高级检索

不同恢复方式下海南东寨港红树林土壤氮垂直分布特征及其影响因素

Vertical distribution characteristics of soil nitrogen and its influencing factors in mangrove wetlands under different restoration methods in Dongzhaigang, Hainan

  • 摘要: 红树林湿地是热带亚热带海岸带重要的生态系统,探究不同恢复方式下红树林湿地土壤氮组分的分布特征及其驱动机制,对于评估红树林湿地生态恢复进程及功能提升具有重要意义。于2023年12月在海南东寨港国家级自然保护区,选取天然红树林及“退塘还湿”“近自然恢复”“光滩造林”3类典型恢复区,通过野外采样与室内分析,研究不同恢复方式下土壤总氮(TN)、铵态氮(NH4+-N)、硝态氮(NO3-N)含量及其关键影响因素。研究结果表明,天然红树林、近自然恢复区、光滩造林区和退塘还湿区土壤TN质量比分别为2.33 g/kg、1.53 g/kg、0.79 g/kg和0.55 g/kg;NH4+-N质量比以近自然恢复区最高(27.05 mg/kg),光滩造林区最低(11.87 mg/kg);NO3-N质量比在不同恢复方式间差异不显著。在垂直分布上,退塘还湿区TN含量呈先增后减趋势,近自然恢复区和光滩造林区TN含量随土层加深而递减;NH4+-N与NO3-N含量在各剖面中多呈波动变化。多元回归分析表明,天然红树林和近自然恢复区土壤TN、NH4+-N的变异主要受有机碳(TOC)、含水率(WS)和容重(BD)影响,模型解释度较高(R2=0.885~0.997);退塘还湿和光滩造林区仅部分氮组分进入回归模型,分别受电导率(EC)和pH调控,解释度较低(R2=0.331~0.810)。不同恢复方式通过改变TOC、WS、BD、EC、pH等环境因子显著影响土壤氮分布。天然红树林土壤氮储量最高,近自然恢复有利于TN积累,而退塘还湿区和光滩造林区可能受恢复年限、植被覆盖度和水文环境等因素影响,氮循环尚不稳定。

     

    Abstract: Mangrove wetlands are critical ecosystems in tropical and subtropical coastal zones. Investigating the distribution characteristics and driving mechanisms of soil nitrogen components under different restoration methods is essential for assessing the process and functional enhancement of wetland ecological restoration. In this study, natural mangroves and three typical restoration areas (pond-to-wetland restoration, near-natural restoration, and mudflat afforestation) were selected in the Hainan Dongzhaigang National Nature Reserve, and soil total nitrogen (TN), ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3-N) contents, as well as key physicochemical properties, were determined through field sampling and laboratory analysis. The results showed that soil TN contents in natural mangroves, near-natural restoration area, mudflat afforestation area, and pond-to-wetland restoration area were 2.33 g/kg, 1.53 g/kg, 0.79 g/kg, and 0.55 g/kg, respectively. NH4+-N content was highest in the near-natural restoration area (27.05 mg/kg) and lowest in the mudflat afforestation area (11.87 mg/kg). No significant difference in NO3-N content was observed among different restoration methods. In terms of vertical distribution, TN content in the pond-to-wetland restoration area showed an initial increase followed by a decrease, while TN contents in the near-natural restoration area and mudflat afforestation area decreased with soil depth. NH4+-N and NO3-N contents mostly fluctuated across soil profiles. Multiple regression analysis indicated that variations in soil TN and NH4+-N in natural mangroves and near-natural restoration area were mainly influenced by total organic carbon (TOC), water content (WS), and bulk density (BD), with high model explanatory power (R2=0.885-0.997). In pond-to-wetland restoration and mudflat afforestation areas, only some nitrogen components entered the regression models, regulated by electrical conductivity (EC) and pH, respectively, with relatively low explanatory power (R2=0.331-0.810). Different restoration methods significantly affected soil nitrogen distribution by altering key environmental factors such as TOC, WS, BD, EC, and pH. Natural mangroves had the highest soil nitrogen storage, and near-natural restoration was favorable for TN accumulation, while nitrogen cycling in pond-to-wetland restoration and mudflat afforestation areas remained unstable, possibly due to factors such as restoration duration and vegetation coverage.

     

/

返回文章
返回