分析采煤塌陷地人工林土壤种子库组成与多样性特征及其对林下植被更新的影响,可为塌陷地人工林的提质增效提供科学依据。以榆神府矿区采煤塌陷地不同恢复年限(1~2 a、3~5 a、6~10 a、11~15 a)的樟子松林为研究对象,分析其土壤种子库的密度、组成和多样性演变特征,探讨其土壤种子库与林下植被的耦合关系,并识别其关键生态影响因子。结果表明:1)塌陷地樟子松林土壤种子库的物种组成由恢复1~2 a的一年生草本植物,向恢复11~15 a的多年生草本转变。2)土壤种子库密度在恢复3~5 a时最高(196粒/m²),随后随恢复年限增加呈下降趋势。各主要科的植物种子库密度达到峰值的时间不同,藜科在恢复1~2 a时最高(97粒/m²)、禾本科在恢复3~5 a时最高(86 粒/m²)、菊科在恢复6~10 a时最高(78粒/m²)、豆科在恢复11~15 a时最高(35粒/m²)。3)土壤种子库物种丰富度指数随恢复年限呈先增后降趋势,在恢复6~10 a时达到最大值,而均匀度指数和多样性指数在各恢复阶段无显著变化。4)土壤种子库与林下植被之间的物种相似性在恢复1~2 a时最低,共有物种为9种,以一年生草本植物为主;在恢复3~5 a时达到最大值(0.48),共有物种为12种,包括一年生和多年生植物;在恢复6~10 a和11~15 a时共有物种分别有11和10种,以多年生草本植物为主。5)林下植被地上生物量、土壤含水率和全氮是影响不同恢复年限樟子松林下种子库密度、多样性和林下植被与土壤种子库相似性的共同因子;恢复1~2 a的樟子松林下土壤容重和林下植被盖度、恢复3~5 a的林下植株密度和土壤有机质、恢复6~10 a的枯落层厚度和枯落物盖度、恢复11~15 a的土壤结皮厚度是影响土壤种子库的主要差异性因子。樟子松林生长初期,土壤种子库特征主要受林下植被和土壤性质影响,随着林分发育,林下枯落物积累和结皮对土壤种子库影响逐渐增加。采煤塌陷地樟子松林在恢复10 a后,土壤种子库密度和多样性降低,对林下植被更新的贡献亦降低,因此,可通过补充土壤种子库和优化生境等措施,促进樟子松林下植被更新,提高林下植被的生态效益。

Characterizing the composition and diversity of soil seed banks in artificial forests within coal mining subsidence areas,along with their effects on understory vegetation regeneration,provide a scientific foundation for the quality and efficiency management of plantation forests in coal mining subsidence land.Taking Pinus sylvestris var. mongholica forests with differentrestoration years(1-2,3-5,6-10 and 11-15 years)in the coal mining subsidence land in the Yushenfu mining area as the research subject,we characterized the evolutionary characteristics of soil seed bank density,composition,and diversity;deciphered the coupling relationships between the soil seed bank and aboveground vegetation;and investigated ecological drivers regulating soil seed bank features through monitoring edaphic factors,understory plant communities,and litter traits.The results showed that:1)The species composition of the soil seed bank shifted from being dominated by annual plants at 1-2 years of restoration to predominantly perennial plants after 11-15 years of recovery.2)The soil seed bank density peakedat 196 seeds/m² in years 3-5,but soil seed bank density progressively declined with the increasing stand age.The densities of Chenopodiaceae,Poaceae,Asteraceae,and Fabaceae plants reached their maximum values at 97 seeds/m² for 1-2 years,86 seeds/m² for 3-5 years,78 seeds/m² for 6-10 years,and 35 seeds/m² for 11-15 years,respectively.3)The species richness index of the soil seed bank initially increased then decreased with stand age,peaking at 6-10 years,while the Pielou evenness index and Shannon-Wiener diversity index exhibited no statistically significant changes.4)The species similarity between the understory soil seed bank and aboveground vegetation was the lowest in 1-2 years of restoration,with 9 common species of annual plants;the similarity reached a maximum value of 0.48 in 3-5 years of restoration,with a total of 12 species including both annual and biennualplants and perennial plants;and there were 11 and 10 common species in years of 6-10 and 11-15,respectively,dominated by perennialplants.5)Aboveground vegetation biomass,soil water content and total nitrogen were the common factors affecting understory soil seed density,diversity and similarity of aboveground vegetation and soil seed bank in different restoration years.In addition,soil capacity and aboveground vegetation cover in 1-2 years,aboveground vegetation density and soil organic matter in 3-5 years,litter layer thickness and cover in 6-10 years,and soil crust thickness in 11-15 years were also the heterogeneous main factors affecting understory soil seed banks in Pinus sylvestris var. mongholica forestry,the characteristics of the soil seed bank in the early succession stage of Pinus sylvestris var. mongholica forests were primarily influenced by aboveground vegetation and soil properties.As community succession progresses,the accumulation of understory litter and the formation of biological crusts exert increasing influence on the soil seed bank.In Pinus sylvestris var. mongholica forests of coal mining subsidence areas,both density and diversity of the soil seed bank decline after 10 years of succession,leading to reduced understory vegetation regeneration,seed bank supplementation and habitat optimization can effectively enhance understory vegetation recovery and improve its ecological functions.