Effects of landscape fragmentation of plantation forests on carbon storage in the Loess Plateau,China

Tree plantation and forest restoration are the major strategies for enhancing terrestrial carbon sequestration and mitigating climate change.The Grain for Green Project in China has positively impacted global carbon sequestration and the trend towards fragmentation of plantation forests.Limited studies have been conducted on changes in plantation biomass and stand structure caused by fragmentation,and the effect of fragmentation on the carbon storage of plantation forests remains unclear.This study evaluated the differences between carbon storage and stand structure in black locust forests in fragmented and continuous landscape in the Ansai District,China and discussed the effects of ecological significance of four landscape indices on carbon storage and tree density.We used structural equation modelling to explore the direct and indirect effects of fragmentation,edge,abiotic factors,and stand structure on above-ground carbon storage.Diameter at breast height(DBH)in fragmented forests was 53.3%thicker,tree density was 40.9%lower,and carbon storage was 49.8%higher than those in continuous forests;for all given DBH>10 cm,the trees in fragmented forests were shorter than those in continuous forests.The patch area had a negative impact on carbon storage,i.e.,the higher the degree of fragmentation,the lower the density of the tree;and fragmentation and distance to edge(DTE)directly increased canopy coverage.However,canopy coverage directly decreased carbon storage,and fragmentation directly increased carbon storage and tree density.In non-commercial forests,fragmentation reduces the carbon storage potential of plantation,and the influence of patch area,edge,and patchy connection on plantation should be considered when follow-up trees are planted and for the plantation management.Thus,expanding the area of plantation patches,repairing the edges of complex-shaped patches,enhancing the connectivity of similar patches,and applying nutrients to plantation forests at regular intervals are recommended in fragmented areas of the Loess Plateau.

Road construction and landscape fragmentation in China

The landscape fragmentation caused by road construction has many direct and indirect impacts on wildlife and ecosystems. By using the GIS and statistic software of fragmentation computation, a comprehensive index, road-induced landscape fragmentation index (RLFI), is proposed to quantify the degree of landscape fragmentation resulting from different levels of road constructions. The results show that road-induced fragmentation index in China ranges from 0.987 to 3.357, with a mean of 1.846 in 2002. The regional differences of landscape fragmentation are obvious and scoring sequence is: North China (2.65) > East China (2.62) > Central China (2.60) > South China (2.51) > Southwest China (2.34) > Northeast China (2.19) > Inner Mongolia (1.88) > Northwest China (1.67) > Qinghai-Tibet Plateau (1.65). The anisotropic analysis indicates that the variation of fragmentation index in east-west direction is larger than that in south-north direction.

Landscape fragmentation associated with the Qingzang Highway and its influencing factors-A comparison study on road sections and buffers

Many studies have examined the effect of roads on landscape fragmentation.Yet they rarely considered local characteristics of the road and road buffer widths.Therefore,this study that took place in the Qingzang Highway(QH)examined the variations in road buffers and road sections of landscape fragmentation.The QH was divided into 32 sections with 23 buffer areas.Based on the indicators of landscape fragmentation from 1980 to 2018,we found significant spatial heterogeneity between sections and buffers.Generally,landscape fragmentation de-creased with increasing buffer distance to the QH.For different sections,the coefficients of variation between buffers were rather high and significantly different.Therefore,fixed-width buffers may overestimate or underes-timate the spatial scope and influence intensity of a road.The impacts of road sections around provincial capitals,prefecture-level cities and main counties on landscape fragmentation were relatively extensive and formed clus-ters of highly fragmented areas.Geodetector results indicated that natural and anthropogenic factors,such as altitude,climate,distance to major settlements and socioeconomic conditions,could well explain the spatiotem-poral characteristics of landscape fragmentation.Altitude,precipitation and the distance to major settlements had higher explanatory power for landscape fragmentation in permafrost regions,whereas slope and socioeconomic condition had higher explanatory power for non-permafrost regions in Xizang Autonomous Region.

Measurement System of Landscape Fragmentation in National Nature Reserves:A Case Study of Dinghu Mountain National Nature Reserve,Guangdong Province

With the advancement of industrialization and urbanization,the natural landscape has been destroyed to varying degrees,presenting the trend of landscape fragmentation and ecosystem degradation.Taking Dinghu Mountain National Nature Reserve as an example,a three-dimension measurement system of separation degree,fractal dimension and interference intensity for landscape fragmentation is established and verified by collecting survey data through questionnaires.The research results will provide a theoretical reference for landscape conservation and sustainable development of national nature reserves.

Landscape fragmentation by urbanization in the Netherlands: options and ecological consequences

In the western part of the Netherlands due to several economic factors there is a strong pressure to extend the urban activities. This means that a large open peatland area of special ecological interest, the so called green heart, will be threatened more and more by urbanization. In this area diary farming predominates and the ecological value is largely dependant on this land use (meadow birds). Scenarios for future landscapes have been developed for this area taken into account different spatial lay out of urbanization. The consequences for nature were evaluated with a decision support system. The so called LEDESS (landscape ecological decision support system) links available landscape ecological knowledge to a geographical information system (GIS) to evaluate the scenarios. LEDESS is based on a deterministic concept of the ecotope dependent on physiotope, vegetation dynamics, target vegetation and management, and of faunal habitat requirements that are also dependent on vegetation structure. It also take 02/12/98s into account the accessibility of the landscape for migrating fauna species. It turns out that urbanization will deteriorate the existing fragmented landscape. As an answer to the scenarios of urbanization different options for nature restoration have been elaborated in additional scenarios. The consequences were evaluated again with the same computer model. The study has concluded that fragmentation can be compensated to some extend by enlargement of habitats, but the effectiveness depends highly upon the spatial allocation of the new habitats.

Cause and consequence of landscape fragmentation and changing disturbance by socio-economic development in mountain landscape system of South Korea

Through the statistics and the analysis of landscape map, changes of lands use regime and landscape structure during 20 years were investigated in the agriculture forestry complexed mountain landscape system of Yangdong Myon, Yangpyung Gun in the central Korea. Landscape changes of this region was inter related to the recent socio economic development of rural life. Utilization of biomass and other traditional forest management were drastically abandoned in recent 10 years. Landscape analysis of maps showed that the area of secondary vegetation that had been sustained by human nature disturbance was decreased by using of plantation during this time. Those decreased areas were replaced to plantation for wood production and other purpose. Past area of woody species dominated in plantation also substituted to other species. Traditional human activity on secondary vegetation was disappeared. Consequently, the advanced management regimes such as new plantation and cultivation extending areas were increased in abandoned land.

Landscape influences and management countermeasures of ginseng planting near Changbai mountain nature reserve

Ginseng planting in Northeast China brings economic benefits but affects forest landscape integrity and native ecological processes.In order to quantify the impacts of ginseng planting on the forest landscape,Fusong County in Jilin Province was selected as a study area.The number and distribution of ginseng fields over different time was quantified based on remote sensing and ground surveys.Grid analysis and multiple regression analysis were used to study the impacts of ginseng planting on the landscape.The results showed that altitudes and slopes of ginseng fields increased and became increasingly scattered and smaller closer to the Changbai Mountain Nature Reserve.Ginseng fields and abandoned fields increased total patches and total area of the local forested landscape,and shared edge lengths between ginseng fields and forests,resulting in continuous fragmentation of the landscape.Although the total area of existing and abandoned ginseng fields accounts for a small fraction of the total landscape,their negative impacts on ecosystem conservation is significant.The local government needs to rationally plan ginseng planting,scientifically implement the restoration of abandoned ginseng lands,and enhance awareness of ginseng farmers to environmental stewardship.Our study has important significance for maintaining the healthy and stable development of the local ginseng industry and for improving the quality of regional ecological environment.

Fractal properties of patch perimeters in a disturbed montane landscape,Beijing,China

The forest landscape has been highly fragmented in Donglingshan montane region, Beijing, China, where the folding degree of patch perimeters considerately influenced the spatial distribution of biological diversity, therefore the quantitative description to it is very helpful to conservation biology studies. The fractal dimensions of landscape patch perimeters of this region were estimated and compared. The results showed that fractal dimensions of all the landscape types were between 1.00 and 1.58. The fractal dimensions of natural vegetation types were higher than that of artificial vegetation type. Where forests (1 21) and shrubs (1.24) are near to farmland (1.12), so they were both highly disturbed by human activities regarding the smallest mean patch areas. But the grassland (1.58) had the largest mean patch area, its disturbance intensity was the lowest in this region. The fractal dimension of the overall landscape was 1.24, which was near to those of forests and shrubs, and obviously different from those of farmland and grassland. The fractal dimension of the overall landscape was 1.13 in small scales, and that was 1.65 in large scales. Which means that a large number of small area patches had regular perimeters, their fragment degrees were higher; whereas the large area patches had folding perimeters, their fragment degrees were lower, they had smaller patch numbers, however occupied most of the landscape area. Large areas and highly folded perimeters were the main property of the landscape patch in Donglingshan montane region.

Change of Land Cover Category and Landscape Pattern in a Valley City From 2000 to 2015

The landscape pattern is affected by human activities and the natural environment.China’s urbanization has been a great achievement in the past 30 years,but also it has caused a variety of environmental problems.The landscape of the mountain valley area is particularly affected by human activities and the natural environment.The rise of remote sensing technologies has promoted a better understanding of ecological process,and the quantitative study on landscape dynamics has received more and more considerable attention.In this paper,four years from 2000,2005,2010,and 2015 were selected as the research time.Using Landsat TM/ETM remote sensing image,DEM,and socioeconomic data,we calculated the landscape pattern indices in four districts(Lishi,Fangshan,Liulin,and Zhongyang)of Luliang City on patch scale,land cover scale and landscape scale respectively.Thus,the change of landscape pattern in four districts from 2000 to 2015 were obtained.The results showed that:①the landscape in the mountain valley area has become more and more fragmented in the past 15 years(2000–2015);②the landscape dynamics of the main and tributary catchment areas of the Sanchuan River were different from that of urban development,which is closely related to the development stages of urban and rural areas;③there were differences in landscape changes between different topographic and landform units,and the landscape at higher altitudes was more vulnerable to disturbance.This study can provide some reference for the ecological restoration and management on landscape scale in the mountain and valley areas of the north and northwest China.

Assessing forest fragmentation in north-western Himalaya:a case study from Ranikhet forest range,Uttarakhand,India

The northwestern Himalaya harbors high levels of biodiversity due to its unique topography, climatic conditions and heterogeneity. Forest fragmentation is one of the major threats causing a decline in biodiversity in the Himalayan region. We assesses forest fragmentation and changes in land use land cover（LULC） patterns using multi-temporal satellite data over a time span of four decades（1976–2013）. Fragmentation analysis using the Landscape Fragmentation Tool（LFT） reveals a decrease in core and edge areas by 14 and 2.3 %, respectively; while an increase in non-forest, patch area and perforation area by 2.1, 0.4, and 14 %, respectively. The LULC dynamics show that the areas under dense forest and scrub forest have decreased by 2.8 % and 1.9 %, respectively; and there is an increase in open forest, crop land and fallow land area by 2.6, 1.7 and 2.1 %, respectively. The quantification of landscape heterogeneity is undertaken with the help of landscape metrics computed using FRAGSTATS at class and landscape level, showing signs of increased fragmentation. Our study provides baseline database that can support the future biodiversity conservation and sustainable forest management initiatives.

Assessing forest cover changes and fragmentation in the Himalayan temperate region: implications for forest conservation and management

This study comprehensively assessed long-term vegetation changes and forest fragmentation dynamics in the Himalayan temperate region of Pakistan from 1989 to 2019.Four satellite images,including Landsat-5 TM and Landsat-8 Operational Land Imager(OLI),were chosen for subsequent assessments in October 1989,2001,2011 and 2019.The classified maps of 1989,2001,2011 and 2019 were created using the maximum likelihood classifier.Post-classification comparison showed an overall accuracy of 82.5%and a Kappa coefficient of 0.79 for the 2019 map.Results revealed a drastic decrease in closed-canopy and open-canopy forests by 117.4 and 271.6 km^(2),respectively,and an increase in agriculture/farm cultivation by 1512.8 km^(2).The two-way ANOVA test showed statistically significant differences in the area of various cover classes.Forest fragmentation was evaluated using the Landscape Fragmentation Tool(LFT v2.0)between 1989 and 2019.The large forest core(>2.00 km^(2))decreased from 149.4 to 296.7 km^(2),and a similar pattern was observed in medium forest core(1.00-2.00 km^(2))forests.On the contrary,the small core(<1.00 km^(2))forest increased from 124.8 to 145.3 km^(2) in 2019.The perforation area increased by 296.9 km^(2),and the edge effect decreased from 458.9 to 431.7 km^(2).The frequency of patches also increased by 119.1 km^(2).The closed and open canopy classes showed a decreasing trend with an annual rate of 0.58%and 1.35%,respectively.The broad implications of these findings can be seen in the studied region as well as other global ecological areas.They serve as an imperative baseline for afforestation and reforestation operations,highlighting the urgent need for efficient management,conservation,and restoration efforts.Based on these findings,sustainable land-use policies may be put into place that support local livelihoods,protect ecosystem services,and conserve biodiversity.

Quantification of Urban Sprawl for Past-To-Future in Abha City,Saudi Arabia

Given that many cities in Saudi Arabia have been observing rapid urbanization since the 1990s,scarce studies on the spatial pattern of urban expansion in Saudi Arabia have been conducted.Therefore,the present study investigates the evidence of land use and land cover(LULC)dynamics and urban sprawl in Abha City of Saudi Arabia,which has been experiencing rapid urbanization,from the past to the future using novel and sophisticated methods.The SVM classifier was used in this study to classify the LULC maps for 1990,2000,and 2018.The LULC dynamics between 1990–2000,2000–2018,and 1990–2018 have been analyzed using delta()change and the Markovian transitional probability matrix.Urban sprawl or urban expansion was modeled using two approaches,such as landscape fragmentation and presence frequency for the first time.The future LULC map for 2028 was predicted using the artificial neural network-cellular automata model(ANN-CA).Future LULC was analyzed using landscape fragmentation and frequency approaches.The results of LULC maps showed that urban areas increased by 334.4%between 1990 and 2018.The Delta change rate showed that 16.34%in urban areas has increased since 1990.While,the transitional probability matrix between 1990 and 2018 reported that the built-up area is the largest stable LULC,having an 83.6%transitional probability value.While 17.9%,21.8%,12.4%,and 10.5%of agricultural land,scrubland,exposed rocks,and water bodies were transformed into built-up areas.Urban sprawl models showed that 139 km^(2)of new urban areas had been set up in 2018,49 and 69 km^(2)in 1990 and 2000.Furthermore,in 2018,more than 200%of urban areas were stabilized or became core urban areas.The future LULC map(2028)showed that the built-up area would be 343.72 km^(2),followed by scrubland(342.98 km^(2))and sparse vegetation(89.96 km^(2)).The new urban area in 2028 would be 169 km^(2).The authorities and planners should focus more on the sustainable development of urban areas;otherwise,it would harm the natural and urban environment.

Impact of urbanization on plant diversity: A case study in built-up areas of Beijing

Urbanization is developing rapidly in the world, which seriously changes the habitat of organisms and has clearly a negative effect on biodiversity. Preservation of biodiversity is crucial in urban planning and management, which is also an important symbol for the level of greening. Problems such as scarcity of urban green space and plant species have become obstacles to the establishment of ecological friendly cities. However, coexistence of nature and modernization, as well the coordination of economic development and biodiversity, are goals that people are seeking. We have taken the builtup areas of Beijing as a study case and discussed the impacts of urbanization on plant diversity, with the support of fieldwork and SPOT remote sensing data. The results are as follows： 1） in the process of urbanization, exotic plants have been widely introduced, which has affected species composition and the proportion of native plants; it is clear that artificial green spaces always will have a lower level of plant diversity than natural green spaces; 2） functional differences of green space types partially decide their species abundance, so that plant diversity in greenbelts and streets is generally lower than in parks; 3） the spatial variety of plant diversity contributes much to the imbalance of district de- velopment and the planning of different functional zones; this variation is embodied in different ring-belts and directions; 4） habitat fragmentation also affects plant diversity to a great extent; there is a significant positive correlation between high fragmentation and low plant diversity. According our results, some suggestions are proposed, which would be suitable for the preservation of plant di- versity and ecological improvement during urbanization.

Assessment of multifunctional landscapes dynamics in the mountainous basin of the Mo River （Togo, West Africa）

In this study, historical landscape dynamics were investigated to（i） map the land use/cover types for the years 1972, 1987, 2000 and 2014;（ii） determine the types and processes of landscape dynamics; and（iii） assess the landscape fragmentation and habitat loss over time. Supervised classification of multi-temporal Landsat images was used through a pixel-based approach. Post–classification methods included systematic and random change detection, trajectories analysis and landscape fragmentation assessment. The overall accuracies（and Kappa statistics） were of 68.86%（0.63）, 91.32%（0.79）, 90.66%（0.88） and 91.88%（0.89） for 1972, 1987, 2000 and 2014, respectively. The spatio-temporal analyses indicated that forests, woodlands and savannahs dominated the landscapes during the four dates, though constant areal decreases were observed. The most important dynamic process was the decline of woodlands with an average annual net loss rate of –2%. Meanwhile, the most important land transformation occurred during the transition 2000–2014, due to anthropogenic pressures. Though the most important loss of vegetation greenness occurred in the unprotected areas, the overall analyses of change indicated a declining trend of land cover quality and an increasing landscape fragmentation. Sustainable conservation strategies should be promoted while focusing restoration attention on degraded lands and fragmented ecosystems in order to support rural livelihood and biodiversity conservation.

黄淮海平原耕地破碎化的时空演化格局及其驱动机制

Exploring the spatio-temporal variations of farmland landscape patterns in a traditional agricultural region can provide scientific support for decision-making on sustainable rural land use and rural vitalization development. This study established a comprehensive evaluation index for farmland fragmentation with multiple aspects(dominance, integrity, aggregation, regularity, and connectivity) at the county scale. The goal was to identify the evolution of farmland fragmentation in the traditional agricultural region of the Huang-Huai-Hai Plain during 2000–2015 and investigate underlying drivers using panel data of 359 counties.Results showed an accelerating but fluctuating fragmentation pattern of the farmland landscape. The indexes of dominance, integrity, and aggregation of farmland decreased most sharply, while the index of connectivity increased. Furthermore, the evolution of the farmland fragmentation pattern showed significant spatio-temporal heterogeneity, which is similar to the trajectory of urbanization and land use transition. Farmland fragmentation in municipal districts also emerged earlier and was more severe than in county-level cities and counties.Factors influenced by advancing urbanization include the proportion of artificial land, population density, and proportion of primary industry;these factors drove the evolution of farmland fragmentation. In contrast, the increase in income of rural residents and production efficiency of farmland were the key factors contributing to the improvement in farmland connectivity.