Most hypotheses explaining the general gradient of higher diversity toward the equator are implicit or explicit about greater species packing in the tropics. However, global patterns of diversity within guilds, including trophic guilds (i.e., groups of organisms that use similar food resources), are poorly known. We explored global diversity patterns of a key trophic guild in stream ecosystems, the detritivore shredders. This was motivated by the fundamental ecological role of shredders as decomposers of leaf litter and by some records pointing to low shredder diversity and abundance in the tropics, which contrasts with diversity patterns of most major taxa for which broad-scale latitudinal patterns haven been examined. Given this evidence, we hypothesized that shredders are more abundant and diverse in temperate than in tropical streams, and that this pattern is related to the higher temperatures and lower availability of high-quality leaf litter in the tropics. Our comprehensive global survey (129 stream sites from 14 regions on six continents) corroborated the expected latitudinal pattern and showed that shredder distribution (abundance, diversity and assemblage composition) was explained by a combination of factors, including water temperature (some taxa were restricted to cool waters) and biogeography (some taxa were more diverse in particular biogeographic realms). In contrast to our hypothesis, shredder diversity was unrelated to leaf toughness, but it was inversely related to litter diversity. Our findings markedly contrast with global trends of diversity for most taxa, and with the general rule of higher consumer diversity at higher levels of resource diversity. Moreover, they highlight the emerging role of temperature in understanding global patterns of diversity, which is of great relevance in the face of projected global warming. 相似文献
This work describes the design of novel Cu(II) complexes and their application in the photocatalytic degradation of methylene blue (MB). The same photocatalyst exhibits antibacterial activity against Escherichia coli (gram-negative) and Bacillus circulans (gram-positive). The characterisation of the photocatalysts has been done by several up-to-date physical methods. The rationale behind the photocatalysts’ beneficial intervention is discussed in this study. Statistical analysis of the degradation of MB is done using a one-way ANOVA, and the significance of means is determined by a multiple comparison test using Turkey HSD. Also, the degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R2?>?0.95), making them useful as simple and low-cost organic dye degradation agents.
In road safety, it may be debated whether all risky behaviors are sufficiently similar to be explained by similar factors. The often assumed generalizability of the factors that influence risky driving behaviors has been inadequately tested. Study 1 (N=116) examined the role of demographic, personality and attitudinal factors in the prediction of a range of risky driving behaviors, for young drivers. Results illustrated that different driving behaviors were predicted by different factors (e.g., speeding was predicted by authority--rebellion, while drink driving was predicted by sensation seeking and optimism bias). Study 2 (N=127) examined the generalizability of these results to the general driving population. Study 1 results did not generalize. Predictive factors remained behavior-specific, but different predictor-behavior relationships were observed in the community sample. Overall, results suggest that future research and practice should focus on a multi-factor framework for specific risky driving behaviors, rather than assuming generalizability across behaviors and driving populations. 相似文献
Mechanisms for evaluating system sustainability should allow for the consideration of three main parameters: social, economic and environmental. While, there are methods for comparing processes, projects or systems on the basis of environmental impact or cost, few incorporate all three parameters into the decision process. Life cycle index (LInX) is an indexing system that is meant to simplify the decision making process by incorporating a life cycle based approach with components of sustainability and safety. Although LInX was designed for large industrial systems, this paper presents the application on a small anaerobic digestion (AD) unit on a dairy farm in Clymer, New York. An AD unit can be used to generate electricity from the combustion of biogas produced from organic waste. From the analysis, the AD unit performed well on environmental and cost parameters, but not as well on risk and social parameters. However, the AD unit performed similar to natural gas and biomass-based production. One recommendation for the method is that consideration be given to modifying parameters and weightings to suit agriculture and location specific needs. 相似文献