内蒙古荒漠草原牧户对气候变化的感知和适应

荒漠草原是气候变化影响的脆弱和敏感地区.荒漠草原的牧户主要依赖天然草原维持生计,正面临着严峻的气候变化挑战.本文采用问卷调查的实证分析方法,在获取内蒙古苏尼特右旗荒漠草原牧户对气候变化和极端气候事件感知和适应的第一手资料基础上,分析了荒漠草原牧户对气候变化趋势和极端气候事件感知和适应的现状与行为特征.结果表明:在降水稀少、气象灾害频繁发生的荒漠草原,干旱是影响范围最广、影响程度最深、发生频率最高的极端气候事件;牧户不仅对干旱的敏感度远高于其他极端气候事件,而且对大风、沙尘暴和大雪等极端气候事件的深刻感知伴随着对干旱的感知而产生;相对于长期气候变化的感知,牧户对短期气候变化趋势的感知更深刻、准确,并主要依据近10年气候变化的感知结果来判断较长期气候变化的总体趋势;牧户认为,气候变化在很大程度上影响了牲畜健康和草场产量,但牧户应对气候变化的行为相对单一,且多为自发性被动适应,缺乏行之有效的主动适应.     

极端降水和极端干旱事件对草原生态系统的影响

当前人类活动的加剧显著地影响着全球大气循环的格局。大气循环的多个模型均预测未来全球气候变化的显著特征是极端降水事件和极端干旱事件发生的频率会显著增加。水分是干旱、半干旱区草原植物生长发育的限制性资源, 而草原生态系统是陆地生态系统中对降水格局变化非常敏感的系统。但是, 关于极端降水事件和极端干旱事件对草原生态系统结构和功能的影响还是以分散的个案研究为主, 甚至关于极端气候事件的定义迄今也不尽相同。为此, 该文在分析极端气候事件定义及其研究方法的基础上, 总结了极端降水事件和极端干旱事件对草原生态系统土壤水分和养分状况、植物生长发育和生理特性、群落结构、生产力和碳循环过程的影响, 并提出了未来极端气候事件研究中应重点关注的5个重要方向, 以及控制试验研究的2个关键科学问题, 对开展全球变化背景下草原生态系统对极端气候事件响应机制的研究具有指导意义。     

2001-2015年天山北坡植被覆盖对干旱的响应——基于土地利用/土地覆盖分析

天山北坡生态系统脆弱,易受干旱影响,全球变暖和不合理的人类活动加剧了干旱的影响,评估植被覆盖对干旱的响应,为改善生态环境和减轻干旱影响提供科学参考。基于MODIS-NDVI遥感数据以及气象数据,计算了2001-2015年天山北坡多尺度标准化降水蒸散发指数（SPEI）和植被覆盖度,总结出植被覆盖度与多尺度SPEI时空动态变化规律,从土地利用/土地覆盖（LUCC）的角度分析了植被覆盖度对气候干旱的响应。结果表明：（1）天山北坡绝大部分区域呈湿润状态,中部（石河子、呼图壁）、西北部（克拉玛依市）呈轻度干旱。3个月、6个月、12个月时间尺度SPEI均表现出干旱化增强的年际变化趋势;（2）天山北坡植被覆盖度整体上属中低覆盖,总体呈南高北低,天山山区、城市绿洲内部高的分布特点。2001-2015年天山北坡植被覆盖度变化总体呈下降趋势;（3）年尺度天山北坡植被覆盖度与SPEI整体呈正相关关系。不同土地利用/土地覆盖的植被覆盖度与12个月时间尺度SPEI（SPEI 12）的相关性不同,大小依次为：草地 > 未利用地 > 城乡用地 > 林地 > 水域 > 耕地;（4）季节尺度夏季和春季干旱对植被覆盖度的影响最明显,不同季节干旱对不同土地利用/土地覆盖植被覆盖度影响程度不同。     

天山北坡城市群生态承载力演变与生态敏感性分析

经济的快速发展及人类活动的不断加剧,造成了各种生态环境问题,对可持续发展构成了严重威胁。探讨城市群土地利用变化、生态承载力演变特征及生态敏感性分析,是推动城市群生态环境优化,提升城市群土地利用管理方式的重要理论依据。以天山北坡城市群为研究区,基于土地利用数据对天山北坡城市群2000—2020年土地利用变化进行分析,采用生态足迹模型对研究区的生态足迹及生态承载力进行推算,并结合植被覆盖度、坡度、人口密度、土地利用类型、高程5个生态敏感性因子,对天山北坡城市群进行多因子综合生态敏感性评价。结果表明：2000—2020年天山北坡城市群内建设用地和耕地转入量较大,分别增长107.79%和46.45%,林地和水域面积逐步减少,反映了天山北坡城市群在研究期内处于快速城镇化阶段,城市建成区的不断扩大对部分生态生产用地构成一定的威胁。在快速城镇化的背景下,天山北坡城市群人均生态足迹总体呈现上升的趋势,生物资源生态赤字问题仍然存在,能源为主的其他资源的生态盈余呈现缩小趋势。生态敏感性高值区域主要分布在天山北坡城市群各城市的周边地区,中度敏感地区环绕在敏感高值区周围,分别占研究区面积的11.21%和35....     

天山南北坡树轮稳定碳同位素对气候的响应差异

利用采自天山南坡阿克苏河流域、天山北坡伊犁河流域和吉尔吉斯斯坦伊塞克湖流域的树木年轮样本,按照树轮稳定碳同位素研究步骤,分别建立了天山南坡和天山北坡各2条树轮稳定碳同位素去趋势序列（δ¹³C_corr）。采用相关函数和共线性分析揭示了天山南北坡树轮稳定碳同位素与各气候要素之间的关系。结果表明,天山南坡树轮稳定碳同位素与生长季降水、相对湿度显著负相关,而与温度没有明显的相关关系,表明影响天山南坡树轮稳定碳同位素分馏的主要气候因子是生长季水分状况,尤其是降水;天山北坡树轮稳定碳同位素与生长季尤其是夏季的平均气温、平均最高气温和饱和水汽压亏缺显著正相关,而与降水量、相对湿度显著负相关,表明影响天山北坡树轮稳定碳同位素分馏的气候因子可能较为复杂。进一步分析表明,夏季温度、降水和相对湿度共同调控着天山北坡雪岭云杉树轮稳定碳同位素分馏。     

干旱区绿洲城市群地表温度时空变化及其影响因素——以天山北坡城市群为例

基于2005—2019年的MYD11A2时间序列LST遥感数据,首先采用均值标准差法对LST进行分级,分析了天山北坡城市群的LST空间分布格局;其次利用Sen′s斜率分析法、Mann-Kendal趋势检验法和Hurst指数揭示了天山北坡城市群LST在2005—2019年和未来的变化趋势;最后借助地理探测器模型并综合考虑地表覆盖、气候、社会经济和地形因素分析了多空间尺度下LST的主要影响因素。结果表明：(1)天山北坡城市群的吐鲁番市是高温(HT)和极高温(EHT)的主要集聚地;白天和夜间的LST格局差异大,在绿洲区域表现为典型的“昼冷岛,夜热岛”特征。(2)LST在白天和夜间的变化率分别为0.04℃/a和0.03℃/a,白天的升温幅度强于夜间;在乌鲁木齐市、昌吉回族自治州、石河子市和五家渠市LST表现出显著的升高趋势,且在未来也具有相同的趋势。(3)在不同的空间尺度上,LST的主要影响因素不同;从整个天山北坡城市群来看气候因素和地形因素是LST的主要影响因素,而在在石河子市、五家渠市和奎屯市LST的主要影响因素是社会经济因素。     

基于牧户感知和野外调查相结合的内蒙古东部草甸草原健康评价

治理草原退化是我国草原管理的重点和难点。我国目前关于草原退化判断、退化程度、原因及治理等系列问题的确定几乎皆以科学研究结果为依据,而忽视了牧户作为草原直接使用者和管理者的重要性。牧户对草原有自己的判断和认知,其与科学方法研究之间的矛盾已经影响到草原生态保护政策的有效实施。以内蒙古东部草甸草原牧户尺度草原为研究对象,借助牧户调研和野外调查相结合的方法,将牧户划分为高、中、低3个经济水平,并运用Condition-Vigor-Organization-Resilience (CVOR)指数评价法,分析评价草原生态系统健康状况。研究结果显示,牧户对草原健康状况的感知主要从植被、土壤、牲畜等方面,与科学方法评价指标选取具有相似性;牧户感知和CVOR指数法评价结果具有一致性,均判定草原生态系统呈现不同程度退化;统计检验显示牧户对植被、土壤、牲畜影响等指标变化感知方面均不存在显著差异(P0.05),CVOR指数法下不同经济水平牧户草场健康指数之间亦无显著差异(P0.05),两种方法均显示不同经济水平牧户草场退化程度无显著差异(P0.05)。研究证实了牧户感知在指标选取、评价结果方面具备用于准确评价草原健康状况的可行性和可信度。两种方法相互补充,将有利于更加准确、实时动态监测和评价牧户尺度草原生态健康状况,为调整优化畜牧业生产实践提供指导和草原生态保护和建设政策的有效实施提供保障。     

内蒙古草甸草原地下芽库对极端干旱的响应

全球变化引发的极端气候事件严重影响草地生态系统结构与功能。然而,作为多年生草地重要繁殖体库,半干旱草甸草原地下芽库如何响应极端干旱尚未明确。本研究以内蒙古呼伦贝尔草甸草原为对象,利用模拟极端干旱样地平台,探究地下芽库及其与地上植被关系对模拟生长季极端干旱的响应。结果表明,环境降水水平与干旱处理下总芽密度分别为1443和1128芽·m^-2;分株总密度分别为1791和1346株·m^-2;群落整体分生组织制约系数分别为0.84和0.83。极端干旱对草甸草原地下芽库、地上分株密度以及二者之间关联均无显著影响。就优势植物功能群根茎型禾草而言,极端干旱对其地下芽库同样无显著影响。因此,地下芽库表现出对极端干旱一定程度的抵抗力,可作为草甸草原植被应对极端气候事件的保险策略,有效促进草甸草原在极端气候胁迫下的种群更新与植被恢复,有助于草甸草原植被稳定性与生态系统功能维持。     

1982—2015年中国温带不同草地植被枯黄期对极端气候事件的响应

随着极端气候事件频率和强度的增加,植被物候正在发生深刻的变化。然而,植被枯黄期(EGS)对极端气候的响应机制目前尚未厘清,特别是对于干旱半干旱地区的草地而言。因此,聚焦我国温带草地,基于1982—2015年全球监测与模型研究工作组归一化植被指数(GIMMS NDVI3g)长时间序列数据提取草地物候参数,并分析其时空变化规律;运用随机森林模型等方法探究温带草地EGS对极端气候变化的响应特征。结果表明：(1)全区多年平均EGS主要发生于270—290儒略日(DOY),59.8%的区域呈延迟趋势,其中显著延迟(P<0.05)的区域分布在新疆天山、阿尔泰山一带和准噶尔盆地西部、黄土高原北部、呼伦贝尔高原的西部和东北小兴安岭。(2)EGS与极端气温暖极值(日最低气温的最大值、日最高气温的最大值、暖夜日数、暖昼日数)之间均以广泛的正相关关系为主;相比之下,极端降水事件与EGS之间的关系相对比较复杂,这与各草地类型自身的生理策略和所处环境密切相关。(3)整体而言,持续干旱日数、气温日较差和暖夜日数对全域草地EGS动态变化具有极大的重要性。就不同草地类型而言,温带草甸草原主要受到气温日较差的影响...     

新疆地区草原革蜱MaxEnt分布预测分析

草原革蜱是新疆地区常见的蜱种之一。该蜱能够携带和传播多种人畜共患病原体。为了分析该蜱在新疆的潜在分布模式, 本次预测分布采用了生物气候数据变量数据, 以及草原革蜱GPS出现位点的元数据, 其中包含48个甄选GPS位点, 用以进行MaxEnt分布预测分析和响应曲线分析。 预测分布结果显示, 草原革蜱主要分布在新疆北部。最适宜生存的区域在准噶尔盆地西缘、天山北坡、伊犁河谷地区、塔城地区、天山南坡以及巴音布鲁克草原。模型的AUC值通过10折交叉验证得出, 最终输出的MaxEnt模型的平均AUC值为0.856 ± 0.044(SD), 表明该模型较为可靠。响应曲线及贡献率结果表明, 6个生物气候变量中, 最干月份降水量(Bio14)、等温性(Bio03)和年平均气温(Bio02)对模型的贡献率总计达到了88.5%, 表明草原革蜱较适宜生存的区域分布在降水量和年均气温较高的区域。本次分布预测模型是基于MaxEnt算法得出的, 首个用于分析新疆地区草原革蜱分布的模型。该MaxEnt预测分布模型将有助于新疆地区蜱类种群分布研究、蜱传病原体检测以及蜱源性疾病的风险评估分析。     

Piospheres and Pastoralists: Vegetation and Degradation in Steppe Grasslands

The Mongolian plateau in East Asia is part of a new hotspot of land cover change. Recent human activity and natural forces have degraded grasslands in northern China with the southern Mongolia steppe similarly vulnerable. Investigating vegetation patterns at piospheres (the area around water points) can identify herder influence on pasture conditions. Through fieldwork and remote sensing this paper examines plant density and species richness at water sources to establish land cover patterns in two Mongolian provinces where overgrazing is thought to be the major cause of degradation. In contrast to standard piosphere patterns, vegetation was greater near water points and decreased with distance. This suggests that livestock are not concentrated at water points in Mongolia and that piosphere dynamics are more influenced by precipitation, edaphic factors and potential distinctive processes in cold drylands. It implies that pastoralism, with mobile livestock management, is a suitable adaptive strategy to the low forage capacity of steppe grasslands.     

Implications of behavioral change for the resilience of pastoral systems—Lessons from an agent-based model

In many dryland regions, traditional pastoral land use strategies are exposed to various drivers such as demographic or socio-economic change. This may lead to an adjustment of livelihood strategies and behavior of pastoral households, involving a change in attitudes toward livestock, pasture condition and social norms. We use an agent-based model to examine long-term social-ecological consequences and implications for system resilience of such behavioral changes (e.g., giving up a social norm). The model captures feedback between pastures, livestock and household livelihood in a common property grazing system. We systematically compare three stylized household behavioral types (traditional, maximizer and satisficer) that differ in their preferences for livestock, their compliance with social norms on pasture resting and how they are influenced by the behavior of others. Simulation results show that the traditional, norm-abiding household type maintains the pasture condition, provided that overall household numbers do not exceed a critical threshold. In contrast, a switch to a maximizer type that ignores norms may lead to long-term pasture degradation and livestock loss, pushing the system to an undesirable state. A change toward a new satisficing household type that constrains its herd size while diversifying its income sources can lead to improved pasture conditions and higher total livestock numbers, even with increased household numbers. We conclude that changes in household behavior have strong implications for long-term social-ecological system dynamics and have to be considered to assess the resilience of pastoral common property systems.     

Effects of Climate Change on Range Forage Production in the San Francisco Bay Area

The San Francisco Bay Area in California, USA is a highly heterogeneous region in climate, topography, and habitats, as well as in its political and economic interests. Successful conservation strategies must consider various current and future competing demands for the land, and should pay special attention to livestock grazing, the dominant non-urban land-use. The main objective of this study was to predict changes in rangeland forage production in response to changes in temperature and precipitation projected by downscaled output from global climate models. Daily temperature and precipitation data generated by four climate models were used as input variables for an existing rangeland forage production model (linear regression) for California’s annual rangelands and projected on 244 12 km x 12 km grid cells for eight Bay Area counties. Climate model projections suggest that forage production in Bay Area rangelands may be enhanced by future conditions in most years, at least in terms of peak standing crop. However, the timing of production is as important as its peak, and altered precipitation patterns could mean delayed germination, resulting in shorter growing seasons and longer periods of inadequate forage quality. An increase in the frequency of extremely dry years also increases the uncertainty of forage availability. These shifts in forage production will affect the economic viability and conservation strategies for rangelands in the San Francisco Bay Area.     

不同草地所有权下家庭牧场生产效率比较分析

选取了甘肃祁连山区肃南县春夏秋冬四季草场均已分配到户的15个牧户和天祝县夏秋草场或四季草场均为公共草场的15个农牧户,从草地生态系统生产功能的角度,通过野外调查、DEA模型(数据包络分析模型)分析,比较两地牧民草场面积,冷季补饲,牧工费,家庭劳动力等投入,出售活畜、毛、奶等畜产品的产出等项目,探讨不同的草地所有权下牧民生产效率平均值、效率分布的差异性以及影响生产效率的因素。结果显示:天祝县农牧民生产效率的平均值大于肃南县(P0.05),且天祝县牧户生产效率的分布优于肃南县。进一步分析得出造成牧业生产效率低的原因从大到小顺序为:补饲投入、能繁母畜、草场面积和劳动力投入。验证了草地所有权会影响家庭牧场生产效率的假设,并且就生产效率角度来说,不完全承包到户的草地所有权优于完全承包到户的。     

Predicting Extreme Droughts in Savannah Africa: A Comparison of Proxy and Direct Measures in Detecting Biomass Fluctuations,Trends and Their Causes

We monitored pasture biomass on 20 permanent plots over 35 years to gauge the reliability of rainfall and NDVI as proxy measures of forage shortfalls in a savannah ecosystem. Both proxies are reliable indicators of pasture biomass at the onset of dry periods but fail to predict shortfalls in prolonged dry spells. In contrast, grazing pressure predicts pasture deficits with a high degree of accuracy. Large herbivores play a primary role in determining the severity of pasture deficits and variation across habitats. Grazing pressure also explains oscillations in plant biomass unrelated to rainfall. Plant biomass has declined steadily and biomass per unit of rainfall has fallen by a third, corresponding to a doubling in grazing intensity over the study period. The rising probability of forage deficits fits local pastoral perceptions of an increasing frequency of extreme shortfalls. The decline in forage is linked to sedentarization, range loss and herbivore compression into drought refuges, rather than climate change. The results show that the decline in rangeland productivity and increasing frequency of pasture shortfalls can be ameliorated by better husbandry practices and reinforces the need for ground monitoring to complement remote sensing in forecasting pasture shortfalls.     

青海省三江源自然保护区生态移民补偿标准

生态补偿是目前生态学研究的热点,生态补偿的关键问题是补偿标准的确定.将三江源自然保护区的生态移民作为对象,结合确定补偿标准的方法的特点,针对研究区域的实际情况以及我国生态补偿存在的主要问题,运用不同的方法提出了生态移民补偿标准的不同方案,所采用的方法分别是:牲畜机会成本法、草场机会成本法、以果洛新村和河源新村两个移民新村为例的地区发展差异法.结果表明:3种方法的侧重点各不相同,所确定的平均生态补偿标准也稍有不同,分别为1.39万元·户-1·a-1;1.03万元·户-1·a-1;1.1万元·户-1·a-1.研究为确定三江源自然保护区生态补偿的标准提供了科学依据,也为其他地区提供一定的借鉴.     

The Role of Livestock Mobility in the Livelihood Strategies of Rural Peoples in Semi-Arid West Africa

Over the past 10 years, mobility of livestock has been portrayed as increasing the resilience of rural households in semi-arid Africa to climate change and variability. With this recognition, there has been important work characterizing livestock mobility and the barriers to it. This paper adds to this work by addressing two gaps in the literature: 1. An understanding in the variation of livestock mobility practices among communities; and 2. An understanding of rural peoples’ views of the advantages and disadvantages of livestock mobility as well as the factors affecting their decisions about herd movements. A mixed-methods approach was adopted to analyze data collected by household survey and group interviews conducted in 32 multi-ethnic villages in Mali and Niger spanning the 12.5° N to 16.5° N latitudinal range. The results of regression and qualitative analyses show that: 1. A large fraction of rural households rely on livestock as part of their livelihood strategies; 2. Grazing management of a large majority of village livestock depends on movements outside of the village territory, especially during the rainy season; 3. The mobility of village livestock is not strongly influenced by the village’s sociprofessional composition (farmer, herder, fisher, artisan..etc.); and 4. The prevalence of extra-village movements of village livestock (sheep and cattle) is higher in areas of higher population density. Despite the advantages of livestock mobility cited by informants, longer-distance movements are inhibited by risks associated with climatic, land-use, and sociopolitical change. Herd managers make decisions using diverse information about potential destinations with greater trust of information gathered by themselves or close kin. The implications of these findings for livestock management and policy in the region are discussed.     

Analyzing Herder Adaptive Capacity to Climate Change: A Case Study from an Ecologically Fragile Area in Inner Mongolia,People’s Republic of China

Based on 224 face-to-face household surveys in an ecologically fragile grazing area in China’s Inner Mongolia Autonomous Region, this study analyzes herder (pastoralist) adaptive capacity for coping with climate change. The Composite Indicator Framework Method and Entropy Weighting Method were applied to calculate each herder’s Adaptive Capacity Index (ACI) based on 16 indicators from seven determinants of adaptive willingness and adaptive capital. Results show that herders have an average ACI value of 0.40. Classifying herders into three groups of relatively high, medium, and low ACI values, we find that financial capital and social capital are the most significant determinants of herder adaptive capacity. Improving financial services and building herder social capital would be the most effective ways of enhancing adaptive capacity for coping with climate change. The methods and indicators developed can be generalized to other similar areas to facilitate better policy interventions for reducing poverty and improving rangeland management.