广东省1980-2018年“三生”用地转型对生态环境质量的影响

[目的] 研究基于格网单元的广东省“三生”用地转型对生态环境质量的影响,为区域生态、经济协调发展提供科学依据。[方法] 基于广东省8期土地利用现状遥感监测数据和“三生”土地利用主导功能分类体系,对该区“三生”用地转型特征及生态环境质量进行定量研究。[结果] ①1980—2018年,广东省农业生产用地面积大幅减少,共减少了5 369.61 km²,城镇生活用地、工矿生产用地面积大幅增加,分别增加了4 526.02 km²,2 406.93 km²,农业生产用地和林地生态用地间转换现象明显。②“三生”用地空间转型主要表现为工矿生产用地、林地生态用地中心逐渐靠近广东省几何中心,农业生产用地、城镇生活用地中心逐渐远离几何中心。③广东省生态环境质量指数从1980年0.648 1降至2018年的0.641 4,生态环境质量空间分异明显,呈现“沿海低—内陆高”的分布特点。④Getis-Ord G_i^*指数表明,生态环境质量变化热点区域集中在粤东西北地区,冷点区域多位于珠江三角洲地区。⑤广东省生态环境存在改善和恶化两种趋势。[结论] 建议充分考虑区域自然条件、功能定位以及导致生态环境变化的主导因素,制定土地政策措施,实现土地利用方式创新,更好地推动广东省区域均衡发展。     

辽宁省抚顺市2000-2020年土地利用格局变化与生态环境效应

[目的] 探讨辽宁省抚顺市退耕还林以来土地利用格局时空变化特征及生态环境效应,揭示土地利用格局变化对环境的影响,为该区土地利用结构优化提供科学依据。[方法] 以2000,2010和2020年3期遥感影像为基础数据,通过土地利用动态度、土地利用程度综合指数、土地利用转移矩阵、NDVI差值分析、区域生态环境质量指数等方法定量分析抚顺市土地利用格局时空变化特征及生态环境效应。[结果] ①2000—2020年研究区各种土地类型存在相互转化的关系,其中林地和耕地变化较为明显。20 a间,耕地面积减少825.59 km²,增长率-7.32%;林地面积增加591.14 km²,增长率5.24%;城镇用地面积增加182.36 km²,增长率1.62%; ②2000,2010和2020年研究区土地利用程度综合指数分别为224.48,225.57和226.12,同比增长0.49%和0.24%,研究区土地开发利用强度缓慢上升; ③研究区20 a间植被覆盖整体呈上升趋势,NDVI减少的区域与城镇用地的扩张区域基本重合; ④3个时期土地利用类型转化的生态环境质量指数分别为0.744 8,0.775 4和0.782 6,10 a间环境质量生态指数分别上升4.11%和0.93%,环境质量整体呈上升趋势。[结论] 20 a间研究区快速推进城镇化进程的同时环境质量整体向好,局部范围内生态环境质量改善与恶化并存。城镇用地、耕地、林地之间的转化为主要原因,退耕还林等环境保护政策使研究区环境质量不断上升,但随着时间的推移,上升趋势趋于平缓。     

抚仙湖流域生态用地时空演变及其驱动因素

[目的] 研究生态用地时空演变规律及形成机制,为维持区域生态平衡和保障生态文明建设提供科学参考。[方法] 运用土地利用变化幅度、洛伦兹曲线、基尼系数、回归分析及GIS技术等方法,分析2010-2018年抚仙湖流域生态用地时空演变特征及其形成机理。[结果] ①抚仙湖流域生态用地以耕地、林地和水域及水利设施用地为主。8 a来,耕地面积减少5.15 km²,林地面积减少1.94 km²,草地面积减少0.81 km²,园地面积减少0.19 km²,其他土地面积减少1.40 km²,水域及水利设施用地面积增加0.03 km²。②流域各种生态用地空间分布差异较大,耕地、林地空间分布较均匀,洛伦兹曲线比较靠近绝对均匀线,基尼系数居0~0.25之间。草地、园地、水域及水利设施用地和其他土地分布相对集中,洛伦兹曲线下凹程度较大,基尼系数多处于0.5之上。生态用地空间分布不均的趋势有所加强。③从驱动机制来看,导致流域生态用地时空变化的主要驱动因素为人口密度、城镇化水平、政策、到主要公路距离、到水域距离、到城镇建成区距离。[结论] 研究时段内,抚仙湖流域生态用地时空变化较显著,其变化是自然条件、社会经济条件及空间区位条件多种因素协同作用的结果。     

黄河流域景观生态风险分析及预测

[目的] 探究黄河流域近20 a土地利用变化并对2030年土地利用进行预测,分析景观格局指数,揭示生态风险状况,助力黄河流域景观保护修复和规划治理。[方法] 使用FLUS模型,根据2000,2010,2020年土地利用数据,结合社会、经济、地形、气候等因子对该区2030年土地利用状况进行预测,通过景观指数构建景观生态风险指数,并进行深入分析探讨。[结果] ①2000—2020年耕地面积减少12 150 km²,林地面积增加2 514 km²,建设用地面积增加10 620 km²。②黄河流域优势景观为草地和耕地,但优势性逐渐降低,整体景观连通性增加、聚集性减弱,景观多样性呈增长趋势,但整体仍不均衡。③工作区景观生态风险以低、较低风险为主,中风险为辅,共占该区总面积88%以上,各生态风险区在空间上相对稳定,在时间上呈逐步恶化趋势。④预测2030年建设用地面积增速减缓,耕地、草地、未利用地面积继续减少,景观破碎度增加,低、较低生态风险区域增加1.12%,高风险区域增加0.26%,其余风险区域变化较小。[结论] 国家人口增长、城市逐步扩张对土地利用影响巨大,进而导致景观破碎,加之黄河流域环境脆弱,风沙强度大,荒漠化程度高,区域生态风险增高,需要国家更加关注该区域的生态保护和高质量发展。     

基于“三生”空间的重庆市土地利用演变与城镇化关系研究

[目的] 分析重庆市土地利用时空演变规律,探究土地利用转型及景观格局响应的演变特征与城镇化的关系,为重庆市"三生"土地规划与城镇化可持续发展提供数据支持。[方法] 基于"三生空间"功能分类的视角构建用地分类标准,利用2000,2010,2020年土地遥感影像和夜间灯光数据,采用转移矩阵、相关性分析及回归分析法进行分析。[结果] ①2000-2020年重庆市生产、生态空间总体减少,生活空间持续扩张。2000-2010年,生产、生态空间减少191.87,252.95 km²,生活空间增大446.03 km²;2010-2020年,生产空间面积减少13.76 km²,生态空间减少324.05 km²,生活空间增大314.87 km²。②重庆市生产功能向生活功能转化较为明显。随着城镇化加强,生态空间转向生产空间显著,功能转变明显聚集于重庆市中心区域。③重庆市空间景观破碎度减小,景观复杂度逐渐提高,林草水生态空间占据主导优势。④2000-2010,2010-2020年土地利用面积变化对夜间灯光值的影响存在差异;2000年,城镇生活空间、农村生活空间变化对夜间灯光变化影响起主导作用,而2020年工业生产空间、城镇生活空间变化对夜间灯光变化影响较强。[结论] 重庆市各类空间发生相互转换,利用不同"三生"空间类型变化和城镇化的关系,推动土地规划与城镇化协调发展。     

生态工程对科尔沁沙地主要生态服务功能的影响

[目的] 研究生态工程实施下科尔沁沙地主要生态服务功能的变化特征,为该区今后生态保护建设提供科学依据。[方法] 运用已有的生态服务评估方法定量评估了2001—2018年科尔沁沙地固碳量、水源涵养及水土保持服务功能的时空变化情况。[结果] ①科尔沁沙地土地利用类型主要以耕地、林地和草地为主,生态工程实施期间,林地、耕地面积分别增加8 448 km²,3 280 km²,草地面积减少12 639 km²; ②科尔沁沙地固碳量稳步增长,林地和耕地的固碳量均增加,草地的固碳量减小,但草地固碳量依然最高; ③科尔沁沙地水源涵养量呈先增加后略微减少的趋势,所有土地类型中林地水源涵养量持续升高; ④科尔沁沙地水土保持量持续上升,约增加1.38×10⁷ t,林地水土保持量增加最显著。受地势的影响,区域水土保持总量呈西高东低的分布特征。[结论] 科尔沁沙地生态工程建设效果良好,创造了显著的生态效益。     

1986—2020年黄河流域十大孔兑土地利用变化及驱动力分析

[目的] 十大孔兑是黄河几字湾的重要组成部分,生态环境敏感脆弱,开展其土地利用变化与驱动力分析对黄河流域高质量发展具有重要生态意义。[方法] 对十大孔兑基于1986年、2000年、2010年、2020年4期遥感影像,运用ArcMap 10.8空间分析法和主成分分析法系统分析其土地利用变化情况及驱动因素。[结果] 林地、建设用地、耕地呈逐期扩张趋势,未利用地、草地、水域呈逐期缩减趋势,截至2020年林地成为占地面积最大地类,面积达6 308.43 km²,占总面积的59.99%。2010—2020年综合动态度最高,达1.59 %,表明土地利用变化在2010—2020年变化最为剧烈。平原区地势平坦,耕地和建设用地在此扩张明显;风沙区在生态治理政策与工程作用下,未利用地向林草地转变,在风沙区东部尤为明显,而在风沙区中部则小比例转变为光伏发电建设用地;丘陵区主要由未利用地转变为林地,由于区域工矿业发达,丘陵区东南部极小部分林地转变为城乡工矿建设用地;水域在孔兑内部共减少75.81 km²,而耕地除北部平原区扩张外,在孔兑沿岸增加明显。土地利用变化主要受社会经济、农业生产力、地势、政策驱动变化。[结论] 近35年来,十大孔兑土地利用变化较大,整体生态向好的方向发展较为明显。该研究结果可为决策部门制定黄河流域生态保护政策提供科学参考。     

额尔齐斯河流域土地利用变化对生态系统服务价值损益时空演变的影响

[目的] 评估土地利用变化与生态系统服务价值损益之间的关联效应,为制定适宜的土地干预政策提供科学依据。[方法] 基于5期额尔齐斯河流域土地利用数据以及CLUE-S模型,量化土地利用变化下流域生态系统服务价值损益时空演变规律。[结果] ①2000—2018年额尔齐斯河流域草地和林地持续地转化为其他土地,耕地面积大幅度增长;到2030年,流域耕地面积的比例将上升4.92%(1 502.48 km²上升到4 070 km²),而林地呈现快速下降趋势,所占比例将下降7.18%(由7 547.26 km²减少到5 424.36 km²)。②额尔齐斯河流域生态系统服务价值由2000年的518.16亿元增长到2018年的1 832.44亿元,到2030年,生态系统服务价值处于波动下降趋势(2030年为1 777.86亿元); ③林地和草地被耕地所占用,导致额尔齐斯河流域生态系统服务价值损失预计达到108.80亿元,依次为：草地转换损失(34.39亿元)>林地转换损失(28.49亿元)>水域转换损失(18.31亿元)。④额尔齐斯河流域生态系统服务价值损益空间分布呈现“北高南低”的发展格局,价值损益在全局和局部上均呈现显著的正向空间自相关。[结论] 人为因素导致大量生态用地被占用,生态系统服务价值下降且损益空间异质性显著,需要进一步采取有效的生态保护与补偿政策推动农牧户生计转型,减小对自然环境的依赖性。     

湖南省重点生态功能区生境质量时空变化及其预测

[目的] 对湖南省南岳重点生态功能区土地利用变化及生境质量开展研究,揭示人类活动导致的林地减少与生境质量之间的关系,为该地区生态保护与经济建设的协调发展提供理论支持。[方法] 基于2009,2012,2015,2018和2021年5期土地利用变更数据得到土地利用转移矩阵,借助InVEST模型和CA-Markov模型分析预测南岳重点生态功能区土地利用结构及生境质量时空分布特征,并运用双变量空间自相关分析方法探究林地与生境质量两者的相关性。[结果] ①2009—2021年研究区林地和耕地主要转出为建设用地;建设用地面积增加15.87%,其中45.37%,36.25%分别由林地和耕地转入。②2009—2021年该地区生境质量呈现出“先快后慢”的持续下降趋势和“西部高,东南低”的空间分布特征。③研究区林地与生境质量在空间分布上的正相关性逐渐增强,以林地和优等生境质量的高高聚集为主要表现类型。④南岳区2025年建设用地将增加4.36%,2030年建设用地面积将达到1 563.53 hm²;未来生境质量将缓慢下降。[结论] 生境质量变化与人类活动干扰导致的林地减少,建设用地扩张紧密联系,应加强对南岳重点生态功能区的资源与环境管控。     

马来西亚吉隆坡市土地利用变化特征分析与预测

[目的] 揭示快速城市化过程中港口城市土地利用景观格局变化规律,为当地编制土地利用规划提供科学依据。[方法] 以马来西亚吉隆坡市2000,2005,2010,2015,2020年5期遥感影像为基础数据,基于交互式数据语言（IDL）,采用指数分类法提取土地利用信息,并应用RS,GIS技术和景观生态学方法对吉隆坡市2000—2020年土地利用景观格局变化进行研究,最后采用灰色预测模型预测2025年吉隆坡市土地利用数据。[结果] 2000—2020年吉隆坡市种植园和林地大幅减少,建设用地迅速增加,港口与城市圈中部区域种植园主要转化为建设用地;土地利用景观形状趋于复杂化、不规则化,景观类型空间连通性降低,景观异质性增强;2025年吉隆坡市建设用地和种植园面积分别为1 624.12 km²和2 216.99 km²,与往年相比,建设用地增加,种植园减少。[结论] 2025年吉隆坡市土地利用类型仍主要以种植园为主。宏观来看,随着城市的快速发展,种植园的数量持续减少。未来发展规划需进一步合理规划土地利用方式,提高土地利用效率,加大对种植园的保护力度。     

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。     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

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.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

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 from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

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 from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

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 from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.