The urban-rural integrated area in Sanshui District of Foshan City was selected for research, and the impact of landscape pattern around the No.269 provincial highway was analyzed based on the land-use data in 2014 us...The urban-rural integrated area in Sanshui District of Foshan City was selected for research, and the impact of landscape pattern around the No.269 provincial highway was analyzed based on the land-use data in 2014 using the spatial analysis in GIS and the moving window method. The results showed that:(1) within the scope of a 2 km-range buffer zone, with a low degree of heterogeneity, land for construction use and water area were the dominant land-use types, while with a high degree of fragmentation, cultivated land, wooded land, grassland, garden land, land for other farm uses, and land unused were scattered;(2) the 250-m square moving window could well detect the change characteristics of landscape pattern on both sides of the road;(3) the gradient analysis of landscape pattern in urban-rural integrated area, which was conducted with the aid of a 750-m transect on both sides of the road, indicated that there were significant differences between landscape indexes both in the urban-rural integrated area and on both sides of the road;(4) the road that had an obvious cutting and fragmentation impact on the landscape was an important factor leading to the increasing fragmentation and heterogeneity to regional landscapes.展开更多
The objective of this study was to evaluate forest cover change and forest degradation in Nyungwe-Kibira Park, a natural reserve straddling Rwanda and Burundi from 1986 to 2015. Landsat TM, ETM+ and 8OLI images of 30 ...The objective of this study was to evaluate forest cover change and forest degradation in Nyungwe-Kibira Park, a natural reserve straddling Rwanda and Burundi from 1986 to 2015. Landsat TM, ETM+ and 8OLI images of 30 m spatial resolution were used as primary datasets. Geographic Information System (GIS) techniques were used for forest cover mapping and landscape metrics were calculated by using FRAGSTATS software. Classification and change analysis of forest cover type and landscape patterns analysis were carried out. In addition, to analyze the correlated external disturbances, the buffer zone of 5 Km was delineated outside the boundary of Nyungwe-Kibira Park. The results revealed that in among 5 land cover classes considered within the Park, the dominant one was dense forest class covering over 70% of the entire Park area while in the buffer zone cultivated and open land dominated at over 90% between the years 1986 and 2015. Change detection highlighted that within Nyungwe-Kibira forest, approximately 0.27% (4.97 Km<sup>2</sup>) of forest cover was cleared while 0.07% (1.22 Km<sup>2</sup>) was regenerated annually. In the buffer zone, the annual cleared forest cover was about 0.76% (13.02 Km<sup>2</sup>). The five landscape indices chosen at class level indicated a considerable fragmentation of forest inside the Park and the highest fragmentation in the buffer zone. Indeed, these results shed a bleak image over the future of the Nyungwe-Kibira forest that should be helpful for the policy-makers and managers of these natural parks to establish adequate policies to mitigate the forest loss and degradation by implementing quick and effective solutions.展开更多
With the support of RS and GIS technology,the ecological environment of Linze was evaluated and the changes of ecological environment were analyzed from the spatial scope of ecosystem with the remote sensing images in...With the support of RS and GIS technology,the ecological environment of Linze was evaluated and the changes of ecological environment were analyzed from the spatial scope of ecosystem with the remote sensing images in 2000 and 2017 as the information source.The results showed that the areas with excellent,relatively good and relatively poor ecological environment in Linze showed a decreasing trend from 2000 to 2017,which decreased by 262.50,7,156.25 and 12,256.30 hm^2,respectively.From the landscape patch pattern,the patch density in areas with relatively good ecological environment increased the fastest from 2000 to 2017,which was 13.05 pieces/hm^2.The largest plaque index in areas with relatively good ecological environment decreased by 1.314%,and the dominance of large plaque in the region decreased.The assessment results of ecological environment based on remote sensing demonstrated that the ecological environment in Linze was generally healthy from 2000 to 2017,and the deterioration was improved.Among them,the area transformed from relatively poor ecological environment to other types was the largest,which was 17,512.92 hm^2,and the proportion of the area transformed into general ecological environment was the highest,accounting for 80.7%of the transformed area of the region.展开更多
Inherited tectonic structures,ongoing tectonic deformation,and variations in relative rock uplift rates play an important role in conditioning the processes of relief development.Their influence among other factors,su...Inherited tectonic structures,ongoing tectonic deformation,and variations in relative rock uplift rates play an important role in conditioning the processes of relief development.Their influence among other factors,such as climate and lithology,can be quantified using landscape analysis,and geomorphometric indices,in particular.The usage of landscape analysis in recent years is increasing systematically due to the constant improvement of the digital elevation models and GIS software that significantly facilitate this approach.In this study,we aim to recognize the influence of tectonic structures and processes on relief development in the low mountains with moderate relief of the Sola River catchment in the Western Outer Carpathians.To this end,we calculated geomorphometric indices(river longitudinal profile,stream-length gradient index,minimum bulk erosion,relief ratio,circulatory ratio,elongation ratio,and hypsometric integral)for the Sola River and its 47 sub-catchments using a 25-m spatial resolution Digital Terrain Elevation Data Level 2.Additionally,we identified lineaments and knickpoints and correlated the computed results with local and regional fault networks,variations in lithology,and climate fluctuations.Obtained results indicate a significant impact of inherited tectonicstructures on the relief development of the Sola River catchment,i.e.,directions of principal ridges and valleys follow the orientation of main folds and faults recorded in this area.Anomalously high values of minimum bulk erosion,river gradient,and streamlength gradient index allowed us to define two areas with higher relative uplift rates:1)the So?a Gorge and 2)the Beskid Zywiecki Mts.Polish Outer Carpathians are generally considered as an area of low strain rate and low seismic activity.However,the possibility of neotectonic processes should be considered in geohazard estimations.Observed bends in the direction of river valleys that do not correspond with changes in lithology could be related to active strikeslip faults.These are probably the reactivated basement structures,copied in the thin-skinned nappe cover,as a result of the accommodation of the Mur-Zilina Fault Zone resulting from the tectonic push of the Alcapa(Alpine-Carpathian-Pannonian)microplate against the European plate.Thus,the role of recent tectonic activity in relief development of the Sola River catchment even though appears to be subsidiary at the most,should not be excluded.展开更多
In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LF...In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LFA) method to assess the function of patches and qualitative capability of a rangeland ecosystem in Gareh By- gone region, Fars province, southwestern Iran. Landscape functionality depends on soil, water and nutrient (col- lectively called "resources") conservation and use within a given ecosystem. Many landscapes are naturally het- erogeneous in terms of resource control and possess patches, where resources tend to accumulate, and in- ter-patches. Assessing rangeland health and function of landscape patches in response to environment and man- agement can give rise to correct management decisions for qualitative improvement of the ecosystem. Therefore, our study area was divided into two parts, i.e. water spreading and control parts, and sampling was done using LFA method in each part separately. Structural parameters, including the number, length and width of patches, and the mean length of inter-patches, were determined by the method to characterize the functional status of the monitoring sites. For each patch/inter-patch type identified in the transect organization log, we recorded its soil surface proper- ties classified according to the Soil Surface Assessment Method. The density, canopy cover and composition of plants were then assessed. The results showed that the number of ecological patches and their dimensions were significantly increased in the water spreading site. Soil stability and the values of nutrient cycling indices were in- creased but the infiltration values were decreased in the water spreading site. It could be related to the effect of suspended materials transported by floods to the soils in the study area. The improvement of ecological patches and rangeland ecosystem was achieved where water spreading systems were practiced. Therefore it can be con- cluded that water spreading as a management plan plays an important role in arid land ecosystem functionality.展开更多
The majority of studies investigating the effects of landscape composition and configuration on bee populations have been conducted in regions of intensive agricultural production, ignoring regions which are dominated...The majority of studies investigating the effects of landscape composition and configuration on bee populations have been conducted in regions of intensive agricultural production, ignoring regions which are dominated by seminatural habitats, such as the islands of the Aegean Archipelago. In addition, research so far has focused on the landscape impacts on bees sampled in cropped fields while the landscape effects on bees inhabiting seminatural habitats are understudied. Here, we investigate the impact of the landscape on wild bee assemblages in 66 phryganic (low scrubland) communities on 8 Aegean islands. We computed landscape metrics (total area and total perimete^area ratio) in 4 concentric circles (250, 500, 750, and 1000 m) around the center of each bee sampling site including 3 habitat groups (namely phrygana, cultivated land, and natural forests). We further measured the local flower cover in 25 quadrats distributed randomly at the center of each sampling site. We found that the landscape scale is more important than the local scale in shaping abundance and species richness of bees. Furthermore, habitat configuration was more important than the total area of habitats, probably because it affects bees' movement across the landscape. Phrygana and natural forests had a positive effect on bee demographics, while cultivated land had a negative effect. This demonstrates that phryganic specialists drive bee assemblages in these seminatural landscapes. This finding, together with the shown importance of landscape scale, should be considered for the management of wild bees with special emphasis placed on the spatial configuration of seminatural habitats.展开更多
A fundamental task in phase retrieval is to recover an unknown signal x∈R^(n) from a set of magnitude-only measurements y_(i)=|〈a_(i),x〉|,i=1,…,m.In this paper,we propose two novel perturbed amplitude models(PAMs)...A fundamental task in phase retrieval is to recover an unknown signal x∈R^(n) from a set of magnitude-only measurements y_(i)=|〈a_(i),x〉|,i=1,…,m.In this paper,we propose two novel perturbed amplitude models(PAMs)which have a non-convex and quadratic-type loss function.When the measurements a_(i)∈R^(n) are Gaussian random vectors and the number of measurements m≥Cn,we rigorously prove that the PAMs admit no spurious local minimizers with high probability,i.e.,the target solution x is the unique local minimizer(up to a global phase)and the loss function has a negative directional curvature around each saddle point.Thanks to the well-tamed benign geometric landscape,one can employ the vanilla gradient descent method to locate the global minimizer x(up to a global phase)without spectral initialization.We carry out extensive numerical experiments to show that the gradient descent algorithm with random initialization outperforms state-of-the-art algorithms with spectral initialization in empirical success rate and convergence speed.展开更多
A fundamental problem in phase retrieval is to reconstruct an unknown signal from a set of magnitude-only measurements.In this work we introduce three novel quotient intensity models(QIMs) based on a deep modification...A fundamental problem in phase retrieval is to reconstruct an unknown signal from a set of magnitude-only measurements.In this work we introduce three novel quotient intensity models(QIMs) based on a deep modification of the traditional intensity-based models.A remarkable feature of the new loss functions is that the corresponding geometric landscape is benign under the optimal sampling complexity.When the measurements ai∈Rn are Gaussian random vectors and the number of measurements m≥Cn,the QIMs admit no spurious local minimizers with high probability,i.e.,the target solution x is the unique local minimizer(up to a global phase) and the loss function has a negative directional curvature around each saddle point.Such benign geometric landscape allows the gradient descent methods to find the global solution x(up to a global phase) without spectral initialization.展开更多
Landscape characterization gives an overall information on the status of Land Use and Land Cover (LULC), changes in its composition and the impact of natural and human influences operating at different spatial and t...Landscape characterization gives an overall information on the status of Land Use and Land Cover (LULC), changes in its composition and the impact of natural and human influences operating at different spatial and temporal scales. This information can be used to monitor changes in natural forest resources and protected areas, delineate potential conservation areas and can serve in effective management of ecologically fragile landscapes. In the present study, geo-spatial tools were used to characterize the landscape of Sariska National Park and its surroundings. Satellite data was used to prepare LULC maps for 1989 and 2000, change detection analysis and computation of landscape metrics. Climatic data, field records and modeling tools were used to map the potential spread of two invasive species, Prosopis juliflora and Adhatoda vasica. The results show that the forest area increased from 1989 to 2000, indicating better management practices. Landscape metrics (PAFRAC, PLADJ and AI) also support this argument. Improvements in the degraded forest can further enhance this effect. The entire reserve however is suitable for the invasion of P. juliflora and A. vasiea but is more pronounced in Boswellia serrata and Anogeissus pendula - Acacia catechu (open) forests. A detailed landscape characterization map can help forest managers to make important policy decisions concerning issues such as invasive species.展开更多
Terrain plays a key role in landscape pattern formation, particularly in the transition zones from mountains to plains.Exploring the relationships between terrain characteristics and landscape types in terrain-complex...Terrain plays a key role in landscape pattern formation, particularly in the transition zones from mountains to plains.Exploring the relationships between terrain characteristics and landscape types in terrain-complex areas can help reveal the mechanisms underlying the relationships. In this study, Qihe River Basin, situated in the transition zone from the Taihang Mountains to the North-China Plain, was selected as a case study area. First, the spatial variations in the relief amplitudes(i.e.,high-amplitude terrain undulations) were analyzed. Second, the effects of relief amplitudes on the landscape patterns were indepth investigated from the perspectives of both landscape types and landscape indices. Finally, a logistic regression model was employed to examine the relationships between the landscape patterns and the influencing factors(natural and human) at different relief amplitudes. The results show that with increasing relief amplitude, anthropogenic landscapes gradually give in to natral landscapes. Specifically, human factors normally dominate the gentle areas(e.g., flat areas) in influencing the distribution of landscape types, and natural factors normally dominate the highly-undulating areas(e.g., moderate relief areas). As for the intermediately undulating areas(i.e.,medium relief amplitudes), a combined influence of natural and human factors result in the highest varieties of landscape types. The results also show that in micro-relief areas and small relief areas where natural factors and human factors are more or less equally active,landscape types are affected by a combination of natural and human factors.The combination leads to a high fragmentation and a high diversity of landscape patterns. It seems that appropriate human interferences in these areas can be conducive to enhancing landscape diversity and that inappropriate human interferences can aggravate the problems of landscape fragmentation.展开更多
基金Sponsored by National Natural Science Foundation of China(41671160)
文摘The urban-rural integrated area in Sanshui District of Foshan City was selected for research, and the impact of landscape pattern around the No.269 provincial highway was analyzed based on the land-use data in 2014 using the spatial analysis in GIS and the moving window method. The results showed that:(1) within the scope of a 2 km-range buffer zone, with a low degree of heterogeneity, land for construction use and water area were the dominant land-use types, while with a high degree of fragmentation, cultivated land, wooded land, grassland, garden land, land for other farm uses, and land unused were scattered;(2) the 250-m square moving window could well detect the change characteristics of landscape pattern on both sides of the road;(3) the gradient analysis of landscape pattern in urban-rural integrated area, which was conducted with the aid of a 750-m transect on both sides of the road, indicated that there were significant differences between landscape indexes both in the urban-rural integrated area and on both sides of the road;(4) the road that had an obvious cutting and fragmentation impact on the landscape was an important factor leading to the increasing fragmentation and heterogeneity to regional landscapes.
文摘The objective of this study was to evaluate forest cover change and forest degradation in Nyungwe-Kibira Park, a natural reserve straddling Rwanda and Burundi from 1986 to 2015. Landsat TM, ETM+ and 8OLI images of 30 m spatial resolution were used as primary datasets. Geographic Information System (GIS) techniques were used for forest cover mapping and landscape metrics were calculated by using FRAGSTATS software. Classification and change analysis of forest cover type and landscape patterns analysis were carried out. In addition, to analyze the correlated external disturbances, the buffer zone of 5 Km was delineated outside the boundary of Nyungwe-Kibira Park. The results revealed that in among 5 land cover classes considered within the Park, the dominant one was dense forest class covering over 70% of the entire Park area while in the buffer zone cultivated and open land dominated at over 90% between the years 1986 and 2015. Change detection highlighted that within Nyungwe-Kibira forest, approximately 0.27% (4.97 Km<sup>2</sup>) of forest cover was cleared while 0.07% (1.22 Km<sup>2</sup>) was regenerated annually. In the buffer zone, the annual cleared forest cover was about 0.76% (13.02 Km<sup>2</sup>). The five landscape indices chosen at class level indicated a considerable fragmentation of forest inside the Park and the highest fragmentation in the buffer zone. Indeed, these results shed a bleak image over the future of the Nyungwe-Kibira forest that should be helpful for the policy-makers and managers of these natural parks to establish adequate policies to mitigate the forest loss and degradation by implementing quick and effective solutions.
文摘With the support of RS and GIS technology,the ecological environment of Linze was evaluated and the changes of ecological environment were analyzed from the spatial scope of ecosystem with the remote sensing images in 2000 and 2017 as the information source.The results showed that the areas with excellent,relatively good and relatively poor ecological environment in Linze showed a decreasing trend from 2000 to 2017,which decreased by 262.50,7,156.25 and 12,256.30 hm^2,respectively.From the landscape patch pattern,the patch density in areas with relatively good ecological environment increased the fastest from 2000 to 2017,which was 13.05 pieces/hm^2.The largest plaque index in areas with relatively good ecological environment decreased by 1.314%,and the dominance of large plaque in the region decreased.The assessment results of ecological environment based on remote sensing demonstrated that the ecological environment in Linze was generally healthy from 2000 to 2017,and the deterioration was improved.Among them,the area transformed from relatively poor ecological environment to other types was the largest,which was 17,512.92 hm^2,and the proportion of the area transformed into general ecological environment was the highest,accounting for 80.7%of the transformed area of the region.
文摘Inherited tectonic structures,ongoing tectonic deformation,and variations in relative rock uplift rates play an important role in conditioning the processes of relief development.Their influence among other factors,such as climate and lithology,can be quantified using landscape analysis,and geomorphometric indices,in particular.The usage of landscape analysis in recent years is increasing systematically due to the constant improvement of the digital elevation models and GIS software that significantly facilitate this approach.In this study,we aim to recognize the influence of tectonic structures and processes on relief development in the low mountains with moderate relief of the Sola River catchment in the Western Outer Carpathians.To this end,we calculated geomorphometric indices(river longitudinal profile,stream-length gradient index,minimum bulk erosion,relief ratio,circulatory ratio,elongation ratio,and hypsometric integral)for the Sola River and its 47 sub-catchments using a 25-m spatial resolution Digital Terrain Elevation Data Level 2.Additionally,we identified lineaments and knickpoints and correlated the computed results with local and regional fault networks,variations in lithology,and climate fluctuations.Obtained results indicate a significant impact of inherited tectonicstructures on the relief development of the Sola River catchment,i.e.,directions of principal ridges and valleys follow the orientation of main folds and faults recorded in this area.Anomalously high values of minimum bulk erosion,river gradient,and streamlength gradient index allowed us to define two areas with higher relative uplift rates:1)the So?a Gorge and 2)the Beskid Zywiecki Mts.Polish Outer Carpathians are generally considered as an area of low strain rate and low seismic activity.However,the possibility of neotectonic processes should be considered in geohazard estimations.Observed bends in the direction of river valleys that do not correspond with changes in lithology could be related to active strikeslip faults.These are probably the reactivated basement structures,copied in the thin-skinned nappe cover,as a result of the accommodation of the Mur-Zilina Fault Zone resulting from the tectonic push of the Alcapa(Alpine-Carpathian-Pannonian)microplate against the European plate.Thus,the role of recent tectonic activity in relief development of the Sola River catchment even though appears to be subsidiary at the most,should not be excluded.
文摘In recent decades, the control of floods is an efficient management practice for the rehabilitation of rangelands in most arid and semiarid areas. To evaluate the benefits, we used the Landscape Function Analysis (LFA) method to assess the function of patches and qualitative capability of a rangeland ecosystem in Gareh By- gone region, Fars province, southwestern Iran. Landscape functionality depends on soil, water and nutrient (col- lectively called "resources") conservation and use within a given ecosystem. Many landscapes are naturally het- erogeneous in terms of resource control and possess patches, where resources tend to accumulate, and in- ter-patches. Assessing rangeland health and function of landscape patches in response to environment and man- agement can give rise to correct management decisions for qualitative improvement of the ecosystem. Therefore, our study area was divided into two parts, i.e. water spreading and control parts, and sampling was done using LFA method in each part separately. Structural parameters, including the number, length and width of patches, and the mean length of inter-patches, were determined by the method to characterize the functional status of the monitoring sites. For each patch/inter-patch type identified in the transect organization log, we recorded its soil surface proper- ties classified according to the Soil Surface Assessment Method. The density, canopy cover and composition of plants were then assessed. The results showed that the number of ecological patches and their dimensions were significantly increased in the water spreading site. Soil stability and the values of nutrient cycling indices were in- creased but the infiltration values were decreased in the water spreading site. It could be related to the effect of suspended materials transported by floods to the soils in the study area. The improvement of ecological patches and rangeland ecosystem was achieved where water spreading systems were practiced. Therefore it can be con- cluded that water spreading as a management plan plays an important role in arid land ecosystem functionality.
文摘The majority of studies investigating the effects of landscape composition and configuration on bee populations have been conducted in regions of intensive agricultural production, ignoring regions which are dominated by seminatural habitats, such as the islands of the Aegean Archipelago. In addition, research so far has focused on the landscape impacts on bees sampled in cropped fields while the landscape effects on bees inhabiting seminatural habitats are understudied. Here, we investigate the impact of the landscape on wild bee assemblages in 66 phryganic (low scrubland) communities on 8 Aegean islands. We computed landscape metrics (total area and total perimete^area ratio) in 4 concentric circles (250, 500, 750, and 1000 m) around the center of each bee sampling site including 3 habitat groups (namely phrygana, cultivated land, and natural forests). We further measured the local flower cover in 25 quadrats distributed randomly at the center of each sampling site. We found that the landscape scale is more important than the local scale in shaping abundance and species richness of bees. Furthermore, habitat configuration was more important than the total area of habitats, probably because it affects bees' movement across the landscape. Phrygana and natural forests had a positive effect on bee demographics, while cultivated land had a negative effect. This demonstrates that phryganic specialists drive bee assemblages in these seminatural landscapes. This finding, together with the shown importance of landscape scale, should be considered for the management of wild bees with special emphasis placed on the spatial configuration of seminatural habitats.
基金supported in part by Hong Kong Research Grant Council General Research Grant Nos.16309518,16309219,16310620 and 16306821supported in part by the Hong Kong Research Grant Council General Research Grant Nos.16306415 and 16308518.
文摘A fundamental task in phase retrieval is to recover an unknown signal x∈R^(n) from a set of magnitude-only measurements y_(i)=|〈a_(i),x〉|,i=1,…,m.In this paper,we propose two novel perturbed amplitude models(PAMs)which have a non-convex and quadratic-type loss function.When the measurements a_(i)∈R^(n) are Gaussian random vectors and the number of measurements m≥Cn,we rigorously prove that the PAMs admit no spurious local minimizers with high probability,i.e.,the target solution x is the unique local minimizer(up to a global phase)and the loss function has a negative directional curvature around each saddle point.Thanks to the well-tamed benign geometric landscape,one can employ the vanilla gradient descent method to locate the global minimizer x(up to a global phase)without spectral initialization.We carry out extensive numerical experiments to show that the gradient descent algorithm with random initialization outperforms state-of-the-art algorithms with spectral initialization in empirical success rate and convergence speed.
基金supported in part by Hong Kong Research Grant Council General Research Grant Nos.16309518,16309219,16310620,and 16306821supported in part by Hong Kong Research Grant Council General Research Grant Nos.16306415 and 16308518
文摘A fundamental problem in phase retrieval is to reconstruct an unknown signal from a set of magnitude-only measurements.In this work we introduce three novel quotient intensity models(QIMs) based on a deep modification of the traditional intensity-based models.A remarkable feature of the new loss functions is that the corresponding geometric landscape is benign under the optimal sampling complexity.When the measurements ai∈Rn are Gaussian random vectors and the number of measurements m≥Cn,the QIMs admit no spurious local minimizers with high probability,i.e.,the target solution x is the unique local minimizer(up to a global phase) and the loss function has a negative directional curvature around each saddle point.Such benign geometric landscape allows the gradient descent methods to find the global solution x(up to a global phase) without spectral initialization.
基金Supported by the Masters Research Programme-TERI University, New Delhi
文摘Landscape characterization gives an overall information on the status of Land Use and Land Cover (LULC), changes in its composition and the impact of natural and human influences operating at different spatial and temporal scales. This information can be used to monitor changes in natural forest resources and protected areas, delineate potential conservation areas and can serve in effective management of ecologically fragile landscapes. In the present study, geo-spatial tools were used to characterize the landscape of Sariska National Park and its surroundings. Satellite data was used to prepare LULC maps for 1989 and 2000, change detection analysis and computation of landscape metrics. Climatic data, field records and modeling tools were used to map the potential spread of two invasive species, Prosopis juliflora and Adhatoda vasica. The results show that the forest area increased from 1989 to 2000, indicating better management practices. Landscape metrics (PAFRAC, PLADJ and AI) also support this argument. Improvements in the degraded forest can further enhance this effect. The entire reserve however is suitable for the invasion of P. juliflora and A. vasiea but is more pronounced in Boswellia serrata and Anogeissus pendula - Acacia catechu (open) forests. A detailed landscape characterization map can help forest managers to make important policy decisions concerning issues such as invasive species.
基金supported by the National Basic Research Program of China(Grant No.2015CB452702)the National Natural Science Foundation of China(Grant Nos.41671090&41601091)
文摘Terrain plays a key role in landscape pattern formation, particularly in the transition zones from mountains to plains.Exploring the relationships between terrain characteristics and landscape types in terrain-complex areas can help reveal the mechanisms underlying the relationships. In this study, Qihe River Basin, situated in the transition zone from the Taihang Mountains to the North-China Plain, was selected as a case study area. First, the spatial variations in the relief amplitudes(i.e.,high-amplitude terrain undulations) were analyzed. Second, the effects of relief amplitudes on the landscape patterns were indepth investigated from the perspectives of both landscape types and landscape indices. Finally, a logistic regression model was employed to examine the relationships between the landscape patterns and the influencing factors(natural and human) at different relief amplitudes. The results show that with increasing relief amplitude, anthropogenic landscapes gradually give in to natral landscapes. Specifically, human factors normally dominate the gentle areas(e.g., flat areas) in influencing the distribution of landscape types, and natural factors normally dominate the highly-undulating areas(e.g., moderate relief areas). As for the intermediately undulating areas(i.e.,medium relief amplitudes), a combined influence of natural and human factors result in the highest varieties of landscape types. The results also show that in micro-relief areas and small relief areas where natural factors and human factors are more or less equally active,landscape types are affected by a combination of natural and human factors.The combination leads to a high fragmentation and a high diversity of landscape patterns. It seems that appropriate human interferences in these areas can be conducive to enhancing landscape diversity and that inappropriate human interferences can aggravate the problems of landscape fragmentation.