快速城市化背景下生态系统服务价值时空演变——以南京市为例

[目的] 分析南京市土地生态服务价值的驱动力影响,为科学地开展生态系统服务价值研究、生态保护与建设、城乡空间布局优化以及土地可持续发展提供重要依据。[方法] 基于江苏省南京市1990—2018年的土地利用数据,估算了各种土地利用类型的生态系统服务价值,分析了南京市生态系统服务价值的时空动态及其对土地利用变化和景观格局变化的响应。[结果] 1990—2018年,南京市建设用地面积变化最大,耕地次之,草地、林地和水域的变化较小,其中建设用地面积增加了105.67%,耕地面积减少了19.93%;南京市斑块密度由0.589 0下降至0.512 5,表明总体景观破碎度指数在持续降低;南京市总的生态系统服务价值总体呈下降的趋势,降低了8.13%,其中水域的生态系统服务价值的变化对总的生态系统服务价值影响最为显著。[结论] 随着南京市社会经济发展,人口对于生态系统服务价值时空变化的影响高于经济因素,人口因素日益成为影响南京市生态系统服务价值的主要驱动因素。     

基于土地利用变化的高阳县生态系统服务价值和碳排放风险研究

研究土地利用变化下区域生态系统服务价值和土地碳排放风险的变化,对于了解土地利用变化的生态环境响应,促进区域经济与环境的协调发展,实现低碳土地利用具有重要意义。以高阳县为研究区,基于2009年和2016年土地利用数据,利用网格法划分评价单元,运用模型法定量评价了生态系统服务价值和土地碳排放风险,并分析了时空演变特征,最后对二者进行了相关性分析。结果表明:2009—2016年高阳县土地利用变化特点为建设用地迅速扩张、水域等生态类用地大量减少;生态系统服务价值总体偏低且研究期间呈下降趋势,县域东中部地区整体高于西部地区;土地碳排放风险总体偏低但在研究期间呈上升趋势,县域中西部地区整体高于北部和东南部地区;土地碳排放风险与生态系统服务价值存在显著负相关关系,表明生态系统服务分析在土地利用碳排放研究中应用的可能。     

延河流域土地利用变化对其生态服务价值的影响

土地利用变化明显影响流域生态系统服务价值.本文在谢高地等制定的中国陆地生态系统服务价值当量表的基础上,结合延河流域土地利用变化情况和生态系统服务特征,完善了延河流域生态系统服务价值估算表,并以延河流域1990年、2000年和2006年土地利用数据为基础,估算了各年度的生态服务价值.分析表明:在16a间,延河流域生态服务价值总体有所提高,2006年比1990年生态服务价值增加了5.72亿元.敏感性分析表明流域内生态服务价值对生态服务价值指数是缺乏弹性的,研究结果是可信的.     

退耕还林对河北顺平县土地利用变化及生态系统服务价值的影响

退耕还林工程的实施,使区域的土地利用与生态环境发生了变化。为定量研究该区域退耕前后土地利用与生态服务价值的变化情况,本文应用Costanza生态系统服务价值计算公式和谢高地等人的中国陆地生态系统单位面积生态服务价值表,对顺平县2001-2008年土地利用变化对生态系统服务价值的影响进行了分析。结果表明:土地利用变化主要体现为耕地、其他农用地、未利用地的减少和园地、林地、建设用地和水域的增加;顺平县的生态系统服务价值在退耕还林期间呈逐年增加的趋势,其生态服务价值与总人口、GDP和农民人均纯收入均表现为显著正相关,反映出退耕还林工程对其生态、社会、经济等方面均起到了一定的积极作用。     

土地利用变化的人文驱动因子对新疆生态系统服务价值的影响

应用谢高地等人的生态系统服务价值系数,结合敏感度分析,探讨了1996-2008年新疆维吾尔自治区土地利用变化所引起的生态系统服务价值的变化,并进一步分析了土地利用变化的人文驱动因子对生态系统服务价值的影响。结果表明,该区域1996-2008年生态系统服务价值从7062.1671亿元增加到7168.987亿元,共增加106.8139亿元,表明该区域生态系统服务价值总体呈现持续增加趋势;在该区域生态系统服务价值中,废物处理价值最高,水源涵养价值次之,原材料价值最低,13a间各服务类型的价值总体上均呈增加趋势;新疆在13a间人均生态系统服务价值损失0.82万元,减幅达19.52%。这表明新疆地区由于人口的增长,环境压力呈持续增大趋势。影响新疆生态系统服务价值变化的人文因子可归纳为经济、人口和城市化水平因子,其中经济因子与生态系统服务价值呈正相关,而人口和城市化水平因子与生态系统服务价值呈负相关。     

重要水源地东圳水库水质变化及其影响因素研究

以地处喀斯特石山区的广西省河池市为例,以研究区单位面积农田生态系统在1988,1998和2003年提供的食物生产服务经济价值为基础,对研究区生态服务功能价值进行估算,并对照3个年份土地利用变化与生态服务功能价值的变化,找出了不同时段土地利用结构变化所引起的生态服务功能价值响应与变化特征.研究结果表明,1988-2003年河池市土地利用变化产生了较大的生态响应,生态服务功能价值总体上呈增长趋势;1988-1998年除了农田生态系统服务功能价值增长仅14.6%外,其它各类生态系统增幅都在25.9%以上;1998-2003年增幅明显减趋缓,草地生态服务功能价值则呈现急剧下滑状态,变化特征基本上与土地利用变化一致.河池市土地利用方式还需要进一步改善,尤其对面积广大的未利用地的生态改造和石漠化地区的生态恢复将会带来更大的生态效益.     

铜川市土地利用变化对生态系统服务价值的影响分析

土地利用类型及其结构的变化引起各类生态系统服务功能价值发生相应变化,应用Constanza生态系统服务价值计算公式,采用谢高地等人的中国陆地生态系统单位面积生态服务价值表,分析了2006-2011年铜川市土地利用的时空变化以及由此导致的生态系统服务价值的时空变化,并运用灰色系统分析方法对各土地利用类型与生态系统服务价值量变化的相关性进行了定量研究.结果表明:研究期内,研究区耕地、林地和建设用地增加,林地增加最多,而草地和未利用地急剧减少;研究区内土地利用程度存在明显的空间差异,其中王益区土地利用程度最大,宜君县最小;生态系统服务价值总量以及各类生态系统服务类型的价值量均呈上升趋势;关联度计算表明,研究区建设用地和林地的生态系统服务价值对生态系统服务价值总量的影响最大.     

喀什市生态系统服务价值对土地利用变化的响应及预测

[目的]通过研究喀什市土地利用变化对生态系统服务价值的影响,为土地科学利用管理决策提供参考。[方法]参考Costanza(1997)和谢高地(2008)等人的研究成果,结合喀什市的实际情况,采用生态系统服务价值计算公式和敏感度分析,通过研究喀什市1997—2010年生态系统服务价值对土地利用变化的响应,并针对喀什市土地利用总体规划(2010—2020年)中土地利用类型的变化,对生态系统服务价值进行预测分析。[结果]按规划发展,1997—2020年,喀什市土地利用结构变化较大。土地利用程度呈加大趋势,生态系统服务总价值则逐年减少,其中耕地、水域的生态服务价值持续下降。敏感性指数分析表明,喀什市生态系统服务价值对生态服务价值系数是缺乏弹性的,研究结果可信。[结论]在喀什市土地利用总体规划实施过程中,应注重提升土地节约和集约利用水平,优化土地利用结构,保持生态系统的平衡和稳定。     

浮梁县土地利用变化及驱动力分析

以江西省浮梁县作为研究区域,采用浮梁县1996-2005年的土地利用变更数据及社会经济统计数据,从土地利用数量变化、土地利用程度变化、土地利用效益变化3方面探讨了研究区域的土地利用变化特征,并运用主成分分析法对引起这些变化的驱动力进行了分析。研究结果表明:（1）耕地和建设用地是浮梁县土地利用数量变化的主要类型,土地利用程度和效益都有一定程度的提高,土地利用总体态势较好;（2）工业化、城市化水平的提高及人口的增长是引起土地利用变化的主要社会经济驱动力,但是城市化和工业化水平的提高是最为主要的驱动因素。     

甘州区土地利用格局变化及生态服务价值变化评价

生态系统服务功能价值评估研究是可持续发展评估研究的关键内容和焦点,通过分析甘州区土地利用及其变化,并在此基础上,对甘州区生态服务功能价值评价进行研究。通过研究分析,结果表明:2005~2020年间,甘州区土地利用格局变化总体趋势为少数几种土地利用类型占主导地位的情况得到缓解;土地利用均匀度指数略微有所升高,说明社会经济的发展较2005年相比更为平衡;土地利用多样化程度也稍有增加。而这一变化直接影响到生态服务功能价值的变化。甘州区生态用地的结构和布局规划合理,能够满足社会经济发展和生态建设对生态用地的需求。期望通过建立环境友好型土地利用模式,优化生态用地结构与强化土地生态功能,以确保生态安全目标的实现。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Collection and preliminary evaluation of native turfgrass accessions in Italy

Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Leaf position and genotype differences for mineral element concentrations in sorghum grown on tropical acid soil 1

Mineral element deficiencies and toxicities are common problems associated with sorghum [Sorghum bicolor (L.) Moench] production on acid soils. To better understand some of the mineral element problems and the analysis of plant tissue of sorghum plants grown on acid soils, four sorghum genotypes were grown on an acid Oxisol at Carimagua, Colombia limed with dolomite at 2 and 6 Mg ha^‐1.

Samples for mineral element analyses were obtained from leaves at different positions on the four genotypes. Concentrations of P and Mg were highest in the flag leaf (Leaf No. 1) and decreased as the position on the plant declined from the top of the plant for plants grown at 2 Mg lime ha^‐1. Similar decreases in P, Mg, K, and Zn concentrations occurred in plants grown with 6 Mg lime ha^‐1. Concentrations of Ca, S, Si, Mn, Fe, Cu, and Al increased as leaf position declined from the flag leaf for plants grown at 2 and 6 Mg lime ha^‐1. The higher lime supply enhanced Ca and reduced Mn and Fe concentrations in leaves. Differences in mineral element concentrations for the four genotypes used were fairly extensive. The elements to show the greatest range among genotypes were Al and Si and the elements to show the least range among genotypes were P, K, and S. Care should be used in collecting leaf samples for plant analysis and genotypic differences for accumulation of mineral elements should be considered in interpretation of results.     

Short-term variation in the concentration of selected ions within individual tropical rainstorms

Rainwater was collected at the campus of the University of Brunei Darussalam in Bandar Seri Begawan, Brunei Darussalam, using a funnel-in-bottle sampler. Polypropylene bottles were changed at intervals during rainstorm events. The pH and conductivity were determined immediately after collection on aliquots of the sample. Samples were refrigerated at 5°C for subsequent chemical analysis. Analyses for Na, Mg, Ca, Zn and Fe were carried out by means of inductively coupled plasma atomic emission spectroscopy (ICP-AES); Cu and Mn were analysed by graphite furnace atomic absorption spectroscopy (GFAAS); K was analysed using flame atomic emission spectroscopy (FAES); and Cl^–, NO₃ ^– and SO₄ ^2– were analysed by ion chromatography (IC). Concentration versus time profiles are reported for three rainstorm events. All ions exhibited a decrease in concentration during the rainstorm. The first sample contained the highest concentration of ions, consistent with a first-flush effect. The contribution of the initial stages of the shower to the total quantity of ion deposited during the entire rainstorm is quite overwhelming; in many cases 20 to 30% of the mass was deposited in less than 5% of rainstorm duration. On the other hand, the pH and conductivity variation during rainstorms did not exhibit a consistent pattern.     

Leaf litter selection by detritivore and geophagous earthworms

Summary Litterbag experiments with 10 different kinds of leaf litter showed that detritivore (Lumbricus species) and geophagous (Aporrectodea species) earthworms prefer certain litter types over others, since different numbers of worms were found below the litter after 50–52 days of exposure in a pasture. The detritivores preferred Fraxinus, Tilia, and predecomposed Ulmus and Fagus litter to Fagus litter and paper, while geophages preferred Tilia litter to Alnus and Ulmus litter, so that the two groups of earthworms showed different preferences. The detritivores seemed to be more selective than the geophages. The palatability of the litter was examined in relation to the C: N ratio, the lignin concentration and the initial and final polyphenol concentration. The numbers of detritivores were significantly correlated with the C: N ratio and the final polyphenol concentration, so that selection of litter seems to be related to palatability. The numbers of geophages were not significantly correlated with any of the parameters for palatability. The disappearance of litter after 50–52 days appeared to be due to detritivore activity, since the numbers found below the litter were positively and significantly correlated with the litter disappearance. There was no significant correlation with geophage activity. This indicates that detritivores use litter as food, and therefore influence the composition of the litter layer.     

The 5S rRNA gene diversity in the genus <Emphasis Type="Italic">Secale</Emphasis> and determination of its closest haplomes

We analyzed 127 rDNA sequences (5S DNA units) obtained from 23 seed accession samples from more or less 10 taxa in wild and cultivated rye, genus Secale L. The sequences fell into two known groups, here assigned to two unit classes, viz. long R1 and short R1 (designations to reflect on R haplome of rye). The different taxa could not be fully differentiated based on the 5S DNA units. We searched for 5S DNA sequences from known unit classes most closely similar to the long R1 and the short R1. One set with the long R1 unit class contained sequences of the long P1 unit class from Agropyron (P haplome) and from Kengyilia (StYP haplome), long J1 from Thinopyrum (J haplome), whereas the set with the short R1 included the long S1 from Pseudoroegneria (St haplome) and Kengyilia (StYP haplome), the short J1 from Thinopyrum (J haplome) and the short V1 from Dasypyrum (V haplome). Each of the two sets was analyzed separately by maximum likelihood (ML) phylogenetic analysis from which we were able to infer that the 5S DNA units of Secale differentiated in a non-clock fashion and followed the HKY substitution model in the gene tree with the long R1 unit class and the HKY + G in the gene tree with the short R1 unit class. A complementary Bayesian analysis yielded identical tree topologies to the ML ones for each of the two sequence sets. In the tree with the long R1 units the long P1 and long J1 unit classes were closest to the long R1 unit class, whereas in the tree with the short R1 units the long S1 and short J1 unit classes were closest to the short R1 unit class, indicating possibly a close relationship between the St, J and R haplomes.