Phenotypic trait differences betweenIris pseudacorusin native and introduced ranges support greater capacity of invasive populations to withstand sea level rise

Abstract

AbstractAimTidal wetlands are greatly impacted by climate change, and by the invasion of alien plant species that are being exposed to salinity changes and longer inundation periods resulting from sea level rise. To explore the capacity for the invasion ofIris pseudacorusto persist with sea level rise, we initiated an intercontinental study along estuarine gradients in the invaded North American range and the native European range.LocationSan Francisco Bay‐Delta Estuary; California, USA and Guadalquivir River Estuary; Andalusia, Spain.MethodsWe compared 15 morphological, biochemical, and reproductive plant traits within populations in both ranges to determine if specific functional traits can predict invasion success and if environmental factors explain observed phenotypic differences.ResultsAlienI. pseudacorusplants in the introduced range had more robust growth than plants in the native range. The vigour of the alien plants was reflected by expression of higher leaf water content, fewer senescent leaves per leaf fan, and more carbohydrate storage reserves in rhizomes than plants in the native range. Moreover, alien plants tended to show higher specific leaf area and seed production than native plants.I. pseudacorusplants in the introduced range were less affected by increasing salinity and were exposed to deeper inundation water along the estuarine gradient than those in the native range.Main ConclusionsFunctional trait differences suggest mature populations ofI. pseudacorusin the introduced range have greater adapted capacity to adjust to environmental stresses induced by rising sea level than those in the native range. Knowledge of these trait responses can be applied to improve risk assessments in invaded estuaries and to achieve climate‐adapted conservation goals for conservation of the species in its native range.