Forest as the largest ecosystem on the land can provide people recreational spaces and pleasant environments,and ensure the sustainable development,which contributes a lot in reliving environmental crises of cities an...Forest as the largest ecosystem on the land can provide people recreational spaces and pleasant environments,and ensure the sustainable development,which contributes a lot in reliving environmental crises of cities and realizing the optimized utilization of resources.The authors,from the perspective of ecological and visual landscape researches,elaborated the intimate relationship between forest and landscape,to achieve the greatest exploitation and integration of the ecological value,aesthetic value and sustainable value of forest.展开更多
Landscape ecology is playing an increasingly important role in resources management and landuse planning in recent decades and attracting much attention from resource managers and scientists in China as well as in the...Landscape ecology is playing an increasingly important role in resources management and landuse planning in recent decades and attracting much attention from resource managers and scientists in China as well as in the world. Reviews of landscape ecology development in China have been well documented, whereas forest landscape ecology and its applications receive relatively fewer reviews. In this paper, we first present a brief review of the historical development and current advances of landscape ecology in China and then introduce the applications of landscape ecology to forest park designs, urban greenspace planning, ecological restoration, biodiversity conservation and forest eco-hydrology. Finally, the problems with the application of forest landscape ecology in China, such as inadequate synthesis and integration, lack of basic research on patterns and processes, basic data shortage and model usage problem are discussed on the basis of which we suggest a future direction of forest landscape ecology in China.展开更多
On the basis of traditional aesthetics, contemporary western aesthetic circles add environmental aesthetics with ecological ethical thinking, trying to solve the increasingly serious ecological environment problems an...On the basis of traditional aesthetics, contemporary western aesthetic circles add environmental aesthetics with ecological ethical thinking, trying to solve the increasingly serious ecological environment problems and subvert people’s inherent values through its theory and practice. Landscape aesthetics, as an important branch of environmental aesthetics, should seek effective intervention of new ideas with epochal criticism on the basis of in-depth exploration of its historical form. Based on the vertical time axis, this study combed the traditional aesthetic theory and its application in landscape practice, summed up the transformation of landscape aesthetics from subject-object dichotomy to experience-based empiricism, and introduced ecological ethics and scientific knowledge into contemporary landscape aesthetics to determine its value orientation of the times, in order to provide theoretical reference for solving ecological crisis and expanding the study of landscape aesthetics.展开更多
Visual quality is a significant issue in today’s modern world which needs to be evaluated. This assessment is based on the observer’s perception and sight of space and attempts to introduce the criteria of spatial d...Visual quality is a significant issue in today’s modern world which needs to be evaluated. This assessment is based on the observer’s perception and sight of space and attempts to introduce the criteria of spatial desirability in the landscape. Analysis of the relationships between visual quality and structural features of the landscape is an effective way of conducting cognitive research. For this purpose, the analysis of visual quality was considered by compiling measurement and evaluation criteria, based on the concept of user preferences, in the part of Tehran-Qom Freeway, near the northeastern side of Imam Khomeini International Airport (Iran). The main objective of this research is to present a strategic plan for preserving and restoring the ecological landscape, creating a sense of place in the region, emphasizing gradual changes in the landscape during the movement and considering its relation to landscape aesthetics. For this purpose, after the questionnaire was prepared, the classifying visual quality method (Q-Sort) was used. Finally, using the results obtained from landscape analysis, identifying the components which led to the lack of visibility of individuals, and by using the geographic information systems (GIS), the strategic design of the area was designed.展开更多
As a key for constructing ecologically safe scenery, forest landscape pattern in Chongqing Section of the Three Gorges has shown degradation, fragmentation and revision of varying degrees. To ensure normal and safe op...As a key for constructing ecologically safe scenery, forest landscape pattern in Chongqing Section of the Three Gorges has shown degradation, fragmentation and revision of varying degrees. To ensure normal and safe operation of the Three Gorges, and meet requirements of integrated development strategies for ecological and economic effects in Chongqing City on the ecological security of land use in Chongqing section of the Three Gorges, the following points should be attached more importance in making future strategies for an ecologically safe land use pattern with the restoration of degraded forest landscape as its starting point:a. Ecological effects and economic functions that can be supplied by forest landscape elements in different restoration patterns should be understood to obtain background effect of the ecological security pattern scenario of land use in the reservoir region; b. Relationship between restoration of degraded forest landscapes and serious ecological interference factors such as degradation background, artificial disturbance and engineering stress, should be simulated to figure out the influence of natural or artificial driving factors on landscape pattern, determine the future restoration mode for the degraded forest landscapes in the reservoir region, so as to facilitate the construction of great ecological-economic security pattern of the Three Gorges. The findings will provide scientific basis for the decision-making in building an ecologically safe land use pattern in the Three Gorges reservoir area (Chongqing), when using the degradation of forest landscape restoration as a carrier at present or in the future. Further, they will help realize the development goals of "Livable Chongqing, Expedite Chongqing, Forestry Chongqing, Safe Chongqing and Healthy Chongqing".展开更多
Landscape conversion becomes a continuous process in a natural landscape for any strategic development.In a forest landscape mosaic,the conversion from non-forest land to forest land implies a constructive approach.Va...Landscape conversion becomes a continuous process in a natural landscape for any strategic development.In a forest landscape mosaic,the conversion from non-forest land to forest land implies a constructive approach.Various bio-geographic processes are enriched and developed when the land was converted to forest land in a given landscape matrix.The present study evaluated how the increased forest cover improves the ecological quality of forest in Jhargram District of West Bengal State,India,from 1985 to 2015.The quality of forests includes dominance,fragmentation and connectivity,which are the basis ecological indicators of habitat structure.To address this issue,we extracted forest cover maps of 1985 and 2015 from land use/land cover classification.A grid framework was overlaid on these forest cover maps for patch-matrix model analysis.Reliable landscape ecological indices were used for the measurements of forest landscape quality in 1985 and 2015.Then a simple linear regression model was used to compare the results.Temporally,forest cover increased in Jhargram District from 1985 to 2015.The comparison of measurement indices depicts that although only a small amount of land was changed into forest land in the study area,this small change has greatly improved the structural compositional quality of the forest land.Compared with 1985,the forest land area increased by about 6930.56 hm^(2) in 2015.This increased forest cover improved the basic landscape ecological characters,such as inter patch connectivity,forest core area,forest habitat dependence,forest habitat dominance and forest edge effect.As a result,the ecosystem function in Jhargram District has been improved,which again attracts wildlife and enriches biodiversity.展开更多
Taking Wutong Mountain Rhododendron moulmainense ecological landscape forest in Shenzhen City as an example,the value of the forest was assessed by constructing an ecological service value assessment system and accoun...Taking Wutong Mountain Rhododendron moulmainense ecological landscape forest in Shenzhen City as an example,the value of the forest was assessed by constructing an ecological service value assessment system and accounting method.The assessment results showed that the total ecosystem service value of R.moulmainense ecological landscape forest was 13.195 billion yuan,and the top three services included the value of forestry products,the value of biodiversity maintenance and the value of leisure and recreation,indicating that the ecosystem service of Wutong Mountain R.moulmainense ecological landscape forest in Shenzhen has great ecological and economic value,especially in forestry products,biodiversity maintenance,and leisure and recreation.展开更多
Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cy...Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cycles, each natural forst landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape variability.Methods: The study encompassed a forested area of 175 000 km2 divided into 14 landscapes. Using a framework that integrates fire cycles, age structure and forest dynamics, we characterized the forest composition and age structures that resulted from three historical fire cycles(110,140, and 180 years) representative of the boreal forest of eastern Canada. The modeled natural landscapes were compared with present-day landscapes in regard to the proportion of old-growth forests(landscape level) and the proportion of late-successional forest stands(landscape level and potential vegetation type).Results: Four landscapes(39%) remain within their natural range of variability. In contrast, nine landscapes(54%)show a large gap between natural and present-day landscapes. These nine are located in the southern portion of the study area, and are mainly associated with Abies-Betula vegetation where human activities have contributed to a strong increase in the proportion of Populus tremuloides stands(early-successional stages) and a decrease of oldgrowth forest stands(more than 100 years old). A single landscape(7%), substantially changed from its potential natural state, is a candidate for adaptive-based management.Conclusion: Comparison of corresponding natural(reference conditions) and present-day landscapes showed that ten landscapes reflecting an important shift in forest composition and age structure could be considered beyond the range of their natural variability. The description of a landscape's natural variability at the scale of several millennia can be considered a moving benchmark that can be re-evaluated in the context of climate change.Focusing on regional landscape characteristics and long-term natural variability of vegetation and forest age structure represents a step forward in methodology for defining reference conditions and following shifts in landscape over time.展开更多
Background: An examination of the distribution of ancient charcoal kiln sites in the forest landscape seems to be worthwhile, since general trends in the selection of suitable kiln site locations in the past might be...Background: An examination of the distribution of ancient charcoal kiln sites in the forest landscape seems to be worthwhile, since general trends in the selection of suitable kiln site locations in the past might become obvious. In this way forest landscape elements with a more intense usage by charcoal burning can be identified. By doing this, we can expect to gain information on the former condition and tree species composition of woodland. Investigations on the spatial distribution of charcoal kiln sites in relation to landscape attributes are sparse, however, probably due to the high on-site mapping effort. The outstanding suitability of LiDAR-derived digital terrain models (DTMs) for the detection of charcoal kiln sites has been recently proved. Hence, DTM-based surveys of charcoal kiln sites represent a promising attempt to fill this research gap. Methods: Based on DTM-based surveys, we analyzed the spatial distribution of charcoal kiln sites in two forest landscapes in the German federal state of Hesse: Reinhardswald and Kellerwald-Edersee National Park. In doing so, we considered the landscape attibutes "tree species composition", "water supply status", "nutrient supply status", "soil complex classes", "altitude", "exposition", and "inclination". Results: We found that charcoal kiln sites were established preferably on hillside locations that provided optimal growing and regeneration conditions for European beech (Fagus sylvatico) due to their acidic brown soils and sufficient water supply. These results are in line with instructions for the selection of appropriate kiln site locations, found in literature from the 18th to the 19th century. Conclusions: We conclude that there were well-stocked, beech-dominated deciduous forest stands in northern Hesse before 1800, particularly at poorly accessible hillside locations. These large stocks of beech wood were utilized by the governments of the different Hessian territories through the establishment of ironworks and hammer mills. Our argumentation is well in line with findings which underline that not all Hessian forests were overexploited in the 18th century. Frequently repeated complaints about "wood shortage" seemed to be more a political instrument than reality, not only in Hesse, but all over Europe. Consequently, a differentiated assessment of woodland conditions in proto-industrial times is strictly advised, even if contemporary sources draw a dark picture of the historic situation.展开更多
By landscape restoration design and through creation of natural landscape,obvious artificial traces in construction waste treatment field on lower Wei Mountain of Shenzhen City had been eliminated and the treatment fi...By landscape restoration design and through creation of natural landscape,obvious artificial traces in construction waste treatment field on lower Wei Mountain of Shenzhen City had been eliminated and the treatment field became coordinating with surrounding landscape.The landscape had been identified as evergreen deciduous mingled forest,characterized by flower sea,colored patches and rich seasonal change.The mountain had been divided into upper and lower part to build ecological forest zone of field type and ecological forest zone of city background type respectively,forming "small community and large mingled forest" and "large community and large mingled forest".By taking plants' flowering pe-riod and color difference into comprehensive consideration,seasonal and color change of landscape forest would be manifested,forest landscape patches with distinctive characteristic would be built in large scale,and forest line and seasonal landscape would be enriched.By adopting mixed forest,and using ecological dam,coverage on sloping field,soil reclamation and greening irrigation,landscape restoration effect of integration of close view and distant view would be created finally.展开更多
Owls have the potential to be keystone species for conservation in fragmented landscapes, as the absence of these predators could profoundly change community structure. Yet few studies have examined how whole communit...Owls have the potential to be keystone species for conservation in fragmented landscapes, as the absence of these predators could profoundly change community structure. Yet few studies have examined how whole communities of owls respond to fragmentation, especially in the tropics. When evaluating the effect of factors related to fragmentation, such as fragment area and distance to the edge, on these birds, it is also important in heterogeneous landscapes to ask how 'location factors' such as the topography, vegetation and soil of the fragment predict their persistence. In Xishuangbanna, southwest China, we established 43 transects (200 mx60 m) within 20 forest fragments to sample nocturnal birds, both visually and aurally. We used a multimodel inference approach to identify the factors that influence owl species richness, and generalized linear mixed models to predict the occurrence probabilities of each species. We found that fragmentation factors dominated location factors, with larger fragments having more species, and four of eight species were significantly more likely to occur in large fragments. Given the potential importance of these birds on regulating small mammal and other animal populations, and thus indirectly affecting seed dispersal, we suggest further protection of large f ragments and programs to increase their connectivity to the remaining smaller fragments.展开更多
文摘Forest as the largest ecosystem on the land can provide people recreational spaces and pleasant environments,and ensure the sustainable development,which contributes a lot in reliving environmental crises of cities and realizing the optimized utilization of resources.The authors,from the perspective of ecological and visual landscape researches,elaborated the intimate relationship between forest and landscape,to achieve the greatest exploitation and integration of the ecological value,aesthetic value and sustainable value of forest.
文摘Landscape ecology is playing an increasingly important role in resources management and landuse planning in recent decades and attracting much attention from resource managers and scientists in China as well as in the world. Reviews of landscape ecology development in China have been well documented, whereas forest landscape ecology and its applications receive relatively fewer reviews. In this paper, we first present a brief review of the historical development and current advances of landscape ecology in China and then introduce the applications of landscape ecology to forest park designs, urban greenspace planning, ecological restoration, biodiversity conservation and forest eco-hydrology. Finally, the problems with the application of forest landscape ecology in China, such as inadequate synthesis and integration, lack of basic research on patterns and processes, basic data shortage and model usage problem are discussed on the basis of which we suggest a future direction of forest landscape ecology in China.
基金Sponsored by Fundamental Research Funds for the Central Universities of Beijing Forestry University(2018RW04)
文摘On the basis of traditional aesthetics, contemporary western aesthetic circles add environmental aesthetics with ecological ethical thinking, trying to solve the increasingly serious ecological environment problems and subvert people’s inherent values through its theory and practice. Landscape aesthetics, as an important branch of environmental aesthetics, should seek effective intervention of new ideas with epochal criticism on the basis of in-depth exploration of its historical form. Based on the vertical time axis, this study combed the traditional aesthetic theory and its application in landscape practice, summed up the transformation of landscape aesthetics from subject-object dichotomy to experience-based empiricism, and introduced ecological ethics and scientific knowledge into contemporary landscape aesthetics to determine its value orientation of the times, in order to provide theoretical reference for solving ecological crisis and expanding the study of landscape aesthetics.
文摘Visual quality is a significant issue in today’s modern world which needs to be evaluated. This assessment is based on the observer’s perception and sight of space and attempts to introduce the criteria of spatial desirability in the landscape. Analysis of the relationships between visual quality and structural features of the landscape is an effective way of conducting cognitive research. For this purpose, the analysis of visual quality was considered by compiling measurement and evaluation criteria, based on the concept of user preferences, in the part of Tehran-Qom Freeway, near the northeastern side of Imam Khomeini International Airport (Iran). The main objective of this research is to present a strategic plan for preserving and restoring the ecological landscape, creating a sense of place in the region, emphasizing gradual changes in the landscape during the movement and considering its relation to landscape aesthetics. For this purpose, after the questionnaire was prepared, the classifying visual quality method (Q-Sort) was used. Finally, using the results obtained from landscape analysis, identifying the components which led to the lack of visibility of individuals, and by using the geographic information systems (GIS), the strategic design of the area was designed.
文摘As a key for constructing ecologically safe scenery, forest landscape pattern in Chongqing Section of the Three Gorges has shown degradation, fragmentation and revision of varying degrees. To ensure normal and safe operation of the Three Gorges, and meet requirements of integrated development strategies for ecological and economic effects in Chongqing City on the ecological security of land use in Chongqing section of the Three Gorges, the following points should be attached more importance in making future strategies for an ecologically safe land use pattern with the restoration of degraded forest landscape as its starting point:a. Ecological effects and economic functions that can be supplied by forest landscape elements in different restoration patterns should be understood to obtain background effect of the ecological security pattern scenario of land use in the reservoir region; b. Relationship between restoration of degraded forest landscapes and serious ecological interference factors such as degradation background, artificial disturbance and engineering stress, should be simulated to figure out the influence of natural or artificial driving factors on landscape pattern, determine the future restoration mode for the degraded forest landscapes in the reservoir region, so as to facilitate the construction of great ecological-economic security pattern of the Three Gorges. The findings will provide scientific basis for the decision-making in building an ecologically safe land use pattern in the Three Gorges reservoir area (Chongqing), when using the degradation of forest landscape restoration as a carrier at present or in the future. Further, they will help realize the development goals of "Livable Chongqing, Expedite Chongqing, Forestry Chongqing, Safe Chongqing and Healthy Chongqing".
文摘Landscape conversion becomes a continuous process in a natural landscape for any strategic development.In a forest landscape mosaic,the conversion from non-forest land to forest land implies a constructive approach.Various bio-geographic processes are enriched and developed when the land was converted to forest land in a given landscape matrix.The present study evaluated how the increased forest cover improves the ecological quality of forest in Jhargram District of West Bengal State,India,from 1985 to 2015.The quality of forests includes dominance,fragmentation and connectivity,which are the basis ecological indicators of habitat structure.To address this issue,we extracted forest cover maps of 1985 and 2015 from land use/land cover classification.A grid framework was overlaid on these forest cover maps for patch-matrix model analysis.Reliable landscape ecological indices were used for the measurements of forest landscape quality in 1985 and 2015.Then a simple linear regression model was used to compare the results.Temporally,forest cover increased in Jhargram District from 1985 to 2015.The comparison of measurement indices depicts that although only a small amount of land was changed into forest land in the study area,this small change has greatly improved the structural compositional quality of the forest land.Compared with 1985,the forest land area increased by about 6930.56 hm^(2) in 2015.This increased forest cover improved the basic landscape ecological characters,such as inter patch connectivity,forest core area,forest habitat dependence,forest habitat dominance and forest edge effect.As a result,the ecosystem function in Jhargram District has been improved,which again attracts wildlife and enriches biodiversity.
文摘Taking Wutong Mountain Rhododendron moulmainense ecological landscape forest in Shenzhen City as an example,the value of the forest was assessed by constructing an ecological service value assessment system and accounting method.The assessment results showed that the total ecosystem service value of R.moulmainense ecological landscape forest was 13.195 billion yuan,and the top three services included the value of forestry products,the value of biodiversity maintenance and the value of leisure and recreation,indicating that the ecosystem service of Wutong Mountain R.moulmainense ecological landscape forest in Shenzhen has great ecological and economic value,especially in forestry products,biodiversity maintenance,and leisure and recreation.
基金funded by the Ministère des Forêts,de la Faune et des Parcs du Québec(MFFP).The funds were used mainly for the salary of the authors working for the MFFP
文摘Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cycles, each natural forst landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape variability.Methods: The study encompassed a forested area of 175 000 km2 divided into 14 landscapes. Using a framework that integrates fire cycles, age structure and forest dynamics, we characterized the forest composition and age structures that resulted from three historical fire cycles(110,140, and 180 years) representative of the boreal forest of eastern Canada. The modeled natural landscapes were compared with present-day landscapes in regard to the proportion of old-growth forests(landscape level) and the proportion of late-successional forest stands(landscape level and potential vegetation type).Results: Four landscapes(39%) remain within their natural range of variability. In contrast, nine landscapes(54%)show a large gap between natural and present-day landscapes. These nine are located in the southern portion of the study area, and are mainly associated with Abies-Betula vegetation where human activities have contributed to a strong increase in the proportion of Populus tremuloides stands(early-successional stages) and a decrease of oldgrowth forest stands(more than 100 years old). A single landscape(7%), substantially changed from its potential natural state, is a candidate for adaptive-based management.Conclusion: Comparison of corresponding natural(reference conditions) and present-day landscapes showed that ten landscapes reflecting an important shift in forest composition and age structure could be considered beyond the range of their natural variability. The description of a landscape's natural variability at the scale of several millennia can be considered a moving benchmark that can be re-evaluated in the context of climate change.Focusing on regional landscape characteristics and long-term natural variability of vegetation and forest age structure represents a step forward in methodology for defining reference conditions and following shifts in landscape over time.
文摘Background: An examination of the distribution of ancient charcoal kiln sites in the forest landscape seems to be worthwhile, since general trends in the selection of suitable kiln site locations in the past might become obvious. In this way forest landscape elements with a more intense usage by charcoal burning can be identified. By doing this, we can expect to gain information on the former condition and tree species composition of woodland. Investigations on the spatial distribution of charcoal kiln sites in relation to landscape attributes are sparse, however, probably due to the high on-site mapping effort. The outstanding suitability of LiDAR-derived digital terrain models (DTMs) for the detection of charcoal kiln sites has been recently proved. Hence, DTM-based surveys of charcoal kiln sites represent a promising attempt to fill this research gap. Methods: Based on DTM-based surveys, we analyzed the spatial distribution of charcoal kiln sites in two forest landscapes in the German federal state of Hesse: Reinhardswald and Kellerwald-Edersee National Park. In doing so, we considered the landscape attibutes "tree species composition", "water supply status", "nutrient supply status", "soil complex classes", "altitude", "exposition", and "inclination". Results: We found that charcoal kiln sites were established preferably on hillside locations that provided optimal growing and regeneration conditions for European beech (Fagus sylvatico) due to their acidic brown soils and sufficient water supply. These results are in line with instructions for the selection of appropriate kiln site locations, found in literature from the 18th to the 19th century. Conclusions: We conclude that there were well-stocked, beech-dominated deciduous forest stands in northern Hesse before 1800, particularly at poorly accessible hillside locations. These large stocks of beech wood were utilized by the governments of the different Hessian territories through the establishment of ironworks and hammer mills. Our argumentation is well in line with findings which underline that not all Hessian forests were overexploited in the 18th century. Frequently repeated complaints about "wood shortage" seemed to be more a political instrument than reality, not only in Hesse, but all over Europe. Consequently, a differentiated assessment of woodland conditions in proto-industrial times is strictly advised, even if contemporary sources draw a dark picture of the historic situation.
文摘By landscape restoration design and through creation of natural landscape,obvious artificial traces in construction waste treatment field on lower Wei Mountain of Shenzhen City had been eliminated and the treatment field became coordinating with surrounding landscape.The landscape had been identified as evergreen deciduous mingled forest,characterized by flower sea,colored patches and rich seasonal change.The mountain had been divided into upper and lower part to build ecological forest zone of field type and ecological forest zone of city background type respectively,forming "small community and large mingled forest" and "large community and large mingled forest".By taking plants' flowering pe-riod and color difference into comprehensive consideration,seasonal and color change of landscape forest would be manifested,forest landscape patches with distinctive characteristic would be built in large scale,and forest line and seasonal landscape would be enriched.By adopting mixed forest,and using ecological dam,coverage on sloping field,soil reclamation and greening irrigation,landscape restoration effect of integration of close view and distant view would be created finally.
基金financially supported by the 1000 Plan Recruitment Program of Global Experts of China to EG
文摘Owls have the potential to be keystone species for conservation in fragmented landscapes, as the absence of these predators could profoundly change community structure. Yet few studies have examined how whole communities of owls respond to fragmentation, especially in the tropics. When evaluating the effect of factors related to fragmentation, such as fragment area and distance to the edge, on these birds, it is also important in heterogeneous landscapes to ask how 'location factors' such as the topography, vegetation and soil of the fragment predict their persistence. In Xishuangbanna, southwest China, we established 43 transects (200 mx60 m) within 20 forest fragments to sample nocturnal birds, both visually and aurally. We used a multimodel inference approach to identify the factors that influence owl species richness, and generalized linear mixed models to predict the occurrence probabilities of each species. We found that fragmentation factors dominated location factors, with larger fragments having more species, and four of eight species were significantly more likely to occur in large fragments. Given the potential importance of these birds on regulating small mammal and other animal populations, and thus indirectly affecting seed dispersal, we suggest further protection of large f ragments and programs to increase their connectivity to the remaining smaller fragments.