ABSTRACT
The acceleration of urbanization and the frequent occurrence of natural disasters have led to increasingly fragmented habitats and decreased ecological connectivity, which in turn hinder rural sustainable development. Constructing ecological networks is a key direction in the spatial planning. By strengthening source protection, corridor construction, and ecological control, it can effectively alleviate the contradiction between regional ecological and economic development imbalance and promote biodiversity enhancement. With Yanqing District as an example, we constructed the ecological network by means of the morphological spatial pattern analysis, the connectivity analysis software, and the minimum cumulative resistance model. We analyzed various network elements from a county perspective, and provide suggestions for the development of towns. The results showed that the ecological network of Yanqing District as a whole presented the distribution characteristics of "the Mountain and the Plain". A total of 12 ecological sources were identified, covering an area of 1085.54 km2, accounting for 54.4% of the total area. 66 ecological corridors were screened with a total length of 1057.18 km, including 21 important corridors and 45 general corridors, with the length of which accounting for 32.6% and 67.4%, respectively. 27 first-class ecological nodes and 86 second-class ecological nodes were identified, which were concentrated in "the Mountain" such as Qianjiadian and Zhenzhuquan. The distribution of ecological networks in different towns was closely related to their geographical environment and development orientation. The towns such as Qianjiadian and Zhenzhuquan were located in "the Mountain", covering a wide range of ecological sources and corridors. Strengthening protection of ecological source was the focus of network construction, which can promote the coordinated development of ecology and tourism in towns. The towns such as Liubinbao and Zhangshanying were located at the junction of "the Mountain-Plain", hence strengthening corridor connectivity was the main direction of network construction, which could promote the construction of ecological landscape in towns. The towns such as Yanqing and Kangzhuang were located in the "the Plain", with serious landscape fragmentation due to the lack of ecological sources and corridors. Those towns need to build green livable towns through increasing ecological nodes and strengthening ecological restoration. This study enriched the construction of ecological networks at the county scale, explored the interface with spatial planning, strengthened ecological restoration and ecological control, which had reference value for promoting the sustainable development of towns and the construction of a multi-scale ecological network.
Subject(s)
Conservation of Natural Resources , Ecology , Beijing , Ecosystem , Biodiversity , ChinaABSTRACT
Under the background of the carbon peaking and carbon neutrality goals, the evolution of the spatiotemporal pattern of carbon storage has recently emerged as a research hotspot. The change in land use and land cover (LULC) is the primary driver of carbon storage changes. Understanding the spatiotemporal variations of LULC and carbon storage at the small scale of district and county level and proposing strategies to improve carbon sink, will contribute to the ecological conservation, restoration and sustainable development of districts or counties. With Yanqing District in Beijing as an example, we calculated carbon storage from 1990 to 2020 based on the InVEST model and used the PLUS model to predict LULC type changes under three scenarios (natural growth, ecological conservation and economic development) from 2020 to 2050. We further predicted the carbon storage and proposed mea-sures to improve carbon sink. The results showed that the key LULC change in Yanqing between 1990 and 2020 were the conversion of 88.9% of grassland to forest, 50.1% of farmland to forest, and 39.5% of cropland to impervious surface. The total carbon storage showed an upward trend, with an increase of 3.34×106 Mg. The spatial distribution of carbon storage presented "high in the northeast, low in the southwest, and high in the mountainous areas, low in the riverine areas." The increase in forest and the decrease in grassland were the main reasons for the increase and decrease in carbon storage, respectively. Between 2020 and 2050, the ecological restoration efforts under the ecological protection scenario increased, and the probability of other LULCs transforming into forest increased, resulting in a 5.8% increase in carbon storage, which had the highest increase and carbon storage under the three scenarios. High-value carbon storage areas were concentrated in the northeast, northwest, and south of Yanqing District, basically corresponding to the mountainous regions of Yanqing with high forest coverage, and the low-value areas generally corresponded to the plains with high development intensity and low forest coverage. We could implement comprehensive ecological protection and restoration measures, including forest and grassland ecosystem protection, water environment ecological restoration, farmland ecological restoration, to promote sustainable development in Yanqing District and to achieve the "dual carbon" goal.
Subject(s)
Carbon Sequestration , Ecosystem , Beijing , Carbon , Economic Development , Forests , Conservation of Natural Resources , ChinaABSTRACT
Pollinators provide important ecosystem services for crop production and food security. With the development of agricultural economy and the increasing intensity of land-use, a large number of natural or semi-natural habitats have been converted to croplands. Landscape homogenization and intensive management lead to the decline of wild bee diversity and threaten the sustainable agricultural production. In this study, we investigated the effects of landscape complexity (proportion of semi-natural habitats), local management practices (local flowering plant diversity and soil total nitrogen), and their interactions on diversity of bee pollinators in apple orchard in Changping District, Beijing. A total of 8642 bee individuals were captured, including 5125 honey bees and 3517 wild bees from 5 families, 14 genera, and 49 species. The optimal landscape scale for the response of bee diversity to landscape complexity and local management intensity was 500 m. Within 500 m radius of the site, the abundance of overall bees and wild bees significantly increased with increasing proportion of semi-natural habitats. The landscape complexity interacting with local flowering plant diversity significantly affected the richness of overall bee and wild bee. When the proportion of semi-natural habitats surrounding the apple orchards was low (≤29.9%), we found a positive effect of flowering plant diversity on the richness of overall bee and wild bee, whereas a reversed trend was found when the proportion of semi-natural habitats surrounding the apple orchards was high (>29.9%). In addition, the abundance of honey bees significantly increased with the increase of local flowering plant diversity and soil total nitrogen. The soil total nitrogen interacting with local flowering plant diversity significantly affected the honey bee abundance. At low levels of soil total nitrogen (≤1.9 g·kg-1), there was a positive effect of flowering plant diversity on honey bee abundance; whereas this trend was reversed at high levels of soil total nitrogen (>1.9 g·kg-1). Increasing the proportion of semi-natural habitats in agricultural landscape was beneficial to the increase of wild bee abundance, and flowering plant diversity could promote bee diversity but depending on landscape scale (proportion of semi-natural habitats) and local scale (nitrogen application). Therefore, multi-scale factors should be considered to develop conservation strategies to maintain the diversity of wild bees in agricultural landscape. Maintaining a higher proportion of cultivated land as much as possible is still a long-term requirement for production, while maintaining intermediate landscape complexity, increasing the diversity of flowering plants on the ground, and reducing the application of nitrogen fertilizer would be effective ways to promote the diversity of pollinating bees in apple orchards.
Subject(s)
Malus , Pollination , Agriculture , Animals , Bees , Beijing , Ecosystem , Pollination/physiologyABSTRACT
Spiders are important natural enemies in agricultural ecosystems. The biodiversity and community characteristics of spider directly determine the quality of ecosystem services such as pest control in cropland. Cropland and its surrounding recovery habitats are important for spiders. We used trap method to examine species composition, species diversity, and functional characteristics of spider communities at three altitudes (871, 1360 and 1635 m) and three habitats (cropland, natural recovery grassland, artificial restoration woodland) in Chongli District, Zhangjiakou, Hebei Province, China. The results showed that diversity index of different habitats was significantly diffe-rent. The abundance of spiders in artificial restoration woodland was 124.3, which was significantly higher than that in natural recovery grassland (70.1) and cropland (38.6). Species richness of artificial restoration woodland (16.3) and natural recovery grassland (21.4) were not significantly different, but both were significantly higher than those of cropland (8.9). The Shannon diversity index of artificial restoration woodland (2.04) and natural recovery grassland (2.05) was not significantly different, and both were significantly higher than that of cropland (1.55). There were significant differences in community composition among all three habitats. Spider body length was positively correlated with spider hunting types. Large spiders tended to get food by hunting. Natural recovery grassland and cropland spiders were dominated by safari, and artificial restoration woodland with more web-forming spiders. Spiders at higher altitude were generally small. Both natural recovery grassland and artificial restoration woodland could increase spider diversity and played important roles in regional biodiversity protection. Spider community composition differentiated in different habitats, with the overall functional characteristics of spider communities being changed and some habitats being retained. The index of spider diversity of the two recovery habitats was higher than that of cropland habitats, with differences in the species composition of the two recovery habitats, both of which had the function of protecting endemic species. Our results were useful for the protection and restoration of spider biodiversity on cropland and regional scales.
Subject(s)
Ecosystem , Spiders , Animals , Biodiversity , China , Crops, AgriculturalABSTRACT
This study was conducted before and after harvesting of wheat and maize in a typical agricultural landscape of the North China Plain. We investigated the diversity of two important natural enemy groups, carabids and spiders, using pitfall traps at crop field margin with different vegetation structures and their neighboring crop field. Throughout the comparison of the spatial and temporal distribution of the diversity of carabids and spiders in field margin and neighboring field, and the investigation of the relationship between arthropod communities and vegetation structure, this study aimed to understand the role of semi-natural field margin in biodiversity conservation of different natural enemy taxa. Results showed that the abundance of spiders was significantly higher in field margin than in neighboring fields over the entire period. No significant difference of the diversity of carabids in field margin and crop field was observed, but the community composition was different. Number of spider families increased in field margin but deceased in crop field after harvesting, indicating a migration activity between field and field margin. Vegetation structure in the field margin had different association with carabids than with spiders, with diversity of dominant carabid species positively associated with herb coverage and negatively with wood coverage, while the diversity of spider family Linyphiidae was positively associated with herb coverage only. Semi-natural habitat benefited the conservation of the diversity of arthropod natural enemies in crop field via promoting their dispersal to crop field, while such impacts differed from different vegetation structures and varied from target beneficial natural enemy communities. Future studies should focus on in-depth understanding of the food and habitat source requirement of different natural enemy taxa, and hence to design suitable semi-natural habitats to maintain a high diversity of natural enemy communities.
Subject(s)
Agriculture , Biodiversity , Spiders , Animals , China , Crops, Agricultural , EcosystemABSTRACT
Green space plays an important role in reducing PM2.5, since it can efficiently absorb suspended particles in the air. A quantificational method of dust detention service of green space was proposed in this study, based on the mechanism of PM2.5 reduction by plant. Daily, summer, winter and whole year cumulative dust amounts reduced by green space with different landscape types of Haidian District, Beijing, were quantified. The results showed that both of dust reduction frequency and daily cumulative dust amount in winter were considerably lower than those in summer. Mountain woodlands in the west of Haidian District provided the highest average PM2.5 reduction service, and the fragmented agricultural and forest landscapes in the northern plains provided the highest total dust detention service, while the southern area had the lowest dust detention service except for several parks. PM2.5 detention service model was very useful to quickly quantify how much dust could be reduced by green space and where were these services, which was very important for the development of urban green space and improvement of air quality.
Subject(s)
Air Pollutants/analysis , Air Pollution/prevention & control , Environmental Monitoring , Particulate Matter/analysis , Beijing , Dust , Forests , SeasonsABSTRACT
Based on the concept and methods of landscape character assessment (LCA) in England, this paper applied a complete process of landscape character assessment with a case study in Qiaokou Town, which is located in a typical southern paddy fields area in Changsha City. We drew the landscape character map of Qiaokou Town through desk classification and field survey, identified and compared the key characters of each character area, and proposed suggestions on the improvement and stewardship of landscape characters. The results showed that Qiaokou could be divided into 2 landscape character types and 7 landscape character areas with the main differences in cropland and vegetation pattern as well as aesthetic characters. The case study indicated that LCA could be a critical tool to identify the characteristics in rural area, and provide helpful guidance to protect, restore and maintain the unique culture and characters of rural landscape, which is useful for targeted rural landscape development. In the future, we suggested that the assessment on the effects of landscape construction measures on the ecosystem services should be incorporated in LCA research as well.
Subject(s)
Agriculture , Ecosystem , China , Cities , Rural PopulationABSTRACT
Non-cropped habitat in farm landscape plays a significant role in biodiversity, the functions of arable land and crop yields. This study focused on Shenbei New District in Shenyang City of Liaoning Province in Northeast China, which was a typical area with contradiction between biodiversity conservation and the high demand of agricultural production in the process of urbanization. Information entropy model, hand-picking and Baermann method were used for survey and identification of arthropods and nematodes in soils in urban suburban (US), urban fringe area (UFA) and rural area ( RA). The cooperative relations between the number of soil animals and types, structure as well as the total amount of non-cropped habitat were investigated in these three types of areas using linear regression. Our results showed that the area of single patch in non-cropped habitat was smaller than one hectare in Shenbei New District, and the types and the proportion of non-cropped habitat patches were increasing along with the increase of their distance to the urban center. But the proportion of non-cropped habitats areas appeared under an inverted U-type change. The proportion of non-cropped habitat patches was from 8.6% to 27.8%. The individual number of soil animals showed the U-type trend, while their species number changed irregularly. The individual number of soil animals increased with the increase of the proportion of non-cropped habitat patches in RA and US. There was no obvious correlation between the individual number of soil animal and the proportion of non-cropped habitat patches in UFA. The individual number of soil animals decreased with the increase of the proportion of non-cropped habitats areas. There was no cooperative relation in the proportion of non-cropped habitats and the number of soil animal species.
Subject(s)
Agriculture , Arthropods , Ecosystem , Nematoda , Soil , Animals , Biodiversity , China , Cities , Models, Theoretical , UrbanizationABSTRACT
By the method of pitfall trap sampling, an investigation was conducted on the carabid assemblage in four typical habitats (maize field, peanut field, orchard, and semi-natural woodland) in the agricultural landscape in Xitiange Village of Miyun County, Beijing. Among the four habitats, orchard had the highest alpha-diversity of carabid assemblage, followed by woodland and maize field, and peanut field had the lowest one. The species composition of the assemblage in woodland, peanut field, and orchard had evident difference, but was similar to that in maize field to some extent. The number of the individuals of predatory and omnivorous carabid sub-assemblages was larger in orchard, and the predatory sub-assemblage presented more distinct difference in its species turnover rate than the omnivore sub-assemblage among the habitats. This study showed that low-intensively managed orchard habitat could sustain higher alpha-diversity of carabid assemblage than semi-natural woodland habitat, and the landscape with diversified habitats could benefit the beta-diversity of carabid assemblage and its predatory sub-assemblage. To attach importance to the conservation of diversified habitats and low-intensively managed farmland habitat would have significance for the conservation of carabid assemblage diversity and its pest control function in agricultural landscape.
Subject(s)
Biodiversity , Coleoptera/growth & development , Crops, Agricultural/growth & development , Ecosystem , Animals , Arachis/growth & development , China , Coleoptera/classification , Fruit/growth & development , Population Dynamics , Zea mays/growth & developmentABSTRACT
In order to understand the effects of landscape heterogeneity induced by habitat restoration and landform change on the biodiversity in degraded landscapes, an investigation by using light trap was conducted on the geometrid moth (Lepidoptera: Geometridae) diversity in the cropland and reforested semi-natural habitats in three villages at different altitudes of Bashang Plateau in 2006 and 2007. There existed significant differences in the species richness and individual number of geometrid moth between cropland and reforested semi-natural habitats and in the species richness of geometrid moth between the villages at different altitudes, but no significant differences in the individual number of geometrid moth between the villages at different altitudes and in the standardized sparseness index and Fisher' s alpha index between the villages and between the cropland and reforested semi-natural habitats within each village. The non-metric multi-dimensional scaling (NMDS) indicated that the community structure of geometrid moth in different habitats and at different altitudes differed significantly. This study indicated that the landscape heterogeneity induced by land-form change had significant effects on the community structure and diversity of geometrid moth on Bashang Plateau, and, both cropland and reforested semi-natural habitats were the important habits for geometrid moth. It was suggested that to protect the landscape mosaics containing cropland and reforested semi-natural habitats across the varied landform of Bashang Plateau would have significances in the conservation of high gamma-diversity of geometrid moth, but whether the reforestation and creation of semi-natural habitats could improve the biodiversity of geometrid moth should be monitored in long term.
Subject(s)
Biodiversity , Crops, Agricultural/growth & development , Ecosystem , Lepidoptera/physiology , Trees/growth & development , Altitude , Animals , China , Environment , Lepidoptera/classificationABSTRACT
A total of ten single indices mainly reflecting the ecological and aesthetic quality of agricultural landscape, including ecosystem function, naturalness, openness and diversity, contamination probability, and orderliness were selected, their different weights were given based on field survey and expert system, and an integrated evaluation index system of agricultural landscape quality was constructed. In the meantime, the land use data provided by GIS and the remote sensing data of vegetation index were used to evaluate the Beijing agricultural landscape quality and its spatial variation. There was a great spatial variation in the agricultural landscape quality of Beijing, being worse at the edges of urban area and towns, but better in suburbs. The agricultural landscape quality was mainly related to topography and human activity. To construct a large-scale integrated index system based on remote sensing data and landscape indices would have significance in evaluating the spatial variation of agricultural landscape quality.
Subject(s)
Conservation of Natural Resources/methods , Crops, Agricultural/growth & development , Ecosystem , Environmental Monitoring/methods , China , City Planning , Geographic Information Systems , Satellite CommunicationsABSTRACT
Based on a two-year household survey data, the yield gap of winter wheat in Quzhou County of Hebei Province, China in 2003-2004 was studied through comparative performance analysis (CPA). The results showed that there was a greater yield gap (from 4.2 to 7.9 t x hm(-2)) between field blocks, with a variation coefficient of 0.14. Through stepwise forward linear multiple regression, it was found that the yield model with 8 selected variables could explain 63% variability of winter wheat yield. Among the variables selected, soil salinity, soil fertility, and irrigation water quality were the most important limiting factors, accounting for 52% of the total yield gap. Crop variety was another important limiting factor, accounting for 14%; while planting date, fertilizer type, disease and pest, and water press accounted for 7%, 14%, 10%, and 3%, respectively. Therefore, besides soil and climate conditions, management practices occupied the majority of yield variability in Quzhou County, suggesting that the yield gap could be reduced significantly through optimum field management.
Subject(s)
Agriculture/methods , Biomass , Soil/analysis , Triticum/growth & development , China , Regression Analysis , SeasonsABSTRACT
Biodiversity conservation in agriculture not only relates to the sustainable development of agriculture, but also is an essential part of species conservation. In recent years, the landscape planning approach for biodiversity was highlighted instead of species-focused approach. In this paper, the landscape factors affecting the biodiversity in agriculture were reviewed, and the possible landscape approaches at three different scales for more efficient conservation of biodiversity in agro-landscape were suggested, including: (1) the increase of the proportion of natural or semi-natural habitats in agriculture, diversification of land use or crop pattern, and protection or construction of corridor at landscape level; (2) the establishment of non-cropping elements such as field margin at between-field level; and (3) the application of reasonable crop density, crop distribution pattern and rotation, and intercrop etc. at within-field level. It was suggested that the relevant policies for natural conservation, land use planning, and ecological compensation should be made to apply the landscape approaches for biodiversity conservation at larger scale.
Subject(s)
Agriculture/methods , Biodiversity , Conservation of Natural Resources/methods , Crops, Agricultural/growth & development , Conservation of Natural Resources/trends , Crops, Agricultural/classification , Ecosystem , Environment DesignABSTRACT
Large scale spatial and temporal land use survey data were used to study the dynamics of land use change in China recently. With the aid of GIS, the spatial-temporal dynamic change of land resource degradation at the national level was investigated using authoritative datasets from detailed land use surveys (early 1990s approximately 2003). As a result, seven major types of land degradation processes were identified, including sandy desertification, rocky desertification, secondary salinification, non-agricultural land occupation, deforestation, natural grassland degradation and wetlands shrinking. This paper comprehensively explored the characteristics of these land degradation processes and revealed the status and trend of the holistic land resource degradation in China. Results shows that: (1) Although land degradation has been controlled in local area, but it is still continuing to spread in the whole country. The total degradation index of the holistic land resource presented fluctuating trend. Indexes of non-agricultural construction occupation and wetland shrinking process are far more than that of other process, which are two primary causes contribution to heading straight towards full-scale land resource deterioration in China. (2) Land resource degradation process of China focused on natural grass land, and non-agricultural construction land, which attained 66.27%; Land resource degradation rehabilitation mainly focused on desertification and forest restoration, which accounts for 57.5%. (3) Sandy desertification and rocky desertification process have been reversing greatly. The total net change of their quantities was decreased by 15,578km2. But most of the rehabilitation of land desertification was concentrated on the originally ecological vulnerable northwestern zone, whereas newly added desertified land has been expanding and aggravating in eastern zone, especially around river watersheds. (4) Over two-thirds of non-agriculture land expansion came from cultivated land. In addition, almost 60 percent of the loss cultivated land occupied by non-agricultural land was appeared in the Northeast, the Eastern coast and Central China where have many high productive agricultural lands of China. This kind of land degradation has threatened food security of China seriously. (5) However, large scale reclamation of ecological land transferred into cultivated land was the most dominant factor of degradation. For example, the conversion of wetland resource to croplands by reclamation accounts for over 50 percent of wetland shrinking.
