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181.
This study reports the results of restoration management on sand dune environments along the coastal belt of the Castelporziano
nature reserve (Rome, Italy) and the subsequent monitoring phases to test the sustainability of the ‘soft techniques’ applied.
In the area concerned, over a length of ca. 3 km, 40 dunes were built up along with three belts located at <40 m, 40–70 m,
and >70 m, respectively, from the shoreline. On each of 38 dunes 20 individuals ofAmmophila littoralis were planted; this species is one of the local autochthonous species considered particularly suitable for stabilizing sand
dunes. After one year, two years and five years, respectively the changes in height and surface of each dune, the survival
rates ofA. littoralis, and its changes in cover, the appearance of new shoots and the establishment of new species were observed. A progressive
increase in species number, which five years after the restoration amounted to about 60% of those characterizing the natural
dunes, was reported indicating a progressive trend towards populations similar to natural ones. In the colonization of new
species there is a prevalence of theSporobolus-Elymetum farcti and theSalsolo Kali-Cakiletum maritimae association, while the species established successively refer to theEchinophoro spinosae-Ammophiletum arundinaceae association and theCrucianellion maritimae alliance as occurring in natural successions.
This succession runs parallel to the natural dune colonization processes. In particular, the data regarding survival, cover
and number of vegetative shoots indicate that the dune belt between 40 and 70 m from the sea is the one most suitable for
restoration.
Some changes in dune morphology was observed: the height of the artificial dunes tended to decrease considerably in the five
years of observation, whereas a progressive increase in their surface area was observed. During the study period.A littoralis favoured the establishment of new species, but as yet exercises no action on increasing dune height. 相似文献
182.
A test of elemental defence against slugs by Ni in hyperaccumulator and non-hyperaccumulator Streptanthus species 总被引:2,自引:0,他引:2
Summary. Tissues of most plant species contain < 10 μg Ni g−1 but Ni hyperaccumulators contain more than 1000 μg Ni g−1 . Hyperaccumulated Ni can defend plants from some herbivores but the defensive role of lesser Ni concentrations is little explored. We raised five species of Streptanthus (Brassicaceae) native to ultramafic soils, one of which (S. polygaloides) is a Ni hyperaccumulator whereas the others are simply Ni-tolerant, on Ni-amended and unamended green-house soils to create plants differing in Ni concentrations. On high-Ni soil, leaves of the hyperaccumulator contained 3800 μg Ni g−1 whereas leaves of non-hyperaccumulator species contained 41–64 μg Ni g−1. Plants of all species grown on low-Ni soils had < 14 μg Ni g−1. Slugs (Limax maximus) were fed plant material in no-choice tests over a 50-day period and survival and mass changes were recorded. All slugs fed high-Ni leaves of the hyperaccumulator species died within 21 d. Slugs fed high-Ni leaves of the other species did not differ significantly in survival or mass change from those fed low-Ni leaves. In choice tests, slugs (Lehmannia valentiana) offered both high- and low-Ni S. polygaloides leaves did little damage to high-Ni leaves. We conclude that hyperacumulated Ni can defend S. polygaloides from slug herbivory via both toxicity and deterrence, but these defensive effects do not extend to Streptanthus species containing < 70 μg Ni g−1. 相似文献
183.
Franke van der Molen Jac. A. A. Swart Henny J. van der Windt 《Journal of Environmental Policy & Planning》2018,20(5):564-577
In order to successfully inform environmental management, environmental research needs to balance legitimacy, credibility, and salience. This paper aims to identify trade-offs and synergies between these three attributes in collaborative research for environmental management, and draws lessons for organizing such research. Empirically, it draws on a study of a research program on the ecological effects of coastal protection through sand nourishment. Our findings suggest that the legitimacy and salience of knowledge creation, particularly in an interactive governance context, are complementary. At the same time, we found trade-offs between practical relevance and fundamental knowledge creation, as well as between issue diversity and the depth and quality of scientific inquiry. Balancing the legitimacy, credibility, and salience of knowledge may be enabled by interactive knowledge creation involving policy-makers, experts and stakeholders. We conclude that successful management-oriented environmental research, particularly in the case of wicked problems, requires both a careful design of arrangements for stakeholder engagement, and well- established linkages to broader regulatory and institutional contexts. 相似文献
184.
Coastal zone management is inconceivable without the mobilization and integration of different types of knowledge – that is, without knowledge co-production practices. This article applies the concept of knowledge co-production to analyze the process of emergence, standardization, and enculturation of environmental management systems (EMSs) within port communities in the Dutch Wadden Sea. Moreover, it is a report from the field in which we reflect on the participatory practices conducted to facilitate the knowledge arrangements required to develop EMSs for a group of ports. The article concludes that this type of knowledge arrangement and co-production practices (involving different types of actors and knowledge) might become mandatory in the near future to stabilize the EMS phenomenon in the practices of ports. 相似文献
185.
Nguyen Cao Don Hiroyuki Araki Nguyen Thi Minh Hang Hiroyuki Yamanishi Kenichi Koga 《Environment, Development and Sustainability》2008,10(2):219-231
Groundwater is an important resource in the alluvial coastal lowland plains. In the Shiroishi lowland plain, southwestern
Kyushu Island of Japan, land subsidence due to groundwater development has long been recognized as an environmental issue.
Land subsidence can have several negative economic and social implications. In this study, an integrated numerical groundwater
and land subsidence model, which combines a three-dimensional numerical groundwater flow model and a one-dimensional soil
consolidation model, was used to simulate the dynamic groundwater flow and ground subsidence due to pumping. On the other
hand, a groundwater optimization model was also formulated to search for an optimal safe yield of groundwater pumping without
violating physical, environmental, social-economic constraints. The model results reveal that groundwater levels in the aquifers
greatly vary from season to season in response to varying climatic and pumping conditions. Consequently, land subsidence has
rapidly occurred throughout the area with the central prone in Shiroishi plain. The study also proposes a countermeasure against
subsiding process in the area by means of numerical models. The optimization model result suggests that pumping can be increased
in the northern part of the study area without leading to significant land subsidence. 相似文献
186.
Direct measurement of denitrification activity in a Gulf coast freshwater marsh receiving diverted Mississippi River water 总被引:1,自引:0,他引:1
Wetland loss along the Louisiana Gulf coast and excessive nitrate loading into the Gulf of Mexico are interrelated environmental problems. Nitrate removal by soil denitrification activity was studied in a ponded freshwater marsh receiving diverted Mississippi River water for the purpose of reversing or slowing wetland loss. Labeled 15N-nitrate was applied at 3.8 g N m−2 into four replicate study plots after removing above ground vegetation. Nitrogen gas (N2) and nitrous oxide (N2O) emissions from the plots were determined by isotope ratio mass spectrometry (IRMS). Nitrous oxide emissions were also compared with the results determined by gas chromatograph (GC). Results showed that it took 2 weeks to remove the added nitrate with N2O emission occurring over a period of 4 d. The apparent denitrification dynamics were assumed to follow the Michaelis–Menten equation. The maximum denitrification rate and Km value were determined as 12.6 mg N m −2 h−1, and 6.5 mg N l−1, respectively. Therefore the maximum capacity for nitrate removal by the marsh soil would be equivalent to 110 g N m−2 yr−1, with more than 30% of nitrogen gas evolved as N2O. For typical nitrate concentrations in Mississippi River water of about 1 mg N l−1, nitrate would be removed at a rate of 14.7 g N m−2 yr−1 with N2O emission about 1.5%. A denitrification dynamic model showed that the efficiency of nitrate removal would largely depend on the water discharge rate into the ponded wetland. Higher discharge rate will result in less retention time for the water in the marsh where nitrate is denitrified. 相似文献
187.
Snoussi M Kitheka J Shaghude Y Kane A Arthurton R Le Tissier M Virji H 《Environmental management》2007,39(5):587-600
Anthropogenic factors associated with damming and water abstraction, and the resultant environmental pressures, are reviewed
in six African river catchments using records and forecasts of climatic, demographic, and land-use change. Changes in the
states of the flow regime through catchment drainage systems to the coastal sea are considered in conjunction with climate
change and other human-induced pressures. The impacts of these changes on downstream and coastal environments and their communities
are described in past, present, and future perspectives. Linkages between the issues and the pressures of damming and water
abstraction are appraised and scientific, policy, and management responses proposed aimed at remedying existing and perceived
future negative impacts. The study proposes that there is a need to integrate catchment and coastal management to account
for the whole water flow regime together with its human dimensions. Management priorities relating to the operation of existing
damming and abstraction schemes and planning of future schemes include the following: consideration of ways in which water
discharges could be adjusted to provide improvements in downstream and coastal environmental and socioeconomic conditions;
addressing the problem of sediment trapping impacting on the sustainability of dam reservoirs; and assessment of downstream
and coastal impacts of future schemes in the light of climate change forecasts. 相似文献
188.
This study demonstrates the integration of rehabilitation and flood management planning in a steep, boulder-bedded stream
in a coastal urban catchment on the South Island of New Zealand. The Water of Leith, the primary stream flowing through the
city of Dunedin, is used as a case study. The catchment is steep, with a short time of concentration and rapid hydrologic
response, and the lower stream reaches are highly channelized with floodplain encroachment, a high potential for debris flows,
significant flood risks, and severely degraded aquatic habitat. Because the objectives for rehabilitation and flood management
in urban catchments are often conflicting, a number of types of analyses at both the catchment and the reach scales and careful
planning with stakeholder consultation were needed for successful rehabilitation efforts. This included modeling and analysis
of catchment hydrology, fluvial geomorphologic assessment, analysis of water quality and aquatic ecology, hydraulic modeling
and flood risk evaluation, detailed feasibility studies, and preliminary design to optimize multiple rehabilitation and flood
management objectives. The study showed that all of these analyses were needed for integrated rehabilitation and flood management
and that some incremental improvements in stream ecological health, aesthetics, and public recreational opportunities could
be achieved in this challenging environment. These methods should be considered in a range of types of stream rehabilitation
projects. 相似文献
189.
Solar and Tidal Modulations of Fecal Indicator Bacteria in Coastal Waters at Huntington Beach,California 总被引:1,自引:1,他引:0
The coastal waters at many beaches in California and the United States are afflicted with fecal pollution, which poses a health
risk for people exposed to the water through recreational activities such as swimming, surfing, and diving. Identifying sources
of pollution is complicated by oceanographic transport/mixing processes and the nonconservative behavior of microorganisms
exposed to sunlight and hostile marine conditions. This article investigates the variation of fecal indicator bacteria (FIB)
concentrations in the surf zone and the adjacent coastal marsh by applying autocorrelation and cross-correlation analyses
that illustrate solar and tidal modulations. A steady state bioreactor model was developed to explain solar inactivation in
the surf zone, whereas a dynamic model was applied to explain tidally influenced disturbances in the coastal marsh. These
models applied to intensive monitoring datasets on FIB and environmental variables have provided insights into the biologic
and physical processes controlling coastal water quality, specifically the influence of sunlight and tides on bacterial levels. 相似文献
190.
The costs of the maneuvers that fishermen and shrimp farmers have to undertake in a coastal scenario where both the access to navigable waters and water quality have decreased were interpreted as defensive expenditures. Maneuvers were prompted by profound changes in water circulation and siltation mode imposed by major shifts in regional and local land-use patterns. In coastal scenarios under heavy land-based discharges and local geomorphic modifications, local users with little chance to move away may modify their routines in order to maintain existing levels of utility. The concept of defensive expenditures could be used to assess social responses to adverse changes in environmental and resource conditions, as a means to distinguish stages in which local sectors respond individually from qualitatively different stages in which intersectoral events are more conspicuous. 相似文献