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421.
Monitoring Long-Term Ecological Changes Through the Ecological Monitoring and Assessment Network: Science-Based and Policy Relevant 总被引:2,自引:0,他引:2
Ecological monitoring and its associated research programshave often provided answers to various environmental management issues. In the face of changing environmental conditions, ecological monitoring provides decision-makers with reliable information as they grapple with maintaining a sustainable economy and healthy environment. The EcologicalMonitoring and Assessment Network (EMAN) is a national ecological monitoring network consisting of (1) about 100 casestudy sites across the country characterized by long-term multi-disciplinary environmental work conducted by a multitudeof agencies (142 partners and counting); (2) a variety of lesscomprehensive yet more extensive monitoring sites; (3) a network where core monitoring variables of ecosystem change aremeasured; and (4) geo-referenced environmental observations. Environment Canada is the co-ordinating partner for the network through the EMAN Co-ordinating Office. EMAN's mission is to focus a scientifically-sound, policy-relevant ecosystem monitoring and research network based on (a) stabilizing a network of case-study sites operated by a varietyof partners, and (b) developing a number of cooperative dispersedmonitoring initiatives in order to deliver unique and needed goods and services. These goods and services include: (1) an efficient and cost-effective early warning system which detects,describes and reports on changes in Canadian ecosystems at a national or ecozone scale; and (2) cross-disciplinary and cross-jurisdictional assessments of ecosystem status, trends and processes. The early warning system and assessments of ecosystem status, trends and processes provide Environment Canada and partner organizations with timely information thatfacilitates increasingly adaptive policies and priority setting. Canadians are also informed of changes and trends occurring in Canadian ecosystems and, as a result, are betterable to make decisions related to conservation and sustainability. 相似文献
422.
Martínez-de la Puente J Merino S Tomás G Moreno J Morales J Lobato E Martínez J 《Die Naturwissenschaften》2011,98(2):99-106
Parasites are undoubtedly a biotic factor that produces stress. Heat shock proteins (HSPs) are important molecules buffering cellular damage under adverse conditions. During the breeding season, blue tit Cyanistes caeruleus (L.) adults are affected by blood parasites, nest-dwelling parasites and biting flies, potentially affecting their HSP-mediated responses. Here, we treated females with primaquine to reduce blood parasites and fumigated nests with permethrin to reduce nest-dwelling parasites to test whether these treatments affect HSP60 level during the breeding season. Medicated females, but not controls, had a significant reduction of the intensity of infection by Haemoproteus spp. blood parasites. However, final intensity of infection did not differ significantly between groups, and we did not find an effect of medication on change in HSP60 level. Fumigation reduced the abundance of nest-dwelling parasites (mites, fleas and blowfly larvae) and engorged biting midges in nests. Females breeding in non-fumigated nests increased HSP60 levels during the season more than those breeding in fumigated nests. Furthermore, the change in HSP60 level was positively correlated with the abundance of biting midges. These results show how infections by nest ectoparasites during the breeding period can increase the level of HSPs and suggest that biting midges impose physiological costs on breeding female blue tits. Although plausible, the alternative that biting midges prefer to feed on more stressed birds is poorly supported by previous studies. 相似文献
423.
Influence of soil texture on the distribution and availability of 238U, 230Th, and 226Ra in soils 总被引:1,自引:0,他引:1
Blanco Rodríguez P Vera Tomé F Lozano JC Pérez-Fernández MA 《Journal of environmental radioactivity》2008,99(8):1247-1254
The influence of soil texture on the distribution and availability of (238)U, (230)Th, and (226)Ra in soils was studied in soil samples collected at a rehabilitated uranium mine located in the Extremadura region in south-west Spain. The activity concentration (Bqkg(-1)) in the soils ranged from 60 to 750 for (238)U, from 60 to 260 for (230)Th, and from 70 to 330 for (226)Ra. The radionuclide distribution was determined in three soil fractions: coarse sand (0.5-2mm), medium-fine sand (0.067-0.5mm), and silt and clay (<0.067 mm). The relative mobility of the natural radionuclides in the different fractions was studied by comparison of the activity ratios between radionuclides belonging to the same radioactive series. The lability of these radionuclides in each fraction was also studied through selective extraction from the soils using a one-step sequential extraction scheme. Significant correlations were found for (238)U, (230)Th, and (226)Ra between the activity concentration per fraction and the total activity concentration in the bulk soil. Thus, from the determination of the activity concentration in the bulk soil, one could estimate the activity concentration in each fraction. Correlations were also found for (238)U and (226)Ra between the labile activity concentration in each fraction and the total activity concentration in bulk soil. Assuming that there is some particle-size fraction that predominates in the process of soil-to-plant transfer, the parameters obtained in this study should be used as correction factors for the transfer factors determined from the bulk soil in previous studies. 相似文献
424.
Brígido Flores O Montalván Estrada A Rosa Suárez R Tomás Zerquera J Hernández Pérez A 《Journal of environmental radioactivity》2008,99(12):1834-1837
An extensive research project to investigate the radioactive properties of Cuban building materials was carried out because there is a lack of information on the radioactivity of such materials in Cuba. In the framework of this project 44 samples of commonly used raw materials and building products were collected in five Cuban provinces. The activity concentrations of natural radionuclides were determined by gamma ray spectrometry using a p-type coaxial high purity germanium detector and their mean values were in the ranges: 9-857Bqkg(-1) for (40)K; 6-57Bqkg(-1) for (226)Ra; and 1.2-22Bqkg(-1) for (232)Th. The radium equivalent activity in the 44 samples varied from 4Bqkg(-1) (wood) to 272Bqkg(-1) (brick). A high pressure ionisation chamber was used to measure the indoor absorbed dose rate in 543 dwellings and workplaces in five Cuban provinces. The average absorbed dose rates in air ranged from 43nGyh(-1) (Holguín) to 73nGyh(-1) (Camagüey) and the corresponding population-weighted annual effective dose due to external gamma radiation was estimated to be 145+/-40microSv. This value is 51% lower than the effective dose due to internal exposure from inhalation of decay products of (222)Rn and (220)Rn and it is 16% higher than the calculated value for the typical room geometry of a Cuban house. 相似文献
425.
Human Adenovirus 41 (Ad41) is an important human enteric pathogen and widely prevalent in the environment. The aim of this study was to assess the survival of Ad41 based on genome stability and infectivity in different types of manure and three types of biosolids. For viral survival studies, Ad41 was added to pelletized poultry litter (PL), alum-treated poultry litter (AL), raw poultry litter (RPL), liquid dairy manure (DM), swine manure (SM), and three types of biosolids 1, 2, 3. All samples were stored at 20 or 4°C and analyzed every 10 days for up to 60 days. Quantification PCR (qPCR) standard curves were generated for PL, AL, biosolids 1, and DM to measure the number of viral genomic copies remaining in the samples. To study the infectivity, all contaminated manure/biosolids samples were added to mammalian cell culture and viral mRNA was detected using one-step RT–PCR. Overall, Ad41 viral genomes were stable at both 20 and 4°C and there was no significant loss of viral DNA after 60 days in PL, AL, biosolids type 1, and DM. However, infectivity was lost almost immediately in high pH biosolids type 2 and 3, and infectivity decreased quickly in DM, with estimated T90 of 4.3 and 8.7 days at 20 and 4°C, respectively. Ad41 had ~1.9 log loss of infectivity after added in SM and biosolids type 1 at day 0, and estimated T90 was 12.5 and 28.6 days for biosolids type 1, and 19.1 and 51.0 days for SM at 20 and 4°C, respectively. Ad41 maintained infectivity in all three poultry litter, and after 60 days incubation, there were significantly more infectious virus in PL, AL, and RPL than biosolids 1, SM, and DM at 20°C. 相似文献
426.
David Eilam Pazit Zadicario Tom Genossar Joel Mort 《Behavioral ecology and sociobiology》2012,66(6):959-968
Social animals behave collectively in order to maintain a cohesive group. This collective behavior is often led by a few individuals of specific gender, social rank, or spatial physical location in the group (i.e., perimeter or front). We examined how individual social voles (Microtus socialis) in same-gender compared with mixed-gender groups respond to an owl attack. We found that anxiety level, as measured by the time that each individual spent in less-sheltered sectors (open arms of elevated plus-maze and center of open arena), was affected by both the social context and the gender of the tested individuals. While both female and male voles generally reduced their activity in the open following owl attack, males in mixed-gender groups were exceptional in dichotomizing into those that spent a short period and those that spent a long period in the open arms of the plus-maze. Based on the similar responses of the same-gender groups, we suggest that anxiety is contagious, and based on the lower anxiety level of the mixed-gender groups, we suggest that natural groups that comprise both males and females are better able to cope with life-threat compared with same-gender groups. Finally, we suggest that the differential responses of males in the mixed-gender groups were due to a few males that displayed a low level of anxiety. These males were probably individuals of high social rank, and their response reflects their natural protective role, as previously described in social voles. 相似文献
427.
Manuel Soler Liesbeth de Neve Gianluca Roncalli Elena Macías-Sánchez Juan Diego Ibáñez-Álamo Tomás Pérez-Contreras 《Behavioral ecology and sociobiology》2014,68(2):333-342
The post-fledging period is a critical phase for juvenile survival, and parental care provided during this period is a key component of avian reproductive performance. Very little is known about the relationships between foster parents and fledglings of brood parasites. Here, we present the results of a 5-year study about the relationships between fledglings of the non-evictor brood parasitic great spotted cuckoo (Clamator glandarius) and its magpie (Pica pica) foster parents. Sometimes, great spotted cuckoo and magpie nestlings from the same nest can fledge successfully, but most often parasitic nestlings outcompete host nestlings and only cuckoos leave the nest. We have studied several aspects of cuckoo post-fledging performance (i.e. feeding behaviour, parental defence and fledgling survival) in experimental nests in which only cuckoos or both magpie and cuckoo nestlings survived until leaving the nest. The results indicate that great spotted cuckoo fledglings reared in mixed broods together with magpie nestlings were disadvantaged by magpie adults with respect to feeding patterns. Fledgling cuckoos reared in mixed broods were fed less frequently than those reared in only cuckoo broods, and magpie adults approached less frequently to feed cuckoos from mixed broods than cuckoos from only cuckoo broods. These results imply that the presence of host's own nestlings for comparison may be a crucial clue favouring the evolution of fledgling discrimination; and furthermore, that the risk of discrimination at the fledgling stage probably is an important selection pressure driving the evolution of the arms race between brood parasites and their hosts. 相似文献
428.
Unsightly and environmentally damaging debris is an ever present problem for waterways and beaches around the world. This debris has numerous sources, and is comprised of materials ranging from metal and wood to plastics and paper. the aesthetic, economic, and environmental impacts of debris have been well documented over the past several years. in an effort to control the release of trash and debris into our waters, there are many activities ongoing in the US. One such activity is a coordinated effort between the US Environmental Protection Agency (EPA), other federal Agencies (National Oceanic and Atmospheric Administration (NOAA), United States Coast Guard (USCG), United States Navy (USN), National Park Service (NPS), Department of Interior (DOI)), industry (the Society of the Plastics Industry, INC. (SPI)), environmental, and local groups. This paper describes the results of field assessments, and the other activities undertaken by EPA as part of this coordinated effort to control the release of debris to our nation's waterways. 相似文献
429.
430.
Tom Hart Richard Mann Tim Coulson Nathalie Pettorelli Phil Trathan 《Marine Biology》2010,157(7):1543-1553
Recording the activity of animals as they migrate or forage has proven hugely advantageous to understanding how animals use
their environment. Where animals cannot be directly observed, the problem remains of how to identify distinct behaviours that
represent an animal’s decision-making process. An excellent example of this problem is that of foraging penguins, which travel
to sea to find prey to provision their young. Without direct sampling of the prey field, we cannot calibrate patterns of movement
with prey capture, and therefore we cannot determine how different activities link to decision-making. To overcome this, we
use a hidden markov model (HMM), which is a machine-learning technique that seeks to identify the underlying states of a system
from observable outputs. We apply HMM to determine classes of behaviour from repetitive dives. We take dive data from 103
breeding macaroni penguins at Bird Island, South Georgia, for which we have measures of weight gain over a trip. We identify
two classes of behaviour; those of short-shallow and long-deep dives. Using these two behaviours, we calculate the transition
probabilities between these states and analyse these data to determine what predicts variation in the transition probabilities.
We found that the stage of reproduction during a season, the sex and year of an individual influenced the probability of transition
between long-deep and short-shallow sequential dives. We also found differences in the hourly transition rates between the
four reproductive stages (incubation, broodguard, crèche and premoult) over a daily cycle. We conclude that this application
of HMMs for behavioural switching is potentially useful for other species and other types of recorded behaviour. 相似文献