基于熵权法TOPSIS模型综合评价石漠化区4种苔藓植物的生态修复效益

Evaluation on the Ecological Restoration Benefits of Four Bryophytes in Rocky Desertification Area Based on Entropy Weight TOPSIS Model

[目的]探讨典型苔藓植物在石漠化区的生态修复效益,为进一步把苔藓植物运用于石漠化治理中提供数据支撑。[方法]选取石漠化区4类生境中大灰藓(Hypnum plumaeforme)、牛舌藓(Anomodon viticulosus)、小石藓(Weisia controversa)、蕊型真藓(Bryum coronatum)优势苔藓物种,基于熵权法TOPSIS模型从苔藓植物饱和吸水率、蒸腾速率、抗冲刷能力、改善土壤养分这4个方面综合评价4种苔藓植物的生态修复效益。[结果](1) 4种苔藓植物的饱和吸水率和蒸腾速率具有显著差异性;饱和吸水率最高的是蕊型真藓(1384.93%±80.77%),最低的是小石藓(602.74%±34.78%)。蕊型真藓平均蒸腾速率最高值为402.43 g/(m^(2)·h),大灰藓平均蒸腾速率最弱为146.86 g/(m^(2)·h);饱和吸水率与蒸腾速率、干重、假根密度、假根根长呈正相关;蒸腾速率与假根密度、干重、饱和吸水率呈正相关,与假根根长呈负相关。(2)通过人工为期6个月种植苔藓植物后研究发现,与纯土组对比,苔藓植物对土壤中全氮、全磷、全钾、总有机碳含量的影响总体趋势并不显著(p<0.005),但均能显著提高土壤中碱性磷酸酶、脱氢酶、蔗糖酶、脲酶的活性(p<0.005);由主成分分析PCA得到牛舌藓对土壤养分改良较其他3种苔藓植物更具有优势。(3)当冲刷流量较小时,4种苔藓抗冲刷能力差异性不显著,抗冲刷能力随着冲刷流量增加具有显著性差异;大灰藓和蕊型真藓抗冲刷能力较其他两种苔藓植物强。抗冲刷能力与假根密度、冲刷苔藓植物生物量、假根根长、饱和吸水率、糙率呈显著正相关,与蔗糖酶呈负相关,与脲酶、碱性磷酸酶、脱氢酶相关性不大。(4)选取饱和吸水率、蒸腾速率、抗冲刷能力和土壤养分改良4个指标,利用熵权法TOPSIS模型综合评价4种苔藓植物在石漠化区的生态修复效益,4个指标权重分别为21.68%,24.55%,16.84%,36.93%,评价结果为牛舌藓和蕊型真藓在石漠化区生态修复效益较优。[结论]石漠化生态恢复重建中引入牛舌藓和蕊型真藓等苔藓植物可以增加种源,达到更好的修复效益。

[Objective]The ecological restoration benefits of typical bryophytes in rock desertification areas were explored to provide data support for further application of bryophytes in rocky desertification management.[Methods]The dominant bryophytes in four types of habitats,such as Hypnum plumaeforme,Anomodon viticulosus,Weisia controversa,Bryum coronatum were selected from four habitats in typical rocky desertification area.The ecological restoration benefits of four bryophytes were comprehensively evaluated based on the entropy power TOPSIS model in terms of saturated water absorption rate,evaporationrate,anti-scouring ability and improvement of soil nutrients.[Results](1)The saturated water rate and evaporationrate of the four bryophytes were significantly different,the highest saturated water rate was the Bryumcoronatum(1384.93%±80.77%)and the smallest was the Weisia controversa(602.74%±34.78%).The maximum average evaporation rate of Bryumcoronatum was 402.43 g/(m^(2)·h),and the average evaporation rate of Bypnum plumaeforme was the weakest with the value of 146.86 g/(m^(2)·h).The saturated water rate(SWR)was positively correlated with pseudoroot density(RD),dry weight(DW),root length of pseudoroot(RLD),the evaporationrate(EV).EV was positively correlated with the RD,DW and SWR,and negatively correlated with the RLD.(2)The overall trend of the effect of the bryophytes on the total nitrogen(TN),total phosphorus(TP),total potassium(TK)and total organic carbon(TOC)contents of the soil was not significant(p<0.005)when compared with the pure soil group after artificially growing bryophytes for a period of 6 months.All of them could significantly improve the activities of alkaline phosphatase(ALP),dehydrogenase(DHO),invertase(IN)and urease(UR)in soil(p<0.005).Principal component analysis(PCA)showed that Anomodon viticulosus had more advantages on soil nutrient improvement than other three bryophytes.(3)Then the scour flow was small,the difference of the anti-scour ability(ASA)of the four bryophytes was not significant,but the ASA was significantly different with the increase of the scour flow;the ASA of Hypnum plumaeform and Bryum coronatum is stronger than the other.The ASA was positively correlated with RD,scour bryophyte biomass(ASA-BOM),RLD,SWR and RC,negatively correlated with IN,and not significantly correlated.(4)Four indicators of SWR,EV,ASA and soil nutrient improvement(ISN)were selected to evaluate the ecological restoration benefits of four bryophytes in rocky desertification area using the entropy weighting method TOPSIS model,and the weights of the four indicators were 21.68%,24.55%,16.84%and 36.93%,respectively.The evaluation results showed that the ecological restoration benefits of Anomodon viticulosus and Bryum coronatum were better in rocky desertification area.[Conclusion]It is suggested that bryophytes of Anomodon viticulosus and Bryum coronatum can be introduced in the ecological restoration and reconstruction to increase the seed source to achieve better restoration benefits.