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1.
This paper presents a spatially explicit bioeconomic analysis of species conservation in agricultural areas. Wild species in fragmented agricultural landscapes are best approached as metapopulations consisting of a finite number of local populations. Economic analysis of species conservation in fragmented habitat needs to deal with metapopulation theory and its theoretical implications. This paper presents a spatially explicit bioeconomic model consisting of a straightforward economic land use model and an applied metapopulation model. This paper demonstrates that multiple equilibria and multiple local optima in metapopulations might lead to nonconvexities in the production possibilities set of agricultural profits and species conservation.  相似文献   

2.
Industrialized agriculture currently substitutes many of the ecological functions of soil micro-organisms, macroinvertebrates, wild plants, and vertebrate animals with high cost inputs of pesticides and fertilizers. Enhanced biological diversity potentially offers agricultural producers a means of reducing the cost of their production. Conservation of biodiversity in agricultural landscapes may be greatly enhanced by the adoption of certain crop management practices, such as reduced pesticide usage or measures to prevent soil erosion. Still, the vast monocultures comprising the crop area in many Canadian agricultural landscapes are often of limited conservation value, thus the inclusion of appropriate wildlife habitat in and around arable lands is a fundamental prerequisite for the integration of wild species within agricultural landscapes. This review of current literature considers the potential for non-crop areas within agricultural landscapes to be reservoirs of agronomically beneficial organisms including plants, invertebrates, and vertebrate species. Non-crop habitats adjacent to crop land have been identified as significant for the maintenance of plant species diversity, for the conservation of beneficial pollinating and predatory insects, and as essential habitat for birds. A key component for enhancement of biodiversity is the reintroduction of landscape heterogeneity by (1) protection and enhancement of key non-crop areas, (2) smaller fields and farms, and (3) a greater mixture of crops, through rotation, intercropping and regional diversification. The benefits of increased biodiversity within arable lands are reviewed for various species groups. In the Canadian context, any serious attempt to derive significant agronomic benefit from increased biodiversity will require considerable changes in the agricultural programs and policies which shape mainstream industrialized agriculture. The problems of crop depredation by vertebrate species, weed and insect competition, which still represent significant impediments to the creation and proper management of wildlife habitat, are also discussed.  相似文献   

3.
In agricultural landscapes, studies that identify factors driving species richness and occupancy are important because they can guide farmers to use conservation practices that minimize species loss. In this context, anurans are threatened by habitat loss because they depend on the characteristics of both local water bodies and adjacent landscapes. We used a model selection approach to evaluate the influence of local and landscape variables in determining anuran species richness and occurrence in 40 freshwater bodies in a heavily deforested region of semideciduous Atlantic Forest in southeastern Brazil. Our aim was to develop recommendations for conservation of anuran communities in rural areas. Pond hydroperiod and area were the most important variables for explaining anuran species richness and occupancy, with greatest species richness being found in water bodies with intermediate hydroperiod and area. Other important variables that reflected individual species occupancies were the number of vegetation types and pond isolation. In addition, recent studies evidenced that water bodies near forest fragments have higher anuran abundance or diversity. In conclusion, we suggest the maintenance of semi-permanent ponds, isolated from large rivers or reservoirs and near forest fragments, as an effective strategy to conserve anuran fauna in agricultural landscapes of southeastern Brazil. Brazilian government requires the maintenance of forests as legal reserve in each farm, and farmers need to maintain ponds as drinking water for cattle or crop irrigation. For this reason, the guidelines suggested in the present study can be easily adopted, without additional costs to rural productivity.  相似文献   

4.
Conservation buffers have the potential to reduce agricultural nonpoint source pollution and improve terrestrial wildlife habitat, landscape biodiversity, flood control, recreation, and aesthetics. Conservation buffers, streamside areas and riparian wetlands are being used or have been proposed to control agricultural nonpoint source pollution. This paper proposes an innovative strategy for placing conservation buffers based on the variable source area (VSA) hydrology. VSAs are small, variable but predictable portion of a watershed that regularly contributes to runoff generation. The VSA-based strategy involves the following three steps: first, identifying VSAs in landscapes based on natural characteristics such as hydrology, land use/cover, topography and soils; second, targeting areas within VSAs for conservation buffers; third, refining the size and location of conservation buffers based on other factors such as weather, environmental objectives, available funding and other best management practices. Building conservation buffers in VSAs allows agricultural runoff to more uniformly enter buffers and stay there longer, which increases the buffers capacity to remove sediments and nutrients. A field-scale example is presented to demonstrate the effectiveness and cost-effectiveness of the within-VSA conservation buffer scenario relative to a typical edge-of-field buffer scenario. The results enhance the understanding of hydrological processes and interactions between agricultural lands and conservation buffers in agricultural landscapes, and provide practical guidance for land resource managers and conservationists who use conservation buffers to improve water quality and amenity values of agricultural landscape.  相似文献   

5.
Characteristics of urban natural areas and surrounding landscapes were identified that best explain winter bird use for 28 urban natural areas in southern Ontario, Canada. The research confirms for winter birds the importance of area (size) and natural vegetation, rather than managed, horticultural parkland, within urban natural areas as well as percent urban land use and natural habitat in surrounding landscapes. Alien bird density and percent ground feeding species increased with percent surrounding urban land use. Higher percent forest cover was associated with higher percentages of forest, bark feeding, small (<20 g) and insectivorous species. Natural area size (ha) was related to higher species richness, lower evenness and higher percentages of insectivorous, forest interior, area-sensitive, upper canopy, bark feeding, and non-resident species. Higher number of habitat types within natural areas and percent natural habitat in surrounding landscapes were also associated with higher species richness. Common, resident bird species dominated small areas (<6.5 ha), while less common non-residents increased with area, indicative of a nested distribution. Areas at least 6.5 ha and more generally >20 ha start to support some area-sensitive species. Areas similar to rural forests had >25% insectivores, >25% forest interior species, >25% small species, and <5% alien species. Indicator species separated urban natural areas from rural habitats and ordination placed urban natural areas along a gradient between urban development and undisturbed, rural forests. More attention is needed on issues of winter bird conservation in urban landscapes.  相似文献   

6.
Protected areas (PAs) are cornerstones of biodiversity conservation, but small parks alone cannot support wide-ranging species, such as the tiger. Hence, forest dynamics in the surrounding landscapes of PAs are also important to tiger conservation. Tiger landscapes often support considerable human population in proximity of the PA, sometimes within the core itself, and thus are subject to various land use activities (such as agricultural expansion and road development) driving habitat loss and fragmentation. We synthesize information from 27 journal articles in 24 tiger landscapes to assess forest-cover dynamics in tiger-range countries. Although 29% of the PAs considered in this study have negligible change in overall forest cover, approximately 71% are undergoing deforestation and fragmentation. Approximately 58% of the total case studies have human settlements within the core area. Most changes—including agricultural expansion, plantation, and farming (52%), fuelwood and fodder collection (43%), logging (38%), grazing (38%), and tourism and development (10%)—can be attributed to human impacts largely linked to the nature of the management regime. This study highlights the need for incorporating new perspectives, ideas, and lessons learned locally and across borders into management plans to ensure tiger conservation in landscapes dominated by human activities. Given the increasing isolation of most parks due to agricultural, infrastructural, and commercial developments at the periphery, it is imperative to conduct planning and evaluation at the landscape level, as well as incorporate multiple actors and institutions in planning, instead of focusing solely on conservation within the PAs as is currently the case in most tiger parks.  相似文献   

7.
Although human presence is one of the main characteristics of the Mediterranean identity since ancient times, a false dialectic between conservation and social-economic development has emerged in recent decades. On the one hand, an economic growth policy is taken as the paradigm of social-economic development; on the other hand, there is a multi-scale conservation policy, in which natural protected areas, as patches of preserved nature, are used as one of the main tools to deal with the challenge of sustainability. The Mediterranean Basin is the habitat of many unique species and one of the 25 main biodiversity hotspots in the world, and as a consequence a strong conservation policy has been used to protect environmental values. At the same time, Mediterranean countries are deeply involved in promoting strong economic growth policies, which are not always compatible with environmental ones. In this paper, Spain has been studied as one model of this situation. Due to political reasons, Spanish economic growth and conservationist policies were pursued together during the last 20 years. As a result, Spain owns one of the largest networks of natural protected areas in Western Europe, and at the same time it has experienced one of the strongest periods of economic growths in the European and Mediterranean context during the 1980s and 1990s. An historical series of resource use in five annual periods in the last 20 years of conservation policy, and the effects on the preservation of natural capital have been investigated by means of the eMergy (spelled with an 'm') synthesis approach, which was used to characterize the flow of environmental services supplied by ecosystems, but not in monetary terms. This study shows that Spain is becoming less self-sufficient and more inefficient in resource use, comprehensively measured in eMergy terms. A large part of Spain's economy depends on imported goods and services, and most economic activities are based on tourist services and associated construction, which promotes intensification in the urban use of the territory and more intense environmental impacts and resource use intensification of those countries supplying the raw materials. The consequence is a decoupling of the Spanish economy from local environmental services and the increase of Ecological footprint of Spain, measured by means of eMergy-based indicators. In spite of the increase in number, area and associated budget of the natural protected areas and other conservation measures, the general sustainability of the nation is decreasing.  相似文献   

8.
Traditional strategies of resource use in lowland coastal areas may play a very significant role in modern environmental management since, in many ways, the cultural and biological diversity peculiar to these ecoystems that we now wish to protect are the product of human efforts rather than the product of nature alone. We will illustrate this using the example of the so-called closes (enclosures) in the Natural Park of the Aiguamolls de l'Emporda (Catalonia, Spain). Closes are pasture fields surrounded by tree screens that remain inundated part of the year but that can be used for cattle grazing during the rest of the time. Because of agricultural modernization in the 1960s and 1970s many closes were turned into permanent agricultural fields. Since the creation of the Natural Park in 1983, there has been an attempt to recover these traditional land uses although not without some opposition by the farming sector.  相似文献   

9.
Fallow vegetation within landscapes dominated by shifting cultivation represents a woody species pool of critical importance with considerable potential for biodiversity conservation. Here, through the analysis of factors that influence the early stages of fallow vegetation regrowth in two contrasting forest margin landscapes in Southern Cameroon, we assessed the impact of current trends of land use intensification and expansion of the cultivated areas, upon the conservation potential of shifting cultivation landscapes. We combined the analysis of plot and landscape scale factors and identified a complex set of variables that influence fallow regrowth processes in particular the characteristics of the agricultural matrix and the distance from forest. Overall we observed a decline in the fallow species pool, with composition becoming increasingly dominated by species adapted to recurrent disturbance. It is clear that without intervention and if present intensification trends continue, the potential of fallow vegetation to contribute to biodiversity conservation declines because of a reduced capacity, (1) to recover forest vegetation with anything like its original species composition, (2) to connect less disturbed forest patches for forest dependent organisms. Strategies to combat biodiversity loss, including promotion of agroforestry practices and the increase of old secondary forest cover, will need not only to operate at a landscape scale but also to be spatially explicit, reflecting the spatial pattern of species reservoirs and dispersal strategies and human usage across landscapes.  相似文献   

10.
The study analyses the contribution of relevant economic actors to the provision of private and public goods in agricultural landscapes. A method consisting of a multi-sectoral perspective and an integrated approach based on the analytic network process (ANP) and the use of selected local stakeholders is applied. The usefulness of the method is demonstrated in three European case studies in Austria, Italy and Spain. The results show that agriculture and tourism are the sectors that contribute the most and the least, respectively, to the provision of goods and services in agricultural landscapes. Moreover, the results underscore that policy instruments towards such provision need to be targeted differently in different areas and must take into account the different roles of the local actors involved.  相似文献   

11.
Many native bird species in production landscapes of south-eastern Australia demonstrably are declining, with loss of native vegetation as the major cause. Our biodiversity management objectives must be to increase the probabilities of persistence of birds that should occur in the landscape. To do so, there needs to be extensive amounts of new plantings. However, one must be conscious that: (1) new plantings in the impoverished soils and increasing aridity of southern Australia will take many decades to mature, and, also, will offer suitable habitats for a sequence of different species over the course of that maturation process; and (2) much existing vegetation is senescent or will be in a few decades' time. Recent landscape rebuilding models do not explicitly consider maturation time-lags. These hystereses in habitat maturation may create 'bottlenecks' at future times (e.g. in 50yr) that might prevent some species from persisting in whole landscapes even though such landscapes may be much more suitable in 100yr than now. There are several critical issues: (1) species differ in habitat needs and even one species may require different kinds of habitats for foraging and for breeding; (2) landscapes must be conceived, and managed, as spatial and temporal mosaics to allow for persistence of the full set of species that should occupy them, meaning that senescing and replanted habitats may need to be juxtaposed; and (3) in certain particularly problematic landscapes, some highly productive agricultural lands may need to be used for providing habitat because maturation can be fast-tracked in fertile, well-watered locations. The problem is a complex one of scheduling and placement, and its optimization presents major theoretical and analytical challenges.  相似文献   

12.
Nepal is considered a leader among developing nations with regard to conservation legislation and programs; it was among the first Asian nations to develop national conservation legislation, sign CITES, and develop a national conservation strategy. We review the history of modern conservation law in Nepal from the Rana period (early 1950s) to the present. The early legislation focused mainly on strict preservation of areas and species; this phase culminated in the National Parks and Wildlife Conservation Act of 1973. Subsequent legislation has evolved more in the direction of an integrated, holistic approach to conservation and is beginning to incorporate the participation of local people; subsequent amendments to the 1973 act allowed greater rights to rural villagers, and the designation of conservation areas in addition to the more strictly defined protected areas (national parks, wildlife reserves, etc.). Our review of conservation legislation suggests that Nepal has had many successes to date; the country has a protected area system covering over 10% of its land area, and many target species are recovering in parks and reserves. There are also some causes of concern, including staff shortages, financial constraints within the Department of National Parks and Wildlife Conservation, and the fact that there is little legal infrastructure outside of protected areas to enforce conservation laws; further, some aspects of hunting regulations are in need of revision. Primary needs include a comprehensive review of these policies and a nationalized strategy to ameliorate the shortcomings.  相似文献   

13.
The Conservation Reserve Program (CRP), created in 1985, provides conservation benefits and agricultural supply control through voluntary, long-term retirement of crop land. While the effects of the CRP on the agricultural sector are well understood, the implications of its conservation benefits for rural economies remain largely undocumented. To quantify the effects on rural economies, this study addressed the net economic effects of decreased agricultural activity and increased recreational activity associated with the CRP in six rural areas of North Dakota from 1996 to 2000. Based on the level of economic activity that would have occurred in the absence of the program, net revenues from CRP land if returned to agricultural production in the six study areas were estimated at $50.2 million annually or $37 per acre of land currently enrolled in the CRP. Recreational (hunting) revenues as a result of the CRP in the study areas were estimated at $12.8 million annually or $9.45 per CRP-acre. The net economic effect of the CRP (lost agricultural revenues and gains in recreational expenditures) indicated that several areas of the state are not as economically burdened by the CRP as previous research has suggested. In addition, the net economic effects of the program would appear more favourable if revenues from all CRP-based recreation were included. The degree that recreational revenues offset agricultural losses might be further enhanced by enterprises that capitalize on the economic opportunities associated with expanded recreational activities on CRP lands.  相似文献   

14.
The ecological value of some fine-scale landscape elements tends to be overlooked when they are found in highly human-influenced landscapes, such as peri-urban agricultural ones. These landscapes usually fall beyond the scope of the defined categories of landscape protection, and are thus mapped as areas of little or no ecological interest in the context of extensive analysis. In this paper, we present a method for assessing and visualizing the existing nodes in the field pattern of a peri-urban agricultural landscape. Nodes are identified from the field pattern and characterized according to the presence of relevant features and land uses from the viewpoint of their ecological functions. The method is applied in the Vega del Guadalfeo (south of Spain). Our results show an innovative map of the Vega which may be interpreted as its eco-structure; a model based on nodes to represent the ecological value of the peri-urban agricultural landscape.  相似文献   

15.
Western European landscapes have drastically changed since the 1950s, with agricultural intensifications and the spread of urban settlements considered the most important drivers of this land-use/land-cover change. Losses of habitat for fauna and flora have been a direct consequence of this development. In the present study, we relate butterfly occurrence to land-use/land-cover changes over five decades between 1951 and 2000. The study area covers the entire Swiss territory. The 10 explanatory variables originate from agricultural statistics and censuses. Both state as well as rate was used as explanatory variables. Species distribution data were obtained from natural history collections. We selected eight butterfly species: four species occur on wetlands and four occur on dry grasslands. We used cluster analysis to track land-use/land-cover changes and to group communes based on similar trajectories of change. Generalized linear models were applied to identify factors that were significantly correlated with the persistence or disappearance of butterfly species. Results showed that decreasing agricultural areas and densities of farms with more than 10 ha of cultivated land are significantly related with wetland species decline, and increasing densities of livestock seem to have favored disappearance of dry grassland species. Moreover, we show that species declines are not only dependent on land-use/land-cover states but also on the rates of change; that is, the higher the transformation rate from small to large farms, the higher the loss of dry grassland species. We suggest that more attention should be paid to the rates of landscape change as feasible drivers of species change and derive some management suggestions.  相似文献   

16.
Future conservation efforts will need to transcend geopolitical boundaries in efforts to protect entire landscapes and ecosystems. Neotropical migratory birds are as a group a useful conservation tool for linking diverse landscapes and people due to their dependence on multiple habitats, sensitivity to habitat changes, and universal public appeal. The conservation of neotropical migrants can therefore function as a powerful hemispheric umbrella for ecosystem protection. Efforts to protect neotropical migratory birds on their nonbreeding grounds have traditionally been focused on Mexico, Central America, and the Caribbean. To assess the importance of South America to neotropical migrants, an ecoregional classification system was used to determine species distributions in the Andean/Southern Cone Region (Bolivia, Colombia, Ecuador, Paraguay, Peru, and Venezuela). The occurrence of migrants in protected areas that are part of The Nature Conservancy's Parks in Peril program was also assessed. Of the 406 neotropical migrant species, nearly one third (132) occur as regular nonbreeding residents in the region and for almost half of these species (53), South America is their main nonbreeding ground. All Parks in Peril sites were found to harbor neotropical migrants. Forty-eight species (36%) have declining longterm North American Breeding Bird Survey population trends and/or high Partners in Flight concern scores and thus are of significant conservation concern. Most importantly, 29 species (22%) of conservation concern use South America as their primary nonbreeding ground, indicating a need for focused conservation action. The nature of the ecoregional approach used in this endeavor makes future prioritization of ecoregions and conservation strategies for neotropical migrants across national boundaries possible. The ability to link diverse landscapes using a common element such as migratory birds allows for unique transboundary partnerships and opportunities for habitat conservation, which support the goal of the Conservancy's new Migratory Bird Initiative.  相似文献   

17.
This work analyses land cover changes occurring between 1990 and 2000 within a Natural Protected Area, southwest of Madrid (Spain). We develop a new methodology that considers the net change in different land cover categories in each municipality of the study area. Our methodology, which uses Factorial Correspondence Analysis, allows identification of the most important changes at the municipality level and groups the municipalities where land use dynamics are similar. This method is a powerful tool for synthesis and can potentially be applied to non-spatial geographical data sources (e.g. agrarian census statistics). Our results show that the land cover around SW Madrid is highly dynamic. The shrub vegetation, arable land, heterogeneous agricultural and human-created area categories show the highest total change. The dynamics of the changes detected are dominated by decreases in the area of different types of crops and increases in forest areas. These changes may have indirect effects on the conservation of natural resources and wildlife if not managed appropriately.  相似文献   

18.
This study investigates the effect of environmental investment and related spillover effects on productivity in the agricultural sector by using a panel data of horticultural firms in Andalusia (Southern Spain). The results indicate a positive relationship between firm investment in environmental practices and productivity improvement, also showing the presence of positive environmental spillovers. In a second-stage of analysis, the incidence of environmental factors in firm specific individual technical efficiency is estimated. This analysis also shows the link between environmental knowledge diffusion and horticultural firms' performance.  相似文献   

19.
Noncrop areas such as hedgerows in agricultural landscapes can perform several ecological and agronomic functions (e.g., habitat, movement corridors, windbreak, etc.), but their dynamics and drivers of changes are often poorly known. We conducted a study in three agricultural landscapes of southern Quebec, Canada, to assess and compare the spatial and temporal (1958–1997) dynamics of three hedgerow networks in relation to geomorphic conditions (marine, glacial, and mixed deposit) and land-use changes. Hedgerow networks were mapped and described in terms of their structure (density, degree of connectivity, and presence of trees or shrubs) and their relationship to other components of the landscape (connection to woodland). Relationships were assessed in time and space using nonparametric correlation, Mantel test, and principal components analysis (PCA). Results show significant differences between hedgerow structure for the three landscapes and distinct temporal and spatial dynamics that can be related to changes in management practices and agricultural policies. On marine deposits, increases in hedgerow density did not always correspond to an increase in their degree of connectivity, suggesting a possible reduction in network quality. On glacial deposits, hedgerow density declined following abandonment of agricultural land, but rather than disappearing, these linear structures were integrated into adjacent brush or forested areas. Our analysis reveals the complex spatial and temporal dynamics of the hedgerow networks and highlights the need to take into account spatial attributes such as connectivity and connection to woodland to evaluate more accurately overall network quality.  相似文献   

20.
The present study compares the spatial distribution of selected rural land use classes in Italy with two soil indicators (a Soil Quality Index [SQI] and the Maximum potential Water Capacity of the soil [MWC]) at three points in time (1960, 1990 and 2006). Results of the analysis showed that landscape changes reflect a ‘migration’ of both semi-natural (forests, pastures) and agricultural (arable land, vineyards) uses towards areas with lower-quality soils. In particular, the agricultural ‘mosaic’ and shrubland-pasture classes that occupied land in 2006 had significant lower values of both the SQI and MWC compared to 1960. These processes may have implications for the stability of agro-forest ecosystems in the medium term. Due to its versatility, the procedure illustrated represents a monitoring tool for sustainable land management at the regional and country scales.  相似文献   

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