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231.
Kristen M. Hart Autumn R. Sartain Zandy-Marie Hillis-Starr Brendalee Phillips Philippe A. Mayor Kimberly Roberson Roy A. Pemberton Jr. Jason B. Allen Ian Lundgren Susanna Musick 《Marine Biology》2013,160(10):2567-2580
Surveys of juvenile hawksbills around Buck Island Reef National Monument, US Virgin Islands from 1994 to 1999 revealed distributional patterns and resulted in a total of 75 individual hawksbill captures from all years; turtles ranged from 23.2 to 77.7 cm curved carapace length (CCL; mean 42.1 ± 12.3 cm SD). Juveniles concentrated where Zoanthid cover was highest. Length of time between recaptures, or presumed minimum site residency, ranged from 59 to 1,396 days (mean 620.8 ± 402.4 days SD). Growth rates for 23 juveniles ranged from 0.0 to 9.5 cm year?1 (mean 4.1 ± 2.4 cm year?1SD). Annual mean growth rates were non-monotonic, with the largest mean growth rate occurring in the 30–39 cm CCL size class. Gastric lavages indicated that Zoanthids were the primary food source for hawksbills. These results contribute to our understanding of juvenile hawksbill ecology and serve as a baseline for future studies or inventories of hawksbills in the Caribbean. 相似文献
232.
Yuichi Fukunishi Howard I. Browman Caroline M. F. Durif Reidun M. Bjelland Steven D. Shema David M. Fields Anne Berit Skiftesvik 《Marine Biology》2013,160(10):2591-2596
Levels of ultraviolet-B radiation (UV-B: 280–315 nm) reaching the earth’s surface have increased over the past few decades due to ozone depletion. It is well documented that exposure to UV-B radiation increases mortality in marine fish larvae. However, few studies have examined sub-lethal effects of UV-B radiation such as, for example, the possibility that it affects prey consumption by fish larvae. Atlantic cod larvae were exposed to a sub-lethal level of ultraviolet-B radiation (UV-B: 280–315 nm) for 15 h. After the exposure, rotifers (4/mL) were fed to cod larvae at three different post-exposure intervals (20 min, 3 and 6 h). Trials were replicated three times for each post-exposure interval. The number of rotifers in the gut and the percent of empty guts (number of fish with empty gut/number of fish examined × 100) were analyzed. Results were compared to those of unexposed fish (the control treatment). UV-B exposed cod larvae had consumed significantly fewer rotifers than control fish at all post-exposure intervals. There was no significant difference in the frequency of empty guts between fish in the UV-B treatment versus fish in the control treatment at any of the post-exposure time points (although the difference at 20 min post-exposure was borderline significant). These observations suggest that cod larvae exposed to sub-lethal levels of UV-B have lower net energy gain which may lead to reduced growth rate and possibly poorer survival. 相似文献
233.
Morna K. Gillespie D. C. Howard M. J. Ness R. M. Fuller 《Environmental monitoring and assessment》1996,39(1-3):385-398
The Institute of Terrestrial Ecology (ITE) has been studying land use and the effects of land use on ecology for two decades. A series of national field surveys have been undertaken by the Land Use Section of ITE since 1978, the most recent being Countryside Survey 1990 (CS1990). The three-year project brought together field survey and remote sensing data which were analyzed using Geographical Information Systems (GIS). National and regional land-cover patterns were described and changes estimated.The data collected by the field survey part of CS1990 recorded stratified samples based on a land classification. Thematic maps for surveyed 1-km squares covered physiography, agriculture and semi-natural vegetation, forestry, structures and boundaries. The same sites were surveyed in 1984 and 1990 with 14 000 digital maps produced describing both years. GIS was used to generate stock figures for each year, and overlay allowed change between survey dates to be estimated.GIS was used to compare data collected from both field survey and satellite imagery so that both sets of information could be qualified when expressed as national figures.This paper describes the historical development of the ITE Land Classification, examines the way in which data were collected for surveys, with particular reference to Countryside Survey 1990, and shows how satellite and field survey data can be linked through GIS. 相似文献
234.
Doak DF Estes JA Halpern BS Jacob U Lindberg DR Lovvorn J Monson DH Tinker MT Williams TM Wootton JT Carroll I Emmerson M Micheli F Novak M 《Ecology》2008,89(4):952-961
Ecological surprises, substantial and unanticipated changes in the abundance of one or more species that result from previously unsuspected processes, are a common outcome of both experiments and observations in community and population ecology. Here, we give examples of such surprises along with the results of a survey of well-established field ecologists, most of whom have encountered one or more surprises over the course of their careers. Truly surprising results are common enough to require their consideration in any reasonable effort to characterize nature and manage natural resources. We classify surprises as dynamic-, pattern-, or intervention-based, and we speculate on the common processes that cause ecological systems to so often surprise us. A long-standing and still growing concern in the ecological literature is how best to make predictions of future population and community dynamics. Although most work on this subject involves statistical aspects of data analysis and modeling, the frequency and nature of ecological surprises imply that uncertainty cannot be easily tamed through improved analytical procedures, and that prudent management of both exploited and conserved communities will require precautionary and adaptive management approaches. 相似文献
235.
Previous soil lead studies in New Orleans focused on the geochemical footprint and its health impacts. This study examines
the human geography of race, income, and age in pre-Katrina metropolitan New Orleans within the context of lead accumulation
in soils. Sample points of soil lead data (n = 5,467) collected in 1998–2000 were mapped in a geographic information system (GIS), binned into 9 ranges, and queried by
(1) 2000 Census racial demographic data, (2) 1999 median household income, and (3) 2000 age data. The absolute population
generally declines as lead levels increase except at lead levels from 200–400 to 400–1,000 mg/kg when population increases;
the African–American population comprises a disproportionate share of this cohort. The high-lead areas occur in the inner
city, home to the largest populations of African-Americans in New Orleans. The mean household income curve indicates that
lower economic groups are at risk to higher levels of lead. A total of 44,701 children under the age of 5 years, plus 123,579
children aged 5–17, lived in census block groups containing at least one sample point with over 100 mg/kg lead, and these
include 23,124 and 64,064 young people, respectively, who live near at least one point over 400 mg/kg. Lead exposure affects
a panoply of outcomes that influence the health and welfare of the community. Unless corrected, children are likely to return
to the same or, because of lack of lead-safe practices during renovation, even higher exposure risks than before the flooding
of New Orleans. 相似文献
236.
Ian Christoplos Le Duc Ngoan Le Thi Hoa Sen Nguyen Thi Thanh Huong Lily Salloum Lindegaard 《Disasters》2017,41(3):448-467
How do disasters shape local government legitimacy in relation to managing climate‐ and disaster‐related risks? This paper looks at how local authorities in Central Vietnam perceive their social contract for risk reduction, including the partial merging of responsibilities for disaster risk management with new plans for and investments in climate change adaptation and broader socioeconomic development. The findings indicate that extreme floods and storms constitute critical junctures that stimulate genuine institutional change. Local officials are proud of their strengthened role in disaster response and they are eager to boost investment in infrastructure. They have struggled to reinforce their legitimacy among their constituents, but given the shifting roles of the state, private sector, and civil society, and the undiminished emphasis on high‐risk development models, their responsibilities for responding to emerging climate change scenarios are increasingly nebulous. The past basis for legitimacy is no longer valid, but tomorrow's social contract is not yet defined. 相似文献
237.
Elise Howard 《Ambio》2023,52(3):518
This systematic review aims to address gaps in understanding how concepts of gender, climate change and security are given meaning and linked in empirical scholarship within the Pacific Islands Region. The review assesses the 53 articles returned through Web of Science, SCOPUS and ProQuest databases that are derived from empirical research and refer to gender, climate change and security. The findings indicate that this is an emerging topic in a region that is one of the most vulnerable to climate change across the globe. Most frequently gender analysis is given superficial treatment; there is limited literature that connects gendered vulnerabilities to historical legacies and structural inequalities; and women’s critical roles that create security are often overlooked and devalued. The review indicates that greater work is needed to question perceived threats to security and to reveal how climate change, gendered institutions, systems and spaces, historical legacies and politics interact to construct security in the Pacific Islands Region. 相似文献
238.
Allan Curtis Ian Byron Jacinta MacKay 《Journal of the American Water Resources Association》2005,41(3):549-563
ABSTRACT: Watersheds are widely accepted as a useful geography for organizing natural resource management in Australia and the United States. It is assumed that effective action needs to be underpinned by an understanding of the interactions between people and the environment. While there has been some social research as part of watershed planning, there have been few attempts to integrate socio‐economic and biophysical data to improve the efficacy of watershed management. This paper explores that topic. With limited resources for social research, watershed partners in Australia chose to focus on gathering spatially referenced socio‐economic data using a mail survey to private landholders that would enable them to identify and refine priority issues, develop and improve communication with private landholders, choose policy options to accomplish watershed targets, and evaluate the achievement of intermediate watershed plan objectives. Experience with seven large watershed projects provides considerable insight about the needs of watershed planners, how to effectively engage them, and how to collect and integrate social data as part of watershed management. 相似文献
239.
240.
Evaluation of sequentially-coupled POP fluxes estimated from simultaneous measurements in multiple compartments of an air-water-sediment system 总被引:4,自引:0,他引:4
Palm A Cousins I Gustafsson O Axelman J Grunder K Broman D Brorström-Lundén E 《Environmental pollution (Barking, Essex : 1987)》2004,128(1-2):85-97
Bulk atmospheric deposition fluxes, air-water exchange fluxes, particle settling fluxes out of the upper water column, sediment trap fluxes in deep waters, and sediment burial fluxes of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in the Koster Fjord, eastern Skagerak, on the Swedish west coast. The aim of the study was to compare the magnitude and direction of the compound fluxes in the system in order to diagnose key fate processes. The PCB and PAH fluxes via net atmospheric deposition, settling particles out of the surface and through deep waters, as well as into the accreting underlying sediments were shown to be remarkably similar, agreeing within a factor of a few for any given target compound. Fluxes of all PCB and PAH target compounds remained fairly constant with water column depth. Thus there was no evidence for net desorption from sinking particles. The net unidirectional and near balancing of vertical fluxes suggests a net transport of PCBs and PAHs from the atmosphere to the continental shelf sediments in the Koster Fjord, which is consistent with the hypothesis that the shelf sediments are important sinks for these compounds. 相似文献