6 resultados para Marine resources

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


Relevância:

70.00% 70.00%

Publicador:

Resumo:

Marine spatial planning (MSP) is advocated as a means of managing human uses of the sea in a manner that is consistent with the maintenance of the ecological goods and services of the marine environment. The adoption of a system of MSP is seen as urgent in the face of ever-increasing demands on marine resources. This is particularly so in Ireland with its extensive seas, belatedly being recognised as a significant development resource. MSP is promoted by the European Commission (EC) in a recent Green Paper to which Member States of the Union, including Ireland, generally have responded positively. Arising from this consultative process, the EC has published the 'Blue Book' that commits support for MSP. It has also issued guidelines for an integrated approach to maritime policy. The recently adopted EU Marine Strategy Framework Directive strengthens the case for implementing MSP as it requires each Member State to develop a strategy for its marine resources. There is evidence that a diverse range of stakeholders at national and local levels in Ireland are positively disposed toward MSP but no practical manifestation of the concept is in place, though some preparatory work is underway to facilitate its likely implementation into the future. © 2010 WIT Press.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

A series of shell middens and miscellaneous habitation sites, located in a dune
system in west County Galway, have been exposed and are slowly disappearing
through wind, wave and surface erosion. In 1992 a project was initiated to
record, sample and date some of these sites and the radiocarbon results
demonstrated that activity in the area spanned the Early Bronze Age through to
the Iron Age and into the early and post medieval periods. This preliminary
fieldwork was succeeded by the excavation of three of the better-preserved sites; a Bronze Age midden in 1994 and two early medieval sites (the subject of this paper), in 1997. The medieval sites dated to the late-seventh to ninth century adand were represented by a sub-circular stone hut with a hearth and the charred remains of a more ephemeral wooden tent-like structure. The discovery of a bronze penannular brooch of ninth/tenth century date at the latter site wouldsuggest that the settlements are not the remains of transient, impoverishedpeoples of the lower classes of society, eking out a living along the coast. The calcareous sands ensured good preservation of organic remains*fish and mammal bones, charred cereal grains, seeds and seaweed, and marine molluscs. Analyses of these indicated exploitation of marine resources but, otherwise, were comparable with the diet and economy represented by assemblages from established contemporary site types of the period. Unlike raths, cranno´gs and monastic settlements, however, the volume of material represented at the Galway sites was slight, despite the excellent preservation conditions. A range of seasonal indicators also suggested temporary habitation: probable latespring/summer occupation of the stone hut site and autumnal occupancy of the second, less substantial site. It is suggested that the machair plain, beside which the dunes are located, was most probably the attraction for settlers to the area and was exploited as an alternative pasture for the seasonal grazing of livestock.
*

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A central question in community ecology is how the number of trophic links relates to community species richness. For simple dynamical food-web models, link density (the ratio of links to species) is bounded from above as the number of species increases; but empirical data suggest that it increases without bounds. We found a new empirical upper bound on link density in large marine communities with emphasis on fish and squid, using novel methods that avoid known sources of bias in traditional approaches. Bounds are expressed in terms of the diet-partitioning function (DPF): the average number of resources contributing more than a fraction f to a consumer's diet, as a function of f. All observed DPF follow a functional form closely related to a power law, with power-law exponents indepen- dent of species richness at the measurement accuracy. Results imply universal upper bounds on link density across the oceans. However, the inherently scale-free nature of power-law diet partitioning suggests that the DPF itself is a better defined characterization of network structure than link density.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Stakeholder participation is advanced as a key element of marine spatial planning (MSP) by the U.S. Interagency Ocean Policy Task Force. It provides little guidance, however, regarding stakeholder participation. We argue that much can be learned from existing ecosystem-based marine management initiatives. The Channel Islands National Marine Sanctuary, which utilizes an advisory council to facilitate stakeholder participation, is evaluated in this article with a view to identifying key lessons for new MSP initiatives. A set of criteria, derived from collaborative planning theory, is employed to evaluate the effectiveness of this approach. The advisory council meets some criteria for effective stakeholder participation but is found to be lacking in key elements, including shared purpose and interdependency. Benefits associated with stakeholder participation are constrained accordingly. Deficiencies in the design of the council and its decision-making procedures, requiring attention in order to facilitate more effective stakeholder participation in new MSP initiatives, are highlighted. © 2012 Copyright Taylor and Francis Group, LLC.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Marine Protected Areas (MPAs) are an important conservation tool. For marine predators, recent research has focused on the use of Species Distribution Models (SDMs) to identify proposed sites. We used a maximum entropy modelling approach based on static and dynamic oceanographic parameters to determine optimal feeding habitat for black-legged kittiwakes (Rissa tridactyla) at two colonies during two consecutive breeding seasons (2009 and 2010). A combination of Geographic Positioning System (GPS) loggers and Time-Depth Recorders (TDRs) attributed feeding activity to specific locations. Feeding areas were <30 km from the colony, <40 km from land, in productive waters, 25–175m deep. The predicted extent of optimal habitat declined at both colonies between 2009 and 2010 coincident with declines in reproductive success. Whilst the area of predicted optimal habitat changed, its location was spatially stable between years. There was a close match between observed feeding locations and habitat predicted as optimal at one colony (Lambay Island, Republic of Ireland), but a notable mismatch at the other (Rathlin Island, Northern Ireland). Designation of an MPA at Rathlin may, therefore, be less effective than a similar designation at Lambay perhaps due to the inherent variability in currents and sea state in the North Channel compared to the comparatively stable conditions in the central Irish Sea. Current strategies for designating MPAs do not accommodate likely future redistribution of resources due to climate change. We advocate the development of new approaches including dynamic MPAs that track changes in optimal habitat and non-colony specific ecosystem management.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Studies of competition, predator–prey dynamics and food webs typically consider conspecifics as equal, however, individuals from the same population that are seemingly identical can show considerable variation with regards to a number of processes. Such phenomena may be demonstrated in terms of diet, and the quantities and types of resources that are consumed are commonly considered. The marine amphipod Echinogammarus marinus, a recently demonstrated predator on intertidal rocky shores, has been shown to consume a wide range of food types but it is unknown how this may vary between individuals. Here, we investigated the variation that occurs both among and within individuals of a population of E. marinus with respect to the mean numbers consumed of a common prey item, the isopod Jaera nordmanni. First, by comparing the length of starvation times, used as a proxy for hunger level, individuals maintained without food for up to 24 h consumed significantly less prey during feeding trials than those starved for 48 h and longer. The degree of inter-individual variation within each starvation period was also found to differ, with greater variation among individuals starved for shorter periods of time than those starved for longer time periods. Secondly, we tested whether individual amphipods tracked over time consumed consistently similar numbers of prey or whether they showed intra-individual variation, and if so, to what degree. We found that the numbers of prey consumed per individual could be predicted in the short-term between consecutive feeding trials, however over the long-term this relationship broke down. These results are discussed with respect to potential physiological and behavioural mechanisms, as well as the implications that such variation may have for stability of prey populations in the field.