Using Paleoecological Data to Inform the Conservation Strategy for Floristic Diversity and Isoetes taiwanensis in Northern Taiwan

Abstract

Paleoecological data can be used to inform nature conservation practice. Dream Lake (DL) is the best-preserved peat bog in the Tatun Volcanic Group of northern Taiwan. We analyzed continuous pollen and charcoal data from a well-dated sediment core from DL to reconstruct the changes in climate, lacustrine condition, and floristic diversity during the last 4500 cal BP. An absence of volcanic ash from all sediments indicates weak volcanic activity. Significant changes in lithology and pollen composition show that DL changed from a deep lake to a shallow peat bog from 3000 cal BP onwards. The palynological diversity index was negatively correlated with fire frequency. A substantial decline in Isoetes (quillwort) spores suggests increased vulnerability during the peat bog period. Natural terrestrialization will lower the mean water depth of DL below the minimum required for Isoetes taiwanensis survival within 300 years. Our findings indicate that winter precipitation driven by intense East Asian winter monsoons is the critical force determining the long-term variation in floristic diversity and abundance of I. taiwanensis. This long-term ecological history of DL, derived using paleoecological techniques, will be used to inform conservation practice in the Tatun Volcanic Group.