桉树人工林改造对林下植物群落的短期影响

Short-term effects of Eucalyptus robusta plantation transformation on understory plant communities

摘要

【目的】探究桉树（Eucalyptus robusta）纯林改造对林下植物群落的短期影响。【方法】以广东东江林场 11 年生（EP1）、4 年生（EP2）桉树纯林及分别改造后形成的混交林（EM1、EM2）为研究对象，通过林下植被调查与多样性指数计算，分析不同林龄林分改造后林下植物群落的变化。【结果】1）林分改造影响林下植物群落组成，EM1 中灌木和草本型植物的相对重要值占比在短期内分别提高 8.95%和 8.87%，小乔木、藤本和蕨类植物的相对重要值占比分别下降 3.45%、5.50%和 8.87%；EM2 中小乔木和蕨类植物的相对重要值占比分别下降 22.56%和 21.84%，而灌木、藤本及草本植物的相对重要值占比分别增加 10.24%、12.32%和 21.84%。2）与 EP2 相比，EM2 中灌木层物种丰富度、Shannon-Wiener 指数、Simpson 指数和 Pielou 均匀度指数在短期内显著提高 78.48%、124.24%、106.70%和 78.45%（P＜0.05），而草本层物种丰富度显著下降 40.15%（P＜0.05）；与 EP1 相比，EM1 中灌木层和草本层多样性指数整体变化不显著（P＞0.05）。3）冗余分析表明，土壤全磷含量与灌木层群落组成显著相关，有效磷含量与草本层群落组成显著相关。【结论】桉树纯林改造为混交林后在短期内影响了林下群落的物种组成和生活型结构，且林下植物群落的变化具有明显的林龄依赖性和层次差异。土壤磷素与植物群落变化关系显著，林下植物群落可能沿磷素可利用性梯度发生重组。建议未来在更长时间尺度上对林下植物群落变化进行监测，以期为桉树人工林改造提供更充分的理论支持。

Abstract

[Objective] To investigate the short-term effects of transforming Eucalyptus robusta monocultures into mixed stands on understory plant communities. [Method] 11- (EP1) and 4- year-old (EP2) E. robusta monoculture plantations and their corresponding transformed mixed stands (EM1 and EM2, respectively) in the Guangdong Dongjiang Forestry Farm, were selected as study sites. Changes in understory plant communities following stand transformation at different stand ages were analyzed based on understory vegetation surveys and diversity index calculations. [Result] 1) Stand transformation affected the composition of understory plant communities. In EM1, the relative importance values of shrubs and herbs increased by 8.95% and 8.87%, respectively, in the short term, while those of small trees, lianas, and ferns decreased by 3.45%, 5.50%, and 8.87%, respectively. In EM2, the relative importance values of small trees and ferns decreased by 22.56% and 21.84%, respectively, whereas those of shrubs, lianas, and herbs increased by 10.24%, 12.32%, and 21.84%, respectively. 2) Compared with EP2, shrub-layer species richness, Shannon–Wiener index, Simpson index, and evenness in EM2 increased significantly by 78.48%, 124.24%, 106.70%, and 78.45%, respectively (P < 0.05), whereas herb-layer species richness decreased significantly by 40.15% (P < 0.05). In contrast, no significant changes were detected in the diversity indices of either the shrub or herb layer between EP1 and EM1 (P > 0.05). 3) Redundancy analysis indicated that soil total phosphorus was significantly associated with shrub-layer community composition, while available phosphorus was significantly associated with herb-layer community composition. [Conclusion] The transformation of E. robustamonocultures into mixed stands can reshape the species composition and growth-form structure of understory plant communities, exhibiting pronounced stand age dependence and layer-specific differences. Soil phosphorus is a key environmental factor explaining changes in plant community composition, and understory communities may be redistributed along gradients of phosphorus availability. Long-term monitoring of understory vegetation dynamics is recommended to provide stronger theoretical support for the sustainable transformation and management of Eucalyptus plantations.

关键词

桉树人工林 / 林分改造 / 林下植物群落 / 物种组成 / 物种多样性

Key words

Eucalyptus robusta plantation / stand transformation / understory plant community / species composition / species diversity

参考文献

[1] Shang R, Chen J M, Xu M Z, et al. China’s current forest age structure will lead to weakened carbon sinks in the near future[J].Innovation, 2023, 4(6): 100515.

[2] 叶永昌,张浩,陈葵仙,等 .香港人工林改造对林下植物自然更新和物种多样性的早期影响[J].林业与环境科学,2016,32(6):1-9.

[3] Liu C L C, Kuchma O, Krutovsky K V . Mixed—species versus monocultures in plantation forestry: Development, benefits, ecosystem services and perspectives for the future[J].Glob Ecol Conserv, 2018, 15: e00419.

[4] Chen R J, Guo X L, Ge Y X, et al. Tree species mixing effects on the radial growth of Pinus massoniana and Cas— tanopsis hystrix: a comparison between even—aged and uneven—aged stands[J].For Ecol Manag, 2024, 566: 122058.

[5] Gong C, Tan Q Y, Liu G B, et al. Impacts of tree mixtures on understory plant diversity in China[J].For Ecol Manag, 2021, 498: 119545.

[6] Das Gupta S, Pinno B D . Drivers of understory species richness in reconstructed boreal ecosystems: a structural equation modeling analysis[J].Sci Rep, 2020, 10: 11555.

[7] Jin Y Q, Liu C G, Qian S S, et al. Large—scale patterns of understory biomass and its allocation across China’s forests[J].Sci Total Environ, 2022, 804: 150169.

[8] 毛亦杨, 陈富强, 郭勇, 等. 不同林龄红锥人工林林下植被物种多样性恢复动态[J].应用与环境生物学报, 2021, 27(4): 930-937.

[9] Nilsson M C, Wardle D A . Understory vegetation as a forest ecosystem driver: evidence from the northern Swedish boreal forest[J].Front Ecol Environ, 2005, 3(8): 421-428.

[10] Fu X L, Yang F T, Wang J L, et al. Understory vegetation leads to changes in soil acidity and in microbial communities 27 years after reforestation[J].Sci Total Environ, 2015, 502: 280-286.

[11] Su X P, Zheng G C, Chen H Y H . Understory diversity are driven by resource availability rather than resource heterogeneity in subtropical forests[J].For Ecol Manag, 2022, 503: 119781.

[12] Ares A, Berryman S D, Puettmann K J . Understory vegetation response to thinning disturbance of varying complexity in coniferous stands[J].Appl Veg Sci, 2009, 12(4): 472-487.

[13] 李俊杰, 韩梦豪, 赵家豪, 等. 间伐对马尾松人工林林下植物多样性的动态影响[J].生态学杂志, 2023, 42(4): 788-795.

[14] Balandier P, Mårell A, Prévosto B, et al. Tamm review: forest understorey and overstorey interactions: So much more than just light interception by trees[J].For Ecol Manag, 2022, 526: 120584.

[15] 罗应华, 孙冬婧, 林建勇, 等. 马尾松人工林近自然化改造对植物自然更新及物种多样性的影响[J].生态学报, 2013, 33(19): 6154-6162.

[16] Li X K, Li Y N, Zhang J, et al. The effects of forest thinning on understory diversity in China: a meta—analysis[J].Land Degrad Dev, 2020, 31(10): 1225-1240.

[17] Yu J T, Zhang X N, Xu C Y, et al. Thinning can increase shrub diversity and decrease herb diversity by regulating light and soil environments[J].Front Plant Sci, 2022, 13: 948648.

[18] 叶绍明, 温远光, 杨梅, 等. 连栽桉树人工林植物多样性与土壤理化性质的关联分析[J].水土保持学报, 2010, 24(4): 246-250.

[19] 温远光, 左花, 朱宏光, 等. 连栽对桉树人工林植被盖度、物种多样性及功能群的影响[J].广西科学, 2014, 21(5): 463-468.

[20] 张兵 . 林分改造对桉树林土壤养分含量及氮磷径流流失的影响[D].广州: 华南农业大学, 2016.

[21] Pereira A P A, Durrer A, Gumiere T, et al. Mixed Euca— lyptus plantations induce changes in microbial communities and increase biological functions in the soil and litter layers[J].For Ecol Manag, 2019, 433: 332-342.

[22] 温远光, 张祖峰, 周晓果, 等. 珍贵乡土树种与桉树混交对生态系统生物量和碳储量的影响[J].广西科学, 2020, 27(2): 111-119.

[23] 陈秋海, 周晓果, 朱宏光, 等. 桉树与红锥混交对土壤养分及林下植物功能群的影响[J].广西植物, 2022, 42(4): 556-568.

[24] 王磊, 温远光, 周晓果, 等. 尾巨桉与红锥混交对林下植被和土壤性质的影响[J].生态环境学报, 2022, 31(7): 1340-1349.

[25] 王家妍, 陈亮, 莫冰萍, 等. 杉木人工林套种不同树种对林分生长和植物多样性的影响[J].桉树科技, 2024, 41(2): 57-64.

[26] 黄立新 . 东江林场主要植被类型及群落类型分析[J].林业勘查设计, 2017, 46(2): 109-111.

[27] 张柳桦, 齐锦秋, 柳苹玉, 等. 林分密度对桉树人工林群落结构和物种多样性的影响[J].西北植物学报, 2018, 38(1): 166-175.

[28] Liu X, Reich P B, Liang C, et al. Ecosystem—level warming reduces microbial necromass in the topsoil but not in deeper soil of a subtropical forest[J].Geoderma, 2025, 458: 117336.

[29] 张星元, 张璐, 马丁, 等. 不同冠层结构下的植物生长型与生活型特征[J].中南林业科技大学学报, 2018, 38(7): 37-44.

[30] 陈涵, 郭弘婷, 陈睿, 等. 杉木人工林林下植物多样性及其环境对不同间伐强度的短期响应[J].生态学报, 2023, 43(24): 10274-10284.

[31] 吴安驰, 邓湘雯, 任小丽, 等. 中国典型森林生态系统乔木层群落物种多样性的空间分布格局及其影响因素 [J].生态学报, 2018, 38(21): 7727-7738.

[32] Forrester D I, Pretzsch H . Tamm Review: On the strength of evidence when comparing ecosystem functions of mixtures with monocultures[J].For Ecol Manag, 2015, 356: 41-53.

[33] Xu H D, Yuan H J, Yu M K, et al. Large macroaggregate properties are sensitive to the conversion of pure plantation to uneven—aged mixed plantations[J].Catena, 2020, 194: 104724.

[34] Cheng C P, WANG Y D, FU X L, et al. Thinning effect on understory community and photosynthetic characteristics in a subtropical Pinus massoniana plantation[J].Can J For Res, 2017, 47(8): 1104-1115.

[35] 张勇强, 李智超, 厚凌宇, 等. 林分密度对杉木人工林下物种多样性和土壤养分的影响[J].土壤学报, 2020, 57(1): 239-250.

[36] Ares A, Neill A R, Puettmann K J. Understory abundance, species diversity and functional attribute response to thinning in coniferous stands[J].For Ecol Manag, 2010, 260(7): 1104-1113.

[37] Ingwell L L, Wright S J, Becklund K K, et al. The impact of lianas on 10 years of tree growth and mortality on Barro Colorado Island, Panama [J].J Ecol, 2010, 98(4): 879-887.

[38] Ampoorter E, Baeten L, Koricheva J, et al. Do diverse overstoreys induce diverse understoreys? Lessons learnt from an experimental—observational platform in Finland[J].For Ecol Manag, 2014, 318: 206-215.

[39] 杨玉婷, 石玉林, 李战刚, 等. 陕北“三北”防护林下草本群落特征及其与林分结构和土壤养分的关系[J].生态学报, 2020, 40(18): 6542-6551.

[40] 周润惠, 唐永彬, 王敏, 等. 威远不同年龄桉树人工林林下物种多样性和土壤理化性质[J].应用与环境生物学报, 2021, 27(3): 742-748.

[41] 张俊艳, 陆元昌, 成克武, 等. 近自然改造对云南松人工林群落结构及物种多样性的影响[J].河北农业大学学报, 2010, 33(3): 72-77.

[42] 庞圣江, 张培, 贾宏炎, 等 .不同造林模式对桉树人工林林下植物物种多样性的影响[J].西北农林科技大学学报(自然科学版), 2020, 48(9): 44-52.

[43] 姚俊宇, 齐锦秋, 张柳桦, 等. 人为干扰对碧峰峡山矾次生林群落物种多样性和土壤理化性质的影响[J].生态学杂志, 2018, 37(10): 2942-2950.

[44] 李婷婷, 唐永彬, 周润惠, 等. 云顶山不同人工林林下植物多样性及其与土壤理化性质的关系[J].生态学报, 2021, 41(3): 1168-1177.

[45] 苏波, 韩兴国, 黄建辉, 等. 植物的养分利用效率(NUE)及植物对养分胁迫环境的适应策略[J].生态学报, 2000, 20(2): 335-343.

[46] Denslow J S . Tropical rainforest gaps and tree species diversity[J].Annu Rev Ecol Syst, 1987, 18: 431-451.

基金资助

山东省自然科学基金青年科学基金项目(ZR2024QC343)

山东省高等学校青创科技支持计划项目(2023KJ298)