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Effects of Roadway Crossings on Leaf Litter Processing and Invertebrate Assemblages in Small Streams
The effects of the Maine Turnpike (Interstate 95) on leaf litter processing were examined in five first- and second-order coastal plain streams in southern Maine, U.S.A. Invertebrate assemblages and red maple leaf softening and loss rates were compared at 53 stations arrayed upstream and downstream of the turnpike. Litter softening rate was not affected by the roadway. Litter loss rate was significantly faster at downstream stations (-0.0024 degree-day(-1)) than at upstream stations or at stations nearest the roadway, which were not different from each other (-0.0022 degree-day(-1)). Litter softening and loss rates were more strongly related to physical and chemical habitat variables than to shredder assemblage characteristics. Significant among-stream differences were observed in most community structural metrics and in biomass of important shredder taxa, but effects of the roadway were rarely consistent among streams. This is attributed in part to habitat variation, which was greater among streams than within streams. This study suggests that while the presence of the Maine Turnpike may influence stream water quality and habitat structure, the relatively subtle effects of roadway runoff and associated habitat modifications on stream ecosystem processes are masked by within- and among-stream variability in litter processing and leaf pack invertebrate assemblage structure. 相似文献
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Vollenweider P Woodcock H Kelty MJ Hofer RM 《Environmental pollution (Barking, Essex : 1987)》2003,125(3):467-480
Leaf ozone symptoms in natural ecosystems are increasingly reported but ozone effects on tree growth and the mediation of site conditions are still little documented. This study tests two hypotheses: (1) leaf injury in black cherry is associated with decline in radial growth, (2) symptoms are more prevalent on mesic sites. On sites supporting black cherry across Massachusetts, tree growth and leaf ozone injury were surveyed in 1996 using a randomized plot network established in the 1960s. Forty-seven percent of 120 trees sampled for ozone symptoms were symptomatic with generally low levels of injury. Over a 31-year period symptomatic trees had 28% lower stem growth rates than asymptomatic trees. Ozone symptom expression was enhanced in well growing stands on moister, cooler and more elevated sites. Ozone appeared to increase environmental stress and had a more pronounced effect on growth in better growing black cherry stands. This complicates management decisions as thinning increases growth and moisture availability. 相似文献
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Engineering line diagram development from process flowsheets: Part 1: Shortfalls in current practice
S. Long P. D. B. Bujac D. C. Woodcock M. L. Preston A. G. Rushton I. W. Cumming 《Journal of Loss Prevention in the Process Industries》2000,13(6):459-465
Engineering line diagram (ELD) development forms a distinct phase in process plant design. It is a complex and expensive activity and as such warrants considerable effort to minimise costs and maximise effectiveness. In this paper, the nature of the ELD design task is analysed in order to understand how it could be carried out more effectively. A number of shortfalls in current practice are discussed. These shortfalls were identified through a combination of the following activities: a review of the literature; a survey of current practice and follow-up line diagram development exercise; and task analysis work carried out at ICI. The most significant findings of the survey of current practice are presented. It is proposed that the shortfalls identified can be overcome by introducing structure to the design task. The manner in which this can be achieved is the subject of the second part of this paper. 相似文献
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Thomas S. Woodcock Laura J. Pekkola Cara Dawson Fawziah L. Gadallah Peter G. Kevan 《Environmental monitoring and assessment》2014,186(8):5041-5057
The value of pollination to human society is not limited to agricultural production, but also in the sustainability of ecosystems and the services that they provide. Seed set can be used as a comparative measure of pollination effectiveness, with minimum variability expected when other resources are not limiting. Six species of self-incompatible fall asters (Symphyotrichum) were used to evaluate pollination service at 12 sites across a spectrum of expected levels of pollination. Seed set per inflorescence was generally lower at sites with lower pollinator numbers and diversity, although as expected pollinator assemblage characteristics were highly variable within and between sites. However, rankings of sites showed consistency of response across phytometer species and between years; the summed ranks across multiple species appears to have as the greatest value in Pollination Service Measurement (PSM). Abundance, richness, and Shannon diversity of pollinator assemblages were highly autocorrelated and showed variable relationships with seed set depending on plant species and temporal scale of pollinator assemblage assessment. Use of seed set to directly measure pollination service at a site was consistent and cost effective when compared to less certain and more labour-intensive methods of pollinator collection and identification, and shows promise for implementation in pollination monitoring and bioassessment practices. 相似文献
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Making literature reviews more reliable through application of lessons from systematic reviews
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Review articles can provide valuable summaries of the ever‐increasing volume of primary research in conservation biology. Where findings may influence important resource‐allocation decisions in policy or practice, there is a need for a high degree of reliability when reviewing evidence. However, traditional literature reviews are susceptible to a number of biases during the identification, selection, and synthesis of included studies (e.g., publication bias, selection bias, and vote counting). Systematic reviews, pioneered in medicine and translated into conservation in 2006, address these issues through a strict methodology that aims to maximize transparency, objectivity, and repeatability. Systematic reviews will always be the gold standard for reliable synthesis of evidence. However, traditional literature reviews remain popular and will continue to be valuable where systematic reviews are not feasible. Where traditional reviews are used, lessons can be taken from systematic reviews and applied to traditional reviews in order to increase their reliability. Certain key aspects of systematic review methods that can be used in a context‐specific manner in traditional reviews include focusing on mitigating bias; increasing transparency, consistency, and objectivity, and critically appraising the evidence and avoiding vote counting. In situations where conducting a full systematic review is not feasible, the proposed approach to reviewing evidence in a more systematic way can substantially improve the reliability of review findings, providing a time‐ and resource‐efficient means of maximizing the value of traditional reviews. These methods are aimed particularly at those conducting literature reviews where systematic review is not feasible, for example, for graduate students, single reviewers, or small organizations. 相似文献
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Raffaele Sasso Luigi Iodice Christine M. Woodcock John A. Pickett Emilio Guerrieri 《Chemoecology》2009,19(4):195-201
Flight responses of the aphid parasitoid Aphidius ervi to tomato volatiles have recently demonstrated that different plant stresses can lead to increases in attractiveness for
this parasitoid. For example, infestation of tomato plants by the aphid Macrosiphum euphorbiae results in the overexpression of defensive genes, as well as the release of volatile compounds that attract aphid parasitoids.
Here, we determine which of the induced compounds elicit a significant electrophysiological response from parasitoid antennae.
Compounds shown to be detected at the antennal level were then tested at a range of doses in a wind tunnel assay. A significant
electroantennogram response was demonstrated for three compounds, (8S,9R)-(E)-caryophyllene, methyl salicylate, and (Z)-3-hexen-1-ol, over four concentrations. These compounds proved to be significantly attractive in the wind tunnel at a rate
not always proportionally dependent upon the dose. The practical implications of these findings are discussed in the framework
of sustainable control for pest aphids in agriculture. 相似文献
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M. Subchev T. Toshova C. Koshio S. Franke A. Tröger R. Twele W. Francke J. A. Pickett L. J. Wadhams C. M. Woodcock 《Chemoecology》2009,19(1):47-54
The plum moth, Illiberis rotundata Jordan (Lepidoptera: Zygaenidae: Procridinae), is a pest of orchards in Japan and China. Few chemical ecological studies
have been directed towards the Zygaenidae and particularly the Procridinae. To investigate the sex pheromone of this species,
extracts of pheromone glands from adult female I. rotundata were analyzed by coupled gas chromatography-electroantennography (GC-EAG) and coupled gas chromatography-mass spectrometry
(GC-MS). Whilst GC-EAG on male moths showed an active peak, identified as 2-butyl (7Z)-dodecenoate, GC-MS also revealed the presence of the homologue 2-butyl (9Z)-tetradecenoate. Electroantennographic investigations, as well as field tests, strongly suggested the natural compounds to
have the (R)-configuration at the stereogenic centre. Field results demonstrate 0.2 mg of a 1:1-mixture of (2R)-butyl (7Z)-dodecenoate and (2R)-butyl (9Z)-tetradecenoate to be a powerful lure that may be used in pest control measures against I. rotundata. The chemical structures of the new pheromone components show the same features as those of other zygaenid species: unsaturated
fatty acids esterified with a short chain chiral alcohol. This is the first example of a two-component blend constituting
the pheromone of a procridinid species. 相似文献