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Tropical cyclones are often accompanied by large amount of precipitation potentially impacting stream hydrochemistry. Global warming is altering typhoon disturbance regime. Little is known about how cyclone changes, especially cyclone‐frequency reduction may affect stream hydrochemistry. In this study, we compared water and nutrient input via precipitation and output via streamflow between a frequent‐typhoon period (2013–2017), with 1.2 typhoon yr−1, and a no‐typhoon period (2018–2022) at a long‐term monitoring site, the Fushan Experimental Forest of Taiwan. Precipitation and streamflow quantities were not different between the two periods because typhoons increased the fluctuation but not the mean of monthly precipitation in the major typhoon months (July–September). Inputs of Mg2+, NO3−, and SO42− via precipitation were greater in the frequent‐typhoon period than the no‐typhoon period while inputs of other ions were not different between the two periods. Only the output of Mg2+ was different between the two periods, greater in the frequent‐typhoon period. Output/input ratio of NO3− was greater in the no‐typhoon period than the frequent‐typhoon period despite the greater input in the frequent‐typhoon period, while no differences were found for others. Increases in mineralization rates due to warming is suggested to be the cause of the greater NO3− output/input ratio during the no‐typhoon period. Relationships between stream discharge and ion export were similar between the two periods both with and without removing typhoon events. The limited variation in hydrochemistry between periods of contrasting cyclone activities suggests high resilience of the undisturbed subtropical forests to changes in cyclone frequency at the decadal scale. Plain Language Summary: Tropical cyclones often bring large quantity of rainfall through which affect stream water quantity and quality. The frequency and intensity of tropical cyclones is changing because of climate change. We examined how reduction in typhoon frequency affects nutrient cycling in a forest watershed by comparing streamwater quality and quantity between a frequent (six) typhoon period (2013–2017) and a no‐typhoon period (2018–2022) in a forest watershed in Taiwan. Surprisingly, although the typhoons brought substantial rainfall, the annual and typhoon season rainfall and streamwater were similar between the two periods. Input and output of most ions were also similar between the two periods. However, NO3− export was higher in the no‐typhoon period, possibly resulting from greater mineralization associated with warmer temperatures. Patterns of ion export in relation to streamwater were also similar between the two periods. Thus, the hydrochemistry of the undisturbed forest was resilent to changes in typhoon frequency. Key Points: A no‐typhoon period (2018–2022) was observed in Taiwan despite an average of two typhoons per year in 1958–2017Relationships between stream discharge and ion export were similar between the two periodsOutput/input ratio of NO3− was greater in the no‐typhoon period despite the greater input in the frequent‐typhoon period [ABSTRACT FROM AUTHOR]

The testing association of environmental variables with genetic and epigenetic variation could be crucial to deciphering the effects of environmental factors playing roles as selective drivers in ecological speciation. Although ecological speciation may occur in closely related species, species boundaries may not be established over a short evolutionary timescale. Here, we investigated the genetic and epigenetic variations using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP), respectively, and tested their associations with environmental variables in populations of four closely related species in the R. pseudochrysanthum complex. No distinctive species relationships were found using genetic clustering analyses, neighbor-joining tree, and neighbor-net tree based on the total AFLP variation, which is suggestive of the incomplete lineage sorting of ancestral variation. Nonetheless, strong isolation-by-environment and adaptive divergence were revealed, despite the significant isolation-by-distance. Annual mean temperature, elevation, normalized difference vegetation index, and annual total potential evapotranspiration were found to be the most important environmental variables explaining outlier genetic and epigenetic variations. Our results suggest that the four closely related species of the R. pseudochrysanthum complex share the polymorphism of their ancestor, but reproductive isolation due to ecological speciation can occur if local environmental divergence persists over time. [ABSTRACT FROM AUTHOR]