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OA

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 res-toration outcomes.In this study,two restoration models,a Kandelia obovata monoculture and a mixed plantation of K.obovata and Ae-giceras 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 a-chieved 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 signifi-cant 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 nitro-gen(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 advanta-ges 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.