北缘分布区退化红树林生态恢复短期成效评估与策略探讨

Short-Term Evaluation of Ecological Restoration Effectiveness and Restoration Strategies for Degraded Mangroves at Their Northern Distribution Limit

  • 摘要: 受人类活动等多重因素影响,部分红树林面临生境退化和生态功能衰退等问题,亟需开展科学恢复与成效评估。以福建省福鼎市秋茄(Kandelia obovata)纯林、秋茄+桐花树(Aegiceras corniculatum)混交林恢复模式为研究对象,通过比较植株生长特征和土壤养分状况,评估不同恢复模式的短期生态恢复成效。结果表明,2种恢复模式均取得良好效果,植株保存率均超过80%,其中混交林保存率达88.8%,显著高于纯林的83.3%(P<0.05)。混交林的平均地径、树高、冠幅分别为14.2 mm、68.4 cm、22.3 cm,较纯林分别提高36.6%、18.9%、40.8%,表现出明显的生长优势。土壤理化性质分析显示,红树林恢复对土壤盐度无显著影响,但在一定程度上降低了土壤pH、并提高了有机质含量。恢复后土壤总碳和总氮含量变化不显著,而氨态氮和有效磷含量显著降低(P<0.05)。相关性分析表明,土壤硝态氮与植株地径和冠幅均呈显著正相关关系(P<0.05),表明无机氮有效性对红树林植株生长具有重要调控作用;同时,土壤碳磷比与植株保存率呈显著正相关关系(P<0.05)。综上,北缘退化红树林生态恢复在短期内显著改善植被生长状况和土壤质量,其中混交恢复模式在提高植株成活率、促进生长及优化土壤养分方面表现更优,可为福建省及我国红树林北缘分布区恢复模式优化与北移造林实践提供参考。

     

    Abstract: Mangroves in many regions have experienced habitat degradation and declines in ecosystem functioning due to multiple stressors,particularly anthropogenic disturbances,highlighting the urgent need for effective restoration and rigorous evaluation of restoration outcomes.In this study,two restoration models,a Kandelia obovata monoculture and a mixed plantation of K.obovata and Aegiceras corniculatum,were established in Fuding,Fujian Province.Restoration performance was evaluated by comparing plant growth characteristics and soil nutrient properties between the two restoration models.The results showed that both restoration models achieved favorable outcomes,with plant survival rates exceeding 80%.The mixed plantation exhibited a significantly higher survival rate(88.8%)than the monoculture(83.3%)(P<0.05).In addition,the mixed plantation showed superior growth performance,with mean basal diameter,plant height and crown width reaching 14.2 mm,68.4 cm and 22.3 cm,representing increases of 36.6%,18.9% and 40.8%,respectively,compared with the monoculture.Analysis of soil physicochemical properties indicated that mangrove restoration had no significant effect on soil salinity but slightly reduced soil pH and increased soil organic matter content.No significant changes were observed in soil total carbon(TC)or total nitrogen(TN)after restoration,whereas ammonium nitrogen(NH+4-N)and available phosphorus(AP)contents decreased significantly(P<0.05).Correlation analysis further revealed that soil nitrate nitrogen(NO-3-N)was positively correlated with basal diameter and crown width(P<0.05),suggesting that inorganic nitrogen availability plays an important role in regulating mangrove growth.Moreover,the soil C∶P ratio was positively correlated with plant survival rate(P<0.05).Overall,ecological restoration of degraded mangroves at the northern distribution limit significantly improved vegetation growth and soil quality in the short term.Compared with monoculture restoration,the mixed plantation demonstrated greater advantages in enhancing plant survival,promoting growth,and optimizing soil nutrient conditions.These findings provide scientific support for optimizing restoration strategies and facilitating northward afforestation of mangroves in Fujian Province and other northern marginal mangrove regions in China.

     

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