Ain’t no mountain high enough: the impact of severe typhoon on montane stream fishes

Abstract

Typhoons are a regular occurrence in tropical Taiwan. Local flora and fauna should be adapted to typhoons, however more severe storms in the past decade most likely due to climate change have caused an apparent impact on local ecosystems and diversity. Heavy rainfall from typhoon events has been associated with declines in density and biodiversity of low altitude freshwater fish. Montane streams on the other hand are assumed to be more resilient to typhoons as these habitats receive less washed-off pollutant and is buffeted by established vegetation. However, as access to isolated montane streams, especially after a typhoon, is difficult, the effects of typhoons on these habitats are rarely studied. In this study, we overcame many obstacles to survey montane freshwater fishes in Beikeng Creek shortly after a typhoon event. We demonstrated extreme changes in physical characteristics, but little changes in chemical characteristics of the stream. We also documented the absence of the endemic Rhinogobius rubromaculatus (red spotted goby) and the crashed population of Onychostoma barbatulum, (Taiwan shovel-jaw carp) after typhoon. Although these two endemic species are expected to survive in other unaffected montane creeks and streams in the vicinity, the dramatic decline in montane fish population in Beikeng Creek suggests that conservation management may need to be reconsidered to prevent possible extinction under increasing human and natural perturbations.