丝栗栲次生林种群天然更新研究

发布时间：2018-06-04 07:52

本文选题：丝栗栲 + 种群更新　；参考：《福建农林大学》2017年硕士论文

【摘要】：丝栗栲(Castanopsis fargesii)是福建海拔1000 m以下山地常绿阔叶林的主要优势种和建群种之一,培肥土壤、涵养水源能力较强。由于气候环境和人为因素的双重影响,现存的以丝栗栲为建群种的丝栗栲天然林多为次生林,更新速度下降,面积下滑。因此,促进丝栗栲种群更新,使丝栗栲林能够长期稳定发展,是次生林抚育经营较为关注的问题。本研究以永安典型丝栗栲次生林为研究对象,以森林培育学、种群生态学和地统计学为基础理论依据,对丝栗栲种群的年龄结构、空间分布格局和种间关系、更新幼苗幼树与林下土壤养分空间异质性关系进行了探析,并编制了永安丝栗栲种群静态生命表,以期为该地区丝栗栲次生林植被恢复和生态系统保护等提供科学依据。主要研究结论如下:(1)丝栗栲种群在该次生林中占绝对优势,更新占林分更新总株数的32.29%。坡向对丝栗栲种群密度和更新密度有明显的影响,表现为阴坡大于阳坡。阴坡种群密度为2124株/hm2,更新占比77.78%;阳坡种群密度为1612株/hm2,更新占比69.23%。丝栗栲种群属于增长型,两个坡向均表现为幼苗幼树多,中树、大树少,幼苗贮备量大,天然更新良好。坡向对更新的地径级没有明显的影响,仅在Ⅰ级(0～10mm)上存在差异。坡向对更新的高度级存在明显的影响,阴坡呈近似双峰分布,阳坡呈明显的左偏山状分布。整体上,幼苗幼树地径和树高结构良好,供给稳定。(2)两个坡向上丝栗栲种群均表现出聚集分布特征,最大聚集强度均出现在目标个体周围1m距离内,且随尺度的增大逐渐变为随机分布。坡向对各发育阶段的空间格局没有明显影响。幼苗主要呈聚集分布,幼树和中树在个别尺度上聚集,主要表现为随机分布,而大树主要呈随机分布,个别尺度表现为均匀分布,总体上从幼苗到大树呈现出聚集到随机或均匀的分布规律。种子扩散限制和生境异质性在一定程度上解释了丝栗栲种群聚集的格局,密度制约是调节丝栗栲种群不同发育阶段格局表现的主要形式。更新空间异质性研究表明,阳坡和阴坡的聚集斑块最大半径分别为12.63 m、8.7 m。更新具有很强的空间格局变异,结构性因素引起的变异占90%以上,空间分布表现出显著的各向异性(p0.05),两个坡向呈现完全相反的空间变异格局。(3)坡向对丝栗栲更新的种内和种间关联性具有显著的影响,并且随尺度发生变化。阳坡上,幼苗和幼树、中树、大树在21m尺度内以显著正关联为主,在大于21m尺度上没有显著关联性;幼树和中树、大树没有显著关联性。阴坡上,幼苗和幼树、中树、大树在7-20 m尺度上以显著正关联为主,幼树和中树、大树在个别尺度存在负关联。更新的种内关系比较稳定。阳坡上,更新幼苗幼树的种间正关联较多,并且随尺度增加逐渐减弱,主要表现为正向和对丝栗栲更新有利的生态关系;米槠、绒毛润楠、华南樟、檫树成树在小尺度对丝栗栲更新存在抑制作用。阴坡上,米槠、绒毛润楠、钩栲、细枝柃幼苗幼树和丝栗栲幼苗幼树存在竞争;米槠、酸枣、青冈栎成树在小尺度对丝栗栲更新存在抑制作用。(4)通过对丝栗栲种群生命表分析,生境对丝栗栲种群的结构和更新动态有较大影响。死亡率和消失率曲线变化趋势相同,存在3个高峰(第1、6和10龄级),种群存活曲线更倾向于Deevey-Ⅱ型(对角线型),种群的生存率和累计死亡率曲线变化趋势互为相反,在第6龄级出现明显转折(速度变缓),死亡密度和危险率函数曲线变化一致。谱分析显示,丝栗栲种群动态存在明显的基本周期和小周期波动,能够促进种群更新和种群稳定性。(5)丝栗栲次生林下,土壤pH在两个坡向差异不显著(P0.05),而全钾、全磷、全氮、硝态氮、铵态氮、有效磷、速效钾在两个坡向均呈显著差异(P0.05)。丝栗栲次生林中土壤养分异质性明显,不同空间样点间土壤各指标含量均存在很大的差异。阳坡样地,pH、全磷、硝态氮、速效钾、综合养分在较大尺度(有效变程依次为 203.16 m、99.87 m、77.059 m、53.642 m、45.05 m)呈明显的空间自相关变异,占空间总变异的63.2%以上;全氮、全钾、铵态氮、有效磷在相对小的尺度范围(依次为13.47m、16.98m、15.72m、8.94m)呈很强的空间自相关变异,占空间总变异的82.1%以上。阴坡样地,pH、全钾、硝态氮在较大尺度(依次为53.75 m、79.71m、55.18 m)呈明显的空间自相关变异,占空间总变异的60%以上;全磷、铵态氮、综合养分在较大尺度(分别为243 m、52.52 m、49.12 m)呈很强的空间自相关变异,结构性因素变异在77.5%以上;而全氮、有效磷、速效钾在相对小的尺度(依次为25.84 m、25.79 m、43.15 m)上呈现明显的空间自相关性,结构性因素和随机因素对3个指标的空间变异同等重要(空间结构占比稍大于50%)。(6)丝栗栲更新和土壤养分的相关性在两个坡向上差异显著。阳坡上,丝栗栲更新数量与土壤速效钾、硝态氮、全氮、综合养分异质性之间存在极显著正相关(p0.01),在含量相对高的斑块中,更新发生数量最多;与土壤pH、全钾呈极显著负相关(p0.01),在含量相对低的斑块中,更新发生数量较多;与有效磷、铵态氮异质性之间的相关性不明显。阴坡上,丝栗栲更新数量与土壤8个指标及综合养分指标的相关性均不明显,更新数量主要和物种生物学特性和荫蔽的林分环境有关。(7)在丝栗栲次生林抚育中,应对不同坡向采取不同的人为干扰以促进种群的天然更新。阳坡上,适度择伐丝栗栲幼苗幼树周围的建润楠、细枝柃幼苗幼树及米槠、绒毛润楠、华南樟、檫树成树。阴坡上,适度择伐丝栗栲幼苗幼树2 m范围内的米槠、润毛润楠、钩栲幼苗幼树及酸枣成树以减少其对目标幼苗幼树的竞争。根据种内关系和存活曲线分析,增加丝栗栲中树周围的空间和光照利于其成功进入大树阶段,占据林分最上层。在丝栗栲林业栽培中,可选择对丝栗栲更新有正关联或者无关联的幼苗幼树进行伴生种植;也可以在对丝栗栲更新有正关联的成树下对丝栗栲幼苗幼树进行补植。
[Abstract]:Castanopsis fargesii is one of the dominant species and one of the dominant species in the evergreen broad-leaved forest in Fujian under 1000 m altitude. The ability of fertilizing soil is stronger. Because of the dual effects of climate and human factors, the existing natural Castanopsis kankanis forest with Castanopsis fargesii is the secondary forest, the rate of regeneration is decreased and the area is decreased. Therefore, promoting the regeneration of Castanopsis fargesii, making the Castanopsis fargesii forest sustainable development for a long time, is a concern for secondary forest tending management. In this study, the secondary forest of Castanopsis fargesii in Yongan is the research object. Based on the theory of forest cultivation, population ecology and geostatistics, the age structure and space of the Castanopsis fargesii population are on the basis of the theoretical basis. The relationship between the distribution pattern and the interspecific relationship was discussed, and the spatial heterogeneity of soil nutrients in the young seedlings of the seedlings was updated and the static life table of Castanopsis fargesii population in Yongan was compiled in order to provide scientific basis for the restoration of the secondary forest and the protection of the ecosystem in this area. The main conclusions are as follows: (1) the population of Castanopsis kankam is in this secondary life. The 32.29%. slope in the forest accounted for an obvious influence on the population density and regeneration density of Castanopsis fargesii, which showed that the shady slope was larger than the sunny slope. The population density of the shady slope was 2124 /hm2, the regeneration was 77.78%, the population density of the sunny slope was 1612 /hm2, and the regeneration accounted for the growth type and two slope of the Castanopsis fargesii population. There are many young seedlings, middle trees, few trees, large trees, large trees and good natural regeneration. The slope direction has no obvious influence on the updated ground level, only on the grade I (0 ~ 10mm). The slope direction has an obvious influence on the height of the updated height, the shady slope is approximately Shuangfeng distribution and the sunny slope is obviously left partial mountain distribution. The soil diameter and height of the young trees were well constructed and the supply was stable. (2) the population of Castanopsis tantana showed the characteristics of aggregation distribution, and the maximum aggregation intensity appeared in the 1m distance around the target individual, and gradually changed to a random distribution with the increase of the scale. The slope direction had no obvious influence on the spatial pattern of each stage. In the collection distribution, the young and middle trees were aggregated on a few scales, mainly in random distribution, while the large trees were distributed randomly and the individual scales were evenly distributed. In general, the distribution of the seedlings from the seedlings to the big trees showed a random or uniform distribution rule. The seed diffusion restriction and the heterogeneity of the habitat explained the species of Castanopsis fargesii to a certain extent. The aggregation pattern, density restriction is the main form of regulating the pattern of different developmental stages of Castanea Castanea population. The study of spatial heterogeneity of regeneration shows that the maximum radius of the aggregated patches in the sunny and shady slopes is 12.63 m, and the 8.7 M. renewal has a strong spatial pattern variation, and the variation caused by the structural factors is over 90%, and the spatial distribution is shown. There was significant anisotropy (P0.05), and the two slope directions presented a completely opposite spatial variation pattern. (3) the interspecific and interspecific associations of Castanopsis fargesii were significant and varied with the scale. On the sunny slope, the seedlings and young trees, the middle trees and the big trees were dominant in the 21m ulnar degree, and were not obvious on the 21m scale. There was no significant correlation between the young and middle trees. There was no significant correlation between the young trees and the trees. The seedlings and the young trees, the middle trees and the big trees were dominant on the 7-20 m scale, the young trees and the middle trees and the big trees were negatively correlated on the individual scales. Gradually weakening, the main expression is positive and favorable ecological relationship to the regeneration of Castanopsis fargesii, Castanopsis Castanopsis, choriowood, Southern China camphor and sassafras tree in the small scale inhibition of the regeneration of Castanopsis fargesii. On the shady slope, Castanopsis Castanopsis, chorioopsis, Castanopsis, young trees of the seedlings and young trees of Castanopsis kankanin are competitive; Castanopsis, jujube, green oak are in the tree. The small scale inhibited the regeneration of Castanopsis fargesii. (4) through the analysis of the life table of Castanopsis fargesii population, habitat had a great influence on the structure and regeneration of Castanopsis fargesii population. The variation trend of the mortality and vanishing rate curve was the same, there were 3 peaks (1,6 and 10 years), and the population survival curve was more inclined to Deevey- type II (diagonal). The variation trend of survival rate and cumulative mortality curve was opposite, and there was a clear turning point at the sixth age level (speed change), and the change of death density and risk rate function curve was the same. The spectrum analysis showed that the dynamics of Castanopsis fargesii population dynamics had obvious basic cycle and small cycle fluctuation, which could promote population regeneration and population stability. (5) Castanopsis kankam times The difference of soil pH in two slopes was not significant (P0.05), while total potassium, total phosphorus, total nitrogen, nitrate, ammonium nitrogen, available phosphorus, and available potassium were significantly different in two slope directions (P0.05). The soil nutrient heterogeneity in the secondary forest of Castanea Castanea was obvious, and there were great differences in the soil indexes between different space samples. Nitrate nitrogen, quick acting potassium, comprehensive nutrient in a larger scale (203.16 m, 99.87 m, 77.059 m, 53.642 m, 45.05 m) in a larger scale, and accounted for more than 63.2% of the total spatial variation, and total nitrogen, total potassium, ammonium nitrogen, and effective phosphorus in a relatively small scale (13.47m, 16.98m, 15.72m, 8.94m) in a relatively strong space self. The related variation accounted for more than 82.1% of the total spatial variation. On the shady slope, pH, total potassium and nitrate nitrogen were obvious spatial autocorrelation variations (53.75 m, 79.71m, 55.18 m), accounting for more than 60% of the total spatial variation; total phosphorus, ammonium nitrogen, and comprehensive nutrients were strong spatial autocorrelation at a large scale (243 m, 52.52 m, 49.12 m, respectively). The variation of structural factors was more than 77.5%, while total nitrogen, effective phosphorus and available potassium showed obvious spatial autocorrelation on relatively small scale (25.84 m, 25.79 m, 43.15 m, respectively). Structural factors and random factors were equally important to the spatial variation of 3 indexes (the space structure ratio was slightly greater than 50%). (6) the regeneration of Castanopsis kantanus and soil nutrients The correlation between the two slopes was significantly different. On the sunny slope, there was a very significant positive correlation between the number of fresh chestnut Castanopsis and the soil available potassium, nitrate nitrogen, total nitrogen, and comprehensive nutrient heterogeneity (P0.01). In the relatively high patches, the number of regeneration occurred most, and was significantly negatively correlated with soil pH, total potassium (P0.01), and in relatively low content patches. There was no significant correlation between the number of regeneration and the availability of available phosphorus and ammonium nitrogen heterogeneity. On the shady slope, the correlation between the number of regeneration of Castanopsis kankam and the 8 indexes of soil and the comprehensive nutrient index were not obvious. The number of regeneration was mainly related to the biological characteristics of species and the forest environment in the shade. (7) in the secondary forest tending of Castanopsis fargesii Different anthropogenic disturbances were taken to promote the natural regeneration of the population. On the sunny slope, the young trees of the seedlings of Castanea Castanea were moderately chosen, the young trees and Castanopsis Castanopsis, the villas, the Southern China camphor and sassafras trees. On the shady slope, Castanopsis Castanopsis in the 2 m range of the young trees of Castanopsis fargesii, moistening Mao Runnan, young trees of the seedlings of Castanopsis fargesii and the young trees of Castanopsis fargesii were selected. According to the intraspecific relationship and survival curve, the space and light of the tree in Castanopsis fargesii can be added to the tree stage and occupy the top of the tree. In the forest cultivation of Castanopsis kankani, the young seedlings of Castanopsis kankam are more new and unrelated to the seedlings. It is also possible to replant young Castanopsis fargesii seedlings under positive correlation with the regeneration of Castanopsis fargesii.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S718.5

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