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1.
An emergy evaluation was carried out to assess the carrying capacity of a small, uninhabited island (Woosedo) off the southwestern coast of Korea. The sea area within 1 km from the high tide level of the island was included in the evaluation. The total environmental emergy input to Woosedo was 1.66E19 sej/yr, with the most emergy contribution from the tidal energy. The land and marine ecosystems of Woosedo contributed 4.97 million Em$ (7600 Em$/ha/yr) to the Korean economy annually. If Woosedo was developed to the national average at the emergy investment ratio of 2.86, its carrying capacity was estimated at 1034 people at the current living standard of Korea. With this population, the island system would not be sustainable with a very low emergy sustainability index of 0.36. At the same living standard used in the developed scenario, the carrying capacity of the island would be 370 people for a sustainable development scenario and 270 people if the renewable emergy were the only source to support the population. The emergy contribution of the marine ecosystem of the island was the major source of support in determining the level of carrying capacity of the island.  相似文献   

2.
We describe a simulation model representing the most important human and natural factors driving land use and cover changes (LUCC) in southern Chile. We evaluate the model by examining its ability to simulate LUCC observed over the past three decades, conduct a sensitivity analysis of simulated trends to changes in important model parameters, and use the model to project likely landscape transformations over the next decade under “as usual,” “pessimistic,” and four “optimistic” scenarios. The model consists of five submodels representing LUCC on two distinct soil formations (volcanic ash and gleysols) and four major land use categories: native forest, agricultural land, shrubland, and urban land. Land use and cover sub-categories include old growth forests, secondary forests, and low and flooded shrubland. The model simulated well general historic trends in forest cover, agricultural land, shrubland, and urban land: from a forest-dominated landscape in 1976 to a landscape dominated by shrubland and agricultural land by 2007. Forest loss, forest degradation by logging and clearing for agriculture were the most important direct drivers of LUCC: forest logging and clearing were most important from 1976 to 1985, whereas after 1985 logging for firewood, driven by population growth, was most important. Sensitivity analysis indicated that model projections of general trends in the main land use and cover categories were not overly sensitive to changes in important model parameters, although further study is necessary to improve our estimates of the proportion of pasture requirements supplied by clearing low shrubland. Projections of LUCC suggested that a reduced amount of secondary forest would be left by 2017 if no actions are taken to reduce forest loss (“as usual”). Increasing population (“pessimistic scenario”) resulted in similar trajectories than those predicted by the as usual scenario, whereas reducing logging for firewood and increasing forest recruitment from shrubland could reduce loss of native forest by nearly one-third (“optimistic scenarios”). Surprisingly, shrubland exhibited the most complex and influential dynamics in all scenarios, being the immediate outcome of forest loss and the main long-term source of land for agriculture, urban expansion, and forest recovery. Few studies in Chile, or elsewhere, have considered the importance of this intermediate successional stage. Of the scenarios simulated, financial incentives targeted toward channeling shrubland into regenerated forest seemed most promising, although obstacles to such a management strategy exist.  相似文献   

3.
Land-use change significantly contributes to biodiversity loss, invasive species spread, changes in biogeochemical cycles, and the loss of ecosystem services. Planning for a sustainable future requires a thorough understanding of expected land use at the fine spatial scales relevant for modeling many ecological processes and at dimensions appropriate for regional or national-level policy making. Our goal was to construct and parameterize an econometric model of land-use change to project future land use to the year 2051 at a fine spatial scale across the conterminous United States under several alternative land-use policy scenarios. We parameterized the econometric model of land-use change with the National Resource Inventory (NRI) 1992 and 1997 land-use data for 844 000 sample points. Land-use transitions were estimated for five land-use classes (cropland, pasture, range, forest, and urban). We predicted land-use change under four scenarios: business-as-usual, afforestation, removal of agricultural subsidies, and increased urban rents. Our results for the business-as-usual scenario showed widespread changes in land use, affecting 36% of the land area of the conterminous United States, with large increases in urban land (79%) and forest (7%), and declines in cropland (-16%) and pasture (-13%). Areas with particularly high rates of land-use change included the larger Chicago area, parts of the Pacific Northwest, and the Central Valley of California. However, while land-use change was substantial, differences in results among the four scenarios were relatively minor. The only scenario that was markedly different was the afforestation scenario, which resulted in an increase of forest area that was twice as high as the business-as-usual scenario. Land-use policies can affect trends, but only so much. The basic economic and demographic factors shaping land-use changes in the United States are powerful, and even fairly dramatic policy changes, showed only moderate deviations from the business-as-usual scenario. Given the magnitude of predicted land-use change, any attempts to identify a sustainable future or to predict the effects of climate change will have to take likely land-use changes into account. Econometric models that can simulate land-use change for broad areas with fine resolution are necessary to predict trends in ecosystem service provision and biodiversity persistence.  相似文献   

4.
Simulating future land use and ecosystem services in Northern Thailand   总被引:1,自引:0,他引:1  
Enhancing ecosystem services is important as it provides foundation for the wellbeing of people. This paper presents the future land use simulation for enhancing ecosystem services using CLUMondo dynamic spatial model. The land use change was assessed from 1989 to 2013 in Wang Thong watershed of Northern Thailand using GIS and a set of ecosystem services was assessed using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. Future land uses until 2030 were projected for three policy scenarios, namely business-as-usual, integrated land use development, and enhancing environmental services with different levels of emphasis on ecosystem services. In business-as-usual scenario, it was observed that ecosystem services will decline by 2030 from the base year of 2013, whereas in integrated land use development scenario, the ecosystem services will increase by 5% compared to base year due to anticipated effective protection of remaining forests in all existing and proposed protected areas of the study area. In enhancing environmental services scenario, the ecosystem services will increase by 15%. Such results can serve as useful information in policy formulation in developing land use options, which help enhance ecosystem services in future.  相似文献   

5.
Increased future demands for food, fibre and fuels from biomass can only be met if the available land and water resources on a global scale are used and managed as efficiently as possible. The main routes for making the global agricultural system more productive are through intensification and technological change on currently used agricultural land, land expansion into currently non-agricultural areas, and international trade in agricultural commodities and processed goods. In order to analyse the trade-offs and synergies between these options, we present a global bio-economic modelling approach with a special focus on spatially explicit land and water constraints as well as technological change in agricultural production. For a global bioenergy demand scenario reaching 100 ExaJoule (EJ) until 2055 we derive a required rate of productivity increase on agricultural land between 1.2 and 1.4 percent per year under different land allocation options. A very high pressure for yield increase occurs in Sub-Saharan Africa and the Middle East, even without additional bioenergy demand. Moreover, we analyse the implicit values (shadow prices) of limited water resources. The shadow prices for bioenergy are provided as a metric for assessing the trade-offs between different land allocation options and as a link between the agricultural and energy sector.  相似文献   

6.
Human activities have become so extensive that all ecosystems on the planet have been altered to some extent. The fate of humankind will be determined by how sustainable ecosystems and the renewable resources in them are managed. The implication of this is obvious: humanity must live within nature's carrying capacity. In recent years, humans have recognised that growth of the economy depends on natural capital, and it is important that we now recognise that we are part of an international ecological economics community, so as to better integrate the economy and ecology. However, there are few successful examples of this. The aim of this paper is to show a method for integrated analysis between economic growth and natural carrying capacity by linking the concepts of ecological footprint and valuation of ecosystem services. When applied to China for the period 1987–2003, the empirical evidence suggests that the size of the Chinese economy surpassed the carrying capacity in 1992. Perhaps, we should abandon our high-growth predilection and initiate a transition to a steady-state economy.  相似文献   

7.
《Ecological modelling》2004,180(1):73-87
Spatial modeling of forest patterns can provide information on the potential impact of various management strategies on large landscapes over long time frames. We used LANDIS, a stochastic, spatially-explicit, ecological landscape model to simulate 120 years of forest change on the Nashwauk Uplands, a 328,000 ha landscape in northeastern Minnesota that lies in the transition between boreal and temperate forests. We ran several forest management scenarios including current harvesting practices, no harvests, varied rotation ages, varied clearcut sizes, clustered clearcuts, and landowner coordination. We examined the effects of each scenario on spatial patterns of forests by covertype, age class, and mean and distribution of patch sizes. All scenarios reveal an increase in the spruce-fir (Picea-Abies) covertype relative to the economically paramount aspen-birch (Populus-Betula) covertype. Our results also show that most covertypes occur in mostly small patches <5 ha in size and the ability of management to affect patch size is limited by the highly varied physiography and landuse patterns on the landscape. However, coordination among landowners, larger clearcuts, and clustered clearcuts were all predicted to increase habitat diversity by creating some larger patches and older forest patches. These three scenarios along with the no harvest scenario also create more old forest than current harvesting practices, by concentrating harvesting on some portion of the landscape. The no harvest scenario retained large, fire-regenerated aspen-birch patches. Harvests fragment large aspen-birch patches by changing the age structure and releasing the shade-tolerant understory species. More sapling forest, and larger sapling patches resulted from the shortened rotation scenario.  相似文献   

8.
Scientists, resource managers, and decision makers increasingly use knowledge coproduction to guide the stewardship of future landscapes under climate change. This process was applied in the California Central Valley (USA) to solve complex conservation problems, where managed wetlands and croplands are flooded between fall and spring to support some of the largest concentrations of shorebirds and waterfowl in the world. We coproduced scenario narratives, spatially explicit flooded waterbird habitat models, data products, and new knowledge about climate adaptation potential. We documented our coproduction process, and using the coproduced models, we determined when and where management actions make a difference and when climate overrides these actions. The outcomes of this process provide lessons learned on how to cocreate usable information and how to increase climate adaptive capacity in a highly managed landscape. Actions to restore wetlands and prioritize their water supply created habitat outcomes resilient to climate change impacts particularly in March, when habitat was most limited; land protection combined with management can increase the ecosystem's resilience to climate change; and uptake and use of this information was influenced by the roles of different stakeholders, rapidly changing water policies, discrepancies in decision-making time frames, and immediate crises of extreme drought. Although a broad stakeholder group contributed knowledge to scenario narratives and model development, to coproduce usable information, data products were tailored to a small set of decision contexts, leading to fewer stakeholder participants over time. A boundary organization convened stakeholders across a large landscape, and early adopters helped build legitimacy. Yet, broadscale use of climate adaptation knowledge depends on state and local policies, engagement with decision makers that have legislative and budgetary authority, and the capacity to fit data products to specific decision needs.  相似文献   

9.
In the flat fish Limanda limanda L., feeding rate and conversion efficiency were studied as functions of body weight, sex, temperature and food quality. When offered herring meat at 13 °C (series I), females (live weights 1 to 150 g) consume more food than males; the magnitude of this difference is body weight-dependent. With increasing wieght, both females and males consume less food per unit body weight per day. Variations in daily ration are considerable; the range of deviation from mean feeding rate is about 60% for males and 40% for females. The range of deviation does not vary significantly among females and males of different body weights. At the same temperature level (13 °C; series II), females consume almost the same, or even less, cod meat than males. Among individuals of series I and II, there is a little difference in the feeding rate; however, herring-fed individuals obtain about 2 times more energy than cod-fed individuals. Each gram wet weight of herring meat yields 2001, each gram cod meat 1137, calories. Small individuals completely cease to feed at 3°C; they feed little at 8 °C. Larger females consume maximum amounts at 8 °C. Small individuals consume maximum amounts at higher temperatures. Thus, with increasing body weight (age), the temperature for maximum feeding shifts downwards. Feeding with cod or herring meat results in considerable changes in composition and calorific content of L. Limanda. The magnitude of these changes depends both on temperature and food quality. Food conversion efficiency values of herring-fed individuals are about 1 1/2 times higher than of cod-fed individuals. In series I and II, females are more efficient converters than males. In individuals weighing more than 50 g, conversion efficiency decreases in the order: 8°, 13°, 18° C; in smaller individuals this order is 13°, 18°, 8 °C. Conversion rate is about 2 to 5 times faster in individuals fed herring meat than those receiving cod meat. Conversion rate decreases in the order 13°, 8°, 18 °C in males, and in the order 18°, 13°, 8 °C in females; females of more than 80 g are exceptional in that they reach the maximum at 8 °C. From the data on food intake and food conversion, the biologically useful energy available for metabolism has been calculated for each test individual kept at 13° and 18 °C. At these temperature levels, the weight exponents are about 0.6; the a value or metabolic level for the 18 °C series is about 2 times higher than that at 13 °C. Thus, temperature affects metabolic rate but not the exponential value. The exponential value for the body weight-metabolism relation at 13 °C is for dab fed herring meat 0.9; the a value amounts to about half that for dab fed cod meat. Food quality, unlike temperature, alters not only the exponential value but also metabolic rate.  相似文献   

10.
The crop livestock integrated farming system practiced in hilly regions of developing countries largely depends on the ecosystem as a whole. More especifically, the livestock component of the farming system relies heavily on natural resources such as forest, grazing and agricultural land for the supply of feed and fodder. The importance of animals as agents of nutrient recycling, sources of rural energy in terms of draft power and fuel, as well as being major contributors to the farm economy, has resulted in an increased population of ruminants in these regions, creating a threat to the sustainability and productivity of these land resources. This paper is an attempt to evaluate the livestock carrying capacity of land resources and to formulate the optimum herd size compatible with the differently resourced farm categories within the sub-watershed region of the mid-hills in Nepal. Our analysis reveals that the livestock carrying capacity of the land resources at the watershed level is 11696 Livestock Units (LU), whereas current stocking is 12985 LU, suggesting an overstocking of 1289 LU at the watershed level. Total feed supply from different sources is 12668 mt/yr whereas current Total Digestive Nutrient (TDN) demand is 14060 mt/yr, a negative balance of 1393 mt/yr. The excess livestock at the sub-watershed level directly implies excess livestock holding, producing a poor nutritional status for the farm household. Linear programming analysis reveals that the farmers of large, medium and small category farms can optimize their livestock holding by a combination of 3 LU buffaloes and 4 LU goats, 2 LU buffaloes and 4 LU goats and 1 LU buffaloes and 4.4 LU goats, thus giving maximum return to the farm family without exerting pressure on fragile natural resources.  相似文献   

11.
The estimation of nutrient fluxes, the determination of spatial and temporal response and the understanding of biogeochemical changes in the past, present and future in the Axios River catchment, in Greece, as well as the impacts to the coastal zone of Thermaikos Gulf were accomplished by the use of harmonized watershed and coastal zone models. The mathematical model MONERIS was the watershed management model that was used to model the export loads of nutrients in Axios River. MONERIS was developed to estimate the nutrient inputs into river basins by point sources and various diffuse pathways. Watershed hydrologic and water quality data were collected and synthesized to develop input data sets for the simulation of Axios River catchment. The model was modified to better assess organic nitrogen export loads in Mediterranean watersheds. The results showed the importance of agricultural and livestock activities, concerning their nutrients emissions in the River. MONERIS was integrated with the coastal zone model WASP 6.0 to assess the impacts of the nutrient loads to the eutrophication status of the coastal zone. Several management scenarios were assessed. Management scenarios included measures for reduction in the emissions from the fertilizer plant of Veles, removal of phosphorous from the detergents in FYROM, treatment of urban wastes to EU Standards, reduction in N-fertilizer input, reduction in erosion and the green scenario that represented the maximum reduction scenario of all the measures together. The model simulations indicated that the coastal zone of Axios mouth will be eutrophic for nitrate (2.69–3.34 μM) and phosphate (0.2–0.68 μM) and upper mesotrophic for chlorophyll-a (0.74–1.45 μg/l) for the scenarios tested. The results suggest that the impact of the management scenarios will be largely negligible (no change in trophic status) for the Thermaikos Gulf sector nearby the Axios River due to additional sources such as the loads from Thessaloniki's waste water treatment plant which appear to affect the region to a greater extent. The integration of watershed and coastal zone models can be used to assess management scenarios in order to illustrate the significance of various land use practices to the eutrophication of the Gulf.  相似文献   

12.
Land degradation threatens environmental well-being and is a growing global issue. China is among the most affected countries in the world in terms of the extent, intensity and economic impact of land degradation. Sustainable and successful intervention requires clear definition and quantification of land degradation. Based on land resource variation survey data from 1991 to 2002, this paper identified, defined and classified land resource degradation, and analyzed dynamic changes in the degradation and rehabilitation process. Through the establishment of a land resource degradation index, the status and trend of degradation in China was explored to enable the design and planning of interventions for mitigation and establishment of sustainable land use and management practices. Results showed that: (1) The total land degradation index (A) fluctuated upwards from 1991 to 2002, although some parts improved. (2) Sand and rock desertification, deforestation and wetland loss reduced slightly, whereas secondary salinification, non-agricultural land occupation and natural grassland further deteriorated. (3) 66.27% of degradation was in natural grassland and non-agricultural land; while 57.5% of rehabilitation focused on sandy desertification and forests. (4) Non-agricultural land occupation and wetland shrinkage are primary causes of land resource deterioration in China. (5) Grassland, cultivated land and forest land accounted for 83.9% of degradation. (6) All the degradation processes are interrelated. These results provide useful information to combat future land resource degradation in China.  相似文献   

13.
The ecological and economic consequences of rain forest conversion and fragmentation for biodiversity, ecosystem functioning, and ecosystem services like protection of soils, water retention, pollination, or biocontrol are poorly understood. In human-dominated tropical landscapes, forest remnants may provide ecosystem services and act as a source for beneficial organisms immigrating into adjacent annual and perennial agro-ecosystems. In this study, we use empirical data on the negative effects of increasing forest distance on both pollinator diversity and fruit set of coffee to estimate future changes in pollination services for different land use scenarios in Sulawesi, Indonesia. Spatially explicit land use simulations demonstrate that depending on the magnitude and location of ongoing forest conversion, pollination services are expected to decline continuously and thus directly reduce coffee yields by up to 18%, and net revenues per hectare up to 14% within the next two decades (compared to average yields of the year 2001). Currently, forests in the study area annually provide pollination services worth 46 Euros per hectare. However, our simulations also revealed a potential win-win constellation, in which ecological and economic values can be preserved, if patches of forests (or other natural vegetation) are maintained in the agricultural landscape, which could be a viable near future option for local farmers and regional land use planners.  相似文献   

14.
Guoliang Liu  Shijie Han 《Ecological modelling》2009,220(13-14):1719-1723
In their efforts to deal with global climate change, scientists and governments have given much attention to the carbon emissions associated with fossil fuels and to strategies for reducing their use. While it is very important to burn less fossil fuel and to employ alternative energy sources, other carbon-reduction options must also be considered. Given that forests comprise a large portion of the global landbase and that they play a very significant role in the global carbon cycle, it is logical to examine how forest management practices could effect reductions in carbon emissions. Many papers that discuss forest carbon sinks or sources refer only to the short term (<20 years). This paper focuses on the sustainable carbon storage contributions of a forest over the long term. This paper explains that long-term carbon storage and reduced carbon fluctuation can be achieved by a combination of improved forest management and efficient transfer of carbon into wood products. Here we show how three different forest management scenarios affect the overall carbon storage capacity of forest and wood products combined over the long term. We used a timber supply model and scenario analysis to predict forest carbon and other resource conditions over time in the Prince George Forest District, a 3.4-million-ha landbase in northern British Columbia. We found that the high-harvest scenario stores 3% more carbon than the low-harvest scenario and 27% (120 million tonnes) more carbon than the no-harvest scenario even though only 1.2-million ha is in timber harvesting landbase. Our results tell us that forest management practices that maintain and increase forest area, reduce natural disturbances in the forest, improve forest conditions, and ensure the appropriate and timely transfer of carbon into wood products lead to increasing overall carbon storage, thereby reducing carbon in the atmosphere.  相似文献   

15.
Species shift their distribution in response to climate and land-cover change, which may result in a spatial mismatch between currently protected areas (PAs) and priority conservation areas (PCAs). We examined the effects of climate and land-cover change on potential range of gibbons and sought to identify PCAs that would conserve them effectively. We collected global gibbon occurrence points and modeled (ecological niche model) their current and potential 2050s ranges under climate-change and different land-cover-change scenarios. We examined change in range and PA coverage between the current and future ranges of each gibbon species. We applied spatial conservation prioritization to identify the top 30% PCAs for each species. We then determined how much of the PCAs are conserved in each country within the global range of gibbons. On average, 31% (SD 22) of each species’ current range was covered in PAs. PA coverage of the current range of 9 species was <30%. Nine species lost on average 46% (SD 29) of their potential range due to climate change. Under climate-change with an optimistic land-cover-change scenario (B1), 12 species lost 39% (SD 28) of their range. In a pessimistic land-cover-change scenario (A2), 15 species lost 36% (SD 28) of their range. Five species lost significantly more range under the A2 scenario than the B1 scenario (p = 0.01, SD 0.01), suggesting that gibbons will benefit from effective management of land cover. PA coverage of future range was <30% for 11 species. On average, 32% (SD 25) of PCAs were covered by PAs. Indonesia contained more species and PCAs and thus has the greatest responsibility for gibbon conservation. Indonesia, India, and Myanmar need to expand their PAs to fulfill their responsibility to gibbon conservation. Our results provide a baseline for global gibbon conservation, particularly for countries lacking gibbon research capacity.  相似文献   

16.
Strategies for conserving plant diversity in agroecosystems generally focus on either expanding land area in non-crop habitat or enhancing diversity within crop fields through changes in within-field management practices. In this study, we compare effects on landscape-scale species richness from such land-sharing or land-sparing strategies. We collected data in arable field, grassland, pasture, and forest habitat types (1.6 ha sampled per habitat type) across a 100-km2 region of farmland in Lancaster County, Pennsylvania, USA. We fitted species-area relationships (SARs) for each habitat type and then combined extrapolations from the curves with estimates of community overlap to estimate richness in a 314.5-ha landscape. We then modified these baseline estimates by adjusting parameters in the SAR models to compare potential effects of land-sharing and land-sparing conservation practices on landscape richness. We found that species richness of the habitat types showed a strong inverse relationship to the relative land area of each type in the region, with 89 species in arable fields (66.5% of total land area), 153 in pastures (6.7%), 196 in forests (5.2%), and 213 in grasslands (2.9%). Relative to the baseline scenario, major changes in the richness of arable fields produced gains in landscape-scale richness comparable to a conversion of 3.1% of arable field area into grassland habitat. Sensitivity analysis of our model indicated that relative gains from land sparing would be greatest in landscapes with a low amount of non-crop habitat in the baseline scenario, but that in more complex landscapes land sharing would provide greater gains. These results indicate that the majority of plant species in agroecosystems are found in small fragments of non-crop habitat and suggest that, especially in landscapes with little non-crop habitat, richness can be more readily conserved through land-sparing approaches.  相似文献   

17.
The South American dry Chaco is a mosaic of woody vegetation and grasslands with high deforestation rates in recent decades. Considering forests and grasslands as the main natural habitats, we assessed the trade-offs between bird populations and agricultural production to compare the potential consequences of different land use strategies (‘sharing’, ‘sparing’, and intermediate) for populations of bird species sensitive to agriculture, while attaining a regional production target. We evaluated how populations responded to scenarios with different proportions of forest and grasslands, considering three reference states (100% forest, 80:20% and 50:50% forest and grasslands, respectively); and scenarios capable of meeting three after-farming scenarios, with land destined to reach a regional production target with three variations of forest:grasslands within spared land. We fitted curves to relate bird abundance to agricultural yield along a gradient of meat production intensity; and we classified bird species as ‘losers’ (if their populations were lower than the baseline population in the reference state, at any level of production) and ‘winners’ (if their current populations were higher than the baseline population). At the ‘current’ (c. 2010) level of regional agricultural production, we found a similar number of loser species maximized by land-sparing and land-sharing strategies; while intermediate strategies were the least favourable to balance production and bird populations. Under the most probable scenarios of increases in regional meat production, most loser bird species populations were maximized by a land-sparing strategy, suggesting that if meat production targets are going to increase in the region, this can be more efficiently achieved by combining well-protected forests and grasslands, and high-yielding mechanized agriculture (e.g. soybean). Our results highlight the importance of assessing all the important natural habitats (e.g. forests and grasslands) of a region to explore conservation strategies at a regional scale.  相似文献   

18.
在赤红壤坡地幼龄果园间种6种牧草,对其生态环境效应进行了试验观测。结果发现,果园间种牧草可明显增大地面覆盖,增加土壤的保水能力,减少水土流失,提高了土壤肥力和土地生产力。然而,由于有些牧草生长旺盛、生物量大,高度和覆盖度大,不可避免地与果树争肥、争水、争光,特别是在贫瘠的坡地上或在干旱季节里。文章指出,幼龄果园间种牧草是一种较好的坡地可持续利用模式,但在牧草品种的适应性选择应加以深入研究。  相似文献   

19.
The Convention on Biological Diversity's (CBD) strategic plan will expire in 2020, but biodiversity loss is ongoing. Scientists call for more ambitious targets in the next agreement. The nature-needs-half movement, for example, has advocated conserving half of Earth to solve the biodiversity crisis, which has been translated to protecting 50% of each ecoregion. We evaluated current protection levels of ecoregions in the territory of one of the CBD's signatories, the European Union (EU). We also explored the possible enlargement of the Natura 2000 network to implement 30% or 50% ecoregion coverage in the EU member states’ protected area (PA) network. Based on the most recent land-use data, we examined whether ecoregions have enough natural area left to reach such high coverage targets. We used a spatially explicit mixed integer programing model to estimate the least-cost expansion of the PA network based on 3 scenarios that put different emphasis on total conservation cost, ecological representation of ecosystems, or emphasize an equal share of the burden among member states. To realize 30% and 50% ecoregion coverage, the EU would need to add 6.6% and 24.2%, respectively, of its terrestrial area to its PA network. For all 3 scenarios, the EU would need to designate most recommended new PAs in seminatural forests and other semi- or natural ecosystems. Because 15 ecoregions did not have enough natural area left to implement the ecoregion-coverage targets, some member states would also need to establish new PAs on productive land, allocating the largest share to arable land. Thirty percent ecoregion coverage was met by protecting remaining natural areas in all ecoregions except 3, where productive land would also need to be included. Our results support discussions of higher ecoregions protection targets for post-2020 biodiversity frameworks.  相似文献   

20.
In the last decades, Brazil has been consolidated as one of the world’s largest producers of food, with emphasis on soybeans, sugarcane and beef production. With the opening of new markets and the increase in demand, a competitive scenario was developed among farming activities, resulting in changes in land use and cover. Thus, this study aimed to verify the spatial and temporal land use changes, through intensity analysis, in the microregion of Presidente Prudente, São Paulo state, in two time intervals, 2004–2007 and 2007–2015, in addition to determining the relevance of pasture in this context. The identification of land uses occurred through the analysis of the spectrum-temporal pattern of the Normalized Difference Vegetation Index (NDVI) from Moderate-Resolution Imaging Spectroradiometer (MODIS), in such a way that six classes were identified, annual crop, water, sugarcane, forest, pasture and urban area. The categories annual crop and sugarcane had more intense variations of losses and gains in the studied time intervals. The category pasture was the primary supplying source of the area, showing a reduction of approximately 180,000 hectares in the analyzed period, losing area with greater intensity for the categories of annual crop and sugarcane.  相似文献   

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