茂兰喀斯特森林自然恢复过程中植物叶片—凋落物—土壤生态化学计量特征研究

发布时间：2018-07-11 09:48

本文选题：喀斯特森林 + 演替阶段　；参考：《中国林业科学研究院》2017年博士论文

【摘要】：本文基于生态化学计量学理论,借助以空间替代时间的方法,以茂兰喀斯特森林自然恢复过程中的草本群落阶段(HS)、灌木灌丛阶段(SS)、乔林阶段(AS)和顶极常绿落叶阔叶混交林阶段(CS)等为研究对象,对各演替阶段的植物叶片、凋落物和土壤的C、N、P、K含量和化学计量特征以及N、P养分重吸收率、群落多样性指数和比叶面积等进行了研究。主要结果如下:1.植物叶片C、N、P、K含量及化学计量特征的总体分布(1)茂兰喀斯特地区68种优势植物叶片C、N、P、K含量的变化范围分别为309.57～573.21 g·kg-1、5.01～41.62 g·kg-1、0.56～5.79 g·kg-1 和 2.50～39.11 g·kg-1;变异系数分别为10.16%、29.61%、52.33%和62.72%,其中;C含量属弱变异性,N含量属中等变异性,而P、K含量均属强变异性。C:N、C:P、C:K、N:P、N:K和P:K的变化范围分别为11.06～57.39、58.20～886.69、9.94～217.80、3.57～30.88、0.38～6.31 和 0.04～0.56;变异系数分别为 31.11%、39.58%、54.86%、35.06%、49.18%和 50.71%,除 C:K 和 P:K 属强变异性以外,其余均属中等变异性。(2)植物叶片的C、N、P、K含量以及与化学计量特征之间的相关性因生长阶段的不同而存在一定差异;但总的来看:其C与N含量之间呈极显著的负相关(P0.01),但与P含量的相关性不显著(P0.05),而N与P含量之间则呈显著的正相关(P0.05),除P:K以外,植物叶片各养分含量与其余化学计量特征之间基本均为显著(P0.05)或极显著(P0.01)的负相关;且通过进一步的函数模型拟合发现,它们之间均为二次函数、指数函数或冥函数的非线性耦合关系。(3)植物叶片的C、N、P、K含量及化学计量特征因其生活型、系统发育类型以及生长阶段的不同而存在较大差异,其中:草本植物较灌木和乔木具有较高的N、P含量以及较低C:N、C:P和N:P,符合生态化学计量学的“生长速率”理论;而各功能(类)群植物不同生长阶段的C:N和P:K基本都保持一个较稳定的水平,则可能是“内稳态”理论的体现。另外,通过冗余分析(RDA),结果表明:以生活型对其化学计量特征影响最大,解释程度高达61.86%;植物比叶面积(SLA)和系统发育类型次之,分别为16.67%和12.43%;生长阶段最低,仅为9.04%。2.不同演替阶段植物叶片-凋落物-土壤的养分含量及其化学计量特征(1)不同演替阶段植物叶片、凋落物和土壤的C、N、P、K含量及化学计量特征随演替的进展,其变化趋势因群落层次、凋落物分解层次、植物生长阶段以及土层深度的不同均存在一定差异;其中:除SS以外,其余各演替阶段不同群落层次植物叶片的养分含量及化学计量特征的变异系数基本均属弱变异性,在一定程度上也是“内稳态”理论的体现;而SS的灌木层较其它演替阶段的主要群落层次(HS的草本层、AS和CS的乔木层),其植物叶片具有较高的N、P含量以及较低的C:N、C:P和N:P,则可能是为了应对其物种组成及群落结构的变化而形成的一种养分利用策略,也是“生长速率”理论的一种体现。(2)各生长阶段不同演替群落“植物叶片-凋落物-土壤”的C、N含量均表现为:植物叶片凋落物土壤;C:P、C:K、N:P、N:K和P:K则均表现为:凋落物植物叶片土壤;而P、K含量和C:N则由于生长阶段或演替阶段的不同而不同。3.不同演替阶段的限制性养分因子通过比较各演替阶段主要群落层次植物叶片的N:P、N:K和P:K,结合其阈值范围,对其限制性养分因子进行了判别,结果表明:各演替群落不同生长阶段存在不同的限制性养分因子;在生长阶段Ⅰ,演替前中期(由HS至SS)群落易受N素限制,演替中后期(由AS至CS)群落倾向于受N、P和K素的共同限制,且越至演替后期受P素的限制越强;在生长阶段Ⅱ,各演替群落均主要受N素的限制。而K:P临界值可能并不适合作为对该地区限制性养分因子进行判别的依据。当然,要想更加科学、合理的判别其养分限制性,必须辅以施肥实验来进行。4.不同演替阶段的N、P养分重吸收特征生长阶段Ⅰ和Ⅱ,不同演替群落的N重吸收率分别为15.82%～55.06%和12.35%～61.14%,P重吸收率分别为51.19%～75.69%和54.72%～71.31%,且随演替的进展基本上均呈降低趋势。从不同生长阶段来看,HS和AS的N重吸收率均表现为ⅡⅠ,SS和CS的则均表现为ⅠⅡ;除CS以外,其余演替阶段的P重吸收率均表现为ⅠⅡ。另外,各生长阶段不同演替群落的P重吸收率均要高于N重吸收率。综合各演替阶段的限制性养分因子,进一步论证了受N(或P素)限制的群落并不一定就具有高的N(或P素)重吸收率。5.不同演替阶段植物叶片-凋落物-土壤间的相互作用(1)各生长阶段不同演替群落凋落物和土壤各养分含量与C植物含量基本均为负相关,且Ⅰ的相关性均达到显著(P0.05)或极显著(P0.01)水平。生长阶段Ⅰ的P凋落物和Ⅱ的C凋落物分别与N植物含量存在极显著(P0.01)和显著(P0.05)的正相关;而土壤各养分含量与N植物含量均无明显相关性。P凋落物与P植物含量均为正相关,且Ⅱ的相关性达到显著水平(P0.05);TP土壤与p植物含量均为负相关,但相关性均不显著(P0.05)。K凋落物和TK土壤与K植物含量均无显著相关性(P0.05),但SOC和TP土壤与K植物含量则均存在显著(P0.05)或极显著(P0.01)的负相关。C凋落物和P凋落物含量与N:P植物均为负相关,N凋落物和K凋落物含量与其均为正相关,且Ⅰ的C凋落物和N凋落物含量与N:P植物的相关性均达到显著水平(P0.05);土壤各养分含量与N:P植物均为正相关,且Ⅰ的相关性均达到显著(P0.05)或极显著(P0.01)水平。另外,N:P凋落物与N:P植物均存在极显著的正相关(P0.01);N:P土壤与N:P植物均为负相关,但相关性均不显著(P0.05)。(2)植物叶片与凋落物、凋落物与土壤以及土壤与植物叶片养分含量及化学计量特征间的相关性,在一定程度上也体现了养分含量间的传承性与共变性;而由于研究区域、研究尺度、植被类型以及生长阶段等因素的不同,导致“植物-凋落物-土壤”养分含量及化学计量特征之间相关性的差异,则可能是植物对环境变化的一种弹性适应机制。(3)综合演替阶段、生长阶段、群落多样性指数、凋落物现存量、土壤水分物理性状等影响因子,通过RDA分析其对不同演替阶段植物叶片、凋落物和土壤化学计量特征的影响程度,结果表明:以SLA、P凋落物含量和P重吸收率对植物叶片的影响最大,解释程度分别为41.78%、17.84%和17.54%;对凋落物影响最大的因子分别是N重吸收率和P植物含量,解释程度分别为49.65%和14.62%;而不同土层深度和演替阶段对土壤的影响最大,解释程度分别为32.82%、32.19%,占了总解释程度的65%以上。
[Abstract]:Based on the theory of ecological stoichiometry, by means of spatial substitution time, the herbaceous community stage (HS), shrub Shrub Stage (SS), Jolin stage (AS) and the top evergreen deciduous broad-leaved mixed forest stage (CS) in the course of natural restoration of Karst forest in Maolan were studied, and the leaves, litter and litter of plants in each succession stage were studied. Soil C, N, P, K content and stoichiometric characteristics as well as N, P nutrient reabsorption, community diversity index and specific leaf area were studied. The main results are as follows: 1. the total distribution of C, N, P, K content and stoichiometric characteristics of plant leaves (1) 68 dominant plants in Maolan region, C, N, and 309.57, the range of variation is 309.57, respectively. 573.21 G. Kg-1,5.01 ~ 41.62 G. Kg-1,0.56 ~ 5.79 G. Kg-1 and 2.50 ~ 39.11 G. Kg-1; variation coefficients were 10.16%, 29.61%, 52.33% and 62.72%, respectively. The C content belonged to weak variability, N content was of moderate variability, while P, K content was 11.06 to 886.69. The coefficients of variation were 31.11%, 39.58%, 54.86%, 35.06%, 49.18% and 50.71%, respectively, from 9.94 to 217.80,3.57 to 30.88,0.38 to 6.31 and 0.04 to 35.06%, 49.18% and 50.71%, except for the strong variability of C:K and P:K. (2) the correlation between the C, N, P, K content and the chemical metrology characteristics of plant leaves existed because of the different growth stages. In general, there was a significant negative correlation between C and N content (P0.01), but the correlation with the content of P was not significant (P0.05), but there was a significant positive correlation between N and P content (P0.05). Except P:K, there was a significant negative (P0.05) or extremely significant (P0.01) negative between the nutrient content of plant leaves and the other chemical measurements. Correlation; and through further functional model fitting, it is found that both of them are two functions, exponential functions or nonlinear coupling relations of the Pluto function. (3) the C, N, P, K content and chemical measurement characteristics of plant leaves differ greatly from their living types, phylogenetic types and growth stages, among which herbaceous plants are more than shrubs and shrubs. The tree has higher N, P content and lower C:N, C:P and N:P, which conforms to the "growth rate" theory of ecological stoichiometry; while the C:N and P:K in different growth stages of plant groups are basically a stable level, which may be the embodiment of the "internal steady state" theory. In addition, the result of redundancy analysis (RDA) shows that: The life type had the greatest influence on its chemometric characteristics, and the explanation was as high as 61.86%; the plant specific leaf area (SLA) and the phylogenetic type were 16.67% and 12.43%, respectively, and the lowest in the growth stage, only the nutrient content and stoichiometric characteristics of plant leaves litter and soil in different stages of the 9.04%.2. succession stage (1) the plant leaves of different succession stages The variation trend of C, N, P, K content and chemical measurement characteristics of litter and soil with succession, the variation trend of the soil layer, the litter decomposition level, the plant growth stage and the depth of the soil layer were different, among them, the nutrient content and stoichiometry of the leaves of different community levels except for SS. The variation coefficient of the sign is basically a weak variation, and to a certain extent it is also the embodiment of the "internal steady state" theory; while the SS shrub layer is higher than the other succession stages (HS's herb layer, AS and CS tree layer), and the plant leaves have higher N, P content and lower C:N, C:P and N:P, which may be to cope with their species group. A nutrient utilization strategy formed by the change of the community structure was also a manifestation of the "growth rate" theory. (2) the content of C, N content of plant leaves litter and soil in different stages of growth, were all: plant leaf litter soil; C:P, C:K, N:P, N:K and P:K were all: leaf soil of litter plants; The limiting nutrient factors of P, K and C:N in different succession stages of.3., due to the different stages of growth or succession, were identified by comparing the N:P, N:K and P:K of plant leaves at the main community level in each succession stage, and the limiting nutrient factors were judged by the threshold range. The results showed that the different growth stages of the succession communities were different. There are different limiting nutrient factors in the segment. In the stage of growth I, the community before succession (from HS to SS) is easily restricted by N, and the community in the middle and late succession (from AS to CS) tends to be limited by N, P and K, and the more the limit of P in the later stage of succession; in the stage of growth, each succession community is mainly restricted by N element. And K:P critical value It may not be the basis for discriminating the restrictive nutrient factors in the region. Of course, in order to be more scientific and reasonable to discriminate its nutrient constraints, it must be supplemented by fertilization experiments to carry out N in different stages of.4. succession, P nutrient reabsorption characteristic growth stage I and II, and the N reabsorption rate of different succession communities is 15.82% to 55.06, respectively. % and 12.35% ~ 61.14%, P reabsorption rates were 51.19% ~ 75.69% and 54.72% ~ 71.31%, respectively, and the N reabsorption rate of both HS and AS showed II I from different growth stages, and SS and CS were all I II. Except for CS, the reabsorption rate of P in the residual succession stage was I II. The P reabsorption rate of different succession communities in each growth stage was higher than that of N reabsorption rate. The limiting nutrient factors of each succession stage were further demonstrated that the communities restricted by N (or P) did not necessarily have high N (or P) reabsorption rate.5. in different succession stages of plant leaf litter and soil interaction (1) each growth order The contents of litter and soil nutrients in different succession communities were negatively correlated with the content of C plants, and the correlation of I was significant (P0.05) or extremely significant (P0.01). The P litter and C litter of the growth stage I was positively correlated with the content of N plants (P0.01) and significant (P0.05), respectively, while the soil nutrients were contained. There was no significant correlation between the content and the content of N plants,.P litter and P plant content were positively correlated, and the correlation of II was significant (P0.05); TP soil and P plant content were negatively correlated, but the correlation was not significant (P0.05).K litter and TK soil and K plant content had no significant correlation (P0.05), but SOC and soil and plant content The negative correlation.C litter and P litter content were negatively correlated with N:P plants, and the content of N litter and K litter content was positively correlated with the content of N litter and K litter, and the correlation of C litter and N litter content to N:P plants reached significant level (P0.05), and the contents of soil nutrients and N:P plants were all positive. Correlation, and the correlation of I was significant (P0.05) or extremely significant (P0.01) level. In addition, there was a very significant positive correlation between N:P litter and N:P plants (P0.01); N:P soil was negatively correlated with N:P plants, but the correlation was not significant (P0.05). (2) plant leaves and litter, litter and soil, and soil and plant leaf nutrient content and The correlation between stoichiometric features also reflects the inheritance and covariance of nutrient content to a certain extent, and the difference in the correlation between the nutrient content and the chemical measurement characteristics of the plant litter soil may be the plant due to the different factors such as the study area, the study scale, the vegetation type and the growth stage. An elastic adaptation mechanism for environmental changes. (3) the influence factors of the comprehensive succession stage, the growth stage, the community diversity index, the litter size, the soil moisture physical properties and so on, through the RDA analysis of the effects on the plant leaves, litter and soil chemical measurements in different succession stages. The results show that the contents of SLA, P litter content And P reabsorption rate has the greatest impact on plant leaves, which are 41.78%, 17.84% and 17.54% respectively. The most influential factors for litter are N reabsorption rate and P plant content, respectively 49.65% and 14.62%, while different soil depth and succession stage have the greatest influence on soil, and the interpretation degree is 32.82%, 32.19%, respectively. More than 65% of the total interpretation.
【学位授予单位】：中国林业科学研究院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S714

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