基于景观格局视角的土地整治对农地细碎化影响评价研究

以江西省宜丰县土地整治项目区为例,选择斑块类型、景观类型、廊道特征3类景观格局指数,从景观格局视角定量评价土地整治对农地细碎化的影响。研究表明:(1)水田的斑块密度由8.916 1个/hm~2下降至8.423 4个/hm~2,平均斑块面积由0.075 1 hm~2提升至0.076 9 hm~2,边缘密度由1 203.431 8降低至1 127.134 7,面积加权的平均形状因子由1.238 6下降至1.216 3,最大斑块指数由0.17%上升至0.18%,景观格局指数均得到不同程度改善;但旱地除面积加权的平均形状因子以外,其他指标均表明旱地趋于细碎化。(2)土地整治导致项目区破碎化程度加剧,斑块数量由3 530个提升至4 175个,平均斑块面积由0.070 6 hm~2增加至0.059 7 hm~2,面积加权平均形状因子由1.672 3增加至1.816 0,最大斑块指数由2.06%降低至2.01%。(3)土地整治优化了农村道理和沟渠布局,廊道特征指数均有不同程度改善。但农村道路和沟渠的修建割裂了斑块,是导致项目区破碎化程度加剧的主要原因。因此,在土地整治规划设计中需要注重旱地、农村道路、沟渠的景观格局设计,达到有效治理农地细碎化和提高土地整治景观生态效益的目的。     

Demographic Parameters of the Tartarian Roe Deer Population in the Transural Region and the Main Factors Determining Them

The demographic parameters (sex and age structure, fecundity, and population growth) and the main environmental factors (legal hunting and poaching, predators, weather, and food supply) affecting the structure and dynamics of the large Tartarian roe deer (Capreolus pygargus Pall.) population of Kurgan oblast were studied. The question of the conformity between the population size and the carrying capacity of its range is considered.     

山区县乡公路建设对沿线景观格局的影响研究——以昆明市东川区蒋家沟小流域为例

公路建设对区域的各种生态过程、灾害活动等影响引起广大学者的关注,目前对小尺度区域公路沿线景观格局的影响效应研究较少。利用3S技术对云南省昆明市东川区蒋家沟小流域内县乡级公路沿线三期影像的景观进行分类和制图,运用Fragstats3.3软件和景观指数计算方法,从斑块和景观两个层次上研究公路建设前后景观格局的变化。结果表明:(1)不同时期建设公路及全部公路沿线均出现坡耕地显著减少、梯田显著增加的趋势;在不同距离梯度上,针叶林、灌丛、坡耕地景观百分比不断降低,梯田、草地面积增加。(2)公路沿线景观格局动态变化则表现为:在斑块层次上,1973年前建设公路沿线景观形态更复杂,破碎化程度高,1973年后建设公路沿线阔叶林、针叶林斑块数量增加,破碎化趋势明显;在景观层次上,公路沿线景观多样性增加,景观内部连通性降低,整体景观格局破碎化加剧,但1973年前建设公路沿线空间连接性有所提升,1973年后建设公路沿线则表现出空间连接性下降的趋势,公路全线两侧150 m范围对景观水平指数的影响最大。     

岷江上游高山森林凋落叶在冬季河流中的质量损失特征

凋落叶在高山森林河流中的分解不仅是生态系统物质循环的重要内容,而且与森林养分流失以及下游水体环境密切相关,并可能受到冬季雪被变化和土壤季节性冻融的影响,但一直缺乏必要的关注。因此,以岷江上游高山森林4种代表性植物康定柳(Salix paraplesia)、高山杜鹃(Rhododendron lapponicum)、方枝柏(Sabina saltuaria)和四川红杉(Larix mastersiana)凋落叶为研究对象,采用凋落叶分解袋法,研究了一个冬季不同冻融时期(冻结初期、冻结期和融化期)的质量损失特征。经过一个冬季(162d)的分解,康定柳、高山杜鹃、方枝柏和四川红杉凋落叶分别完成了初始干重45.5%、18.9%、26.4%和23.8%的分解;除康定柳凋落叶质量损失在融化期最大外,其余3种凋落叶均表现为冻结初期最大;康定柳、方枝柏和四川红杉凋落叶质量损失与河流水环境的平均温度和正积温均表现出显著或极显著的正相关关系,且与河流流速和硝态氮显著正相关,而与河流pH显著负相关;高山杜鹃凋落叶质量损失除与HCO3-含量显著相关外,与河流水温及其它水质特征均无显著相关关系。这些结果表明高山森林河流流速及水环境特征显著影响了凋落叶分解及其相关的物质循环过程,但影响程度受到凋落叶特性的调控。     

The State of Populations and Selective Hunting of Game Ungulates in the Middle Urals

The population dynamics of moose, wild boar, and roe deer in the Middle Urals and changes in the proportion of females among the animals taken by hunters were analyzed. For all the three species, a tendency toward selective hunting for females was revealed. In this situation, the proportion of females in a population decreases with time, and its reproductive potential is impaired.     

Profile of Methane Concentrations in Soil and Atmosphere in Alpine Steppe Ecosystem on Tibetan Plateau

The methane concentration profile from -1.5m depth in soil to 32m height in air was measured in alpine steppe located in the permafrost area. Methane concentrations showed widely variations both in air and in soil during the study period. The mean concentrations in atmosphere were all higher than those in soil, and the highest methane concentration was found in air at the height of 16m with the lowest concentration occurring at the depth of 1.5m in soil. The variations of atmospheric methane concentrations did not show any clear pattern both temporally and spatially, although they exhibited a more steadystable state than those in soil. During the seasonal variations, the methane concentrations at different depths in soil were significantly correlated （R^2〉0.6） with each other comparing to the weak correlations （R^2〈0.2） between the atmospheric concentra- tions at different heights. Mean methane concentrations in soil significantly decreased with depth. This was the compositive influence of the decreasing production rates and the increasing methane oxidation rates, which was caused by the descent soil moisture with depth. Although the methane concentrations at all depths varied widely during the growing season, they showed very distinct temporal variations in the non-growing season. It was indicated from the literatures that methane oxidation rates were positively correlated with soil temperature. The higher methane concentrations in soil during the winter were determined by the lower methane oxidation rates with decreasing soil temperatures, whereas methane production rates had no reaction to the lower temperature. Relations between methane contribution and other environmental factors were not discussed in this paper for lacking of data, which impulse us to carry out further and more detailed studies in this unique area.     

长江上游高山森林林窗对凋落物分解过程中可溶性碳的影响

采用凋落物分解袋法, 以川西高山森林典型乔木(四川红杉Larix mastersiana、岷江冷杉Abies faxoniana、红桦Betula albo-sinensis和方枝柏Sabina saltuaria)和灌木(高山杜鹃Rhododendron lapponicum和康定柳Salix paraplesia)凋落物为研究对象, 研究了林窗中心到郁闭林下不同生境(林窗中心、林冠林窗、扩展林窗和郁闭林下)中凋落物第一年分解不同关键时期(雪被形成期、雪被覆盖期、雪被融化期和生长季节)可溶性碳的动态特征。结果表明:6种凋落物可溶性碳和可溶性有机碳在冬季含量增加而在生长季节含量降低, 而可溶性无机碳含量在全年呈降低趋势;雪被形成期, 6种凋落物可溶性碳和可溶性有机碳在郁闭林下达到最大值, 而雪被覆盖期在林窗中心和林冠林窗达到最大值, 生长季节6种凋落物可溶性碳含量均低于初始含量。这表明全球气候变暖情景下, 冬季林内雪被覆盖时间和厚度降低且生长季节延长将减少凋落物可溶性碳含量, 且变化程度受到凋落物质量控制。     

Common Values and Themes for Grazed Open Spaces: “Plant Diversity” and “Watershed” as Communication Intersections for Agriculture and Conservation Groups?

ABSTRACT

Communicating about the use and management of open spaces occurs within a complex social environment replete with diverse stakeholder opinions and meta-narratives. For western US rangelands, production-based enterprises have been the traditional use but increasingly they are valued for ecosystem services such as water, recreation, biodiversity, and aesthetics which have led to additional conflict. We surveyed Wyoming-based members of six agricultural (Ag) and four environmental/conservation (Env/Con) groups to determine grazing-centric mutual exclusivity of special interests, common values, and emergent themes. We assessed 197 survey participants; 150 from Ag groups and 47 from Env/Con groups. Of 10 values assessed, “watershed” and “plant diversity” were similarly valued by both group types. These naturally dichotomous groups also agreed that communication and reliance on science are needed. Communication and conflict resolution about the use of open spaces can benefit from addressing social presuppositions and meta-narratives of broader audiences to facilitate effective dialogue and solutions.     

RS与GIS支持下的南京市景观格局动态变化研究

利用1986、1994、2000年的TM图像和2000年的土地利用现状图,运用GIS和核心景观指数研究南京市自1986年以来景观格局的动态演变规律。结果表明：南京市在快速城市化的过程中,城市景观结构的变化主要表现为耕地、绿地、水体和未利用地等自然或半自然景观向城市、农村居民地、工矿用地以及交通用地等人文景观转变;景观的多样性增加,斑块的平均面积增大,分离度、破碎度和孔隙度减小,城市的开发趋向有序化、规模化;但由于人类活动作用方式或作用程度的不同,不同的景观类型在同一时间段,或者同一景观类型在不同的时间内空间格局的转变模式不同,1986~1994年城市扩展的速度很快,开发比较混乱,城市、农村居民地和交通用地等人文景观的面积大幅增加,耕地、绿地和未利用地的面积大量减少,斑块分布不均匀,空隙度增加,1994~2000年城市扩展的速度减慢,开发趋向有序化,除耕地外,其他景观类型的分离度、破碎度和孔隙度减小,空间分布趋向均匀。     

土地细碎化与农村劳动力转移研究

随着农村剩余劳动力告罄,迫切需要转变农业生产技术与经营方式来释放更多农村劳动力。作为中国农业经营的主要特征之一,土地细碎化是否阻碍了劳动力转移呢?为回答这个研究疑问,本文从理论层面系统地分析了土地细碎化影响农村劳动力转移的各种可能路径及其依据的条件,在此基础上利用农村固定观察点数据进行实证测度。数据描述表明,纵向来看中国耕地细碎化和种植多样化的程度一直在降低,与此同时非农就业持续增加,意味着两者的负相关关系。然而,横向分组对比来看,参与非农就业的农户或劳动力其土地细碎化程度更高。为了控制其他因素的影响进行了计量模型估计。农户非农劳动供给的double-hurdle模型结果表明,土地细碎化不仅降低了农户参与非农劳动供给的概率,还降低了劳动供给时间。劳动力就业选择的Mprobit模型结果表明,土地细碎化既降低劳动力兼职型从事非农就业的概率,也降低了全职型从事非农就业的概率,且对后者的作用更大。随着客观形势的变化,土地细碎化的不利一面正越来越突出;现在土地细碎化已经成为农村劳动力转移的障碍因素。近年来可以观察到一些涌现出来的削减土地细碎化的措施,例如,集体土地重新分配中新规则、通过土地租赁市场的置换合并或整片流转等。政府可以为上述转变提供相应的政策支持,也可以补贴或直接投资农村的土地整理项目。目前正在推广的承包地确权制度倾向于固化土地细碎化产权,后确权时代如何削减细碎化有待进行政策讨论。     

Impact of Cloud on Net Ecosystem CO2 Exchange of Alpine Meadow in Tibetan Plateau

Meteorological elements and CO2 fluxes over alpine meadow ecosystem were observed continuously from 2004 to 2005in Damxung Alpine Meadow Flux Station,China Flux Network.Based on the eddy covariance CO2 fluxes and meteorological data obtained,the relationships among the CO2 fluxes,the cloud amount,and the meteorological factors in alpine meadow ecosystem were explored and analyzed.Some conclusions can be drawn from the discussion with previous researches as following:(1)the cloud amount can affect the net ecosystem CO2 exchange(NEE)of alpine meadow on Tibetan Plateau;(2)the soil temperature sensitive to the cloud amount,is a major environmental controlling factor for NEE,and closely relates to the maximum of NEE.In the morning period with large cloud amount,the NEE reaches its maximum when the clearness index ranges from 0.5 to 0.7; yet in the afternoon it comes to the maximum with the index from 0.2 to 0.35.The span of soil temperature covers from 12 to 15℃ as the NEE at its highest;(3)the scatterplots between NEE and photosynthetic available radiation(PAR)was a significant inverse triangle in the clear day,two different kinds of concave curves in the cloudy day,and strongly convergent rectangular hyperbola in the overcast day.These differences were controlled by the changes of light radiation and soil temperature.     

多年冻土区工程迹地人工恢复区植物和土壤的矿质元素含量特征

选择青藏高原多年冻土区工程迹地的人工恢复植物和紫花针茅草原的优势植物以及对应的土壤样品进行对照,利用原子吸收法分析了它们的矿质元素含量特征。结果表明：多年冻土区工程迹地人工恢复区植物的元素含量：＞1 000 μg/g的元素有Ca、P和Na,100～1 000 μg/g的元素有Mn、K、Fe、Mg和Al;而对照紫花针茅草原优势植物的元素含量：＞1 000 μg/g的元素有Ca和Na,100～1 000 μg/g的元素有P、Mn、K、Fe、Mg和Al。人工恢复区土壤元素含量：＞1 000 μg/g的元素有Ca、Fe和Mn,100～1000 μg/g的元素有Mg、K、Al、P和Na;对照紫花针茅草原土壤元素含量：＞1 000 μg/g的元素有Ca、Fe,100～1 000 μg/g的元素有Mn、Mg、Al、K、P和Na。该区域植物和土壤元素含量都属于Ca > K 型。人工恢复植物和对照的紫花针茅草原植物对土壤元素的吸收能力具有较高的相似性。K和Al元素的累积与其他元素没有显著的相关关系,其他元素之间为正相关关系,元素之间的吸收累积属于协同作用,无明显的撷抗作用     

气候变化对长江源地区高寒草甸生态系统的影响

近十几年来,长江源区气候暖干化趋势明显,冰川退缩、湖泊萎缩、草场退化、土地沙漠化、水土流失等环境问题日益严重。高寒草甸是长江源地区主要的植被类型之一,在全球变化影响下,以耐低温寒冷的嵩草属（Kobresia）植物为建群种的高寒草甸将面临更严重的生态胁迫。以长江源地区高寒草甸生态系统为研究对象,采用国际通用的生物地球化学模型模拟高寒草甸生物量、生产力和土壤有机质等的动态变化,并综合考虑人类活动对生态系统生产力和营养元素生物地球化学循环的影响,探讨了全球气候变化对高寒草甸生态系统可能造成的影响。     

我国南方不同类型草地生产力及对气候变化的响应

为进一步明晰南方不同类型草地的碳源汇关系,预测未来气候情景下可能的碳循环特征,利用本地参数化的BIOME-BGC模型对2001~2010年低山丘陵草原化草甸、典型草山草坡和典型山地草甸样地净初级生产力(NPP)与净生态系统生产力(NEP)进行了模拟估算。不同类型草地的NPP和NEP 10年间变化趋势不同,低山丘陵草原化草甸、典型草山草坡和典型山地草甸的NPP平均值分别为357.17、232.4和191.96gC/(m2·a);NEP的平均值分别为3.25、21.28和81.96gC/(m2·a)。3种类型草地NPP与温度之间存在显著的正相关关系,NEP与温度之间存在着显著的负相关关系;本模型模拟的NPP和NEP与年平均降水量之间相关性不明显。未来气候情景C1P-1T1下(CO2浓度倍增,年均温增加2℃,降水减少10%),低山丘陵草原化草甸样地NPP增加26.93%,NEP增加160%;典型草山草坡样地NPP增加62.20%,NEP增加153%;典型山地草甸样地NPP增加135%,NEP增加206%。3种南方草地类型在未来气候情景下都将有一定的碳汇增长潜力,其中以典型山地草甸的碳汇潜力最为明显,与降水量相比受温度变化的影响相对较大。     

Human use and conservation planning in Alpine areas of Northwestern Yunnan,China

Alpine areas in northwestern Yunnan, China possess globally significant levels of biodiversity and are important locally for livelihood activities such as livestock grazing and medicinal plant collection. Because local land use has important impacts on alpine conditions and communities have significant capacity to manage alpine resources, we emphasized local collaboration during the initial stages of conservation planning. Our collaboration with local communities investigated how livelihood strategies affect the condition of alpine resources in northwestern Yunnan and how future conservation efforts can be compatible with local livelihoods. We sampled three livestock herding sites, each within a different alpine sub-region, using open-ended interviews and maximum variation sampling. According to interviewees, livestock grazing within the alpine zone currently does not appear to be negatively impacting the availability of forage. Medicinal plant collection, however, is showing unsustainable trends. Tourism is as yet a nascent industry, but is seen as having great potential by those interviewed. It is clear that with increases in population, access to regional markets, and tourism, northwestern Yunnan’s rich alpine resources will require careful management. In addition to the data collected, we found that the methodology used may be widely applicable to organizations with limited resources that wish to engage local communities during the formative stages of regional-level conservation planning.