994 resultados para Methodist Epis. Ch., U.S.
Resumo:
This chapter covers coral reef areas under the jurisdiction of the USA in the Wider Caribbean: Florida; Flower Garden Banks; Puerto Rico; U.S. Virgin Islands; and Navassa. The following information is condensed from six chapters of The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2008. Access to the full text of this comprehensive report is available at: http://ccma.nos.noaa.gov/stateofthereefs.
Resumo:
This report is a result of long-term fish monitoring studies supported by the National Park Service (NPS) at the Virgin Islands National Park since 1988 and is now a joint NPS and NOAA collaboration. Reef fish monitoring data collected from 1988 to 2006 within Virgin Islands National Park (VINP) and adjacent reefs around St. John, U.S. Virgin Islands (USVI) were analyzed to provide information on the status of reef fishes during the monitoring period. Monitoring projects were initiated by the National Park Service (NPS) in the 1980s to provide useful data for evaluation of resources and for development of a long-term monitoring program. Monthly monitoring was conducted at two reef sites (Yawzi Point and Cocoloba Cay) starting in November 1988 for 2.5 years to document the monthly/seasonal variability in reef fish assemblages. Hurricane Hugo (a powerful Category 4 storm) struck the USVI in September 1989 resulting in considerable damage to the reefs around St. John. Abundance of fishes was lower at both sites following the storm, however, a greater effect was observed at Yawzi Point, which experienced a more direct impact from the hurricane. The storm affected species differently, with some showing only small, short-term declines in abundance, and others, such as the numerically abundant blue chromis (Chromis cyanea), a planktivorous damselfish, exhibiting a larger and longer recovery period. This report provides: 1) an evaluation of sampling methods, sample size, and methods used during the sampling period, 2) an evaluation of the spatial and temporal variability in reef fish assemblages at selected reef sites inside and outside of VINP, and 3) an evaluation of trends over 17 years of monitoring at the four reference sites. Comparisons of methods were conducted to standardize assessments among years. Several methods were used to evaluate sample size requirements for reef fish monitoring and the results provided a statistically robust justification for sample allocation.
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With the increasing recognition that climate change is occurring and having large impacts on living marine resources, a sound ecosystem approach to management of those resources requires both understanding how climate affects ecosystems and integration of that understanding into management processes. The National Marine Fisheries Service (NMFS) must identify how changing climatic conditions will impact its mission and must be prepared to adapt to these changes. This document identifies the climate related ecosystem concerns in the regional marine ecosystems for which NMFS has living marine resource management responsibilities, what NMFS is currently doing to address these concerns, what NMFS must do going forward to address these concerns, and what climate information is needed to integrate climate into resource management. The regional ecosystems included in this analysis are: the Northeast U.S. Continental Shelf; the Southeast U.S. Continental Shelf, Gulf of Mexico, and U.S. Caribbean; the California Current Ecosystem; the Alaskan Ecosystem Complex; the Pacific Island Ecosystem Complex; the Eastern Tropical Pacific; North Pacific Highly Migratory Species; and the Antarctic.
Resumo:
The U.S. Marine Mammal Protection Act requires that the abundance of marine mammals in U.S. waters be assessed. Because this requirement had not been met for a large portion of the North Atlantic Ocean (U.S. waters south of Maryland), a ship-based, line-transect survey was conducted with a 68 m research ship between Maryland (38.00°N) and central Florida (28.00°N) from the 10-m isobath to the boundary of the U.S. Exclusive Economic Zone. The study area (573,000 km2) was surveyed between 8 July and 17 August 1998. Minimum abundance estimates were based on 4163 km of effort and 217 sightings of at least 13 cetacean species and other taxonomic categories. The most commonly sighted species (number of groups) were bottlenose dolphins, Tursiops truncatus (38); sperm whales, Physeter macrocephalus (29); Atlantic spotted dolphins, Stenella frontalis (28); and Risso’s dolphins, Grampus griseus (22). The most abundant species (abundance; coeffi cient of variation) were Atlantic spotted dolphins (14,438; 0.63); bottlenose dolphins (13,085; 0.40); pantropical spotted dolphins, S. attenuate (12,747; 0.56); striped dolphins, S. coeruleoalba (10,225; 0.91); and Risso’s dolphins (9533; 0.50). The abundance estimate for the Clymene dolphin, S. clymene (6086; 0.93), is the first for the U.S. Atlantic Ocean. Sperm whales were the most abundant large whale (1181; 0.51). Abundances for other species or taxonomic categories ranged from 20 to 5109. There were an estimated 77,139 (0.23) cetaceans in the study area. Bottlenose dolphins and Atlantic spotted dolphins were encountered primarily in continental shelf (<200 m) and continental slope waters (200−2000 m). All other species were generally sighted in oceanic waters (>200 m). The distribution of some species varied north to south. Striped dolphins, Clymene dolphins, and sperm whales were sighted primarily in the northern part of the study area; whereas pantropical spotted dolphins were sighted primarily in the southern portion.
Resumo:
Recreational fisheries in the waters off the northeast U.S. target a variety of pelagic and demersal fish species, and catch and effort data sampled from recreational fisheries are a critical component of the information used in resource evaluation and management. Standardized indices of stock abundance developed from recreational fishery catch rates are routinely used in stock assessments. The statistical properties of both simulated and empirical recreational fishery catch-rate data such as those collected by the National Marine Fisheries Service (NMFS) Marine Recreational Fishery Statistics Survey (MRFSS) are examined, and the potential effects of different assumptions about the error structure of the catch-rate frequency distributions in computing indices of stock abundance are evaluated. Recreational fishery catch distributions sampled by the MRFSS are highly contagious and overdispersed in relation to the normal distribution and are generally best characterized by the Poisson or negative binomial distributions. The modeling of both the simulated and empirical MRFSS catch rates indicates that one may draw erroneous conclusions about stock trends by assuming the wrong error distribution in procedures used to developed standardized indices of stock abundance. The results demonstrate the importance of considering not only the overall model fit and significance of classification effects, but also the possible effects of model misspecification, when determining the most appropriate model construction.
Abundance and distribution of cetaceans in outer continental shelf waters of the U.S. Gulf of Mexico
Resumo:
This report outlines the approaches for estimating the carbon budget for the United States, a data rich subcontinental area, and presents an overview of problems encountered and preliminary results obtained.
Resumo:
基于中国东北样带(NECT)30个植被样方调查和表土孢粉资料,从个体、群落水平研究了孢粉-植被关系,结果表明,孢粉类型与植被关系密切,在 = 0.05的显著性水平上,相关系数大于0.5;表土孢粉组合与植物群落间有较大的相似性,相似系数大于50%。采用定量描述花粉与植物关系的参数:联合指数(association)A、超代表性指数(over-representation)O、低代表性指数(under-representation)U、相关系数(correlation coefficient)C和代表性系数(representation coefficient)R等值,应用TWINSPAN分类、PCA排序和回归分析,把表土花粉类型划分为4类:具代表性类群组Group1,它们能正确反映植被;超代表性类群组Group2,它们常具有高花粉值与植被不成比例;低代表性类群组Group3,它们的花粉很难分离提取;以及低代表性类群的Group4,其花粉在土壤地层中较常见;指出一些常见花粉类型:松(Pinus)、桦(Betula)、栎(Quercus)、椴(Tilia)、槭(Acer)、榆(Ulmus)、蒿(Artemisia)、藜(Chenopodiaceae)、禾本科(Gramineae)和莎草科(Cyperaceae)的回归参数在东部森林区和西部草原区是有变化的,因此回归参数在应用于古植被恢复中要注意适用范围。 以Biomization模型为基础,根据植物的生理生态特性,定义了NECT孢粉类型的植物功能型(PETs)各种生物群区(Biome)的PFTs组合,构建了经表土孢粉检验的适用于NECT的以孢粉数据为驱动的模型框架,该模型模拟的生物群区与其化指标(气候、植物生理、土壤等)模拟划分的BIOME(Holdrige, BIOME3)是可比的,与植被类型有较好的对应性。 根据29剖面(986个样品)的孢粉数据,重建了NECT 6 kaB.P以来的生物群区。从时空二方面阐述了NECT6kaB.P以来生物群区的分布特点: (1)6ka B. P是一暖湿期,气温比现在高1~4℃,降水比现在多50%。落叶阔叶林分最广,面积最大。森林草原、落叶阔叶林、针阔混交林向西延伸最远。 (2)5ka B. P 是一降温期,气温比现在低2℃,降水多30%。有苔原、寒温带针叶林分布。 (3)4ka B. P是一暖湿期,气温比现在高1~2℃,降水比现在多50%。针阔光林和森林草原有最大分布面积。 (4)3Ka-2kaBP的气温与现代相似,降水比现在多20%左右。与4Ka B. P相比,森林和森林草原过渡带都向东移动。 (5)1Ka B. P的气温与现代相似,降水比现在多10%左右。草原向东大幅度扩张,森林分布面积减小。 (6)东部森林,中部森林草原,西部草原的分布格局的3Ka B. P基本确定,此后随着气候的不断变干冷,草原向东扩张。 (7)森林向扩张最大距离的时期发生在6Ka B. P,此时也是森林草原向西扩张最远时期。落叶阔叶林、针阔混交林、森林草原向西移动最大距离的时间是6Ka B. P,草原向西移动最远距离的时期发生在3Ka B. P。