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1.
沙地云杉小树高生长与环境条件关系的数量化模型   总被引:7,自引:0,他引:7  
沙地云杉小树高生长与环境条件关系的数量化模型郑元润徐文铎(中国科学院植物研究所,北京100093)(中国科学院沈阳应用生态研究所,110015)TheModelsofRelationshipbetweenHeightGrowthofPiceamong...  相似文献   

2.
内蒙古白音敖包自然保护区沙地云杉林的基本特征、存在问题与解决途径徐文铎(中国科学院沈阳应用生态研究所,110015)BasicCharacteristics,ExistingProblemsandTheirSolutlonsforSpruceForestonSandlandofBaiyi-naobaoNaturalReserve,InneerMongolia¥XuWenduo(InstituteofAppliedEcology,AcademiaSinica,Shenyang1100l5)(ChineseJournalofEcology,1993,12(5):39-44.Spruceforestonsandlandisaspecialtypeofterrestrialforestecosystem,whichonlyexistsattheedgeoftheXiaotengelideserthInnerMongolia,Mongoliafloraisthedominantspeciesintheforest,whichalsoincludesXinganandNorthChinaflora,Thecomposi  相似文献   

3.
酸雨和SO2暴露对一些不同抗性幼树的影响   总被引:10,自引:0,他引:10  
酸雨和SO2暴露对一些不同抗性幼树的影响陈树元徐和宝谢明云张福珠苗鸿张宏瑞(江苏省中国科学院植物研究所,南京210014)(中国科学院生态环境研究中心,北京100085)EfectsoftheAcidRainandSulfuricDioxideExp...  相似文献   

4.
三江平原沼泽生态系统(疏干)演替对土壤动物的影响   总被引:3,自引:0,他引:3  
孙帆  吕宪国 《生态学杂志》1994,13(2):30-33,39
三江平原沼泽生态系统(疏干)演替对土壤动物的影响孙帆,赵红音吕宪国,杨青(东北师范大学地理系,长春130024)(中国科学院长春地理研究所,130021)ImpactofSwampEcosystemSuccessioninSanjiangPlaino...  相似文献   

5.
柞蚕林生物生产力和干物质转化研究   总被引:5,自引:0,他引:5  
柞蚕林生物生产力和干物质转化研究温达志,杨思河(中国科学院华南植物研究所,广州510650)(中国科学院沈阳应用生态研究所,110015)姜波(辽宁省蚕业科学研究所,凤城118101)BioproductivityandDryMatterTransferofTussah-FeedingOakForest¥WenDazhi(SouthChinaInsti-tuteofBotany,AcademiaSinica,Guangzhou510650),YangSihe(InstituteofAppliedEcology,A-cademiaSinica,Shenyang110015),JiangBo(InstituteofSericulturalScience,Fengcheng,LiaoningProvince113100).ChineseJournalofEcology,1993,12(1):5-10.ThepresentstudydealswiththebioproductivityanddrymattertransferofChineseTussah-feedingoakforestinhillyareaofe  相似文献   

6.
试论景观的动态变化   总被引:12,自引:0,他引:12  
试论景观的动态变化孙中伟(中国科学院沈阳应用生态研究所110015)OnResearchesofLandscapeDynamicCkange.¥SunZhongwei(InstituteofAppliedEcology,AcademiaSinica,...  相似文献   

7.
沙地云杉种群种子雨的时空分布规律   总被引:13,自引:1,他引:12  
沙地云杉种群种子雨的时空分布规律邹春静徐文铎(中国科学院沈阳应用生态研究所,110015)刘广田(内蒙古白音敖包自然保护区,025375)TheSpatial-TemporalDistributionofSeedRaininPiceaMongolic...  相似文献   

8.
诌议土壤盐渍化的生态防治   总被引:25,自引:1,他引:24  
诌议土壤盐渍化的生态防治王春裕(中国科学院沈阳应用生态研究所,110015)DiscusiononEcologicalControlofSoilSalinization.WangChunyu(InstituteofAppliedEcology,Aca...  相似文献   

9.
第三届亚大地区生理学大会1994年11月在沪召开蔡坤华(中国科学院上海生理研究所200031)亚大地区生理学联合会(dederationofAsianandOceanianPhysiologicalSocietices,FAOPS)系隶属于联合国教科...  相似文献   

10.
无性系植物种群生态学研究进展及有关概念   总被引:74,自引:5,他引:69  
无性系植物种群生态学研究进展及有关概念刘庆钟章成(中国科学院成都生物研究所,610041)(西南师范大学生物系,重庆630715)AdvancesinEcologicalResearchofClonalPlantPopulationandSomeRe...  相似文献   

11.
沙地云杉种群增长预测模型研究   总被引:26,自引:2,他引:24       下载免费PDF全文
 本文以沙地云杉种群的静态生命表、生殖力表为基础,运用Leslie种群增长模型,预测了小腾格里沙地白音敖包地区有代表性的藓类云杉林中云杉种群的动态增长过程,揭示了沙地云杉各龄级植株的动态规律。结果表明:沙地云杉为缓慢增长型种群;种群的净增殖率、内禀增长率及周限增长率较高,而种群的世代周期及加倍时间偏低;在50年内种群1年生幼苗的数量及种群的总数量表现出持续递增的趋势,且种群总数目的变化幅度较小。  相似文献   

12.
沙地云杉种群调节的研究   总被引:12,自引:0,他引:12       下载免费PDF全文
 本文运用种群密度调节的-3/2原则研究沙地云杉种群的自疏过程,模拟种群密度变化的动态规律。由于可塑性生长的影响,不同林型中沙地云杉种群的平均胸径、单株平均干重与种群密度关系之间的变化幅度也不相同,但都表现出幂函数的变化特征。运用主成分分析的方法探讨影响沙地云杉种群密度调节的主要因素,表明影响沙地云杉种群自疏过程的主要因子为:坡向、群落类型、坡位、土壤含水量、海拔、土壤平均容重、针叶密度7个因子。分析了沙地云杉种群自疏过程的机制及其在种群密度管理中运用的可能性,对沙地云杉种群的经营管理具有重要的理论与实践意义。  相似文献   

13.
Aim The objectives of the study are: (1) to evaluate the dynamics of the maritime tree line and forest limit of white spruce, Picea glauca, within the dual framework of primary succession induced by the rapid post‐glacial land emergence on the eastern coast of Hudson Bay and the impacts of recent and past climate changes; and (2) to determine the time lapse between land emergence and seedling, tree, and forest establishment in the context of the primary chronosequence occurring on rising, well‐drained sandy beaches and terraces. Location The study area was located on the eastern coast of Hudson Bay (56°20′ N, 76°32′ W) in northern Québec, Canada. Methods We evaluated the colonization dynamics of white spruce as seedlings, tree‐line trees and primary‐forest trees at eight sites distributed along a 200‐km latitudinal gradient based on a mean land emergence rate of 1.2 m century?1. A 30‐m wide by 140–300‐m long quadrat was positioned at random at the centre of each site. The elevation above sea level, position and age of all individuals of spruce present in the quadrat areas were determined, and the soils of each chronosequence were described. Results The main stages of primary succession along the emerging coast were common to all the sites, regardless of latitude, but occurred at different elevations above sea level (a.s.l.). White spruce seedlings colonized near‐shore beaches 2 m a.s.l., whereas the tree line and forest limit tended to form only at about 3–4 m and 4–8 m a.s.l., corresponding approximately to 180–825 years and 310–1615 years after land emersion, respectively. White spruce establishment at the tree line occurred about 50 years ago. Climatic conditions at this time were probably more favourable to tree colonization than when the species established at the forest limit. Soil formation was influenced primarily by distance from the seashore and elevation above sea level, with podzolization being accelerated by white spruce cover. Main conclusions The current tree‐line and forest‐limit positions on the rising coast of eastern Hudson Bay correspond to ecological limits established during the course of primary succession within a context of changing climatic conditions. The recent establishment of trees at the tree line and forest limit at relatively old coastal sites is associated with warmer conditions over the last 100 years. Although white spruce was present nearby, coastal sites were devoid of trees before the 20th century.  相似文献   

14.
Questions: How to evaluate the mixture effect on basal area increment in two‐species forest stands? Is a mixed Norway spruce–silver fir stand more productive than pure adjacent stands of either species? How to develop generic modelling approaches to assess mixture effects in forest stands? Location: In addition to a case study on Norway spruce–silver fir stands in French mountain forests, the generic approach used goes beyond local applications. Methods: We took advantage of National Forest Inventory data to develop a unique stand basal‐area‐increment model for pure and mixed stands of Norway spruce and silver fir that responds to ecological site conditions. The database was made up of 284 pure Norway spruce stands, 196 pure silver fir stands, and 323 mixed stands of these species. Results: Pure silver fir basal area increment is strongly influenced by spring climatic conditions, whereas pure Norway spruce is more influenced by soil conditions. The mixture of these species has a positive effect on silver fir, which decreases as the proportion of fir increases. In contrast, the mixture has no noticeable effect on Norway spruce. Conclusion: We developed a stand basal‐area‐increment model evidencing an advantage of the mixture on silver fir basal area increment, but not on Norway spruce. The mathematical formulation of the model developed is generic and can be used in all two‐species mixture situations. It also makes it possible to compare different mixture situations with each other.  相似文献   

15.
The boreal forest is the largest terrestrial biome in North America and holds a large portion of the world’s reactive soil carbon. Therefore, understanding soil carbon accumulation on a landscape or regional scale across the boreal forest is useful for predicting future soil carbon storage. Here, we examined the relationship between floristic composition and ecosystem parameters, such as soil carbon pools, the carbon-to-nitrogen (C/N) ratio of live black spruce needles, and normalized basal area increment (NBAI) of trees in black spruce communities, the most widespread forest type in the boreal forest of Alaska. Variability in ecosystem properties among black spruce stands was as large as that which had previously been documented among all forest types in the central interior of Alaska; we found an eightfold range in NBAI and fivefold range in mineral soil carbon and nitrogen pools. Acidic black spruce communities had significantly more carbon in the organic soil horizon than did nonacidic black spruce communities, but did not differ in any other measured ecosystem parameter. We explained 48% of the variation in total soil carbon with a combination of plant community indices and abiotic and biotic factors. Plant community composition was at least as effective as any single environmental factor or stand characteristic in predicting soil C pools in Alaskan black spruce ecosystems. We conclude that among the community properties analyzed, the presence of key groups of species, overall species composition, and diversity of certain functional types, especially Sphagnum moss species, are important predictors of soil carbon sequestration in the black spruce forest type.  相似文献   

16.
Question: How rapidly has the sandy beach and maritime forest vegetation on Phuket recovered and regenerated after the impact of the major Indian Ocean tsunami of 2004? What are the characteristics of sandy beach species for regenerating their populations and the invasion patterns of originally non-sandy beach species or other newcomers after the tsunami? Location: Phuket Island, southern Thailand. Methods: Species composition of beaches was studied on the same research plots 6 months before and 9 months after the tsunami. The changes in individual species cover before and after the tsunami were determined by χ2 tests. Change in community composition was analysed by detrended correspondence analysis. The relationship between species and environmental factors was analysed by canonical correspondence analysis. Results: The sites disturbed by the tsunami were often invaded by annuals, especially grasses and asteraceous plants, rather than by perennials. In contrast, species with clonal growth by stolons decreased significantly. Factors determining the species habitat differences were soil hardness (penetration resistance of sandy soil), per cent silt content, soil water content and beach management. Habitat differences among originally non-sandy beach herbaceous species that expanded their population or moved to the coast after the disaster were defined by sand accretion or erosion caused by the tsunami. Many sandy beach herbaceous communities changed into Dactyloctenium aegyptium communities because of the tsunami were originally constituted by non-sandy beach D. aegyptium with Cenchrus echinatus. Although the forest floors of most maritime forests were invaded by originally non-sandy beach Tridax procumbens, Eleusine indica or D. aegyptium because of the tsunami, this did not result in a change in the vegetation unit, because species' loss was restricted to the understorey. In time, these forests will recover their previous community composition. Conclusions: Our results suggest that originally non-sandy beach native species invaded the disturbed beaches rapidly after the tsunami but their habitats differ. Sites where sand accumulated on a beach because of the tsunami were invaded by D. aegyptium and E. indica, whereas soil erosion permitted invasion by Digitania adscendens. Tridax procumbens establishes rapidly on wet sites with hard soil, high per cent silt content and low beach management pressure. Sandy beach species with subterranean long rhizomes are strongly tolerant of such disasters. We concluded that the species composition of the beaches disturbed by a temporary large disaster is determined by dormancy and growth forms, with radicoid form being influential.  相似文献   

17.
李长龙  李增元  高志海  孙斌  王丝丝 《生态学报》2022,42(23):9830-9842
稀疏植被覆盖(草地、沙地、戈壁)演变能够直接表征区域生态环境和人类活动的动态影响变化。但由于大尺度稀疏植被区一般都具有地理跨度大,景观结构复杂多样,破碎化程度高,现有地表覆盖分类产品针对性不足等问题,使得该区域内林草沙的遥感提取难度较大,精度普遍偏低,直接制约生态效应评价模型的应用效果。因此,以典型大尺度稀疏植被区——京津风沙源治理二期工程区为研究区,研建了SNIC-CNN-SVM(SCS)模型,实现了大尺度稀疏植被区林草沙典型要素的信息自动提取和主要土地利用/土地覆盖类型识别。研究结果表明:1)引入惩罚性机制优化后的SNIC分割算法,有效提升了稀疏植被区与沙地区的边界区分度,有助于分类精度的提升;2)基于改进SNIC-CNN-SVM模型方案的研究区总体分类精度达89.41%,较优化前提高了11.17%,特别是乔、灌、草、沙地和戈壁的分类识别精度显著提升,表明该优化方案在以研究区为代表的稀疏植被区域分类中具有较好的应用效果和推广价值;3)分类结果显示,2020年工程区草地面积最大,占到了一半以上(51.52%),沙地占比11.96%,稀疏植被覆盖(草地、沙地、戈壁)区域占比68.68%...  相似文献   

18.
We present results on changes in soil properties following land use change over an approximately 55‐year period at Fort Benning, Georgia, U.S.A. Soil cores were taken at 129 locations that were categorized as reforested (field/bare ground in 1944 and forest in 1999), disturbed (field/bare ground in 1944 and 1999), or reference forests (forest in 1944 and 1999). Soil disturbance included historic agriculture (pre‐1944) and military training (post‐1944). Density in mineral soils exhibited a historic land use legacy effect (reference < reforested < disturbed). Rates of change in bulk density decreased with depth and estimated total times to reach reference forest levels ranged from 83 (0–10 cm) to 165 (30–40 cm) years. A land use legacy effect on C stock was apparent in the O‐horizon and in 30‐ to 40‐cm soil increment (reference > reforested > disturbed). Soil C stock in all other increments and in particulate organic matter was affected by disturbance; however, no legacy was apparent (reference = reforested > disturbed). For the entire soil profile (O‐horizon to 40 cm), rate of C accrual was 28 g m−2 yr−1 (1.5%/yr). Nitrogen stocks were affected by disturbance in the O‐horizon and 0‐ to 10‐cm increment; however, no legacy effect was detected (reference = reforested > disturbed). Nitrogen accumulated at 0.56 g m−2 yr−1 (0.6%/yr) for the entire soil profile. At Fort Benning, soil C and N stocks of reforested stands were similar to those of reference forested stands after approximately 55 years. However, soil bulk density was greater on reforested stands than reference forest stands at 55 years and may require an additional century to reach reference levels.  相似文献   

19.
Abstract: We studied breeding dark-eyed juncos (Junco hyemalis), yellow-rumped warblers (Dendroica coronata), and spruce-nesting birds from 1997 to 1998 among forests with different levels of spruce (Picea spp.) mortality following an outbreak of spruce beetles (Dendroctonus rufipennis) in Alaska, USA. We identified species using live and beetle-killed spruce for nest sites and monitored nests to determine how the outbreak influenced avian habitat selection and reproduction. We tested predictions that 1) nesting success of ground-nesting juncos would increase with spruce mortality due to proliferation of understory vegetation available to conceal nests from predators, 2) nesting success of canopy-nesting warblers would decrease with spruce mortality due to fewer live spruce in which to conceal nests, and 3) both species would alter nest-site selection in response to disturbance. Juncos did not benefit from changes in understory vegetation; nesting success in highly disturbed stands (46%) was comparable to that in undisturbed habitats throughout their range. In stands with low spruce mortality, nesting success of juncos was low (5%) and corresponded with high densities of red squirrels (Tamiasciurus hudsonicus). Yellow-rumped warblers nested exclusively in spruce, but success did not vary with spruce mortality. As disturbance increased, nesting warblers switched from selecting forest patches with high densities of live white spruce (Picea glauca) to patches with beetle-killed spruce. Warblers also placed nests in large-diameter live or beetle-killed spruce, depending on which was more abundant in the stand, with no differences in nesting success. Five of the 12 other species of spruce-nesting birds also used beetle-killed spruce as nest sites. Because beetle-killed spruce can remain standing for >50 years, even highly disturbed stands provide an important breeding resource for boreal forest birds. We recommend that boreal forest managers preserve uncut blocks of infested forest within managed forest landscapes and practice partial harvest of beetle-killed spruce rather than commercial clear-cutting of infested stands in order to sustain breeding bird populations until natural reforestation occurs. Because breeding densities do not always reflect fitness, assessing impacts of a massive natural disturbance should include measuring impacts of changes in vegetation on both reproductive success and predator-prey dynamics.  相似文献   

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