ABSTRACT
Theoretical researches and practices on the life community of mountain-water-forest-farmland-lake-grassland-sandland mosaic and its protection and restoration have been gradually developed in China, which demands the support of a systematic disciplinary theory. Landscape ecology, as an interdisciplinary science of geography and ecology, can meet such demand thanks to its macroscopic spatial theory and technical system. Here, landscape ecology is taken as the supporting discipline of holistic protection and restoration for mountain-water-forest-farmland-lake-grassland-sandland mosaic. Firstly, we clarified that life community of mountain-water-forest-farmland-lake-grassland-sandland is a heterogeneously mosaic landscape, which bears all the characteristics of landscape and thus follows the principles of landscape ecology. Secondly, we expounded how the basic principles of landscape-ecological construction could be applied to the planning and evaluation of holistic protection and restoration for mountain-water-forest-farmland-lake-grassland-sandland mosaic. Finally, we summarized the new trend of landscape-ecological construction research, listed the theoretical and practical problems to be solved, and discussed how the projects of holistic protection and restoration for the mountain-water-forest-farmland-lake-grassland-sandland mosaic can provide a variety of practices for seeking the solutions. The combination of landscape ecology and practical restoration projects would generate effective solutions to realize sustainable development in terms of ecology, economy, and society in China and even the whole world.
Subject(s)
Ecology , Grassland , Farms , Conservation of Natural Resources , Lakes , Water , Forests , China , EcosystemABSTRACT
Urban street canyon is one of the most important characteristics and spatial forms of cities. It is one of the most frequently used public spaces in cities, with the most serious automobile exhaust pollution and the largest population density. The unreasonable space configuration and internal composition might decrease self-purification of urban ventilation but increase local air pollutant concentration. Here, we reviewed the impacts of street canyon morphology, street trees, vehicle flow and meteorological factors on the distribution of air pollutants in street canyons. We scrutinized the relevant methods of numerical simulation, wind tunnel experiments, and field monitoring on the distribution and diffusion of air pollutants in street canyons. We recommended that future research should concentrate on the impacts of various parameters on the distribution and diffusion of air pollutants based on the field monitoring data. Meanwhile, further research should develop optimization strategies for street canyon design which is conducive to the dispersion of air pollutants, and put forward scientific support and optimization scheme for the controlling of air pollutants from the perspective of urban planning and pattern optimization.
Subject(s)
Air Pollutants , Air Pollutants/analysis , Cities , Meteorological Concepts , Models, Theoretical , Vehicle Emissions/analysisABSTRACT
Atmospheric environment in urban built-up area is severely influenced by the surrounding landscape pattern. Understanding the relationship between air pollution and surrounding landscape pattern at small scale has great significance for mitigating air pollution from the perspective of urban construction. The annual average concentrations of NO2, SO2, PM2.5 and PM10 from 266 air pollution monitoring stations in 30 provincial capitals of China in 2017 were chosen as dependent variables. Ten two-dimensional and three-dimensional landscape pattern indices (number of buildings, building aggregation, building density, impervious water ratio, quantitative density of catering, building footprint area, high building ratio, floor area ratio, total building area and building type Shannon diversity index) within the 3 km area around the monitoring stations were used as independent variables. The effects of landscape pattern on the concentration of four air pollutants were analyzed using the boosted regression trees model. The results showed that the concentration of four air pollutants in the central and northern cities were significantly higher than that in the southeast coastal cities and southwest cities. The most important factor affecting the concentrations of NO2, SO2, PM2.5 and PM10 was the impervious ratio, with relative contribution rates of 40.7%, 36.3%, 51.0% and 51.8% respectively. The results of sub-region analysis showed that the most important influencing factor differed in different regions, including the impervious ratio in the East and Central China; the number and density of buildings in South China; the impervious ratio and diversity of building types in North China; the impervious ratio and the number of buildings in Northeast China, the density of buildings in Northwest China. Such differences were mainly caused by climate, topography, urban planning, and other factors.
Subject(s)
Air Pollutants , Air Pollution , Air Pollutants/analysis , Air Pollution/analysis , China , Cities , Environmental Monitoring , Particulate Matter/analysisABSTRACT
The close interactions between abiotic and biotic components create a variety of three-dimensional (3-D) landscape patterns. Landscape ecology, as a discipline of studying patterns and ecological processes, has made rapid progress in the exploration of 3-D space with the improvement of data acquirement ability, such as lidar technology. The real surface landscape can be described considering 3-D data, which improves the consistency between landscape indices and ecological process, and has overcome the shortage of ecological meanings of traditional researches. However, the lack of universality of methods and conclusions still exist due to different study backgrounds. The sensitivities of research results will increase with the expansion from two-dimensional to 3-D scale because of the increasing data quantity and accuracy. How to select and process the suitable scaled data to get more scientific conclusions need to be discussed in the future. The integration of multi-scale, multi-source and a long time series data will be the study trend with data acquisition becoming more convenient. In addition to the dynamic monitoring and prediction studies, the sustainable and ecological restoration application combined with landscape planning and design will be an important research direction.
Subject(s)
Conservation of Natural Resources , Ecosystem , China , EcologyABSTRACT
Maxent niche model was used to project the potential distribution of alien plant species Spartina alterniflora in China, with 96 S. alterniflora records and marine and climatic data along China coastal area. The results showed that suitable area for the distribution of S. alterniflora occupied 85% of coastal areas, with the highly suitable area, the medium, and low suitable area accounting for 18%, 34% and 33%, respectively. Only 15% of the coastal areas were regions with distribution possibility of less than 5%. Its distribution suitability was mainly related to annual lowest seawater temperature, annual mean seawater temperature, annual mean air temperature, and annual lowest temperature in January. However, the importance of annual mean precipitation, annual mean daily diurnal range, seawater salinity, annual highest seawater temperature, annual highest tempe-rature in June and current velocity was relatively small. At the highly suitable areas for S. alterni-flora, the annual lowest seawater temperature ranged from 0.62 to 24.81 â, the annual mean seawater temperature ranged from 10.46 to 27.29 â, the annual mean air temperature was between 9 to 25 â, and the annual lowest temperature in January was between -13.5 and 16.7 â. The distribution possibility of S. alterniflora in the northern coastal area was over 20%, indicating it has a great potential to invade further north in China, especially in Bohai Bay areas. According to the current distribution records and climatic data in China, the invasion risk of S. alterniflora in central and southern coasts of Hainan and most regions of Taiwan Province was low, but the possibility of future invasion can not be excluded.
Subject(s)
Introduced Species , Models, Theoretical , Wetlands , China , Poaceae , TaiwanABSTRACT
The SanJiang Plain is one of the most concentrated and contiGuous area of marshes, which plays an irreplaceable role in maintaining regional ecological security. Based on the 3S technology, we examined the changes in land use and landscape pattern of the SanJiang Plain from 1980 to 2010. The results showed that marshland area lost 7135 km2, with a loss rate of 59.1%. The paddy area increased 18010 km2, with a growth rate of 610.1%. The results of landscape indices analysis showed that the number of patches increased, the landscape fragmentation became stronger, the landscape heterogeneity increased, and the different landscape types became homogenized. The CLUE-S model was validated based on the five different periods of land use maps during 1980-2010. The Kappa index between the simulation and actual measurement at the time scale of 30 years was 0.71, indicating that the model was suitable for 30 years simulation in the study area. The future wetland changes in the SanJiang Plain from 2010 to 2030 was simulated with validated CLUE-S models, including historical development scenario, planning scenario, and ecological restoration scenario. The simulation results showed that the marsh land would decrease 2515.44 km2 and the paddy area would increase 19656.24 km2 in the historical development scenario. The marsh land would decrease 303.28 km2, but the paddy area would increase 1392.08 km2 in the planning scenario. The marsh land would increase 3585.61 km2 and the paddy area would increase 289.72 km2 in the ecological restoration scenario. The landscape patterns of the three scenarios were estimated using landscape indices. The results showed that the landscape pattern fragmentation would become more and more serious in the historical development scenario. The landscape pattern would have no signifi-cant changes in the planning scenario. The wetland area and connectivity would increase, the different landscape types would become balanced, and the landscape pattern would be gradually optimized in the ecological restoration scenario.
Subject(s)
Conservation of Natural Resources , Wetlands , China , Ecology , Ecosystem , Models, TheoreticalABSTRACT
With the expansion of urban area, many cities are facing urban water environment issues, i.e., water resources shortage, lack of groundwater reserves, water pollution, urban waterlogging. For resolving these urban issues, 'sponge city' was proposed in 2015 in China. Liaodong Bay area of Panjin City in Liaoning Province of China was chosen as case study. Based on 'Sponge City Construction Technology Guide: Low Impact Development Rainwater System Building (Trial)', the underlying surface and types of land use in the typical area were analyzed. Sponge city plan of the study area was designed through combining topography, hydrology, rainfall intensity and other factors, and selecting LID measures. The results showed that when the study area reached the ove-rall target control rate (the control rate of the total annual runoff was ï¼75%), the subsidence greenbelt rate was 1%-31%, with a total area of 13.73 km2; the pervious pavement rate was 1%-13%, with a total area of 2.29 km2. This study could provide a case study for planning and designing of 'sponge city', proposing new ideas and methods for the research on landscape pattern and process.
Subject(s)
Agriculture , Cities , Hydrology , China , City Planning , EcologyABSTRACT
Based on field inventory data and vegetation index EVI (enhanced vegetation index), the spatial pattern of the forest biomass in the Great Xing'an Mountains, Heilongjiang Province was quantitatively analyzed. Using the spatial analysis and statistics tools in ArcGIS software, the impacts of climatic zone, elevation, slope, aspect and vegetation type on the spatial pattern of forest biomass were explored. The results showed that the forest biomass in the Great Xing'an Mountains was 350 Tg and spatially aggregated with great increasing potentials. Forest biomass density in the cold temperate humid zone (64.02 t x hm(-2)) was higher than that in the temperate humid zone (60.26 t x hm(-2)). The biomass density of each vegetation type was in the order of mixed coniferous forest (65.13 t x hm(-2)) > spruce-fir forest (63.92 t x hm(-2)) > Pinus pumila-Larix gmelinii forest (63.79 t x hm(-2)) > Pinus sylvestris var. mongolica forest (61.97 t x hm(-2)) > Larix gmelinii forest (61.40 t x hm(-2)) > deciduous broadleaf forest (58.96 t x hm(-2)). With the increasing elevation and slope, the forest biomass density first decreased and then increased. The forest biomass density in the shady slopes was greater than that in the sunny slopes. The spatial pattern of forest biomass in the Great Xing' an Mountains exhibited a heterogeneous pattern due to the variation of climatic zone, vegetation type and topographical factor. This spatial heterogeneity needs to be accounted when evaluating forest biomass at regional scales.
Subject(s)
Biomass , Climate , Forests , Spatial Analysis , China , Larix , Picea , Pinus , Sunlight , TemperatureABSTRACT
LANDIS Pro 7.0 model was used to simulate the dynamics of aboveground biomass of ten broadleaved tree species in the Xiao Xing' an Mountains area under current and various climate change scenarios from 2000 to 2200, and carbon content coefficients (CCCs) were coupled to cal- culate the aboveground carbon sequestration rates (ACSRs) of these species. The results showed that in the initial year of simulation, the biomasses and their proportions of Fraxinus mandshurica, Phellodendron amurense, Quercus mongolica, Ulmus propinqua, and Acer mono were relatively low, while those of Betula costata, Betula platyphylla, and Populus davidiana were higher. A trend of rise after decline occurred in ACSR for pioneer species in the mid and late periods of simulation years, but ACSRs for the other broadleaved tree species were considerably complex. The ACSRs of Q. mongolica and Tilla amurensis fluctuated in the ranges of -0.05-0.25 t · hm(-2) · 10 a(-1) and 0.16-1.29 t · hm(-2) · 10 a(-1) in simulation years, respectively. The ACSRs of F. mandshurica, U. propinqua, A. mono, and B. costata showed a trend of decline after rise in late simulation years. There were significant differences in ACSR for P. amurense and B. davurica among various climate change scenarios in the periods of 2050-2100 and 2150-2200, while no significant difference in ACSR for the other species would be detected. Difference of sensitivity of various species in ACSR for future climate scenarios in the Small Khingan Mountains area existed. However, the un- certainty of future climates would not yield significant difference in ACSR for most broadleaved tree species. Moreover, a time lag would exist in the process of climate change effects on temperate forest's ACSR.
Subject(s)
Carbon Sequestration , Climate Change , Forests , Trees/physiology , China , Models, TheoreticalABSTRACT
Urban expansion was simulated by SLEUTH model based on the data of Fuxin City, Northeast China in 1997-2013. The optimal parameters of urban expansion were obtained from SLEUTH model calibration, with the diffusion coefficient as 6, breed coefficient as 64, spread coefficient as 44, slope resistance as 52 and road gravity as 90. Urban growth types in Fuxin mainly belonged to new center growth and edge growth, i.e., the further expansion of new and old urban centers. Urban expansion was greatly influenced by roads. Fuxin, as a resource-exhausted city, suffered from the natural disasters, such as landslides, subsidence, and so on. The slope resistance of urban expansion was large in the development of urban land. From the perspective of urban scale, road gravity in smaller city was greater than in larger city. The urban expansion in smaller city was more inclined to the new center growth. The locations of enterprises and new development zones were more interested in the area of good transport facilities. Meanwhile, they were inclined to new center growth. Urban expansions were simulated based on optimal parameters of SLEUTH model. The simulated result of edge growth was better than the simulated result of new spreading center growth, because new spreading center growth was susceptible to policymaking, and cellular influence was little. The simulated accuracy of urban land in 2001, 2006, 2010 and 2013 was high.