Seasonal and interannual variations of carbon exchange over a rice-wheat rotation system on the North China Plain

Rice-wheat (R-W) rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding the seasonal and interannual variation of the carbon budget over R-W rotation systems. In this study, measurements of CO2 fluxes and meteorological variables over an R-W rotation system on the North China Plain from 2007 to 2010 were analyzed. To analyze the abiotic factors regulating Net Ecosystem Exchange (NEE), NEE was partitioned into gross primary production (GPP) and ecosystem respiration. Nighttime NEE or ecosystem respiration was controlled primarily by soil temperature, while daytime NEE was mainly determined by photosythetically active radiation (PAR). The responses of nighttime NEE to soil temperature and daytime NEE to light were closely associated with crop development and photosynthetic activity, respectively. Moreover, the interannual variation in GPP and NEE mainly depended on precipitation and PAR. Overall, NEE was negative on the annual scale and the rotation system behaved as a carbon sink of 982 g C m-2 per year over the three years. The winter wheat field took up more CO2 than the rice paddy during the longer growing season, while the daily NEE for wheat and rice were -2.35 and -3.96 g C m-2, respectively. After the grain harvest was subtracted from the NEE, the winter wheat field became a moderately strong carbon sink of 251-334 g C m-2 per season, whereas the rice paddy switched to a weak carbon sink of 107-132 per season.     

Ecosystem services or services to ecosystems? Valuing cultivation and reciprocal relationships between humans and ecosystems

The concept of Ecosystem Services (ES), widely understood as the “benefits that humans receive from the natural functioning of healthy ecosystems” (Jeffers et al., 2015), depicts a one-way flow of services from ecosystems to people. We argue that this conceptualisation is overly simplistic and largely inaccurate, neglecting the reality that humans often contribute to the maintenance and enhancement of ecosystems, as often evidenced (but not exclusively) in many traditional and Indigenous societies. Management interventions arising from Ecosystem Services research are thus potentially damaging to both ecosystems and indigenous rights. We present the concept of ‘Services to Ecosystems’ (S2E) to address this, closing the loop of the reciprocal relationship between humans and ecosystems. Case studies from the biocultural ecosystems of Amazonia and the Pacific Northwest of North America (Cascadia) are used to illustrate the concept and provide examples of Services to Ecosystems in past and current societies. Finally, an alternative framework is presented, advancing the existing framework for Ecosystem Services by incorporating this reconceptualization and the loop of reciprocity. The framework aims to facilitate the inclusion of Services to Ecosystems in management strategies based upon Ecosystem Services, and highlights the need for ethnographic research in Ecosystem Service-based interventions.     

石河子垦区浅层地下水动态变化研究

地下水是水资源的重要组成部分,在干旱半干旱地区,地下水是主要的、有时甚至是唯一的可用水源。选取新疆石河子垦区为研究区,收集相关的水文、气象和地下水监测资料,并进行整理计算、分析垦区浅层地下水年际及年内间的动态变化特征,为干旱区地下水资源可持续开发利用提供一定的理论支持。     

中国人—野猪冲突时空特征及对生态系统“反服务”的启示

中国农村社会经济转型背景下,生态系统“反服务”现象频现,如何协同生态保护与社会经济发展面临巨大挑战。本文基于收集的733件典型人—野猪冲突（又称野猪“肇事”）事件资料,采用荟萃分析法研究了2000—2021年中国野猪“肇事”事件的时空分布、危害和驱动因素。在此期间,野猪“肇事”的数量、空间范围和危害程度均呈递增趋势,涉及省、市和区（县）数量分别由初期的18个、41个和67个增至近期的25个、147个和399个,相应增幅分别为39%、259%和496%。其中2005年以前野猪“肇事”集中在重庆市和湖北省中西部,之后向四周扩张,2015年以后集中在四川盆地、黄土高原、长江中下游以及长白山等丘陵山区,表现形式以破坏农作物、侵害家禽和致人伤亡为主,尤以对农作物的破坏并导致耕地撂荒最为普遍,并伴随致人伤亡事件的快速增加,约占“肇事”总数量的1/4(23.66%)。目前情况下,野猪“肇事”蔓延趋势和危害性是一种典型的生态系统“反服务”现象,这种现象的加剧是生态恢复、禁猎政策、农地与生态用地界线不清、野猪生存力强且缺少天敌等因素的综合作用结果,对撂荒地利用、农户生计改善以及区域生态安全维持已构成明显...     

地理学视角下数字创业生态系统的理论框架和研究展望

中国数字经济方兴未艾,推动数字创业生态系统发展成为社会各界关注的热点议题。在系统梳理有关创业研究的相关文献基础上,建构地理学视角下的数字创业生态系统研究框架,探究数字化嵌入到创业过程中各行动主体的构成,以及新要素建构创业生态系统的空间过程和机制,并且分析总结数字创业生态系统与地方发展的交互动态。最后基于中国情境,着眼于中国创业发展的地方实践,提出未来的研究展望,以期为数字化时代创业地理学研究提供新的理论视角,也为指导中国创新创业发展提供实践指引。     

Spatiotemporal changes and correlation of the new urbanization and urban-rural income gap in Sichuan Province北大核心CSCD

新型城镇化作为健全区域协调发展体制机制的重要举措,对破解城乡及地区间发展不平衡问题、促进经济高质量发展有重要意义。论文以四川省为研究对象,运用空间自相关分析方法、空间计量模型、门限面板模型,分析2009—2019年新型城镇化和城乡收入差距的时空演化情况,揭示二者的关联关系,检验分析城乡收入差距的其他影响因素。结果显示：(1) 2009—2019年,四川省新型城镇化水平逐年上升,城乡收入差距逐年缩小,各年度城乡收入差距均具有显著的空间关联性,其低值区域主要集聚在成渝经济走廊上,其高值区域主要集聚在川西及东北部秦巴山区。(2)新型城镇化对城乡收入差距存在非线性影响,呈倒“U”型关系,主要原因是新型城镇化与农业现代化的不协调、不同步,当农业现代化水平跨越门槛值后,新型城镇化才会由扩大转为抑制城乡收入差距。(3)地区经济不平衡程度、科技创新水平和人力资本水平也是城乡收入差距的显著影响因素。研究结果可为积极稳妥推动新型城镇化、有效缩小城乡收入差距提供理论依据。     

The Effects of Plateau Pika (Ochotona curzoniae) Presence and Population Control on the Structure of an Alpine Grassland Bird Community

China’s Qinghai-Tibetan Plateau (QTP) is an important area for bird conservation, with many endemic and Threatened species. Colonial burrowing mammals play an important role in structuring bird communities in arid grasslands around the world. On the QTP, the plateau pika Ocho tona curzoniae builds colonies which provide a dense source of resources for many bird species. However, pikas are regarded as a pest by local pastoralists, and they are the target of a population reduction campaign which could have a significant impact on the bird communities. We surveyed bird communities at Gansu Yanchiwan National Nature Reserve to investigate the differences in community structure between sites with pika colonies (on colony) and sites without them (off colony), and between pika colonies which had been poisoned and those which had not. Using non-metric multidimensional scaling (NMDS) combined with permutational multivariate analysis of variance (PERMANOVA) and Wilcoxon rank-sum tests, we found that there was no significant difference in bird community composition or abundance between the poisoned and untreated colonies. However, there was a very large and statistically significant difference in bird community structures between on- and off-colony sites. Only horned lark Eremophila alpestris was consistently observed at sites without pika colonies, while ten bird species were observed on colonies. Six species were significantly more abundant on colony than off. While we could not claim that the poisoning campaign at Yanchiwan is altering bird communities, the presence of pika colonies seems to be an indispensable resource for the resident birds.     

Agricultural Heritage Protection and Development Policy from the Perspective of Government Documents

The active utilization and inheritance of agricultural heritage cannot be separated from the support of relevant government policies. This study combined the bibliometric method and content analysis method to analyze the agricultural heritage protection and development policies based on the government’s 410 agricultural heritage official documents and constructed a six-dimensional analysis framework of document release form, release subject, release quantity, document relevance, document type, and document content. The results show that the form and subject of document release are diversified; the number of documents released has an approximate inverted “U”-type characteristic; the number of documents formulated specifically for agricultural heritage is relatively small (21.46%); and information documents and guidance documents are more favored by the government than incentive documents. The discussion of the document content demonstrates that the excavation and application of agricultural heritage are worthy of further improvement; the economic value is widely used in the multifunctional utilization of agricultural heritage; and farmers, enterprises, scientific research institutions, and governments are all crucial participants in the management of agricultural heritage. Some problems remain in the government’s management of agricultural heritage, such as producing too few targeted documents and the insufficient coverage of the documents that have been produced thus far.     

Spatio-temporal analysis of human wellbeing and its coupling relationship with ecosystem services in Shandong province,China

Journal of Geographical Sciences - Rapid economic and social change promotes to improve human wellbeing (HW), but poses threats to ecosystems and the environment. Studying the coupling relationship...     

气候变化情景下中国自然生态系统脆弱性研究——一个基于生态地理区域的研究(英文)

Assessment of vulnerability for natural ecosystem to climate change is a hot topic in climate change and ecology, and will support adapting and mitigating climate change. In this study, LPJ model modified according to features of China's natural ecosystems was employed to simulate ecosystem dynamics under A2, B2 and A1B scenarios. Vulnerability of natural ecosystem to climate change was assessed according to the vulnerability assessment model. Based on eco-geographical regions, vulnerability of natural ecosystem to climate change was analyzed. Results suggest that vulnerability for China's natural ecosystems would strengthen in the east and weaken in the west, but the pattern of ecosystem vulnerability would not be altered by climate change, which rises from southeast to northeast gradually. Increase in ecosystem vulnerable degree would mainly concentrate in temperate humid/sub-humid region and warm temperate humid/sub-humid region. Decrease in ecosystem vulnerable degree may emerge in northwestern arid region and Qinghai-Tibet Plateau region. In the near-term scale, natural ecosystem in China would be slightly affected by climate change. However, in mid-term and long-term scales, there would be severely adverse effect, particularly in the east with better water and thermal condition.