KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 巴音布鲁克草原甘肃马先蒿种群扩张的生态因子研究 | |
| 柳妍妍 | |
| Subtype | 博士 |
| Thesis Advisor | 管开云 ; 田长彦 |
| 2018-06-05 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 理学博士 |
| Keyword | 巴音布鲁克 根部半寄生植物 生态因子 养分 扩张 Bayanbulak Root hemiparasite plant Ecological factor Nutrient Expandsion |
| Abstract | 巴音布鲁克草原作为开都河源头、新疆南疆水源涵养地以及很多濒危珍稀鸟类的主要栖息地，在生态上具有举足轻重的地位。但自 2000 年起，本地种甘肃马先蒿（Pedicularis kansuensisMaxim.）在此区域大量出现并以每年 3.3×103 ha 的速度迅速扩张，给当地畜牧业带来了极其严重的危害。为此，巴音郭楞蒙古自治州政府和中国科学院巴音布鲁克草原生态研究站开展了包括化学防除的甘肃马先蒿的防治措施，但由于该物种的根部半寄生特性，其防治效果很不理想，且存在一定的环境风险和隐患。鉴于此，本论文拟从甘肃马先蒿的根部半寄生特性入手，研究甘肃马先蒿的土壤种子库分布规律、水分对土壤种子库的影响以及刈割、物种移除、养分添加和模拟增温对其发生及所在群落物种及土壤养分的影响；通过与青海省分布区的对比，研究甘肃马先蒿发生区与非发生区群落结构及土壤养分差异，试图找出甘肃马先蒿种群迅速扩张的主要生态因子，以期为甘肃马先蒿的综合防治提供理论依据。研究结果表明：（1）甘肃马先蒿种子比较小（千粒重为：0.64±0.02 g），通过种子或地下休眠芽越冬，易于风传播，单株结实率很高，每株可产生 600-2000 粒种子，说明其繁殖能力极强；室内模拟发芽实验表明 5 月下旬和 6 月上旬为甘肃马先蒿种子在巴音布鲁克草原的最佳萌发时期；距离水源越近，甘肃马先蒿分布越多，其种子数量也越多，土壤中甘肃马先蒿种子数量与土壤含水量存在极显著正相关关系，说明土壤含水量是影响甘肃马先蒿水平分布及生长发育、繁殖和扩散的关键因素之一；土壤种子库中种子数量的垂直分布表现为：枯落物层>腐殖质层>心土层，其中壤土枯落物层甘肃马先蒿种子含量最高（16941±5877 粒），其次为沙土>砾石>沼泽。（2）在刈割和非刈割（对照）处理中土壤养分各因子间及群落物种组成间均无差异；刈割对禾本科和杂类草植物物种数和盖度的影响均不大，但刈割会明显降低甘肃马先蒿种群盖度；刈割处理在降低地上总生物量的同时也会有效降低甘肃马先蒿生物量；围封可显著提高禾本科植物地上生物量，同时可抑制甘肃马先蒿种群扩张。（3）在移除甘肃马先蒿和有/无甘肃马先蒿自然分布的样方中，试验前后样方中的土壤养分无差异，物种数和盖度差异不明显；但甘肃马先蒿的发生降低了禾本科植物所占的比例，但对非禾草类杂草影响不大；无甘肃马先蒿分布样方在试验进行的第二年又有甘肃马先蒿出现，且所占比例和有甘肃马先蒿自然分布的样方相当，说明甘肃马先蒿种群蔓延具有移动性。（4）不同区域甘肃马先蒿发生区和非发生区植物功能群叶片碳含量、氮含量和磷含量及土壤养分之间均无差异性；发生区的物种数明显高于非发生区的，且最高值均出现在称多点，而 Shannon-Wiener 指数和均匀度指数除巴音布鲁克点外，在其余三个点的发生区均高于非发生区；除麦秀点外，其余三个点均表现为发生区禾本科地上生物量低于非发生区，而发生区的总生物量基本上均高于非发生区的，宁秀点除外。（5）添加氮和磷元素对土壤养分的影响不大；磷添加可显著改变植物营养平衡，而氮的添加却显著改变了[P|N]，但对[Fv|C,P,N]间的平衡影响较小，杂类草和甘肃马先蒿比禾本科植物具有较高的[C|P,N]（p≤0.05）；添加氮元素可显著降低甘肃马先蒿盖度和地上生物量，增加禾本科盖度和生物量，不过其基本不受磷元素的影响；氮添加可显著降低杂类草植物物种数。（6）与对照相比，增温显著提高了甘肃马先蒿的生物量向花分配；增温对甘肃马先蒿地上部分生长有抑制作用，同时可限制较小个体根系的发展，但随着个体大小的增大逐渐对根系生长起促进作用；距离水源越近，甘肃马先蒿密度、盖度和生物量越高；土壤含水量与甘肃马先蒿密度呈极显著正相关，禾本科植物和非禾本科杂类草植物受水分影响相对较小；随土壤含水量的降低，甘肃马先蒿所在群落均匀度指数差异明显，但物种多样性指数无明显变化。综上所述，巴音布鲁克草原气温的不断上升提前了甘肃马先蒿种子的萌发时间，同时也会推迟甘肃马先蒿的结实时间。甘肃马先蒿原本属于分布在巴音布鲁克海拔较高地带的本地种，但由于近些年巴音布鲁克草原积雪的短期快速融化，导致其随雪融水移向低海拔。距离河流越近，土壤中甘肃马先蒿种子分布越高，盖度和也生物量也越高。施肥和刈割均会显著降低甘肃马先蒿在其所在群落所占比例，尤其是在高氮水平下甘肃马先蒿几乎消失，但短期的甘肃马先蒿移除对其种群盖度和生物量的影响较小。所有处理在围封两年后甘肃马先蒿盖度和生物量均有显著降低，说明甘肃马先蒿之所以能在巴音布鲁克草原迅速蔓延，与牲畜的过度啃食有很大关系。同时又因其为根部半寄生植物，地上植被盖度的降低可提高甘肃马先蒿在其所在群落中对光的竞争能力，地上部分啃食过大时植物处于保护策略会加大地下根系的投资，对甘肃马先蒿吸器的着生更有利。此外，甘肃马先蒿强大的土壤种子库和极强的繁殖能力均为它的迅速扩张提供了有力保障。 |
| Other Abstract | As the source of Kaidu river, special water conservation in northern Xinjiang and manyendangered and rare birds’ main habitat, Bayanbulak grassland plays a very importantrole in ecology. But since 2000, native species Pedicularis kansuensis Maxim. occurredhere and had been expanding rapidly, threatening the local livestock industry. Therefore,the local government and Bayanbulak grassland research station of Chinese academy ofscience together conducted several methods on P. kansuensis Maxim. control includechemical control, but the effect was not ideal because of its root hemiparasitism.Furthermore, chemical mearsure also existed certain risks and hidden dangers becauseof the Bayanbulak grassland’s special geographic and ecological position.According to the failure control before, we proceeded with its hemiparasiticpeculiarity in this experiment. Therefore, we laied belt transect perpendicular to theriver, and took samples in different soil texture to obtain the seed’s distribution andregularity in different soil, conduct clipping, removing P. kansuensis Maxim. speciesbiotic factor experiments and nutrient addition, warming and along the soil watergradient abiotic experiments, to obtain the change and compose of community and soilnutrient before and after the experiments, the difference between them, and comparedwith distribution areas of Qinghai Province, to research the soil nutrient differencebetween infected areas and non-infected areas, and attempt to find out the mainecological factor of P. kansuensis Maxim.’ expanding and hoping to provide theoreticalbasis on P. kansuensis Maxim. integrated control. The results showed that:(1) P. kansuensis Maxim. seeds was very small (thousand seed weight was 0.64±0.02 g), easy to spread by wind, and had higher fructification percentage, each ofindividuals could produce more than 600-2000 seeds, it meant that they had strongerfecundity, laboratory simulation showed that the best germination period of P.kansuensis Maxim. seed was in late May and early June; the closer the source of water,the more P. kansuensis distribution, and the more seeds there were. There was asignificant positive correlation between the number of seeds of P. kansuensis Maxim.and soil water content, it meant that soil water content was one of the key factor in P.kansuensis Maxim.’s growth, production and spatial expansion; the vertical distribution of soil seed number turned out that: the litter layer>humus layer>subsoil layer, and thehighest number of P. kansuensis Maxim. seed turned up in the litter layer of loam, thenwere sandy soil, gravel and marsh, respectively.(2) There was no difference between clipping and non-clipping treatment’s soilnutrient factors and the species composition of community; clipping had little effect onthe species number and coverage of graminoids plant and forbs, but reduced P.kansuensis Maxim. coverage obviously; mowing treatment could also reduce the totalaboveground biomass of P. kansuensis Maxim. while reducing the total abovegroundbiomass. Enclosure could increase the biomass of graminoids plant significantly,suppress the expansion of P. kansuensis Maxim. meanwhile.(3) There were no difference among removed P. kansuensis Maxim., parasitizedand non-parastized treatments’s soil nutrient; there were no obvious difference in threetreatments’s species number and coverage; the occurance of P. kansuensis Maxim.would decrease the graminoids proportion in its community, but had no influence onforbs; P. kansuensis Maxim. turned up again in the non-parastized plots in the secondgrowing season, and its ratio in total coverage was just like the parasitized plots, itshowed that P. kansuensis Maxim. was spreading movability, and its seeds hadover-year living peculiarity meanwhile.(4) Influence of soil nutrient status and leaf carbon content, nitrogen content andphosphorus did not have a clear pattern on occurrence and expansion of the roothemiparasite, respectively; total aboveground plant biomass in heavily-infected areaswere generally higher than non-infected areas, despite of the parasitism by a largenumber of P. kansuensis Maxim.; aboveground biomass of P. kansuensis Maxim.negatively correlated with graminoid aboveground biomass, but positively correlatedwith that of forbs; P. kansuensis Maxim. occurred more frequently ingraminoid-dominated areas. More studies are required for a better understanding of thedriving forces for spatial expansion of the damaging root hemiparasite.(5) Although fertilization showed marked influence on plant foliar elementconcentrations and dramatically altered N:P ratios in the first growing season, effects offertilization on plant community composition and productivity became robust only inthe second season. Dramatical suppression of the hemiparasite was observed in blocksfertilized with nitrogen (particularly HN). Fertilization with phosphorus had nosignificant influence on plant density and canopy cover of the hemiparasite, butsignificantly reduced its above-ground biomass. HN significantly reduced plant diversity, with the species number of forbs being halved while that of graminoids hardlyaffected. Other fertilization regimes showed no notable influence on plant diversity.Fertilization with both nitrogen and phosphorus showed marked promoting effects onplant productivity, particularly above-ground biomass of graminoids. Competition fromthe vigorous growth of graminoids that benefited more from the imbalanced N:P ratiosdue to fertilization may explain the suppression of P. kansuensis Maxim. and the alteredsurrounding plant community.(6) There existed highly significant difference between warming and CK’s flowerallocation and stem leaf allocation of P. kansuensis Maxim.; warming surpressed P.kansuensis Maxim. aboveground part certainly, and would limit the growth of thesmaller individuals roots, but would play a driving role in roots growing with theenlargement of the individual; the closer the source of water, the higher of P. kansuensisMaxim. density, coverage and biomass; soil water content significant positivelycorrelated with P. kansuensis Maxim. density, the influence of soil water content ongraminoids and forbs was relatively small; the difference of community evenness indexwere evident with the decreasing of soil water content, but species diversity index hadlittle change.Above-mentioned results, we had the following conclusion: global warming is anindisputable fact, the germinate time of P. kansuensis Maxim. seeds was ahead of timewith the warming, and prolonged its period of duration meanwhile. Extreme weathertook place frequently made Bayanbulak accumulated snow melt rapidly in short-term. P.kansuensis Maxim. mainly distributed in higher altitude zone of Bayanbulak originally,but it removed to lower altitude with the snowmelt. Overgrazing led to poor soilnutrients, but it had no influence on P. kansuensis Maxim. population because of itspeculiarity of root hemiparasite, and it had the superiority to survive in the barren soil,overgrazing of livestock has significantly reduced the amount of coverage aboveground,plants increased the investment of belowground biomass. Underground, P. kansuensisMaxim. haustoria produced successful in favour of a large number of roots;aboveground, P. kansuensis Maxim. competed for light with its host plants was in adominant position because of the lower coverage. At the same time, both the powerfulsoil seeds and highly fertility of P. kansuensis Maxim. provided strong supporting for itsspreading rapidly. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14930 |
| Collection | 研究系统_荒漠环境研究室 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 柳妍妍. 巴音布鲁克草原甘肃马先蒿种群扩张的生态因子研究[D]. 新疆乌鲁木齐. 中国科学院大学,2018. |
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