种间关系对中条山油松人工林天然更新及群落稳定性的影响

Effects of Interspecific Relationship on Natural Regeneration and Community Stability of Pinus tabuliformis Plantation in Zhongtiao Mountain

[目的]为了揭示种间关系对中条山油松人工林天然更新及群落稳定性的影响,为油松人工林经营管理提供理论依据。[方法]基于中条山油松人工林群落样地调查数据,分析油松人工林下主要植物的种间关联性、生态位重叠及群落稳定性,并在此基础上探讨种间关联和生态位理论在油松人工林天然更新障碍及群落稳定性形成机制中的作用。[结果]中条山油松人工林下常见物种总体上显著正联结;χ^(2)检验结果显示,无联结种对(372对)远高于有联结种对(34对),说明常见种间联结较松散;联结系数分析结果表明,正联结种对大于负联结种对,但显著正联结种对(AC≥0.20,145对)小于显著负联结种对(AC≤−0.20,168对),且与油松天然更新竞争最激烈的物种主要为土庄绣线菊、五角枫、粗齿铁线莲、青榨槭、金线草、披碱草。Pearson相关分析结果显示:正相关种对大于负相关种对,但显著相关种对远小于无显著相关种对。油松人工林下披针薹草的生态位最宽(23.47),红椋子最窄(3.87),而油松天然更新的生态位宽度为14.69,相对较高;常见种总体生态位重叠较低,但有11个种对生态位重叠指数大于0.98,说明部分种之间存在较大的生态相似性;油松天然更新与费菜、披针薹草、华山松、赤瓟等物种的生态位重叠较大,但联结系数分析结果显示,油松天然更新与以上物种正联结,说明油松天然更新与这几种植物资源利用相似或占据了相近的生态空间;油松人工林群落稳定性交点坐标为(61.28,38.72),显示群落稳定性较差。[结论]中条山油松人工林群落的成熟度相对较低,存在一些以竞争相同资源的物种,群落的总体资源利用率和稳定性较低。竞争可能是导致该区域油松天然更新障碍的主要原因之一,今后在以油松为目标树种的森林经营管理中,应注重清除林下与油松天然更新竞争较强的物种。

[Objective]To examine the influence of interspecific relationship on the natural regeneration and community stability of Pinus tabuliformis plantation in Zhongtiao Mountain,and provide a theoretical basis for the management of P.tabuliformis plantation.[Method]Based on the survey data of the P.tabuliformis plantation community plots in Zhongtiao Mountain,the interspecific association,niche overlap and community stability of the dominant plants under the P.tabuliformis plantation were analyzed,and based on this,the role of interspecies association and niche theory in the formation of natural renewal barriers and community stability of P.tabuliformis plantations were discussed.[Result]The common species under the P.tabuliformis plantation in Zhongtiao Mountain are generally positively connected.The chi-square test results show that the unlinked species(372 pairs)are much higher than the linked species pairs(34 pairs),indicating that the common interspecies connections are loose.Association coefficient analysis results show that the positively connected species pairs are greater than the negatively connected species pairs,but the species pairs with significant positive association(AC≥0.20,145 pairs)are smaller than those with significant negative association(AC≤−0.20,168 pairs),and the most intensely competitive species with the natural regeneration of P.tabuliformis are Spiraea pubescens,Acer pictum subsp.mono,A.davidii,Clematis argentilucida,Rubia membranacea and Elymus dahurica.Pearson correlation analysis results show that the positively related species pairs are greater than the negatively related species pairs,but the significantly related species pairs are much smaller than the non-significantly related species pairs.Under the P.tabuliformis plantation,the niche of Carex lancifolia is the widest(23.47),and that of the Swida hemsleyi is the narrowest(3.87).The niche width of the natural regeneration of P.tabuliformis is 14.69,which is relatively high.The overall niche overlap of common species is low,but 11 species-pair niche overlap indexes are greater than 0.98,indicating that some species have greater ecological similarities.The niche of the natural regeneration of P.tabuliformis has the largest overlap with the niche of Sedum aizoon,Carex lancifolia,Pinus armandii and Thladiantha dubia,however,the results of the association coefficient analysis show that the natural regeneration of P.tabuliformis are positively associated with the species mentioned above,it shows that the natural regeneration of P.tabuliformis is similar to the resource utilization of these types of plants or it occupies a similar ecological space with these types of plants.The coordinate of the intersection point of the stability of the P.tabuliformis plantation community is(61.28,38.72),which shows that the community stability is poor.[Conclusion]The maturity of the P.tabuliformis plantation community in Zhongtiao Mountain is relatively low,there are some species competing for the same resources,and the overall resource utilization and stability of the community is low.Competition may be one of the main reasons impeding the natural regeneration of P.tabuliformis in this area.Therefore,in the forest management activities targeting at P.tabuliformis species,more attention should be paid to removing the species that compete with the natural regeneration of P.tabuliformis under forest.