The intraspecific patterns of morphometric variation were examined in Fucus distichus L. and F. evanescens C.Ag., using samples gathered from 49 sites spread across the North Atlantic. Ten characters were measured on each plant. The data were subjected to bivariate regression analyses, canonical correlation analysis and nested analysis of variance (ANOVA). It was shown that the combined effects of the three environmental variables measured for each site (latitude, longitude and exposure) could only explain 23 and 15% respectively of the intraspecific morphometric variation. Inter-individual, within-site differences accounted for a further 62 and 53%. The remaining variation appears to be expressed on a geographic scale of tens of kilometres at most. Thus, the species seem to take the form of fine-scale phenotypic mosaics, superimposed on weak major clines. Such a pattern has not previously been described for any macroalga, although it is known in some angiosperms. 相似文献
Despite efforts to enclose and control conservation zones around the world, direct human impacts in conservation areas continue,
often resulting from clandestine violations of conservation rules through outright poaching, strategic agricultural encroachment,
or noncompliance. Nevertheless, next to nothing is actually known about the spatially and temporally explicit patterns of
anthropogenic disturbance resulting from such noncompliance. This article reviews current understandings of ecological disturbance
and conservation noncompliance, concluding that differing forms of noncompliance hold differing implications for diversity.
The authors suggest that forms of anthropogenic patchy disturbance resulting from violation may maintain, if not enhance,
floral diversity. They therefore argue for extended empirical investigation of such activities and call for conservation biologists
to work with social scientists to assess this conservation reality by analyzing how and when incomplete enforcement and rule-breaking
drive ecological change. 相似文献
Despite compelling reasons to involve nonscientists in the production of ecological knowledge, cultural and institutional factors often dis-incentivize engagement between scientists and nonscientists. This paper details our efforts to develop a biweekly newspaper column to increase communication between ecological scientists, social scientists, and the communities within which they work. Addressing community-generated topics and written by a collective of social and natural scientists, the column is meant to foster public dialog about socio-environmental issues and to lay the groundwork for the coproduction of environmental knowledge. Our collective approach to writing addresses some major barriers to public engagement by scientists, but the need to insert ourselves as intermediaries limits these gains. Overall, our efforts at environmental communication praxis have not generated significant public debate, but they have supported future coproduction by making scientists a more visible presence in the community and providing easy pathways for them to begin engaging the public. Finally, this research highlights an underappreciated barrier to public engagement: scientists are not merely disconnected from the public, but also connected in ways that may be functional for their research. Many field scientists, for example, seek out neutral and narrowly defined connections that permit research access but are largely incompatible with efforts to address controversial issues of environmental governance. 相似文献
Tire wear particles filed from the treads of end-of-life vehicle tires have been added to sea water to examine the release of Zn and the toxicity of the resulting leachate and dilutions thereof to the marine macroalga, Ulva lactuca. Zinc release appeared to be diffusion-controlled, with a conditional rate constant of 5.4 μg[L(h)1/2]−1, and about 1.6% of total Zn was released after 120 h incubation. Exposure to increasing concentrations of leachate resulted in a non-linear reduction in the efficiency of photochemical energy conversion of U. lactuca and, with the exception of the undiluted leachate, increasing accumulation of Zn. Phototoxicity was significantly lower on exposure to equivalent concentrations of Zn added as Zn(NO3)2, suggesting that organic components of leachate are largely responsible for the overall toxicity to the alga. Given the ubiquity and abundance of TWP in urban coastal sediments, the generation, biogeochemistry and toxicity of tire leachate in the marine setting merit further attention. 相似文献
Objective: To investigate trends of motorcyclist fatalities and identify at-risk populations by motorcyclist demographics and crash characteristics.
Methods: We used the Fatality Analysis Reporting System (FARS) database (2000–2016) to track fatality rate trends, which were quantified by using Poisson mixed-effects regression models comparing 2000–2001 and 2007–2008, as well as 2009–2010 and 2015–2016.
Results: The overall fatality rate per 100,000 population increased from 2000 to 2016, defined by two trend lines—before and after the economic recession in 2008–2009. The overall fatality rate ratio between 2000–2001 and 2007–2008 was 1.60 [95% Confidence Interval (CI): 1.51–1.70], and between 2009–2010 and 2015–2016 was 1.09 (95% CI: 1.02–1.18). Fatality rates increased among all age groups, particularly for motorcyclists aged 60 and older. Those aged 18–29 had the highest fatality rates overall. Age-and-sex standardized state fatality rates were consistently highest in Wyoming, South Dakota, and South Carolina and lowest in Massachusetts, New York and New Jersey.
Conclusion: Motorcycle fatality rates increased overall and across all age groups between 2000 and 2016. Fatalities for the oldest riders showed the steadiest increasing trends. Results highlight the continued public health burden of motorcyclist fatalities and, by extension, the importance of improving motorcycle safety. 相似文献
Wood and other environmental samples were collected from sites that produced beef with higher than average residues of dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF). Analyses of these samples for PCDD/Fs and pentachlorophenol (PCP) indicated that the high beef residues were associated with PCP-treated wood in the animal facilities. Concentrations of PCDD/Fs in wood as toxic equivalents ranged from 10 to 320,000 pg/g. These concentrations were closely related to the concentrations of PCP, indicating that analysis for PCP provides an economical method to identify wood with high concentrations of PCDD/Fs. Further evidence for the PCP-treated wood as the source of the beef residues is provided by the similarity of the congener profiles in beef from the sites and those profiles predicted from the profiles in wood. 相似文献