A review of the effects of tunnel excavation on the hydrology, ecology, and environment in karst areas: Current status, challenges, and perspectives

•Tunnel excavation-induced karst groundwater drawdown changed hydrological processes.•Tunnel excavation changed the distribution patterns of karst water resources.•Tunnel excavation altered the physical and chemical properties of karst soils.•Tunnel excavation changed physiological processes and growth rates of karst plants.•Tunnel excavation induced karst geological hazards.