杭州湾湿地鹭鸟栖息地土壤养分累积特征

Nutrient accumulation characteristics of soil in egret habitat in Hangzhou Bay Wetland

为研究水鸟集群繁殖活动对栖息地土壤理化性质的影响,在杭州湾国家湿地公园有林湿地鹭鸟集群繁殖影响区和无鹭鸟影响区(对照区)设立调查样地,比较不同区域土壤中养分累积的差异。结果表明,鹭鸟影响区土壤中的有机碳(SOC)、全氮(TN)、全磷(TP)、碱解氮(AN)和有效磷(AP)含量分别为(13.28±2.88)g·kg^-1、(1.25±0.24)g·kg^-1、(0.97±0.13)g·kg^-1、(133.3±24.7)mg·kg^-1和(63.9±25.9)mg·kg^-1,分别是对照区的1.64、1.80、1.55、2.07和3.17倍。鹭鸟影响区土壤电导率(EC)(0.784±0.39)mS·cm^-1显著高于对照区(0.299±0.09)mS·cm^-1,土壤pH值则表现为鹭鸟影响区(6.69±0.79)显著低于对照区(7.98±0.19)。相关分析显示,土壤有机碳和全氮在不同区域都表现为显著正相关;土壤有机碳和全磷在对照区相关性不显著,在鹭鸟影响区表现为极显著负相关。杭州湾湿地鹭鸟栖息地土壤养分具有明显的累积现象,这主要与鹭鸟栖息特别是集群繁殖期栖息导致的鸟粪输入有关。土壤全氮、全磷与有机碳含量间相关性的变化也进一步指示着鸟粪输入对土壤养分影响。

Water birds can return large quantities of nutrients to terrestrial ecosystems(from aquatic ecosystems)in the form of feces and food detritus(from predation),thereby affecting the physical and chemical properties of soil in their habitat.In this study,we investigated soil nutrient content in a forest in Hangzhou Bay National Wetland Park,which was affected by the egrets that gregariously inhabit and breed in it(egrets plot).We used the non-affected forest in the wetland as a control(control plot),and our results showed that the soil organic carbon,total nitrogen,total phosphorus,available nitrogen,and available phosphorus content in the egrets plot had values of(13.28±2.88)g·kg^-1,(1.25±0.24)g·kg^-1,(0.97±0.13)g·kg^-1,(133.3±24.7)mg·kg^-1,and(63.9±25.9)mg·kg^-1,respectively.These values were 1.64,1.80,1.55,2.07,and 3.17 times those of the control plot,respectively.Soil conductivity in the egrets plot was significantly higher than that in the control plot[(0.784±0.39)mS·cm^-1 compared to(0.299±0.09)mS·cm^-1].Moreover,the soil pH value was significantly lower in the egrets plot(6.69±0.79)than in the control plot(7.98±0.19).Correlation analysis showed that there was a significantly positive correlation between soil organic carbon and total nitrogen content in the different plot.Correlation between soil organic carbon and total phosphorus was not significant in the control plot,whereas there was a significant negative correlation in the egrets plot.This study shows that the soil in forests in the Hangzhou Bay Wetland,which are affected by the presence of egrets,has been enriched with nutrients.This is mainly due to the addition of droppings from egret predation,especially during the gregarious breeding period.The correlation between the soil organic carbon,nitrogen,and phosphorus contents further indicate the effect of bird droppings on soil nutrients.