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排序方式: 共有291条查询结果,搜索用时 328 毫秒
181.
Elie Gaget Alison Johnston Diego Pavón-Jordán Aleksi S. Lehikoinen Brett K. Sandercock Alaaeldin Soultan Luka Božič Preben Clausen Koen Devos Cristi Domsa Vitor Encarnação Sándor Faragó Niamh Fitzgerald Teresa Frost Clemence Gaudard Lívia Gosztonyi Fredrik Haas Menno Hornman Tom Langendoen Christina Ieronymidou Leho Luigujõe Włodzimierz Meissner Tibor Mikuska Blas Molina Zuzana Musilová Jean-Yves Paquet Nicky Petkov Danae Portolou Jozef Ridzoň Laimonas Sniauksta Antra Stīpniece Norbert Teufelbauer Johannes Wahl Marco Zenatello Jon E. Brommer 《Conservation biology》2022,36(4):e13877
Protected area networks help species respond to climate warming. However, the contribution of a site's environmental and conservation-relevant characteristics to these responses is not well understood. We investigated how composition of nonbreeding waterbird communities (97 species) in the European Union Natura 2000 (N2K) network (3018 sites) changed in response to increases in temperature over 25 years in 26 European countries. We measured community reshuffling based on abundance time series collected under the International Waterbird Census relative to N2K sites’ conservation targets, funding, designation period, and management plan status. Waterbird community composition in sites explicitly designated to protect them and with management plans changed more quickly in response to climate warming than in other N2K sites. Temporal community changes were not affected by the designation period despite greater exposure to temperature increase inside late-designated N2K sites. Sites funded under the LIFE program had lower climate-driven community changes than sites that did not received LIFE funding. Our findings imply that efficient conservation policy that helps waterbird communities respond to climate warming is associated with sites specifically managed for waterbirds. 相似文献
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Bo Liu Jinwen Zhang Linshu Liu Arland T. Hotchkiss 《Journal of Polymers and the Environment》2011,19(3):559-567
Sugar beet pulp (SBP), the residue from sugar extraction, was compounded and turned into in situ thermoplastic composite materials.
The compounding was performed using a common twin- screw compounding extruder and water and glycerol were used as co-plasticizers.
The melt compounding of SBP utilized the water-soluble characteristics of pectin which is one of main components of SBP. The
structure of SBP was destroyed under extrusion and pectin was partially released and plasticized by water and glycerol. Scanning
electron microscopy revealed that the cellulose microfibrils were dispersed in the matrix of pectin and other ingredients.
Effects of the water and glycerol co-plasticizers on rheological, tensile and dynamic mechanical properties of the SBP plastics
were investigated. Effects of relative humidity of the environment on the tensile and dynamical mechanical properties of the
neat SBP compounds were also evaluated. The results demonstrated that SBP could be processed as a plastic with water and glycerol
as co-plasticizers using traditional processing equipments. 相似文献
186.
Zachary M. Laubach Daniel T. Blumstein L. Michael Romero Greg Sampson Johannes Foufopoulos 《Behavioral ecology and sociobiology》2013,67(3):481-492
Status badges, such as crown plumage, mediate intraspecific interactions. The reliability of crown morphology as a status badge in male mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) is uncertain. We examined morphological and physiological correlates of the proportion of crown that was white (“crown-white”) in 178 male mountain white-crowned sparrows during the 2008–2009 breeding seasons. Using a paired experimental design, we presented territory-holding males with white-enhanced and white-reduced decoys and recorded aggressive behaviors. To assess physiological constraints on signal bluffing, a subsample of birds was captured and released after manipulating natural crowns to simulate bluffed white-enhanced or white-reduced crowns; corticosterone concentrations were assayed from blood drawn upon recapture and after a restraint-induced stressor. We found a significant positive association between crown-white and a measure of body size—tarsus length—which is an established indicator of resource-holding potential. In the decoy challenge, males responded more aggressively toward white-enhanced than white-reduced decoys. In the hormone experiment, white-enhanced birds had higher baseline corticosterone levels, whereas white-reduced birds had similar concentrations to controls. Furthermore, white-enhanced birds had an attenuated restraint-induced corticosterone response, while white-reduced birds mounted a significantly larger increase in corticosterone than controls. Taken together, these findings indicate that crown-white is a reliable status badge of resource-holding potential in male mountain white-crowned sparrows during the breeding season. 相似文献
187.
This article describes the gasification of polyethylene–wood mixtures to form syngas (H2 and CO) with the aim of feedstock recycling via direct fermentation of syngas to ethanol. The aim was to determine the effects
of four process parameters on process properties that give insight into the efficiency of gasification in general, and particularly
into the optimum gasification conditions for the production of ethanol by fermentation of producer gas. Gasification experiments
(fluidized bed, 800°–950°C) were done under different conditions to optimize the composition of syngas suitable for fermentation
purposes. The data obtained were used for statistical analysis and modeling. In this way, the effect of each parameter on
the process properties was determined and the model was used to predict the optimum gasification conditions. The parameters
varied during the experiment were gasification temperature, equivalence ratio, the ratio of plastic to wood in the feed, and
the amount of steam added to the process. The response models obtained proved to be statistically significant in the experimental
domain. The optimum gasification conditions for maximization of carbon monoxide and hydrogen production were identified. The
conditions are: temperature 900°C, equivalence ratio 0.15, amount of plastic in the feed 0.11 g/g feed, and amount of steam
added 0.42 g/g feed. These optimum conditions are at the edge of the present experimental domain. The maximum combined CO
and H2 efficiency was 42%, and for the maximum yield of CO and H2 it is necessary to minimize the polyethylene content, minimize the added steam and the equivalence ratio, and maximize temperature. 相似文献
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