August 2000     

The mechanism of crustacean salinity tolerance: Cell volume regulation by K+ and glycine effluxes

The regulation of muscle fiber K⁺ and free amino acid (FAA) concentrations during hypoosmotic stress was investigated in the moderately euryhaline crab Cancer irroratus. After 6 h of exposure to 60% ASW, muscle fiber K⁺ concentration declined from 185 mM to 140 mM. Following this, the blood glycine levels began to increase, indicating an FAA efflux from the cells. These data indicate that both muscle fiber K⁺ and FAA contribute to cell volume regulation in C. irroratus. The early release of K⁺ limits the initial rate of cell hydration. The subsequent efflux of glycine accounts for the volume regulation response of the muscle fibers. The cell volume regulatory system of C. irroratus is a coordinated use of both inorganic ions and FAA.     

Biosorption of cadmium and nickel ions using marine macrophyte,Cymodocea nodosa

ABSTRACT

Seagrass (Cymodocea nodosa) ability to remove cadmium and nickel ions from single metal solutions was investigated in the present study. Metal ions were measured in the solution using an atomic absorption spectrophotometer. Various operational parameters (initial pH, biomass dose, metal ion concentration, and contact time) were tested and found to affect the uptake capacity of Cd (II) and Ni (II). More than 70% of biosorption capacity occurred in the first few minutes for both metal ions. The pseudo-second-order kinetic model and the Langmuir model were found to best fit the experimental data of Cd (II) and Ni (II) biosorption. The maximum uptake capacity (q_max) was 11.6 and 16.7?mg.g^?1 for Cd (II) and Ni (II), respectively. The biosorbent was characterised using Fourier transform infrared spectrometry (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). The infrared spectrum demonstrated that hydroxyl, carboxyl, and phenolic functional groups are the major binding sites for Cd (II) and Ni (II) metals. The ion exchange mechanism plays an important role during biosorption process as shown in EDX analysis. Our results conclude that marine macrophyte C. nodosa can be used as a low-cost biosorbent for the removal of Cd (II) and Ni (II) in wastewater.     

The in-use annual energy and carbon saving by switching from a car to an electric bicycle in an urban UK general medical practice: the implication for NHS commuters

The UK Climate Change Act (CCA) mandates an 80 % reduction in CO₂ emissions by 2050. It is estimated that 3.2 M tonnes pa CO₂ results from travel-related NHS business. The acquisition of an electric bicycle to replace a car for both commuting and home visits allowed comparison of fuel use and CO₂ emissions over a 4-year period. The switch to the use of the electric bicycle reduced the average annual petrol use by 329 l, the energy consumption by 3,140 kWh and the CO₂ released by 748 kg a year. Wider adoption of electric bicycles in urban General Practice will contribute to the requirements of the CCA though to have a significant effect on the current estimated commuting-related carbon footprint of the NHS (0.76 MT pa) would require two-thirds of the workforce to abandon their cars in favour of electric bicycles.     

Enhancing the relevance of organizational behavior by embracing performance management research

There is a science‐practice gap in organizational behavior (OB) whereby entire bodies of scholarly knowledge are ignored by practitioners. We identify research needed to improve performance management practices that is likely to enhance the relevance of OB in the eyes of practitioners and thus help reduce the science‐practice gap. Copyright © 2007 John Wiley & Sons, Ltd.