排序方式： 共有30条查询结果，搜索用时 265 毫秒
1.
Managing by principle: A critical analysis of the European principles of Integrated Coastal Zone Management (ICZM) 总被引：2，自引：2，他引：0
A set of eight principles is contained in the European Recommendation on Integrated Coastal Zone Management. The principles have been adopted with the minimum of critical review. The six core principles form two groups, one concerned with strategic goals and one that has a local focus. The principles are presented as a menu of free-standing options, with no prioritization either within or between groups. This can produce irreconcilable differences in strategy. The principles require clarification, prioritization of the strategic principles and recognition that they are an indivisible integrated set which should not be used to select principles to advance a particular agenda. 相似文献
2.
The tidally inundated marsh surface is an importnat site for energy exchanges for many resident and transient species. In
many areas along the East Coast of the U.S. the dominant vegetation,Spartina alterniflora, has been replaced by the common reed (Phragmites australis). This shift has caused concern about the impact ofPhragmites on marsh fauna but research in this area has been limited. During 1997 and 1998, we examined the effect ofPhragmites on fish and decapod crustacean use of the marsh surface in the brackish water reaches of the Mullica River, in southern New
Jersey, U.S. Fish and decapod crustaceans were sampled with an array of shallow pit traps (rectangular glass dishes, 27.5×17.5×3.7
cm) and with flumes (1.3 m wide×10 m long of 3.2-mm mesh). Fish (2–60 mm TL) dominated pit trap collections withFundulus heteroclitus andFundulus luciae significantly more abundant atSpartina sites.Fundulus heteroclitus was also the dominant fish (15–275 mm TL) collected in flumes but collections with this gear, including a number of species
not collected in pit traps, showed no distinct preferences for different marsh vegetation types. Decapod crustaceans (1–48
mm CW) collected in pit traps were generally less abundant than fishes withCallinectes sapidus andPalaemonetes spp. most abundant inSpartina, whileRhithropanopeus harrisii was most abundant inPhragmites. The same decapod crustacean species (2–186 mm CW) dominanted the flume collections and, similar to the pattern of fish collected
by the flumes, there were no distinct habitat preferences for different marsh vegetation types. As a result of these observations,
with different sampling techniques, it appears there is an overall negative effect ofPhragmites on larval and small juvenile fish but less or no effect on larger fish and decapods crustaceans. 相似文献
3.
Latent heat release associated with tropical deep convective activity is investigated as a source for migrating (sun-synchronous) diurnal and semidiurnal tidal oscillations in the 80–150-km height region. Satellite-based cloud brightness temperature measurements made between 1988 and 1994 and averaged into 3–h bins are used to determine the annual- and longitude-average local-time distribution of rainfall rate, and hence latent heating, between ±40° latitude. Regional average rainfall rates are shown to be in good agreement with climatological values derived from surface rain gauge data. A global linearized wave model is used to estimate the corresponding atmospheric perturbations in the mesosphere/lower thermosphere (80–150 km) resulting from upward-propagating tidal components excited by the latent heating. The annual-average migrating diurnal and semidiurnal components achieve velocity and temperature amplitudes of order 10–20 m s–1 and 5–10 K, respectively, which represent substantial contributions to the dynamics of the region. The latent heat forcing also shifts the phase (local solar time of maximum) of the semidiurnal surface pressure oscillation from 0912 to 0936 h, much closer to the observed value of 0944 h. 相似文献
4.
We explore tropospheric latent heat release as a source of variability of the diurnal tide in the mesosphere and lower thermosphere (MLT) in two ways. First, we present analyses of the UARS WINDII horizontal wind data, which reveal signatures of non-migrating tidal effects as large as 25 m/s during both vernal equinox and boreal winter. These effects are of greater relative importance during the latter season. Complementary global-scale wave model (GSWM) results which account for a tropospheric latent heat source generally underestimate the observed nonmigrat-ing tidal effects but capture the seasonal variability that is observed. Second, we pursue a new parameterization scheme to investigate seasonal variability of the migrating diurnal tidal component of the latent heat source with GSWM. These results confirm previously reported seasonal trends, but suggest that the MLT effects may be as much as an order of magnitude larger than earlier predictions. 相似文献
5.
This paper uses dissipation values derived from UARS/HRDI observations in a recently published diurnal-tide model. These model structures compare quite well with the UARS/HRDI observations with respect to the annual variation of the diurnal tidal amplitudes and the size of the amplitudes themselves. It is suggested that the annual variation of atmospheric dissipation in the mesosphere-lower thermosphere is a major controlling factor in determining the annual variation of the diurnal tide. 相似文献
6.
Ronald?GoldbergEmail author Beth?Phelan Jose?Pereira Stacy?Hagan Paul?Clark Allen?Bejda Anthony?Calabrese Anne?Studholme Kenneth?W.?Able 《Estuaries and Coasts》2002,25(2):215-226
We compared distribution and abundance by habitat for age-0, young-of-the-year (YOY) winter flounder,Pseudopleuronectes americanus, in three estuaries (Hammonasset River, Navesink River, and Great Bay-Little Egg Harbor) in the northeastern United States to better define essential fish habitat (EFH). Two replicates of five representative habitats were sampled in most estuaries: eelgrass (Zostera marina), unvegetated areas adjacent to eelgrass, macroalgae, (primarilyUlva lactuca), unvegetated areas adjacent to macroalgae, and tidal marsh creeks. Fish were sampled every two weeks, May through October 1995 and 1996, with a beam-trawl (1-m width, 3-mm mesh net). Abundance of YOY winter flounder was highest in the Navesink River estuary and similar between years, but was significantly lower and differed between years in the Great Bay-Little Egg Harbor and Hammonasset River estuaries. Annual temperature differences appear to influence estuary use by YOY. In the years and estuaries studied, where habitat-related differences in abundance were significant, YOY were found in higher densities in unvegetated areas adjacent to eelgrass. The exception was in the Hammonasset River in 1995 when densities were higher in eelgrass. We conclude that the type of habitat most important to YOY winter flounder varies among estuaries and as a result, care should be taken in defining EFH, based only on limited spatial and temporal sampling. 相似文献
7.
This paper describes the influences on operational management of erosion at Inch beach, Co. Kerry on the south west coast of Ireland with specific reference to the CONSCIENCE Frame of Reference for erosion management and the key concepts defined under the EUROSION project. It provides an insight of the wave climate and quantifies contemporary erosion patterns through a combination of field analysis and modelling. An attempt is made to assess the response of the coastline to storms with varied return periods and to place current change in an historical context. The reasons for the lack of application of these key concepts are explored in combination with the applicability of the Frame of Reference to the management of Inch Strand. This paper describes the outcomes of attempting to apply this Frame of Reference at Inch Strand and the affect that national coastal policy, or lack thereof, has on the utilisation of internationally recognised erosion management concepts by local stakeholders with responsibility for eroding coastlines. The paper is of significance not only to an Irish audience, but also the wider international community who may face similar challenges in managing their coastal resources. 相似文献
8.
This study examines the spatiality of interlocking directorates of Canadian companies, with particular emphasis given to international interlocks. From a geographical standpoint, do these connections to foreign firms reinforce the importance of Canada’s top corporate cities as ‘gateways’ to international business? Is there a geography associated with the interlocking to these gateway cities? Findings build on James O. Wheeler’s body of research focused on corporate headquarters. This study is placed within the context of the current economic geography dialogue. Particular focus is placed on Saxenian’s theory of brain circulation, wherein she argues that individuals with international experience serve as brokers linking domestic businesses with those in distant regions. A further purpose of this study then is to examine Saxenian’s argument in the context of Canadian corporations. First, is there a geographical association between directors’ foreign educations and where Canadian firms are interlocked to internationally? Second, the corporate performance of Canadian firms interlocked internationally will be measured against those firms that are not. It seems logical to assume that increased connections would yield more diverse and rich knowledge, which could lead to better decisions, and thus corporate performance, in today’s global world. But does it? This study finds that being linked to an international company through a common director did translate into more profitability for Canadian firms. Findings also revealed a geographical link between international interlocks and a director’s foreign education. However, when Canadian firms were interlocked with an international company with a director who had international education, greater profits did not necessarily result. 相似文献
9.
10.
Kenneth W. Able Deborah N. Vivian Gina Petruzzelli Stacy M. Hagan 《Estuaries and Coasts》2012,35(3):743-753
We examined connectivity among marsh subhabitats to determine the structural limits and important components of a polyhaline
salt marsh by studying the patterns of abundance, residency, and movement of a numerically and ecologically dominant nektonic
fish (mummichog, Fundulus heteroclitus). We captured, tagged (n = 14,040 individuals, 30–110 mm), and recaptured from Feb 2001 to Jul 2002, although most recaptures (75–95% by tagging location)
occurred within 150 days. Seasonal residency and movements were common among most subhabitats based on catch per unit effort
and recapture per unit effort. Thus, these (marsh pools, intertidal and subtidal creeks, and marsh surface) should be considered
natural subhabitats within New England type salt marshes. Further, all these subhabitat types should be included in studies
of salt marsh nekton and marsh restoration and creation activities. 相似文献