2011 Vol. 21, No. 4

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Landscape Ecology: Coupling of Pattern, Process, and Scale
FU Bojie, LIANG Di, LU Nan
2011, 21(4): 385-391.
Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales. Studies of landscape ecology focus on understanding the dynamics of ecological patterns and processes, and highlight the integration of multiple disciplines. In this paper, we discussed the problems and challenges that landscape ecology is currently facing, emphasizing the limitations of current methods used to describe dynamic landscape patterns and processes. We suggested that the focus should be on the integration of ground-based observation, mobile monitoring, transect survey, and remote-sensing monitoring, as well as improved coupling of experimental and model simulations. In addition, we outlined the research frontiers in landscape ecology, including scaling, integrated pattern and process modeling, and regional synthesis. Lastly, a brief review of pattern-process-scale coupling studies in China was provided. We concluded by pointing out that pattern-process-scale interactions, correlations between natural, economic, and social processes, and the coupling of human and natural systems will be major research areas in landscape ecology in the future.
Effect of Agricultural Land Use Changes on Soil Nutrient Use Efficiency in an Agricultural Area, Beijing, China
CHEN Liding, QI Xin, ZHANG Xinyu, LI Qi, ZHANG Yanyan
2011, 21(4): 392-402.
Agricultural land use and management practices may affect soil properties, which play a critical role in sustaining crop production. Since the late 1970s, several new agricultural land use types had been introduced in the rural areas of China. The purpose of this study is to evaluate the effect of these land use changes on the soil properties, nutrient absorption rate, and nutrient use economic efficiency ratio in an agricultural area of Beijing. Specifically, the cropland, the orchard and the vegetable field were examined. Results of this study suggest that land use and farming management practices significantly affect the content of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and available phosphorus in the surface layer of 0–25 cm (p < 0.05) in the Yanqing basin, northwestern Beijing. Soil nutrients in each agricultural land use type decrease rapidly with the increasing soil depth. Orchard and vegetable field tend to have higher soil nutrients than the cropland does. However, the soil nutrient-absorption rate (NAR) of the orchard and vegetable field is lower than that of the cropland, even though orchard and vegetable field may provide much higher economic benefit. While increasing SOC, TN, and TP in the orchard and vegetable field by intensive farming may be a valuable option to improve soil quality, potential increase in the risk of nutrient loss, or agricultural non-point source pollution can be a tradeoff if the intensive practices are not managed appropriately.
Effect of Reclamation Time and Land Use on Soil Properties in Changjiang River Estuary, China
SUN Yongguang1, 2, LI Xiuzhen, ülo MANDER, HE Yanlong, et al
2011, 21(4): 403-416.
The objective of this study is to analyze soil physical and chemical properties, soil comprehensive functions and impact factors after different years of reclamation. Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary, China in April 2009 and remotely sensed TM data in 2006, while by virtue of multivariate analysis of variance (MANOVA), geo-statistical analysis (GA), principal component analysis (PCA) and canonical correspondence analysis (CCA), it was concluded that: 1) With the increase in reclamation time, soil moisture, soil salinity, soil electric conductivity and soil particle size tended to decline, yet soil organic matter tended to increase. Soil available phosphorous tended to increase in the early reclamation period, yet it tended to decline after about 49 years of reclamation. Soil nitrate nitrogen, soil ammonia nitrogen and pH changed slightly in different reclamation years. Soil physical and chemical properties reached a steady state after about 30 years of reclamation. 2) According to the results of PCA analysis, the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen, soil organic matter, soil available phosphorous, soil ammonia nitrogen, pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity, soil electric conductivity and soil moisture). The higher the F value is, the better the soil quality is. 3) Different land use types play different roles in the soil function maturity process, with farmlands providing the best contribution. 4) Soil physical and chemical properties in the reclamation area were mainly influenced by reclamation time, and then by land use types. The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (–0.1161).
Predicting Potential Distribution of Tibetan Spruce (Picea smithiana) in Qomolangma (Mount Everest) National Nature Preserve
Using Maximum Entropy Niche-based Model
ZHANG Jiping, ZHANG Yili, LIU Linshan, NIE Yong
2011, 21(4): 417-426.
Tibetan spruce (Picea smithiana) is an endemic species of the Himalayas, and it distributes only in a restricted area with very low number. To address the lack of detailed distributional information, we used maximum entropy (Maxent) niche-based model to predict the species′ potential distribution from limited occurrence-only records. The location data of P. smithiana, relative bioclimatic variables, vegetation data, digital elevation model (DEM), and the derived data were analyzed in Maxent. The receiver operating characteristic (ROC) curve was applied to assess the prediction accuracy. The Maxent jackknife test was performed to quantify the training gains from data layers and the response of P. smithiana distribution to four typical environmental variables was analyzed. Results show that the model performs well at the regional scale. There is a potential for continued expansion of P. smithiana population numbers and distribution in China. P. smithiana potentially distributes in the lower reaches of Gyirong Zangbo and Poiqu rivers in Gyirong and Nyalam counties in Qomolangma (Mount Everest) National Nature Preserve (QNNP), China. The species prefers warm temperate climate in mountain area and mainly distributes in needle-leaved evergreen closed to open forest and mixed forest along the river valley at relatively low altitudes of about 2000–3000 m. Model simulations suggest that distribution patterns of rare species with few species numbers can be well predicted by Maxent.
Responses of Tree Species to Climate Warming at Different Spatial Scales
LIANG Yu, HE Hong S, LEWIS Bernard L
2011, 21(4): 427-436.
Tree species respond to climate change at multiple scales, such as species physiological response at fine scale and species distribution (quantified by percent area) at broader spatial scale. At a given spatial scale, species physiological response and distribution can be correlated positively or negatively. The consistency of such correlation relationships at different spatial scales determines whether species responses derived from local scales can be extrapolated to broader spatial scales. In this study, we used a coupled modeling approach that coupled a plot-level ecosystem process model (LINKAGES) with a spatially explicit landscape model (LANDIS). We investigated species physiological responses and distribution responses to climate warming at the local, zonal and landscape scales respectively, and examined how species physiological response and distribution correlated at each corresponding scale and whether the correlations were consistent among these scales. The results indicate that for zonal and warming-sensitive species, the correlations between species physiological response and distribution are consistent at these spatial scales, and therefore the research results of vegetation response to climate warming at the local scale can be extrapolated to the zonal and landscape scales. By contrast, for zonal and warming-insensitive species the correlations among different spatial scales are consistent at some spatial scales but at other scales. The results also suggest that the results of azonal species at the local scale near their distribution boundaries can not be extrapolated simply to broader scales due to stronger responses to climate warming in those boundary regions.
Seasonal Dynamics of Nitrogen and Phosphorus in Water and Sediment of A Multi-level Ditch System in Sanjiang Plain,
Northeast China
GUO Lei, MA Keming
2011, 21(4): 437-445.
The multi-level ditch system developed in the Sanjiang Plain, Northeast China has sped up water drainage process hence transferred more pollutants from farmlands into the rivers of this region. Understanding the seasonal dynamics of nitrogen (N) and phosphorus (P) transportation in the ditch system and the role of different ditch size is thus crucial for water pollution control of the rivers in the Sanjiang Plain. In this study, an investigation was conducted in the Nongjiang watershed of the Sanjiang Plain to study the nutrient variation and the correlation between water and sediments in the ditch system in terms of ditch level. Water and sediments samples were collected in each ditch level in growing season at regular intervals (once per month), and TN, NO3–-N, NH4+-N, TP, and PO43–-P were analyzed. The results show that nutrient contents in water were higher in June and July, especially in July, the contents of TN and TP were 3.21 mg/L and 0.84 mg/L in field ditch, 4.04 mg/L and 1.06 mg/L in lateral ditch, 2.46 mg/L and 0.70 mg/L in branch ditch, 1.92 mg/L and 0.63 mg/L in main ditch, respectively. In August and September, the nutrient contents in the water were relatively lower. The peak value of nutrient in ditch water had been moving from the field ditch to the main ditch over time, showing a remarkable impact of ditch system on river water environment. The nutrient transfer in ditch sediments could only be found in rainfall season. Nutrient contents in ditch sediment had effect on that in ditch water, but nutrients in ditch water and sediments had different origination. Ditch management in terms of the key factors is hence very important for protecting river water environment.
Responses of Spatial-temporal Variation of Karst Ecosystem Service Values to Landscape Pattern in Northwest of Guangxi, China
ZHANG Mingyang, WANG Kelin, LIU Huiyu, ZHANG Chunhua
2011, 21(4): 446-453.
The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest Guangxi Zhuang Autonomous Region, China, were examined using remote sensing and geographic information system techniques in this paper. The total ecosystem service values declined significantly from 1985 to 1990, and then increased slowly from 1990 to 2005, almost equaled to the 1985 level. The ecosystem service values tended to decline from the west to the east and from mountainous regions to peak-cluster depression areas in 1985, 1990, 2000 and 2005 respectively. During the period from 1985 to 2005, the ecosystem service values have increased in the middle and eastern parts of the study area. Landscape pattern indices, such as total area, largest patch index, contagion, aggregative index, effective mesh and proportion of like adjacencies, are significantly correlated with ecosystem service values. This suggests that ecosystem service values tend to increase with the growth of patch area and patch connectivity. However, there are negative correlations between ecosystem service values and landscape pattern indices, such as division index and patch richness. It indicates that ecosystem service values decrease with patch fragmentation and patch size shrinkage. The ecosystem conditions in the typical Karst area have been improved because of the control measures of rocky desertification. It is important to protect key landscape types, such as woodland, shrub and grassland, and to increase patch size and connectivity to avoid further fragmentation. Furthermore, it is necessary to reduce disturbances to ensure the growth of ecosystem service values and to facilitate the sustainable development in this region.
Geographical Patterns of Chinese Ethnic Minority Population Composition and Ethnic Diversity
SHEN Zehao, LI Peng, SUN Hongkai, PANG Lihua
2011, 21(4): 454-464.
 Ethnicity is a carrier of language and culture. Spatial distribution of ethnic diversity is fundamental for identifying and reconstructing the migration patterns and evolution histories of cultures and languages. Utilizing the Chinese 4th National Census (1990) data, we investigated the specific time geographical patterns of population and diversity of Chinese ethnic minorities. As anticipated, results show that Chinese minorities are chiefly concentrated in distant plateaus and mountains in the southwest, northwest and northeast of China. Further, population density centers of the 10 major minorities are rather scattered, alternatively dominating at different parts of the country. This study provides a first comprehensive quantitative test on a prevailing notion of ′six plates and three corridors′ on the empirical clustering patterns of Chinese ethnic minorities. There are more consistent evidences supporting this notion in the north of China, with the central and southern regions showing more complex patterns, potentially transformed by processes such as migration, fragmentation, and percolation. The results of this study suggest that a geographical approach can provide heuristic and complementary information for better understanding of historical social processes.
Urban Green Space Planning Based on Computational Fluid Dynamics Model and Landscape Ecology Principle: A Case Study of
Liaoyang City, Northeast China
ZHOU Yuan, SHI Tiemao, HU Yuanman, et al.
2011, 21(4): 465-475.
As a result of environmental degradation, urban green space has become a key issue for urban sustainable development. This paper takes Liaoyang City in Northeast China as an example to develop green space planning using the computational fluid dynamics (CFD) model, landscape ecological principles and Geographical Information System (GIS). Based on the influencing factors of topography, building density and orientation, Shou Mountain, Longding Mountain and the Taizi River were selected as the urban ventilation paths to promote wind and oxygen circulation. Oxygen concentration around the green spaces gradually decreased with wind speed increase and wind direction change. There were obvious negative correlation relationships between the oxygen dispersion concentration and urban layout factors such as the building plot ratio and building density. Comparison with the field measurements found that there was significant correlation relationship between simulated oxygen concentration and field measurements (R2 = 0.6415, p < 0.001), moreover, simulation precision was higher than 92%, which indicated CFD model was effective for urban oxygen concentration simulation. Only less than 10% areas in Liaoyang City proper needed more green space urgently to improve oxygen concentration, mainly concentrated in Baitai and west Wensheng districts. Based on landscape ecology principle, green space planning at different spatial scales were proposed to create a green space network system for Liaoyang City, including features such as green wedges, green belts and parks. Totally, about 2012 ha of green space need to be constructed as oxygen sources and ventilation paths. Compared with the current green space pattern, proposed green space planning could improve oxygen concentration obviously. The CFD model and research results in this paper could provide an effective way and theory support for sustainable development of urban green space.
Coordination of Urbanization and Water Ecological Environment in Shayinghe River Basin, China
ZHANG Xiang, HU Hong, XU Jiangang, YIN Haiwei
2011, 21(4): 476-495.
During the rapid industrialization and urbanization of China, urban agglomeration in river basin areas raises the problems of over-use of water resources and pollution of the water environment. Related research in China has mainly focused on the conflicts among economic growth, urban expansion and water resource shortages within administrative boundaries. However, water environments are much more dependent on their physical boundaries than their administrative boundaries. Consistent with the nature of water environment, this study aims at analyzing coordination relationships between urban development and water environment changes within physical river basin boundaries. We chose the Shayinghe River Basin, China, as our case study area which is facing serious challenges related to water environment protection. Then we classified 35 county-level administrative units into upstream, midstream and downstream regions based on their physical characteristics; analyzed the coordination degree of urban agglomeration using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method; and constructed cooperative models using the Linear Programming (LP function) to simulate four scenarios of the coordination relationship between urban population increase and water environment protection based on existing water resources and water pollution data. The results show that the present coordinative situation in Shayinghe River Basin is not sustainable. In general, more than 50% administrative units are in the bad coordinative situation. In particular, the downstream region is under worse condition than the upstream and midstream regions. Cooperative models in scenario analyses indicate that the population scale set in existing urban master plannings is not coordinated with the water environment protection. To reach the goal of regional sustainable development, the total population needs to be controlled such that it will remain at 4.5 × 107 or below by 2020 given the capacity of water environment.
Research Progress on Evaluation Frameworks of Regional Ecological Sustainability
PENG Jian, WANG Yanglin, WU Jiansheng, SHEN Hong, PAN Yajing
2011, 21(4): 496-510.
As natural ecosystems provide the material basis and fundamental support for regional sustainable development, the sustainability of natural ecosystems is an important prerequisite and a viable approach for the achievement of regional sustainable development. It is also the final criteria to assess whether sustainable development paradigm is successful. Along with the increasing impacts of human activities on natural ecosystems, the evaluation of regional ecological sustainability has become one of the key issues for research on macro ecology and sustainable development. Based on different unit of indicators, this study firstly groups the evaluation frameworks of regional ecological sustainability into three major types: comprehensive index evaluation with dimensionless unit, monetary valuation, and biophysical quantity measurement. We then discuss and compare these types in terms of basic principles, scope of applications, advantages and shortcomings. Finally, drawn on the discussion about characteristics of ecological sustainability, we outline the current trend and future directions of regional ecological sustainability evaluation, for instance, transition from sustainable development evaluation to sustainability science, integration of goal-oriented and problem-solving approaches, combination of spatial pattern analysis and ecological sustainability evaluation, and enhancement of ecological sustainability evaluation at landscape scale.