Current Status and Conservation of Springs in Taiwan: Water Quality Assessment and Species Diversity of Aquatic Animals

Abstract

Even though spring ecosystems are ecologically unique and socio-culturally important worldwide, they hardly attract research attention. The aims of this study were to evaluate the environmental status of water quality, and to inventory the species diversity of aquatic animals in 65 springs in Taiwan from 2012 to 2017, of which seven springs were unable to be sampled due the fact that they were dried or sealed up. The environmental status of 58 springs with complete water quality data was assessed by the River Pollution Index (RPI). Based on the RPI, the water quality of these 58 sampled springs was mainly non-/mildly polluted (26 springs, 44.8%) and lightly polluted (23 spring, 39.6%), and nine (15.5%) springs were moderately polluted. However, when applied to springs, the RPI may intensify the pollution rankings because dissolved oxygen is an assessing factor, and hypoxia may naturally be observed in the springs. To avoid this concern, we suggest choosing the concentration of coliform instead of dissolved oxygen content in the RPI when it is applied to springs. During the 6 years of the study period, we collected 48 fish species in 44 springs, 24 gastropoda and bivalve species in 46 springs, 16 shrimp species in 34 springs, and 14 crab species in 18 springs. Within the species collected, 31 fish, 20 gastropoda and bivalves, 12 shrimps, and 14 crabs are native species of Taiwan. They totaled 27.2 to 35% of the known aquatic native species of the island. Thus, springs in Taiwan may be considered to be a conservation hotspot of aquatic animals. Other than native species, exotic aquatic animals also represent threats, as seventeen fishes (35.4%), four gastropoda and bivalves (16.6%), and two shrimps (12.5%) were found in the springs of Taiwan. The springs in Taiwan show diverse and vital ecosystem services, such as delivering social, cultural, and economic value, conserving native and endangered freshwater animals, developing new academic theories, and supplying habitat refugees from climate change. Unfortunately, springs in Taiwan currently are also threatened by multiple anthropogenic disturbances, such as the overconsumption of groundwater by land development and urbanization, deterioration of water quality by agricultural, domestic, and industrial pollution, and inappropriate tourism and management tactics. To restore and sustain the springs in Taiwan, effective strategies and practical measures are urgently required to minimize human-caused threats and revitalize social awareness of springs.