气候变化背景下中国玉米生产潜力变化特征

玉米作为中国第一大粮食作物,探究其生产潜力在气候变化背景下的时空变化特征对中国有效应对气候变化具有重要意义。论文结合全球农业生态区模型、极点对称模态分解方法和集对分析方法,探讨了中国玉米生产潜力的周期性波动特征及长期变化趋势,进而分析了其空间格局演变过程。结果表明：1960—2010年间,中国玉米生产潜力呈增加趋势,由1960年代的9.10亿t增至2000年代的9.45亿t左右。在年际尺度上,中国玉米生产潜力主要以准3 a和准5 a的周期进行波动;在年代际尺度上,存在准10 a和准20 a的波动周期。其中,准3 a的周期波动是中国玉米生产潜力长时间变化的最主要特征,这主要是受年降水量变化的影响。从空间格局来看,中国玉米生长适宜区主要集中在加格达奇—锡林浩特—临河—西宁—天水—中甸沿线以东;1960—2000年间,玉米生产潜力界线在中国东北部和临河—西宁沿线发生了较为明显的移动。华北平原、辽河平原、四川盆地等地区的玉米单产潜力变化趋势具有较强的一致性,松嫩平原、三江平原、关中盆地、长江中下游平原等地区的玉米单产潜力变化过程与上述地区恰好相反。在这2类地区,玉米单产潜力的变化均较显著,但变化方向在年代际尺度上具有交替性。     

武汉市不同等级景区旅游吸引力时空变化

收集2018~2019年网络关注度等有关数据,利用地理集中指数和多元线性回归等方法,分析景区旅游吸引力时空变化及影响因素,结果发现:(1)景区级别越高,其吸引力半径越大,景区50%的客源市场集中在900km范围内,80%的客源市场集中在1 200 km范围内.(2)景区级别越高,旅游吸引力集中度往往越小,客源市场较分散.不同季节各景区旅游吸引力差异较大,旅游吸引力集中度有明显的季节变化.(3)各景区的平均旅游吸引力均存在距离衰减现象,级别越高的景区在不同空间距离范围内的吸引力相差较小,衰减速度较小.不同季节的旅游吸引力衰减速度有所不同.(4)在其它条件相同的情况下,城市经济发展水平越高、人口越多、距离越近,景区对其吸引力越强.     

Integration of InVEST-habitat quality model with landscape pattern indexes to assess mountain plant biodiversity change: A case study of Bailongjiang watershed in Gansu Province

Journal of Geographical Sciences - Mountains in western China, hosted rich biodiversity and millions of people and inhabitant with vital ecosystem services, had experienced the most serious...     

Vulnerable groups and preliminary insights into intersecting categories of identity in Laamu Atoll,Maldives

The notion of vulnerability has acquired a significant role in discussions around reducing risk and identifying vulnerable groups, which is particularly important for targeting risk‐reducing policy and practice. Through ten semi‐structured interviews with 24 stakeholders, this study collected local perceptions on the following groups considered most vulnerable in Laamu Atoll, Maldives: youth and children, women, the elderly, people with disabilities, displaced persons and migrants, and farmers. In doing this, the significance of intersecting categories of identity for understanding vulnerability emerged and was explored; an approach that is often absent or scarcely applied in studies that identify vulnerable groups in the Maldives and elsewhere. Intersections between location, youth and gender or disability, as well as gender and marital status emerged as relevant for the Laamu Atoll context. Although this study acknowledges the incompleteness of its intersectional analysis, these findings provide important preliminary insights into the role of intersectionality in shaping vulnerability experience. To enhance scholarship on vulnerability, future studies could further explore intersectionality in Laamu Atoll and the Maldives using this study as a base and also improve its practical applicability for policy and practice.     

Access routes to high mountain huts facing climate-induced environmental changes and adaptive strategies in the Western Alps since the 1990s

ABSTRACT

In the European Alps, high mountain environments are subject to major impacts resulting from climate change, which strongly affect human activities such as mountaineering. The purpose of the study was to examine changes in access routes to 30 high mountain huts in the Western Alps since the 1990s. Data were derived from the use of two different methods, geo-historical studies and a questionnaire, and were used to identify both the climate-related processes affecting the climbing routes and the strategies implemented by public entities, Alpine clubs, guide companies, and hut keepers to maintain acceptable safety and technical conditions. The case studies revealed issues affecting three access routes and the results from the questionnaire showed that the main processes affecting access routes were loss of ice thickness and retreat from the front of the glaciated areas. Commonly, in situ equipment was installed to facilitate access for mountaineers and/or a part of a route was relocated to a safer area. The authors conclude that in most cases, the measures were effective but they were limited by financial, ethical and legal issues, especially in protected or classified areas that could jeopardise their durability and effectiveness.     

1990～2010年中国人口收缩区分布的时空格局演变——基于不同测度指标的分析

在人口收缩内涵界定的基础上,采用总人口和劳动力等直接指标结合出生率、老龄化率等间接指标进行综合测度,在地级尺度和县市尺度上分析了1990~2010年中国人口收缩区的数量变化、空间分布及演化特征（由于获取限制,未包含港澳台地区数据）,并对比了不同测度指标和方法之间的差异。主要的研究发现如下：①人口收缩区在数量上有明显的增长,收缩程度呈现出明显加剧趋势;②人口收缩区在中部和西部偏东地区快速扩张,川黔渝地区、长江中游地区、东北地区最为严重;③单一指标在识别人口绝对收缩方面效果较好,而且总人口指标往往比劳动力指标更早的反映一个区域的人口状况;④综合指标测度的方法能够更加全面的判断一个区域的人口发展状况,进而识别出人口处于相对收缩状态的区域;⑤人口收缩在县市尺度上比在地级尺度上表现更为明显,但两者的差异呈缩小趋势。基于以上研究发现,建议政府更加重视区域人口收缩问题及其对社会经济发展的影响。     

气候和人为因素对植被变化影响的评价方法综述

系统评价气候变化和人为因素引起的植被退化,对有效开展生态工程建设、实现生态环境的可持续发展具有重要意义。目前绝大多研究主要分析气候因素对植被变化的影响,分析气候因素和人类活动对植被变化的双重影响少有研究。本文主要介绍这一双重影响对植被变化的贡献程度的主要研究方法——定性-半定量法、回归分析法、残差趋势法、基于净第一生产力的评价方法。综述分析了气候和人为因素对植被变化驱动的主要结论,总结目前各研究方法存在的问题,提出了未来需要重点加强气候和人为因素对植被变化驱动因素的分解研究,加强模型评价和不确定性量化研究等。     

Dynamics of the eco-environmental quality in response to land use changes in rapidly urbanizing areas: A case study of Wuhan,China from 2000 to 2018

Journal of Geographical Sciences - The dramatic land use changes that occur in rapidly urbanized areas are important inducement to changes in the eco-environmental quality. Investigating urban land...     

黄河中下游地区旱涝分型及突变的初步分析

采用CEOF(复经验正交函数)对黄河中下游地区15个代表站点近500年来的旱涝等级指数分析结果表明,历史时期本地区的旱涝分布特点可用三种分布型表征:平均型、东西反相型和南北反相型,对上述三种旱涝分布型的时间振幅,应用Mann-Kendall方法进行突变检验,可以发现平均型和东西反相型近500年来发生旱涝突变,而南北反相型则相对比较稳定。     

Last interglacial sea levels on the south coast of New South Wales

Remnants of the Last Interglacial shoreline occur at Middle Lagoon on the far south coast of New South Wales. Relict beach sediments can be traced to a height of at least +4.8 m and are indicative of a former mean sea level of about +3 m. Thermoluminescence (TL) ages of 126 ± 13 ka and 114 ± 15 ka were determined for beach and aeolian facies respectively. Sands in the lower part of an exposure on the adjacent Gillards Beach gave TL ages of 108 ± 13 ka, but sands in the upper part of that exposure gave an age of 19.9 ± 3.5 ka. This chronological evidence of a stratigraphic unconformity in what was initially taken as pedogenic differentiation at Gillards Beach is supported by contrasting electron traps and colour centres in crystal lattices of quartz grains in these two samples. No tectonic displacement is apparent. This site provides the first evidence of the Last Interglacial sea level for 1000 km along the coast between Gippsland and Newcastle.