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151.
M. Kassas 《The Environmentalist》2002,22(1):43-49
The Convention on Biological Diversity set conservation of biodiversity on the world agenda. Gaps in knowledge need to be addressed for actions to be effective and sustainable. Gaps include: species diversity, micro-organisms and their ecological roles, ecological and geographical status of species, human capacity to assess and forecast bio-ecological degradation. Requirements for global inventories call for worldwide collaboration. Criteria for setting priorities need to be formulated and agreed.Biodiversity in an eco-geographical region, the southern Mediterranean, is discussed as a case study. Outlines of national actions to contribute to world endeavor are outlined. 相似文献
152.
Sustainable development in the Mediterranean region 总被引:1,自引:0,他引:1
Arab Hoballah 《Natural resources forum》2006,30(2):157-167
Considering its specific economic, social, environmental and political features, the status and evolution of the Mediterranean have always been of great interest to its countries and concerned partners. From the protection of the sea against pollution, the interest was progressively expanded to land based development and its impacts on environment, to coastal management and finally to sustainable development with the establishment of the Mediterranean Commission on Sustainable Development (MCSD). Cumulated knowledge, coupled with political support and commitment to a common vision, has prepared the ground for the preparation of a regional strategy for sustainable development. Its preparatory process, coordinated by the MCSD Secretariat, has been very interactive, involving various stakeholders. The strategy, adopted in 2005, has raised awareness and induced the preparation of national sustainable development strategies. 相似文献
153.
Félix J. González-EstébanezSergio García-Tejero Patricia Mateo-Tomás Pedro P. Olea 《Agriculture, ecosystems & environment》2011,144(1):262-270
Irrigation effects on biodiversity are poorly known, particularly in Mediterranean agro-ecosystems. In this study we analyzed irrigation effects on butterfly species richness, abundance and diversity as well as on species composition in a farmed landscape under Mediterranean climate. The study area consisted of four contiguous agricultural sub-areas with a decreasing degree of intensification: irrigated, mixed (dry and irrigated), dry and environmentally protected (i.e. Special Protection Area, SPA) dry farmland. Forty one km-transects (ten per sub-area) were searched for butterflies in 2008 and 2009. Contrary to expectations, species richness (alfa, beta and gamma diversity) was highest in both years in the most intensified sub-area (i.e. irrigated) followed by SPA, dry and mixed sub-areas. Landscape characteristics accounted for most of the between-subareas differences in species richness. Species richness was negatively related to mean field size at the landscape level and positively related to the number of trees and large shrubs along transects. Therefore, the higher number of butterfly species recorded in the irrigated farmland could be due to a more complex landscape. In contrast, butterfly abundance was highest in cereal steppes (i.e. dry and SPA sub-areas), with abundance being negatively affected by mean field size. Inter-annual change in butterfly abundance was much sharper in rainfed (i.e. dry and SPA) than in irrigated (i.e. irrigated and mixed) sub-areas. Irrigated farmland may provide more favorable conditions for butterflies by buffering the (year-to-year and summer) drought periods characterising Mediterranean climate. Species composition differed among sub-areas, with differences being partly explained by field size and number of trees and shrubs along transects. Our study suggest an important role of landscape characteristics in boosting butterfly biodiversity in intensively managed irrigated croplands and emphasizes the importance of encouraging studies on farmland butterfly diversity in different (bioclimatic) regions allowing the design of region-specific agri-environmental schemes. 相似文献
154.
海南东部河口和近岸海域总溶解态无机砷的分布及季节变化 总被引:2,自引:0,他引:2
利用氢化物发生原子荧光法对2006年12月和2007年8月航次海南东部河流、河口、近岸及地下水中的总溶解态无机砷(total dissolved inorganic arsenic,TDIAs,As5++As3+)进行了测定.2006年12月万泉河及河口、文昌/文教河及河口、近岸TDIAs的浓度分别为4.0~9.4、1.3~13.3、13.3~17.3 nmol.L-1,2007年8月万泉河及河口、文昌/文教河及河口、近岸、地下水TDIAs的浓度分别为1.6~15.5、2.4~15.9、10.8~17.6、未检出~41.7 nmol.L-1.结果表明,万泉河及文昌/文教河河流、河口TDIAs的浓度不存在显著性季节变化,较我国及世界其它河流、河口偏低,处于自然状态.砷在万泉河口和文昌/文教河口混合过程中均表现为保守混合.以文昌/文教河为例,初步估算出2007年文昌/文教河口地下水向沿岸砷的输送通量为1 153 mol.a-1,约为文昌/文教河砷入海通量的二分之一,表明海南东部沿岸地下水也是沿岸海区砷的主要来源之一. 相似文献
155.
Philip J. Platts Colin J. McClean Jon C. Lovett Rob Marchant 《Ecological modelling》2008,218(1-2):121-134
The Eastern Arc Mountains (EAMs) of Tanzania and Kenya support some of the most ancient tropical rainforest on Earth. The forests are a global priority for biodiversity conservation and provide vital resources to the Tanzanian population. Here, we make a first attempt to predict the spatial distribution of 40 EAM tree species, using generalised additive models, plot data and environmental predictor maps at sub 1 km resolution. The results of three modelling experiments are presented, investigating predictions obtained by (1) two different procedures for the stepwise selection of predictors, (2) down-weighting absence data, and (3) incorporating an autocovariate term to describe fine-scale spatial aggregation. In response to recent concerns regarding the extrapolation of model predictions beyond the restricted environmental range of training data, we also demonstrate a novel graphical tool for quantifying envelope uncertainty in restricted range niche-based models (envelope uncertainty maps). We find that even for species with very few documented occurrences useful estimates of distribution can be achieved. Initiating selection with a null model is found to be useful for explanatory purposes, while beginning with a full predictor set can over-fit the data. We show that a simple multimodel average of these two best-model predictions yields a superior compromise between generality and precision (parsimony). Down-weighting absences shifts the balance of errors in favour of higher sensitivity, reducing the number of serious mistakes (i.e., falsely predicted absences); however, response functions are more complex, exacerbating uncertainty in larger models. Spatial autocovariates help describe fine-scale patterns of occurrence and significantly improve explained deviance, though if important environmental constraints are omitted then model stability and explanatory power can be compromised. We conclude that the best modelling practice is contingent both on the intentions of the analyst (explanation or prediction) and on the quality of distribution data; generalised additive models have potential to provide valuable information for conservation in the EAMs, but methods must be carefully considered, particularly if occurrence data are scarce. Full results and details of all species models are supplied in an online Appendix. 相似文献
156.
Françoise Henry Céline Mahfouz Alice Delegrange Lucie Courcot 《Chemistry and Ecology》2017,33(4):271-280
Mercury (Hg) in fish can present a potential risk to wildlife and human consumers. Mercury levels were determined in 12 fish species and 2 invertebrate species from the French coast of the Eastern English Channel collected in June and November 2012. Total mercury concentrations in the muscle tissues ranged between 0.04 and 1.63 µg g-1 (d.w.). Dab and sandeel displayed a significant positive correlation between Hg concentrations and fish length. Seasonal differences in Hg concentrations were observed for dab and shrimp. The lesser weever showed significantly higher concentrations of Hg (0.97 ± 0.34 µg g-1 d. w.) than all other species. Gobies and sprat, which had the smallest size, showed significantly lower concentrations than herring, whiting, pout and sardine. Among the considered species, flatfish such as dab, flounder, plaice and sole displayed intermediate levels of Hg. In the present study, the fish age expressed as specimen length seems to be one of the major factors governing Hg contents in muscle tissues. Finally, mercury concentrations in commercial fish from the Eastern English Channel were below the levels fixed by the European Union for total mercury in edible parts of fish products. 相似文献
157.
The effects of disturbance based management on the dynamics of Mediterranean vegetation: A hierarchical and spatially explicit modeling approach 总被引:1,自引:0,他引:1
Avi Bar Massada Yohay Carmel Gili Koniak Imanuel Noy-Meir 《Ecological modelling》2009,220(19):2525-2535
The eastern Mediterranean region has been subjected to intensive human disturbance in the past 10,000 years, mainly in the forms of agro-pastoral activities such as grazing, shrub clearing, and prescribed burning. This disturbance history resulted in the formation of highly heterogeneous landscapes, characterized by high biodiversity. Recent changes in human activities have resulted in a decrease of landscape heterogeneity, leading to decreasing biodiversity and increasing fire risk. To conserve heterogeneity, land managers apply disturbance based management practices, using the same activities that created and maintained landscape heterogeneity in the past. However, the long-term and large-scale outcomes of these disturbances are often unknown, due to the complex response of Mediterranean vegetation to disturbance. Here we report on a spatially explicit, hybrid, and spatially hierarchical ecological model developed by us. The model attempts to predict the outcome of various disturbance based management activities on the long-term spatio-temporal dynamics of five common Mediterranean vegetation types. The model uses a spatially explicit state and transition formulation, with continuous transition functions. Model simulations were conducted on a Mediterranean landscape in Northern Israel, incorporating various disturbance practices that are common in the region. Simulation results highlight the potential of disturbance based management as a tool for conserving landscape heterogeneity, as well as the complex interactions between disturbances and the spatial structure of the landscape in Mediterranean regions. 相似文献
158.
A stage structured population (SSP) model based on Fennel's [Fennel, W., 2001. Modelling copepods with links to circulation models. Journal of Plankton Research, 23, 1217–1232] equations is applied to Centropages typicus (Kröyer), a dominant copepod species of the North Western Mediterranean Sea (NWMS) and a prey of small pelagic fish. The model considers five groups of stages and development rates are represented by a mechanistic formulation depending on individual specific growth in each stage. Individual growth is calculated from the individual energy budget depending on food availability and temperature. 相似文献
159.
The simultaneous accounting of effects of natural and anthropogenic changes within a common framework calls for the development of new comprehensive tools capable of integrating biological processes that span a huge range of scales, from viruses to fishes, in addition to their interactions with physical–chemical environmental properties, i.e. End-to-End models. 相似文献
160.
The atmospheric chemical composition is affected by the interaction mechanisms among gases and particulate matter through
a wide range of chemical reactions that can occur with the aid of particulate matter (e.g. particles act as reacting or absorbing
surfaces) or be influenced by the presence of particulate matter in the atmosphere (photochemical reactions). Physical and
chemical processes are also bonded in an interactive way that often leads to the influence of the radiation budget, cloud
physics and the warming or cooling of the lower atmospheric levels. The Euro-Mediterranean region is a key-sensitive area
due to the unique climatic and air quality characteristics associated with the regional climatic patterns, geomorphology (land
and water contrast) and coexistence of pollutants from different origin. Focusing on this region, the gas-aerosol interactions
are studied using state-of-the-art atmospheric and chemical transport modeling tools following the necessary development in
the chemical transport model CAMx. Sensitivity and large-scale simulations have shown significant responses of the modeling
system to the inclusion of natural species emissions, the direct shading effect of dust particles on photochemical processes
and the formation of new types of aerosols through heterogeneous uptake of gases on dust particles. Including such interactions
in the chemical transport model often led to the improvement of the model performance compared with available measurements
in the region. 相似文献