试论植物作用对热带岩溶发育的影响——以广西弄岗自然保护区为例

鼻岗自然保护区位于广西南部龙州与宁明县交界,是我国目前保存较好的热带岩溶季节性雨林保护区。区内为上泥盆统至下二叠统碳酸盐岩。岩溶地貌以典型的热带切割较深的峰丛洼地为主。岩溶水以地下河迳流形式向左江和明江排泄。 本区热带雨林发育,复盖率达90％,植株密,林冠高。热带植物对岩溶发育的作用,主要是:1)林区气候受树木的影响,年降水量较外围多200—400毫米,相对湿度偏大22％,从而促进地下水的循环和溶蚀作用。2)大量的植物残体枯枝落叶使土壤中腐植质含量较高,并含有较丰富的微生物,所产生的有机酸和其它酸类,对岩石能起腐蚀作用。3)植物根系发达,主根粗壮,常沿岩石裂隙向纵深生长,常导致岩石的破碎崩解,有利于加强导水性能和溶蚀作用。4)林区岩溶水水化学受地质和生物因素的影响,其类型为重碳酸钙型水,一般不含侵蚀性CO_2,方解石饱和指数Slc>O。但个别点侵蚀性CO_2含量较高,而Slc 

ON THE EFFECT OF PLANT ACTIVITIES UPON THE TROPICAL KARST DEVELOPMENT CASE HISTORY OF THE LONGANG NATURE CONSERVATION REGION

The Longang Nature Conservation Region is situated along the borders of Longzhou and Ningming counties, south Guangxi. It is at present a well protected tropical karst region with seasonal-rain forest. Geologically this region is characterized by carbonate rocks of Upper Devonian to Lower Permian. The karst feature is typified by deeply cut tropical peak-cluster depressions. Karst water drains to Zuojiang and Mingjiang rivers in the form of subterranean runoff. Tropical-rain forest is developed, cov...