Many questions relevant to conservation decision-making are characterized by extreme uncertainty due to lack of empirical data and complexity of the underlying ecologic processes, leading to a rapid increase in the use of structured protocols to elicit expert knowledge. Published ecologic applications often employ a modified Delphi method, where experts provide judgments anonymously and mathematical aggregation techniques are used to combine judgments. The Sheffield elicitation framework (SHELF) differs in its behavioral approach to synthesizing individual judgments into a fully specified probability distribution for an unknown quantity. We used the SHELF protocol remotely to assess extinction risk of three subterranean aquatic species that are being considered for listing under the U.S. Endangered Species Act. We provided experts an empirical threat assessment for each known locality over a video conference and recorded judgments on the probability of population persistence over four generations with online submission forms and R-shiny apps available through the SHELF package. Despite large uncertainty for all populations, there were key differences between species’ risk of extirpation based on spatial variation in dominant threats, local land use and management practices, and species’ microhabitat. The resulting probability distributions provided decision makers with a full picture of uncertainty that was consistent with the probabilistic nature of risk assessments. Discussion among experts during SHELF's behavioral aggregation stage clearly documented dominant threats (e.g., development, timber harvest, animal agriculture, and cave visitation) and their interactions with local cave geology and species’ habitat. Our virtual implementation of the SHELF protocol demonstrated the flexibility of the approach for conservation applications operating on budgets and time lines that can limit in-person meetings of geographically dispersed experts. 相似文献
Selenium (Se) biofortification of staple cereal crops can improve the Se nutritional status of populations. A field trial employing an enriched stable isotope of Se (77Se) was undertaken over three consecutive cropping seasons in a coarse-textured, calcareous soil in Gilgit-Baltistan, Pakistan. The objectives were to (1) assess the feasibility and efficiency of Se biofortification, (2) determine the fate of residual Se, and (3) assess the consequences for dietary Se intake. Isotopically enriched 77Se (77SeFert) was applied, either as selenate or as selenite, at three levels (0, 10, and 20 g ha?1) to a wheat crop. Residual 77SeFert availability was assessed in subsequent crops of maize and wheat without further 77SeFert addition. Loss of 77SeFert was c.35% by the first (wheat) harvest, for both selenium species, attributable to the practice of flood irrigation and low adsorption capacity of the soil. No 77SeFert was detectable in subsequent maize or wheat crops. The remaining 77SeFert in soil was almost entirely organically bound and diminished with time following a reversible (pseudo-)first-order trend. Thus, repeat applications of Se would be required to adequately biofortify grain each year. In contrast to native soil Se, there was no transfer of 77SeFert to a recalcitrant form. Grain from control plots would provide only 0.5 µg person?1 day?1 of Se. By contrast, a single application of 20 g ha?1 SeVI could provide c. 47 µg person?1 day?1 Se in wheat, sufficient to avoid deficiency when combined with dietary Se intake from other sources (c. 25 µg day?1).
Upon encountering predators, many animals produce specific vocalisations that alert others and sometimes dissuade the predators
from hunting. Callicebus monkeys are known for their large vocal repertoire, but little is known about the function and meaning of most call types.
We recorded a large number of natural predator responses from five different groups of black-fronted titi monkeys in their
Atlantic forest habitat in South Eastern Brazil. When detecting predatory threats, adult group members responded with call
sequences that initially consisted of two brief, high-pitched calls with distinct frequency contours. Call A was mainly given
to raptors but also to predatory capuchin monkeys and other threats within the canopy, while call B was given to predatory
or non-predatory disturbances on the ground. In later parts of the sequences, we also recorded a high-pitched unmodulated
call C and various low-pitched loud calls. Results therefore suggest that calls A and B provide listeners with rapid and reliable
information about the general classes of danger experienced by the caller, while obtaining more specific information through
other call types and combinations and behavioural responses. We discuss these findings in relation to current evolutionary
theory of primate communication. 相似文献
Airborne in-situ measurements were analyzed to investigate the effects of biomass burning and regional background aerosols on cloud condensation nuclei (CCN) activity in the Pacific Dust Experiment (PACDEX) during April and May 2007. Airmass trajectories with both horizontal and vertical motions were provided to identify the aerosol sources. In the biomass burning cases, the elevated aerosol layers were clearly observed at dry conditions because of the convection of airmass in the source region. The relative aging of aerosols was supported by the ratios of BC to particles with size ranging from 0.1 to 1.0 μm (N0.1–1.0) and BC to carbon monoxide. Compared to aerosols in the precedent plume of biomass burning, aged particles in the latter plume were more activated to CCN at 0.4% (CCN0.4%) than 0.1% supersaturation (CCN0.1%) due to aerosols chemical modification during the aging process. On the other hand, significant difference of CCN0.4% and CCN0.1% at regional background aerosols over the Pacific Ocean was due to the activated particles below 1 μm in diameter. Although higher concentrations of aged particles were observed over the eastern Pacific Ocean, activated aerosols to cloud droplet was comparatively similar in the western Pacific Ocean because of the similar concentrations of N0.1–1.0 in both cases. 相似文献
Heavy application of highly toxic synthetic pesticides has been committed to protect crops against insects and diseases, which
have brought about serious environmental problems. Thus, an inevitable and fundamental issue has been how to protect crops
without harmful effects on nature. As a fascinating nature-compatible approach, we have attempted to hybridize soil-compatible
layered double hydroxides (LDHs) with natural antibiotic substances. Only a few of natural antibiotic substances are available
for pest control mainly because of their inherent properties such as easy degradability, high minimum inhibition concentration
for practical application, and often extremely low availability, whereas LDHs exhibit unique properties such as anion exchange
capacity, acid lability, and high affinity to ubiquitous carbonate ion which make them an excellent inorganic matrix to carry
labile biomolecules in soils. This study focuses on the behavior of cinnamate–LDH hybrid in soils and the evaluation of its
potentials as a green pesticide. 相似文献
Polylactic acid (PLA) has been modified by electron beam radiation in the presence of glycidyl methacrylate (GMA) to enhance
the melt strength of PLA. The modified PLA was prepared by varying both the amount of GMA and the irradiation dose and was
characterized by observing the thermal properties, the melt viscoelastic properties and the gel fraction. For comparison,
virgin PLA was also irradiated. All irradiated virgin PLA had a lower complex viscosity and a storage modulus compared to
virgin PLA due to irradiation-induced chain scission. However, these properties were remarkably improved due to formation
of long chain branching and retarding chain scission if GMA was introduced in this system. The increase in melt viscoelastic
property was much dependent on the irradiation dose. At optimum doses of radiation, it showed maximum complex viscosity and
storage modulus. The PLA irradiated with 20 kGy in the presence of 3 phr GMA showed a complex viscosity of about 10 times
higher and a storage modulus of 100 times higher than those of virgin PLA at 0.1 rad/s. Gel fraction measurement revealed
that chain scission and branching was more dominant than crosslinking. The biodegradability of irradiated PLA was slightly
decreased by the presence of GMA. 相似文献
In this study, the cost-benefit analysis technique was developed and incorporated into the Taguchi experimental design to determine the optimal operation combination for the purpose of providing a technique solution for controlling both emissions of PCDD/Fs and PAHs, and increasing both the sinter productivity (SP) and sinter strength (SS) simultaneously. Four operating parameters, including the water content, suction pressure, bed height, and type of hearth layer, were selected and all experimental campaigns were conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. The resultant optimal combination could reduce the total carcinogenic emissions arising from both emissions of PCDD/Fs and PAHs by 49.8%, and increase the sinter benefit associated with the increase in both SP and SS by 10.1%, as in comparison with the operation condition currently used in the real plant. The ANOVA results indicate that the suction pressure was the most dominant parameter in determining the optimal operation combination. The above result was theoretically plausible since the higher suction pressure provided more oxygen contents leading to the decrease in both PCDD/F and PAH emissions. But it should be noted that the results obtained from the present study were based on pilot scale experiments, conducting confirmation tests in a real scale plant are still necessary in the future. 相似文献