农区土地利用强度变化对生物多样性的影响

农业集约化引起的景观变化是导致农业景观生物多样性丧失的重要原因,为评估农业景观结构变化对物种多样性的影响,探索生物多样性未来的变化趋势,研究基于Meta分析(Meta-Analysis)构建我国农区不同土地利用强度的生物多样性数据库,收集了来自全国298个农业景观样地的15 042条物种记录。依据线性混合效应模型构建我国农区土地利用强度-生物多样性关系模型,并以浙江省为例,结合浙江省退耕还林、生态农业发展等土地利用政策和规划,基于Dyna-CLUE模型模拟不同情景下土地利用的空间分布,将土地利用空间分布模拟和土地利用强度-生物多样性关系模型结果输入Flus-Biodiversity模型,从而模拟典型农区生物多样性的空间分布格局,提出浙江省农田生物多样性保护目标优化方案。Meta分析显示,无论在景观尺度还是局部管理尺度上,随着农田土地利用强度的增加,生物多样性均呈显著下降趋势。情景模拟发现,在所有情景中生物多样性都呈下降趋势,其中生态保育情景下降幅度最小,将常规农田转换为生态农田时生物多样性有所提高。因此,为进一步保护多样性、提升生态系统服务、改善生态环境,一方面应尽量保护农田周围的自然和半自然生境,以减少土地利用改变对农业生物多样性的破坏;其次,适当增加农业景观中的半自然生境,如人工林等,构建合理的农业景观格局;第三,适度推动有机管理或生态管理,合理化减少化肥和农药的施用,有利于区域生物多样性的保护;第四,在保证耕地红线的前提下,应深入推进退耕还林政策,严格限制生态功能区的土地开发,同时注重生物多样性完整性损失严重区域的保护。     

城市化对生物多样性的影响

城市化正在全球范围内迅速发展，它对生物多样性的不利影响是明显的，但彼此之间的矛盾也不是不能协调解决。现代化与自然共存、经济建设与生物多样性共存，是人类追求的目标。本文从城市化的发展趋势、城市的生境特点、城市化对生物多样性的影响等方面，来探讨实现现代化与自然共存的途径。     

城市化对生物多样性的影响

城市化正在全球范围内迅速发展，它对生物多样性的不利影响是明显的，但彼此之间的矛盾也不是不能协调解决。现代化与自然共存、经济建设与生物多样性共存，是人类追求的目标。本文从城市化的发展趋势、城市的生境特点、城市化对生物多样性的影响等方面，来探讨实现现代化与自然共存的途径。     

森林土地利用变化及其对碳循环的影响

由于人口剧增，人类活动的影响不断加大，在过去100年全球土地利用／土地覆被发生了巨大的变化。最常见的土地利用变化是由森林转变为农业用地。森林砍伐使森林生态系统地上部生物量大大减少，砍伐后作农业用地，降低了植被生产力，减少了土壤有机质的输入，增强了腐殖质的矿化作用，有机质分解速率增加，有机碳贮量随之降低，从而影响到森林生态系统的碳循环，使大量碳元素释放到大气中，引起温室效应，导致全球变暖。另一个常见的土地利用变化是植树造林和森林恢复，这一过程可以增加森林生态系统的碳储量，从而减缓大气CO2体积分数的上升。     

科尔沁沙地土地利用变化对土壤特性的影响

在中国科学院奈曼沙漠化研究站放牧试验场周围,选取了不同利用方式和类型的草地（封育和放牧）、林地（乔木和灌木）和农田（灌溉和非灌溉）为研究样地,调查了0～30cm土层每隔10cm的土壤水分质量分数和有机养分（有机碳和全氮）,分析了土地利用变化对土壤水分质量分数和有机养分的影响。结果发现,垂直空间分布上,无论哪种土地类型样地,土壤水分质量分数和有机养分各土层间均无显著差异性（P〉0.05）,土层垂直变化对土壤特性影响均较小。在不同土地利用方式水平空间分布上,土壤水分质量分数和有机养分（土壤有机碳和全氮）灌木林地均显著高于乔木林地（P〈0.05）,而封育草地和放牧草地间以及灌溉农田与非灌溉农田间土壤水分质量分数和有机养分均无显著差异性（P〉0.05）。不同土地利用类型水平分布上,草地土壤水分质量分数显著低于林地和农田（P〈0.05）,而土壤养分质量分数草地显著高于林地和农田（P〈0.05）。分析表明,对沙质草地进行围栏封育和旱作农田退耕还林还草的同时,对水浇农田实行保护性耕作和精细管理,有利于沙地土壤环境改善与生态系统恢复。     

气候变化对生物多样性的影响:脆弱性和适应

气候变化对生物多样性影响及其适应直接关系着未来生物多样性的保护.气候变化对生物多样性影响、生物多样性在气候变化影响下的脆弱性、生物多样性适应气候变化方面进行了总结分析,对存在的问题进行了讨论,对今后研究提出了一些建议.过去的气候变化已使物种物候、分布和丰富度等改变,使一些物种灭绝、部分有害生物危害强度和频率增加,使一些生物入侵范围扩大、生态系统结构与功能改变等.未来的气候变化仍将使物种物候和行为、分布和丰富度等改变,使一些物种灭绝、使有害生物爆发频率和强度增加,并将可能使生态系统结构与功能发生改变等.生物多样性适应气候变化包括了自然适应和人为适应两个方面,自然适应体现在物种适应性进化、迁移、生态系统稳定性和弹性等,人为适应体现在种质基因保存、物种异地保护、自然保护区规划设计、生态系统适应性管理、生态恢复和气候灾害防御等.目前,生物多样性对气候变化影响的脆弱性、生物多样性自然适应和人为适应气候变化方面的研究都还不系统深入,需要加强生物多样性自然适应和人为适应气候变化方面的研究.     

国道112线建设对生物多样性的影响分析

以国道112线丰宁至千松梁段为例，首先介绍了事例工程的基本情况和生物多样性的概念，而后从直接和间接两方面详细论述了公路建设对生物多样性的影响，最后得出简明结论。     

基于MIKESHE模型的潮河流域土地利用与降水变化对水文的影响评价

运用多测站校正检验机制率定方法,应用MIKESHE模型量化评价土地利用与降水变化对流域水文的影响。结果表明,尽管MIKESHE模型在流域上游大阁站的模拟性能稍逊于下会站和戴营站,3个测站校正和验证阶段的Nash-sutchliffe系数值分别为0.56和0.49、0.65和0.69、0.57和0.68,但模型对于各测站平均径流的模拟效果较好,说明该模型在潮河流域等华北土石山区具有一定的适用性和应用潜力。与基准期(1963—1979年)相比,1980—1989年潮河流域年径流量减少约22 mm,土地利用与降水变化对流域水文变化的贡献相当,两者分别占总径流变化的59%和41%;1990—1999年年径流量较基准期基本没有变化,这主要是由于降水变化与土地利用变化对流域水文的影响作用相反;2000—2008年,流域年径流量较基准期减少35 mm,降水变化对径流减少的影响作用占80%,土地利用变化则占20%。     

中国农业生物多样性及其保护

对我国农业生物多样性现状与变化态势进行了评述,分析了农业生态多样性丧失的原因,认为生境丧失、退化与破碎化、农业单一化耕作与驯养、农业物种的过度开发利用、外来物种的引进或入侵、环境污染以及全球气候变化等是造成农业生物多样性减少的主要威胁,同时提出一系列相应的保护对策。     

土地利用方式及母质对土壤有机碳的影响

运用物理分组方法分别对海南屯昌县花岗岩砖红壤地区天然次生林(白楸(Mallotus paniculatus (Lam.) Muell. Arg.)、岭南山竹子(Garcinia oblongifolia Champ.))土壤(TSF)和人工橡胶RRIM600 (Hevea brasiliensis. Muell. Arg.)林土壤(TR)以及白沙县紫色砂页岩砖红壤地区天然次生林(白楸 (Mallotus paniculatus (Lam.) Muell.Arg.)、岭南山竹子(Garcinia oblongifolia Champ.))土壤(BSF)和人工橡胶RRIM600 (Hevea brasiliensis. Muell. Arg.) 林土壤(BR)0100 cm土层土壤及其物理组分中的有机碳进行了研究,分析利用方式从天然次生林变为人工橡胶林后不同母质砖红壤及其物理组分有机碳含量变化.结果表明: TSF和TR土壤有机碳分别比BSF和BR土壤有机碳含量高.无论是花岗岩砖红壤还是砂页岩砖红壤,土地利用变化使土壤和微团聚体有机碳含量都极显著降低,TSF变为TR后还造成大团聚体以及粘粒和粉粒(Silt & clay)有机碳显著减少,可以看出土地利用变化引起的花岗岩砖红壤退化程度比砂页岩砖红壤大.土地利用变化主要对第一、二层土壤及其物理组分产生影响,且对第一层影响比第二层大.对比研究发现,砂页岩砖红壤Coarse POM和iPOM组分中有机碳稳定性比花岗岩砖红壤相应物理组分强.     

Effects of site-selection bias on estimates of biodiversity change

Estimates of biodiversity change are essential for the management and conservation of ecosystems. Accurate estimates rely on selecting representative sites, but monitoring often focuses on sites of special interest. How such site-selection biases influence estimates of biodiversity change is largely unknown. Site-selection bias potentially occurs across four major sources of biodiversity data, decreasing in likelihood from citizen science, museums, national park monitoring, and academic research. We defined site-selection bias as a preference for sites that are either densely populated (i.e., abundance bias) or species rich (i.e., richness bias). We simulated biodiversity change in a virtual landscape and tracked the observed biodiversity at a sampled site. The site was selected either randomly or with a site-selection bias. We used a simple spatially resolved, individual-based model to predict the movement or dispersal of individuals in and out of the chosen sampling site. Site-selection bias exaggerated estimates of biodiversity loss in sites selected with a bias by on average 300–400% compared with randomly selected sites. Based on our simulations, site-selection bias resulted in positive trends being estimated as negative trends: richness increase was estimated as 0.1 in randomly selected sites, whereas sites selected with a bias showed a richness change of −0.1 to −0.2 on average. Thus, site-selection bias may falsely indicate decreases in biodiversity. We varied sampling design and characteristics of the species and found that site-selection biases were strongest in short time series, for small grains, organisms with low dispersal ability, large regional species pools, and strong spatial aggregation. Based on these findings, to minimize site-selection bias, we recommend use of systematic site-selection schemes; maximizing sampling area; calculating biodiversity measures cumulatively across plots; and use of biodiversity measures that are less sensitive to rare species, such as the effective number of species. Awareness of the potential impact of site-selection bias is needed for biodiversity monitoring, the design of new studies on biodiversity change, and the interpretation of existing data.     

Effects of land use,cover, and protection on stream and riparian ecosystem services and biodiversity

Protected areas are an important part of broader landscapes that are often used to preserve biodiversity or natural features. Some argue that protected areas may also help ensure provision of ecosystem services. However, the effect of protection on ecosystem services and whether protection affects the provision of ecosystem services is known only for a few services in a few types of landscapes. We sought to fill this gap by investigating the effect of watershed protection status and land use and land cover on biodiversity and the provision of ecosystem services. We compared the ecosystem services provided in and around streams in 4 watershed types: International Union for Conservation of Nature category II protected forests, unprotected forests, unprotected forests with recent timber harvesting, and unprotected areas with agriculture. We surveyed 28 streams distributed across these watershed types in Quebec, Canada, to quantify provisioning of clean water, carbon storage, recreation, wild foods, habitat quality, and terrestrial and aquatic biodiversity richness and abundance. The quantity and quality of ecosystem services and biodiversity were generally higher in sites with intact forest—whether protected or not—relative to those embedded in production landscapes with forestry or agriculture. Clean-water provision, carbon storage, habitat quality, and tree diversity were significantly higher in and around streams surrounded by forest. Recreation, wild foods, and aquatic biodiversity did not vary among watershed types. Although some services can be provided by both protected and unprotected areas, protection status may help secure the continued supply of services sensitive to changes in land use or land cover. Our findings provide needed information about the ecosystem service and biodiversity trade-offs and synergies that result from developing a watershed or from protecting it.     

珠江三角洲土地利用变化对特征大气污染物扩散的影响

在珠江三角洲两种下垫面条件下,应用CALPUFF大气污染扩散模式,对特征污染物SO2、SO42-的扩散进行数值模拟,探讨大规模土地利用变化,尤其是城镇建设用地增加,对珠江三角洲地区大气污染物扩散的影响,并通过对4个典型区污染物月均质量浓度变化特征分析,揭示土地利用变化对不同地区的污染物分布的影响机制。模拟结果表明：土地利用变化,尤其是城镇建设用地增加,不利于污染物扩散,污染源下风方向地区受影响较大,污染物质量浓度明显升高,SO2和 SO42-年均质量浓度分别增加14.07%和3.31%;受影响范围、变化幅度与污染源排污强度呈正相关,变化幅度亦与污染源距离远近呈负相关。土地利用变化后,尤其是城镇建设用地增加,四个典型区 SO2月均质量浓度都表现为升高趋势,且冬季 SO2质量浓度升高幅度最大,夏季升高幅度最小,临近污染源密集区的两个典型区SO2月均质量浓度分别增加33.6%和26.3%。土地利用变化不仅改变局地的污染扩散,也会对区域的污染扩散有一定影响,尤其对污染源分布密集区的大气污染物扩散影响强度最大。因此,建议人类在城市化建设过程中尽可能保留自然斑块,消除人工下垫面对污染物扩散的负面影响。     

Uncertainty analysis on aquatic environmental impacts of urban land use change

Uncertainties hamper the implementation of strategic environmental assessment (SEA). In order to quantitatively characterize the uncertainties of environmental impacts, this paper develops an integrated methodology through uncertainty analysis on land use change, which combines the scenario analysis approach, stochastic simulation technique, and statistics. Dalian city in China was taken as a case study in the present work. The results predict that the Fuzhou River poses the highest environmental pollution risk with a probability of 89.63% for COD in 2020. Furthermore, the Biliu River, Fuzhou River, Zhuang River, and Dasha River have 100% probabilities for NH₃-N. NH₃-N is a more critical pollutant than COD for all rivers. For COD, industry is the critical pollution source for all rivers except the Zhuang River. For NH₃-N, agriculture is the critical pollution source for the Biliu River, Yingna River, and Dasha River, sewage for the Fuzhou River and Zhuang River, and industry for the Dengsha River. This methodology can provide useful information, such as environmental risk, environmental pressure, and extremely environmental impact, especially under considerations of uncertainties. It can also help to ascertain the significance of each pollution source and its priority for control in urban planning.     

Soil quality evolution after land use change from paddy soil to vegetable land

A survey was done in 15 typical villages, 150 soil and 86 vegetable plant samples were taken in Jiaxin prefecture of the Taihu Lake region, northern Zhejian province. Results indicate that after 15-20 years land use changed from the paddy rice-wheat (or oilseed rape) double cropping system, to a continuous vegetable land has caused soil quality dramatic change. (1) Acidification: average soil pH was 5.4; about 61% of total samples were pH < 5.5. It was 0.9 units lower than 10 years ago with same upland vegetable cultivation and was 1.2 units lower than soil pH of paddy rice-wheat (or oilseed rape) rotation. (2) Fertilizer salt accumulation: the average salt content was 0.28%, among these about 36.2% of the total samples contained more than 0.3%. (3) Nitrate N and available phosphorus (P) over accumulation: on average it was 279 mg NO3-N/kg, and 45-115 mg P/kg. Nitrate N four times higher and available P 4-10 times more than it is in present paddy rice-wheat rotation soils respectively. This has caused wide concern because of possible groundwater and well drinking water pollution by leached nitrate N and the P losses to water by runoff from vegetable lands induce surface water eutrophication.     

吉林西部土地利用/覆被时空变化驱动力分析

针对吉林两部土地利用/覆被情况,基于TM影像,借助人机交互解译方法,结合1:10万地形图获得1986年、1996年、2000年和2004年的4期土地利用/覆被变化(LUCC)矢量数据.利用土地利用动态度模型、土地利用转移矩阵.全面揭示研究区15年的LUCC时空变化特征,结果表明.盐碱地扩张,湿地、水域萎缩和草地退化已经成为吉林西部生态环境恶化的突出表现.结合研究区的实际情况选取总人口数、农业人口数、粮食总产置等12个指标作为LUCC:变化的丰十会经济驱动因子,借助多元线性回归模型,建立主要土地利用类型的驱动力模型.结果表明吉林西部土地利用变化的最主要社会经济因子是农业人口数、农民人均纯收入、农业生产技术(农业机械总动力、化肥施用量)和农村用电量,同时提出相应的生态环境保护和社会经济措施.     

盐池北部风沙区土地利用格局变化对沙漠化的影响

以盐池北部风沙区为研究区域,利用1989、1995、2000、2007年土地利用现状图,借助地理信息系统软件提取有关格局分析的基础数据,基于景观生态学原理,构造主要土地利用类型和沙地景观格局指数,探讨不同时段内盐池北部风沙区土地利用格局变化对沙化景观的影响。结果表明：（1）沙地景观在1995年之前不断扩张,1995年以后开始减少,集中连片沙地被零星分布的小沙化斑块取代;（2）林地和草地经历了先减少后增大的过程,土地利用格局变化中,中、低覆盖度草地和灌木林地变动性大;中、低覆盖度草地、耕地、灌木林地不稳定性程度较高;（3）受农作活动影响,尤其在灌溉条件较好区域,草地沙化明显,而灌木林能起到很好的防沙作用;（4）盐池北部风沙区土地利用格局特征指标与沙地面积呈负相关,随着特征指标增大沙化面积减小。土地利用格局变化能够综合反映相应时段内的人类活动结果,以此为切入点研究其对沙漠化的影响,有利于揭示沙漠化的驱动机制。