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《林业资源管理》2015,(4):52-58
长鞭红景天是国家二级保护植物,目前处于近危状态。基于样地-样方调查资料,对长鞭红景天种群年龄结构进行动态量化分析,编制种群静态生命表,绘制种群死亡率曲线、消失率曲线、存活曲线以及生存函数曲线,并运用时间序列模型分析种群数量动态。结果表明,长鞭红景天种群年龄结构总体上呈金字塔型,种群数量变化动态指数Vpi和Vpi均大于零,表明种群属稳定增长型。长鞭红景天种群各龄级个体数量随龄级增长呈逐渐下降趋势,Ⅱ龄级至Ⅴ龄级死亡率较高、达90.29%,整个过程平均死亡率为29.96%,种群存活曲线属Deevey-Ⅱ型B3亚型,种群死亡率与消失率随龄级增长的变化趋势基本保持一致,呈"M"型曲线。生存函数分析表明,长鞭红景天种群前期(Ⅳ龄级前)快速下降,中期(Ⅳ—Ⅵ龄级)相对平稳,后期(Ⅵ龄级后)进入生理衰退期。时间序列预测发现,长鞭红景天种群幼龄个体数量较丰富,未来Ⅱ,Ⅴ和Ⅷ个龄级时间后种群各龄级个体数均有不同幅度的增长。建议保护和改善长鞭红景天种群生存的原生境条件,适当人工辅助散播,建立培育基地及基因库、实施迁地保护,加强病虫害监测。 相似文献
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辽东栎是我国华北地区分布广泛的森林群落建群种和优势种,研究山西庞泉沟辽东栎生命表对于揭示其种群年龄结构和动态具有一定的科学意义。笔者基于野外调查数据,构建了山西庞泉沟自然保护区辽东栎种群的静态生命表并对其进行了分析,包括年龄结构图、存活曲线、死亡曲线等、消失率曲线、生存函数曲线、累积死亡率函数曲线、危险率函数曲线和死亡密度函数曲线。结果表明,辽东栎低龄级(1龄级～2龄级)种群数量较少,年龄结构呈衰退类型;种群死亡率随龄级增加逐渐增加,在最高龄级达到最大;种群存活曲线趋于Deevey-Ⅱ型,与年龄结构反映的衰退类型相同。总体上,死亡率和消失率随龄级增加,在高龄级阶段(7龄级～9龄级)生物量和消失率迅速上升;生存函数与累积死亡率函数呈负相关关系,生存率随龄级的增加而减小。死亡密度函数变化不明显,危险率函数变化趋势随龄级增加而增加,与死亡率变化趋势类似。因此,庞泉沟辽东栎种群年龄结构属于衰退型。 相似文献
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采用样方调查法对南京溧水东庐山麻栎种群结构和分布格局进行了研究。结果表明:(1)麻栎种群的年龄结构呈现偏态性,Ⅰ级幼苗数量较少,Ⅱ级幼苗贮备不足,年龄结构为衰退型;(2)静态生命表中,Ⅰ、Ⅱ龄级的死亡率为负值,而Ⅶ、Ⅸ龄级的死亡率最大,种群生命期望随龄级增加依次递减。(3)种群大小结构表现为中龄、大树所占比例较多,而幼树及老龄个体数量都较少,存活曲线呈现衰退型种群的变化特征。(4)利用负二项参数(K)、扩散系数(C)、扩散型指数(I_δ)、Cassie指标(C_a)、丛生指数(I)、聚块性指标(m*/m)等指标对种群的空间格局进行分析,表明麻栎种群的空间分布格局为集群分布。 相似文献
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大蜀山大叶榉种群数量动态研究 总被引：4，自引：0，他引：4
程红梅 《中南林业科技大学学报(自然科学版)》2009,29(3)
为了更好地了解大蜀山大叶棒Zelkova schneideriana种群的数量动态,根据对大叶榉种群的实地调查资料,以种群生命表及生存分析理论为基础,采用空间序列代时间变化的方法,以林木径级结构代替年龄结构,编制大叶榉种群静态生命表,绘制亏损率曲线、存活曲线、死亡搴曲线和生存函数曲线.结果表明:大叶榉种群的个体数量主要集中在Ⅰ(胸径为0～5 cm)、Ⅰ龄级(胸径为5～10 cm)(个体数量比例占72.60%),幼龄个体数量较多;生命过程中的Ⅰ龄级的年龄阶段为死亡高峰.而Ⅳ龄级(胸径为15～20 cm)死亡率最小,种群存活曲线趋于Deevey-Ⅲ型,大叶榉生长更新良好.更新方式为种子繁殖,幼龄数量储备充足,结合量化分析为增长型种群.结果表明种群在发展前期出现较大的波动,选择合适的恢复和保存方法为大叶榉更新层个体发育创造适宜的生境是保护该物种的有效途径. 相似文献
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内蒙古赛罕乌拉蒙古栎种群的点格局分析 总被引：1，自引：0，他引：1
文章对赛罕乌拉自然保护区蒙古栎(Quercus mongolica)种群的年龄结构、种群空间分布格局、不同龄级的空间分布格局及种间关联性进行研究,对样方内个体定位并测定其树高、胸径等指标,采用年龄大小级划分方法对研究区内蒙古栎个体进行等级划分,使用ADE4对定位数据进行格局分析。结果表明:蒙古栎种群表现为增长型;蒙古栎种群在0~20尺度上呈聚集分布,21~25尺度上呈随机分布;蒙古栎种群的聚集强度随尺度增加而增加,达到一定高峰后随尺度的增加而减弱;蒙古栎种群各龄级间关联性不显著,但龄级Ⅰ与龄级Ⅱ呈显著负相关。 相似文献
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从年龄结构、径级结构、高度级结构3方面分析了粽粑竹无性系种群的结构特征,采用Greig-Smith的相邻格子样方调查法和方差/均值比率法、聚集度指标法分析了粽粑竹无性系种群的空间分布特征。结果表明,Ⅱ龄级的分株所占比例最高(42.3%),其次是Ⅰ龄级的分株(28.9%),表明粽粑竹无性系种群年龄结构呈增长型;地径主要分布在0.81~1.40cm,占总分株数的88.54%;高度主要集中在169.1~229.0 cm,占总分株数的51.8%。粽粑竹无性系种群空间分布格局与龄级有关,除Ⅰ龄级呈随机分布外,其余均为聚集分布。 相似文献
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为了解狭叶坡垒（Hopea chinensis）种群生存现状及动态特征，基于十万大山国家级自然保护区狭叶坡垒固定动态监测样地，编制种群静态生命表、绘制生存函数和存活曲线，分析2015年和2021年种群结构特征及动态变化，通过Ripley’s L函数分析种群空间分布特征。结果表明，狭叶坡垒种群结构总体呈倒“J”型，个体数随龄级增大而减小。2015年，生命期望值在第Ⅴ龄级前随龄级增加而增加，在第Ⅵ龄级减小，第Ⅶ龄级增加，之后随龄级增加而减小；2021年，生命期望值在第Ⅴ龄级前随龄级增加呈先减后增的趋势，第Ⅴ龄级后随龄级增加而减小。存活曲线均趋近于Deevey-Ⅲ型。生存分析表明，2021年种群的生存率相较于2015年稍有提高。狭叶坡垒空间分布格局呈聚集分布。综上所述，群落中的狭叶坡垒种群为增长型种群，处于一个动态平衡的发展状态，具有较高的增长潜力。 相似文献
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文章以大兴安岭呼中区兴安落叶松林为研究对象,结合径级结构、静态生命表、存活率曲线、死亡率曲线和消失率曲线,对兴安落叶松种群的年龄结构和生态特征进行了研究。研究发现在不同龄级下落叶松种群的个体数量有明显差异,I~Ⅲ龄级落叶松种群个体数占绝大多数,IV~VI龄级落叶松种群个体数相对较少;落叶松种群的存活曲线呈DeeveyⅡ型(对角线型);消失率和死亡率曲线变化趋势基本一致,均呈现单峰型,I~Ⅲ龄级落叶松种群的消失率和死亡率逐渐增加,IV~VI龄级落叶松种群消失率和死亡率逐渐减少。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
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本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献