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991.
Aušrinė Armaitienė Vadim L. Boldyrev Ramūnas Povilanskas Julius Taminskas 《Journal of Coastal Conservation》2007,11(1):13-22
The varied and very dynamic landscape with a high biological diversity is a distinctive feature of the Curonian spit at the
regional scale. Throughout the 20th century the main morphodynamic trend in the littoral of the Curonian spit was shoreline
grading on the lagoon side, whereas on the marine side the increasing erosion at the foot of the spit, and increasing accretion
at the head of the spit prevailed. The results of a discriminant analysis (Wilkes’ λ = 0.001626 and F = 29.267 when p < 0.001) show that sites with prevailing erosion, accretion and sediment input from the drifting dunes form regular inter-related
spatial structures in the littoral with distinctive resulting discontinuities of the sediment drift along the lagoon coast.
Dune littoral cells are characterized by Aeolian sediment input and distribution ‘down-drift’, (usually northwards) from the
source. The most likely changes in the current development trends of the lagoon shore zone of the Curonian spit are related
to expected climate changes and further slowing down of the dune drift. The probability of storms and ice-drift events, and
their impact on coasts is expected to increase as a result of climate change. The dune advance will gradually slow down, and
with it, the sand input to the coastal zone will decline. In this paper, we define integrated shoreline management as a system
of long-term shoreline management measures, which is based on a littoral cell approach and aimed at harmonizing human activity
in the coastal zone with the natural development of the shoreline. We propose an integrated management program for the lagoon
shoreline of the Curonian spit, which is site-specific for each littoral cell as a coastal management unit. Drifting dunes
and seaside beaches are the natural amenities, which are best known and best appreciated on the Curonian spit by 49% of the
respondents representing the total Lithuanian population. A responsible tourism development should be considered as the key
means for proper appreciation of the drifting dunes and natural coasts by society, which means to acknowledge and cherish
the aesthetic and conservation values of dune and coastal landscapes of the Curonian spit as a World Heritage Site. There
are at least two pre-conditions for this: (1) to provide visitors with sufficient information about diverse values and functions
of the Curonian dunes and coasts within a broader regional and global heritage conservation context; (2) to enable tourists
to enjoy the most impressive dune and coastal landscapes at close range. In this paper we propose to encourage active dune
tourism, to reintroduce grazing into the Curonian dune areas, to restore and to preserve the most impressive landscapes of
the highest white drifting dunes by bringing the blown out sand from the leeward foot of the dunes back to the crest artificially. 相似文献
992.
C. Ojeda-Martinez J. T. Bayle-Sempere P. Sánchez-Jerez A. Forcada C. Valle 《Marine Biology》2007,151(3):1153-1161
Marine protected areas (MPA) produce a positive effect on fish populations, but this may be difficult to identify due to the
high temporal variability of populations. Meta-analysis is an option for analysing data from different sources and sampling
designs and it can address problems related to temporal and spatial variability in fish populations. We analysed fish abundance
data from visual counts conducted in summer, from 1996 to 2002, in the MPA of Tabarca (Alicante, Spain). The results showed
an overall positive effect of protection at the species and family levels. Overall abundance of fishes inside the reserve
was, on average, 1.22 times higher than outside the reserve boundaries. Positive effect of protection was found for Boops boops, Diplodus annularis, Diplodus cervinus, Epinephelus marginatus, Epinephelus costae and Epinephelus aenus. Species of Labrids were not affected by protection, except for Thalassoma pavo and Symphodus ocellatus. Meta-analysis of temporal data allows evaluation of the protection MPA provide and is particularly useful when data sources
have different experimental designs or sampling programs. The Tabarca MPA has benefited fish populations by increasing their
abundance and we suggest that meta-analysis is a complementary tool for the management of MPAs. 相似文献
993.
Soil erosion and significance for carbon fluxes in a mountainous Mediterranean-climate watershed. 总被引:2,自引:0,他引:2
S V Smith S H Bullock A Hinojosa-Corona E Franco-Vizcaíno M Escoto-Rodríguez T G Kretzschmar L M Farfán J M Salazar-Cese?a 《Ecological applications》2007,17(5):1379-1387
In topographically complex terrains, downslope movement of soil organic carbon (OC) can influence local carbon balance. The primary purpose of the present analysis is to compare the magnitude of OC displacement by erosion with ecosystem metabolism in such a complex terrain. Does erosion matter in this ecosystem carbon balance? We have used the Revised Universal Soil Loss Equation (RUSLE) erosion model to estimate lateral fluxes of OC in a watershed in northwestern Mexico. The watershed (4900 km2) has an average slope of 10 degrees +/- 9 degrees (mean +/- SD); 45% is >10 degrees, and 3% is >30 degrees. Land cover is primarily shrublands (69%) and agricultural lands (22%). Estimated bulk soil erosion averages 1350 Mg x km(-2) x yr(-1). We estimate that there is insignificant erosion on slopes < 2 degrees and that 20% of the area can be considered depositional. Estimated OC erosion rates are 10 Mg x km(-2) x yr(-1) for areas steeper than 2 degrees. Over the entire area, erosion is approximately 50% higher on shrublands than on agricultural lands, but within slope classes, erosion rates are more rapid on agricultural areas. For the whole system, estimated OC erosion is approximately 2% of net primary production (NPP), increasing in high-slope areas to approximately 3% of NPP. Deposition of eroded OC in low-slope areas is approximately 10% of low-slope NPP. Soil OC movement from erosional slopes to alluvial fans alters the mosaic of OC metabolism and storage across the landscape. 相似文献
994.
I. Oller W. Gernjak M. I. Maldonado P. Fernández-Ibáñez J. Blanco J. A. Sánchez-Pérez S. Malato 《Environmental Chemistry Letters》2005,3(3):118-121
Titanium dioxide photocatalysis, using 200 mgl−1 of TiO2, and photo-Fenton, using 20 mg l−1 of iron, were applied to the treatment of dimethoate dissolved in water at 50 mg l−1. A heterogeneous photocatalysis test was performed in a 35-l solar pilot plant with Compound Parabolic Collectors (CPCs)
under natural illumination. A homogeneous photocatalysis test was performed in a different solar pilot plant with four CPC
units and a total volume of 75 l. In this work total disappearance of dimethoate and 90% of mineralization were attained in
both solar treatments. Treatment time, hydrogen peroxide consumption and ferric phosphate precipitation during photo-Fenton
treatment were discussed.
An erratum to this article can be found at 相似文献
995.
J.?M.?IgualEmail author M.?G.?Forero G.?Tavecchia J.?González-Solis A.?Martínez-Abraín K.?A.?Hobson X.?Ruiz D.?Oro 《Marine Biology》2005,146(3):619-624
We investigated the possible effects of a 12-g data-logger attached to a darvic ring on the performance of Corys shearwater (Calonectris diomedea, 600–850 g) from two different colonies in the western Mediterranean Sea. We compared return rates, current breeding success and body condition between equipped and unequipped birds. Effects on feeding ecology during winter and breeding period was also evaluated through the measurement of stable isotopes of carbon (13C) and nitrogen (15N) in one of the colonies. We found no evidence of negative effects of loggers on demographic parameters analysed or in feeding ecology. Power analyses suggested a high power to detect medium effect size, but a low power to detect small changes. Despite the non-significant results we could only exclude medium to strong effects of the devices on one of these parameters. We detected some short-term negative effects on body condition for the equipped birds, but these were unlikely to have had important consequences. Results suggest that the use of loggers is an adequate methodology to obtain information from seabirds at sea, but data should be carefully interpreted with regard to potential biases during severe environmental conditions.Communicated by S.A. Poulet, Roscoff 相似文献
996.
Reproductive activity and production of the calanoid copepods Calanus helgolandicus and Calanoides carinatus were measured during a summer upwelling event off the coast of NW Spain. The upwelling pattern affected the distribution and fecundity of both species in the study area. The demographic composition of both populations and the stage of gonad maturation (e.g. the high abundance of fertilised females with mature ova) indicated active reproduction. C.
carinatus, a highly fecund species associated with the African upwelling zones and considered as an upwelling specialist, showed low production rates (overall means of 15 eggs female–1
day–1 and 3% body C day–1), despite the fact that the food conditions (high phytoplankton biomass dominated by diatoms) seemed to be optimal for this species. By contrast, C. helgolandicus, a temperate species that shows a strong link between spring phytoplankton blooms and reproduction time, seems to be flexible enough to take full advantage of shorter-term, enhanced feeding conditions associated with the pulsed nature of the summer coastal upwelling. Both the egg and carbon-specific production rates attained by this species (overall means of 26 eggs female–1
day–1 and 12% body C day–1) were similar to values reported for a spring bloom situation. This high production would imply a long spring–summer recruitment event of C. helgolandicus in these waters. For both species the stage of gonad maturation was significantly correlated with their egg production rates and likely influenced by the food conditions; a species-specific nutritional requirement for final oogenesis is suggested. The carbon condition factor (carbon weight/prosome volume) of C. carinatus
females was higher than that of C. helgolandicus, suggesting differential use of the carbon ingested; C.
helgolandicus seems to use all ingested carbon to produce eggs at a high rates, whereas C. carinatus seems to store part of the ingested carbon as lipid reserves to ensure female survival and to support production during subsequent unfavourable food conditions.Communicated by S.A. Poulet, Roscoff 相似文献
997.
Elena Diaz-Almela Nuria Marbà Elvira Álvarez Elena Balestri Juan M. Ruiz-Fernández Carlos M. Duarte 《Marine Biology》2006,148(4):723-742
The intensive reconstructive sampling (1957–2004, 39 localities), a systematic direct observation (1992–2004, 1 locality)
and particular direct observations (66 localities) of Posidonia oceanica meadows were analysed together with temporal series of flowering available in the literature (19 localities). This allowed
the examination of temporal and spatial variability in annual flowering prevalence (FP, the fraction of meadows flowering
in a given year) and of annual meadow flowering intensity (FI, number of inflorescences per shoot) for the period 1979–2004
across the Western Mediterranean, as well as spatial variability of flowering frequency (FF, the fraction of years that a
given meadow has flowered) and shoot flowering probability (Pf, fraction of flowering stalks appeared per annual segment).
Each year, on an average 17% of the investigated meadows flowered, ranging from 3 to 86% of meadows among the years. The highest
annual FP and FI values were obtained in 2003 (FP=0.86 and mean FI=0.23±0.03 inflorescences shoot−1). A secondary peak of FP and mean FI occurred 9 years earlier, in 1994 (FP=0.44 and mean FI=0.08±0.02). Both peaks of flowering
occurred after hot summers. Flowering synchrony in particular years across the Western Mediterranean and clines of increased
meadow flowering frequency towards the North and East, suggests the existence of large-scale environmental mechanisms controlling
the floral induction. On the other hand, meadow FF and Pf were highly heterogeneous among and within the meadows, indicating
that local factors also may play a significant role in flowering induction. When flowering, the Western Mediterranean meadows
showed an average 0.11±0.02 inflorescences shoot−1, but FI greatly varied among and along the series (from 0.002 to 0.54 inflorescences shoot−1) and decreased significantly with depth but was independent of meadow shoot density and meadow latitude or longitude. The
shoot flowering probability was quite low (0.007±0.002 inflorescences shoot−1 year−1) and exponentially increased with shoot age. 相似文献
998.
Environmental pollution of urban areas is one of key factors that state authorities and local agencies have to consider in the decision-making process. To find a compromise among many criteria, spatial analysis extended by geostatistical methods and dynamic models has to be carried out. In this case, spatial analysis includes processing of a wide range of air, water and soil pollution data and possibly noise assessment and waste management data. Other spatial inputs consist of data from remote sensing and GPS field measurements. Integration and spatial data management are carried out within the framework of a geographic information system (GIS). From a modeling point of view, GIS is used mainly for the preprocessing and postprocessing of data to be displayed in digital map layers and visualized in 3D scenes. Moreover, for preprocessing and postprocessing, deterministic and geostatistical methods (IDW, ordinary kriging) are used for spatial interpolation; geoprocessing and raster algebra are used in multi-criteria evaluation and risk assessment methods. GIS is also used as a platform for spatio-temporal analyses or for building relationships between the GIS database and stand-alone modeling tools. A case study is presented illustrating the application of spatial analysis to the urban areas of Prague. This involved incorporating environmental data from monitoring networks and field measurements into digital map layers. Extra data inputs were used to represent the 3D concentration fields of air pollutants (ozone, NO2) measured by differential absorption LIDAR. ArcGIS was used to provide spatial data management and analysis, extended by modeling tools developed internally in the ArcObjects environment and external modules developed with MapObjects. Ordinary kriging methods were employed to predict ozone concentrations in selected 3D locations together with estimates of variability. Higher ozone concentrations were found above crossroads with their heavy traffic than above the surrounding areas. Ozone concentrations also varied with height above the digital elevation model. Processed data, spatial analysis and models are integrated within the framework of the GIS project, providing an approach that state and local authorities can use to address environmental protection issues. 相似文献
999.
A.?Gómez de SeguraEmail author J.?Tomás S.?N.?Pedraza E.?A.?Crespo J.?A.?Raga 《Marine Biology》2003,143(4):817-823
Aerial surveys were conducted to estimate the abundance and distribution of loggerhead turtles (Caretta caretta) in the Columbretes Islands Marine Reserve and surrounding waters (western Mediterranean). Four surveys were carried out during 2000 and 2001, following the line transect methodology. Loggerheads appeared to be present at high densities in the area throughout the whole year, although density varied between seasons, being more abundant during the spring. Mean density in the study area was 0.322 turtles/km2 (range 0.200–0.516) and the mean abundance was 1,324 turtles (range 825–2,124). The turtles were distributed homogeneously throughout the study area, we found no difference in loggerhead density between the water around the reserve and that in the rest of the study area. Current conservation measures planned by the local authorities, which include increasing the area of the reserve, would be very positive for the conservation of this stock.Communicated by S.A. Poulet, Roscoff 相似文献
1000.
Recent sedimentary history of anthropogenic impacts on the Culiacan River Estuary,northwestern Mexico: geochemical evidence from organic matter and nutrients 总被引:16,自引:0,他引:16
Ruiz-Fernández AC Hillaire-Marcel C Ghaleb B Soto-Jiménez M Páez-Osuna F 《Environmental pollution (Barking, Essex : 1987)》2002,118(3):365-377
210Pb geochronology and sediment profiles of carbon, phosphorus and nitrogen were used to study time dependent changes in nutrients fluxes to Culiacan River Estuary. Results indicate that the release of urban sewage and agriculture wastes transported through Culiacan River has produced historically increased carbon, phosphorus and nitrogen fluxes to the study area. C:N:P elemental ratios showed that increments in the nutrients input begins simultaneously for C, N and P in 1948 with the clearing of the catchment for agriculture; although excess of nutrients input increased most importantly around the 1970s to roughly follow the rapidly growing population of Culiacan City. C/N ratios, delta13C and delta15N suggested that nutrient enrichment is mostly influenced by sewage delivered through Culiacan River. 相似文献