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681.
Oihana Barrutia Carlos Garbisu José Ignacio García-Plazaola 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1710-270
Two common sorrel (Rumex acetosa) accessions, one from a Zn-Pb contaminated site (CS accession) and the other from an uncontaminated site (UCS accession), were hydroponically exposed to a mixture of heavy metals (Pb2+ + Zn2+ + Cd2+) with and without EDTA at an equimolar rate. The metallicolous CS accession showed a higher tolerance to metal treatment in the absence of the chelating agent, whereas the UCS accession was especially tolerant to EDTA treatment alone. Combination of metal and EDTA treatment resulted in a higher Pb accumulation in shoots of both accessions although plants hardly showed phytotoxic symptoms. Cd and Zn uptake was not augmented by EDTA addition to the polymetallic medium. Chelant-assisted Pb accumulation was 70% higher in the CS accession than in the UCS accession, despite the fact that the former accession evapotranspired less water than the UCS accession. These results support the existence of a non-selective apoplastic transport of metal chelates by R. acetosa roots, not related to transpiration stream. 相似文献
682.
生态环境的恶化已引起各国重视,我国生态环境问题表现在水资源短缺、水土流失、工业污染、森林毁坏及生态物种减少诸方面。我国对于改善生态环境作了很大的努力,我们应该坚持走发展的道路,但在发展的进程中要注意保护环境,即坚持可持续发展。 相似文献
683.
Juan C. Alonso Carlos Palacín Javier A. Alonso Carlos A. Martín 《Behavioral ecology and sociobiology》2009,63(12):1705-1715
Radio tracking of 142 males captured at 44 leks in Spain showed that partial migration of great bustard males in summer is
a widespread behaviour in many Iberian populations, in contrast to their previously assumed sedentariness. A variable number
of males migrated immediately after mating to summering areas with lower temperatures and human population densities and more
trees and rainfall levels than the breeding sites. Birds selected there fields with trees and sunflower crops which provided
shade during the hottest midday hours and protective cover against predators. Males breeding in areas with higher July temperatures
had a higher tendency to migrate, and males from hotter, southern regions migrated longer distances than those from milder,
northern regions and showed a preferred northward direction. These results confirmed various predictions from the weather
sensitivity hypothesis, suggesting that summer migration of great bustard males represents primarily an adaptation to escape
the summer heat of most breeding areas in central and southern Iberia. The hypothesis that males migrated to benefit from
higher food availability at the summering areas could not be rejected by our results. Finally, migrating males also gained
more tranquillity during the post-breeding moult due to the lower human population density at the summering areas. Summer
migration of Iberian great bustard males may thus be interpreted as a form of behavioural thermoregulation which has not been
described for other Palaearctic populations of this species or for other bird species breeding in temperate latitudes. 相似文献
684.
Guilherme da Silva Bertolaccini Idinei Francisco Pires de Carvalho Filho Gustavo Christofoletti Luis Carlos Paschoarelli 《International journal of occupational safety and ergonomics》2018,24(2):311-315
Introduction. Wheelchair configuration is an important factor influencing the ergonomics of the user–device interface and, from a biomechanical point of view, small changes in chair setup may have a positive influence on the demand on the upper limbs during manual propulsion. This study aimed to investigate the influence of the position of the rear wheels’ axle and the use of accessories on the activity of upper limb muscles during manual wheelchair propulsion. Methods. Electromyography signals of the biceps, triceps, anterior deltoids and pectoralis major were collected for 11 able-bodied subjects in a wheelchair propulsion protocol with four different wheelchair configurations (differing in axle position and the use of accessories) on a straightforward sprint and a slalom course. Results. With accessories, moving the axle forward led to a decrease in the activity of all muscles in both the straightforward sprint (significant differences in triceps, anterior deltoids and biceps) and the slalom course (significant difference in anterior deltoids and biceps). However, when propelling the chair without accessories, no difference was found related to axle position. Conclusion. Changes in wheelchair configuration can influence the ergonomics of manual wheelchair propulsion. Reducing the biomechanical loads may benefit users’ mobility, independence and social participation. 相似文献
685.
Thaissa Sobreiro Carlos Edwar de Carvalho Freitas Karen Lorena Prado Fabíola Aquino do Nascimento Rafaela Vicentini Aprígio Mota Moraes 《Environment, Development and Sustainability》2010,12(6):1013-1024
We evaluated the implementation of a fishing agreement, which was created by negotiation among all users of the resources
as a co-management strategy because its definition was a result of meetings between all users of the resources. The fishing
agreement was implemented in Unini River, a tributary of the right bank of Negro River. Our approach was based on the perception
of the people who live in that area, called ribeirinhos. The management strategy was based on spatial distribution of the
different types of fishing. We used two logistic regression models to identify the variables which are important to determine
the previous concordance and satisfaction with the agreement. First, we analyzed the initial effort to implement the agreement.
The variable that influenced the decision of support for the agreement and satisfaction with the results of agreement in both
models was the distance from the interviewee’s residence to the sport fishing area. The results showed that the perception
of improvement in well-being of the communities and structured social organization are crucial for the success of the co-management
strategy. 相似文献
686.
Queen conch, Strombus gigas, is a commercially important gastropod that has been exploited throughout the Caribbean islands for thousands of years. Shell
middens in the region are the physical record of a long-term fishery and their study can provide valuable information on selectivity
patterns followed by fishermen and on resulting morphological shifts reflected by shells. In this study, we surveyed 27 middens
located at Los Roques, Venezuela, to assess pre-Columbian and modern fisheries and measure their impact on local populations
of queen conch. Pre-Columbian middens, covering a period of approximately 350 years of exploitation (1160–1540 A.D.), were
mostly composed of adult shells (89%) and mean length of catch was estimated at 22.4 ± 0.2 cm (mean ± SE). A decrease in mean
length of catch was observed throughout the modern fishery regime, estimated at 22.2 ± 0.3 cm in 1950–1971 and 20.0 ± 0.3 cm
in 1990–1995. Higher proportions of immature individuals ranging from 48 to 67% were found in modern middens. Additionally,
a decrease in mean length of mature individuals was detected throughout the modern fishery regime. The appearance of younger
and smaller specimens is considered as a sign of heavy exploitation of local populations of queen conch during modern fisheries.
Pre-Columbian middens in contrast, permitted to establish a relative baseline from which to compare values registered throughout
modern times. 相似文献
687.
The physical factors that constrain the vertical foraging excursions of the keystone predator, the sea star Pisaster ochraceus, hold considerable interest because they indirectly shape the vivid patterns of zonation of rocky shore communities by impeding
or enhancing the ability of P. ochraceus to traverse the intertidal zone. In this paper, we describe a study conducted in the Pacific Northwest of North America in
which we examined, in the field and laboratory, the abiotic factors that can affect vertical excursions by P. ochraceus. Our field observations revealed that the extreme upward reach and average shore level height reached by P. ochraceus were significantly lower for daylight high tides than nocturnal high tides. Based on diver observations following a severe
storm, it would also appear that these diurnal movements can be impeded by freshwater incursions into the intertidal zone;
a regularly occurring event in the Pacific Northwest. As part of an experimental investigation into this phenomenon, we observed
that sea stars maintained in tall cylindrical aquaria, without tidal flux, remained near the bottom during daylight and moved
to the top of the column at night, suggesting that photoperiod alone can influence the cycle of vertical movement. Adding
a freshwater layer to the aquaria restricted these vertical excursions. Our results suggest that on rocky coastlines susceptible
to fresh water incursions, the suppression of foraging may be an important factor in the spatial and temporal variation in
the intensity of predation. Furthermore, given the relative increase in frequency and intensity of freshwater incursions in
the Pacific Northwest and the intolerance of P. ochraceus to lowered salinity, there is the long-term potential to significantly alter patterns of species zonation in this essential
marine habitat. 相似文献
688.
Marine protected areas are not established in an institutional and governance vacuum and managers should pay attention to the wider social–ecological system in which they are immersed. This article examines Islas Choros-Damas Marine Reserve, a small marine protected area located in a highly productive and biologically diverse coastal marine ecosystem in northern Chile, and the interactions between human, institutional, and ecological dimensions beyond those existing within its boundaries. Through documents analysis, surveys, and interviews, we described marine reserve implementation (governing system) and the social and natural ecosystem-to-be-governed. We analyzed the interactions and the connections between the marine reserve and other spatially explicit conservation and/or management measures existing in the area and influencing management outcomes and governance. A top-down approach with poor stakeholder involvement characterized the implementation process. The marine reserve is highly connected with other spatially explicit measures and with a wider social–ecological system through various ecological processes and socio-economic interactions. Current institutional interactions with positive effects on the management and governance are scarce, although several potential interactions may be developed. For the study area, any management action must recognize interferences from outside conditions and consider some of them (e.g., ecotourism management) as cross-cutting actions for the entire social–ecological system. We consider that institutional interactions and the development of social networks are opportunities to any collective effort aiming to improve governance of Islas Choros-Damas marine reserve. Communication of connections and interactions between marine protected areas and the wider social–ecological system (as described in this study) is proposed as a strategy to improve stakeholder participation in Chilean marine protected areas. 相似文献
689.
Kuntala Lahiri-Dutt Keith Slack Secretariat of the IGCP Programme Lauren Baker Dr. Timothy J. Downs Jeffrey A. McNeely Prof. Tulus Tambunan M. S. Iftekhar Dr. Daniel Franks Prof. Waldemar Souza Simon M. Munthali Dr. Oscar Wambuguh Sylvanus S. P. Doe Carlos C. Peiter Roberto C. Villas Boas 《Natural resources forum》2009,33(3):245-249