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931.
Spatiotemporal distribution patterns in relation to feeding behavior of herbivorous gastropods have been studied extensively,
but still knowledge about small-scale patterns is limited in relation to eutrophication. This experimental study aimed to
describe the small-scale distribution of Littorina littorea in nutrient-enriched and nutrient-unenriched mesocosms in a merely atidal region and relate the distribution to food abundance
and possible competing organisms, while checking simultaneously for feeding activities. The latter part was accomplished through
the “gut fluorescence technique” GFT (which, to our knowledge, has not previously been used for benthic grazers) to estimate
per capita grazing rates and the former part through monitoring of spatial heterogeneity of L. littorea and co-variation with sessile organisms (using semivariograms and cross-semivariograms, respectively). After 5 months of
nutrient addition, the abundance and biomass of L. littorea had increased in enriched systems, which also had significantly higher total biomass of green algae. Gut pigment content
was higher in L. littorea from enriched mesocosms, and gut depletion rate was higher in L. littorea from unenriched mesocosms. Spatial analysis showed that L. littorea exhibited generally random patterns (suggesting feeding activities) but sometimes (often in the morning) spatial patchiness
(clumped distribution) in both enriched and unenriched conditions. There was mainly positive co-variation between L. littorea and biofilm, while different nutrient conditions exhibited contrasting co-variation between L. littorea and barnacles (positive co-variation in enriched and negative co-variation in unenriched mesocosms). The study offered insights
into how feeding behavior and spatial distribution of a species may interact with community components differently under different
nutrient regimes. The applied methodology can be useful for purposes of faster examination of grazing effects among different
regions and also to compare grazing intensities and interactions between grazers and the benthic communities in disturbed
(including pollution and nutrient enrichment) and non-disturbed systems, as well as in up-welling versus non-upwelling areas. 相似文献
932.
Climate change is one of the main factors that will affect biodiversity in the future and may even cause species extinctions. We suggest a methodology to derive a general relationship between biodiversity change and global warming. In conjunction with other pressure relationships, our relationship can help to assess the combined effect of different pressures to overall biodiversity change and indicate areas that are most at risk. We use a combination of an integrated environmental model (IMAGE) and climate envelope models for European plant species for several climate change scenarios to estimate changes in mean stable area of species and species turnover. We show that if global temperature increases, then both species turnover will increase, and mean stable area of species will decrease in all biomes. The most dramatic changes will occur in Northern Europe, where more than 35% of the species composition in 2100 will be new for that region, and in Southern Europe, where up to 25% of the species now present will have disappeared under the climatic circumstances forecasted for 2100. In Mediterranean scrubland and natural grassland/steppe systems, arctic and tundra systems species turnover is high, indicating major changes in species composition in these ecosystems. The mean stable area of species decreases mostly in Mediterranean scrubland, grassland/steppe systems and warm mixed forests. 相似文献
933.
Farming in higher latitudes is generally believed to benefit from a warmer climate due to extended growing season, reduced risk of frost, availability of more productive cultivars, and an opening potential of farming in northern locations. We analyzed the impact of climate change on production of cereals in Russia and found that this general perception of beneficiary effect of a warmer climate is unlikely to hold, primarily due to increasing risk of droughts in the most important agricultural areas of the country. Past impacts of droughts on food security throughout the twentieth century suggest that a number of adaptation options are available to mitigate the increasing risks of crop failure. We analyze the effectiveness of these measures in connection with a set of climate change projections, under two contrasting scenarios of interregional grain trade: “Fortress Market” and “Open Market.” 相似文献
934.
James S. Risbey 《Regional Environmental Change》2011,11(1):197-203
Water resources in Australia are sensitive to changes in rainfall. Ongoing droughts in south-west and south-east Australia are stressing water resources in the major cities and in agricultural regions. Climate change scenarios for Australia include reasonable prospects of long-term drying, which would exacerbate these issues. The dryer scenarios would entail major readjustments and costs on natural and human systems. 相似文献
935.
Andrea M. Bassi 《Regional Environmental Change》2011,11(2):285-295
Observing the many and varied reactions to the Kyoto Protocol, it becomes clear that different governments find themselves
in different contexts that eventually direct them toward taking dissimilar positions on energy issues. This paper, through
five integrated studies, investigates whether contextualizing energy issues is (are) relevant to support energy policy formulation
and evaluation and provides insights into how to operationalize the contextualization. Instead of considering the most widely
accepted tools currently used to assess and evaluate energy policy, this research proposes the utilization of a holistic framework
that incorporates social, economic and environmental factors as well as their relations to the energy sector to better contextualize
global, regional and national energy issues. This framework, which accounts for feedback loops, delays and non-linearity,
is applied to case studies to investigate the longer-term performance of selected energy policies. Results of the study indicate
the likely emergence of various unexpected side effects and elements of policy resistance over the medium and longer term
due to the interrelations existing between energy and society, economy and environment. Furthermore, while side effects and
unintended consequences may arise both within the energy sector and in the other sectors, they simultaneously influence society,
economy and environment. 相似文献
936.
Ecosystem services and hydroelectricity in Central America: modelling service flows with fuzzy logic and expert knowledge 总被引:1,自引:0,他引:1
Bruno Locatelli Pablo Imbach Raffaele Vignola Marc J. Metzger Efraín José Leguía Hidalgo 《Regional Environmental Change》2011,11(2):393-404
Because ecosystem services are generally not produced and used in the same place, their assessment should consider the flows
of services from ecosystems to users. These flows depend on the characteristics and spatial distribution of ecosystems and
users, the spatial relationships between them, and the presence of filters or barriers between ecosystems and users. The objective
of this paper is to map the ecosystem services provided to the Costa Rican and Nicaraguan hydroelectric sectors, which are
crucial sectors for national sustainable development and depend directly on hydrological ecosystem services. The paper presents
an approach for modelling the flows of multiple services from diverse ecosystems to diverse users through different kinds
of filters in a landscape. The approach uses expert knowledge and fuzzy numbers to handle uncertainties. The analyses for
Costa Rica and Nicaragua show how the approach helps identify priority areas for the conservation and restoration of forests
for the services they provide to the hydroelectric sector. As such, it is a useful tool for defining spatially targeted policies
for the conservation of ecosystem services and for involving the users of ecosystem services in ecosystem management. 相似文献
937.
Marc Gracia Nacima Meghelli Lluís Comas Javier Retana 《Regional Environmental Change》2011,11(2):349-358
The current state of Mediterranean mountain areas has been driven by two main factors: intense traditional human activity
and the dynamics of the ecosystem itself. In this study, we examine land-cover changes in a National Park in the Pyrenees
mountains (NE Iberian Peninsula), which was designated a protected area 55 years ago. First, we have analyzed spatio-temporal
changes in land-cover pattern and forest dynamics from 1957 to 2005. During this period, land-cover dynamics consisted of
two main processes: (i) expansion of the forest area and (ii) increasing cover of forests already present in 1957. To analyze
the role of the conservation level of the park, we have also compared the results obtained within the park with those of unprotected,
peripheral areas. In the two areas with different protection level, dense forests increased throughout the period because
of the reduction in forestry activities. The peripheral area showed a higher rate of forest-cover change from 1957 to 2005
compared to the National Park. This higher increase in forest cover in the peripheral area could be related to a higher proportion
in the National Park of screes and rocky areas and to the decline and transformation of forest activities in these peripheral,
lower elevation areas. 相似文献
938.
939.
Renewable energy sources are mainly used in the electrical sector. Electricity is not a storable commodity. Hence, it is necessary
to produce the requested quantity and distribute it through the system in such a way as to ensure that electricity supply
and demand are always evenly balanced. This constraint is actually the main problem related to the penetration of new renewables (wind and photovoltaic power)
in the context of complex energy systems. The paper analyzes some aspects in connection with the problem of new renewable
energy penetration. The case of Italian scenario is considered as a meaningful reference due to the characteristic size and
the complexity of the same. The various energy scenarios are evaluated with the aid of a multipurpose software taking into
account the interconnections between the different energetic uses. In particular, it is shown how the penetration of new renewable
energies is limited at an upper level by technological considerations and it will be more sustainable if an integration of
the various energy use (thermal, mobility and electrical) field will be considered. 相似文献
940.
Masahiko Matsuda 《Environment, Development and Sustainability》2011,13(1):51-64
This study aims to estimate the intensification of rice farming in Myanmar particularly due to chemical fertilizer application,
using farm-level data obtained from field surveys conducted in the 2000s. Relatively high-input rice farming was found in
dry season crop in the delta zone and the double crop in well-irrigated lowlands of the central dry zone. The chemical fertilizer
used there was about 88–159 kg NPK (nitrogen, N; phosphate, P2O5; and potash, K2O) ha−1 (76–110 kg nitrogen (N) ha−1), and the average paddy yield ranged from 2.8 to 3.5 ton ha−1. On the other hand, nutrient input in survey sites of rain-fed lowland was between 11 and 53 kg NPK ha−1 (5 and 36 kg N ha−1), and the yield ranged from 1.1 to 2.3 ton ha−1. The national average of paddy yield and nutrient input of fertilizer was roughly estimated to be around 2.4 ton ha−1 and 60 kg NPK ha−1, respectively. A gap was observed between these calculated values and the official statistics. A comparison of fertilizer
use efficiency for rice production in Myanmar with that in China and Vietnam has shown that the efficiency in Myanmar has
not declined to an inappropriate level even in its intensive ones. Rice production in Myanmar has room for increasing the
yield by capital intensification. Nevertheless, considering its sustainability as well as productivity, further intensification
in rice farming technology in irrigated lowlands of Myanmar may neither be the best nor the only way. 相似文献