Low humidity and hypersalinity reduce cold tolerance in mangroves

Macroclimatic changes are expected to radically alter coastal wetland ecosystems in the coming century. The trajectory of response climate warming may differ based on other concomitantly changing abiotic variables such as soil salinity and relative humidity. Thus, understanding plant responses multiple interacting stressors is required accurately predict shifts under change. ongoing poleward shift mangrove range limits has been linked with a reduction freeze events, yet interactions between low temperature remain underexplored. We grew two common mangroves (Avicennia germinans Rhizophora mangle, n = 1222) from propagules for 10 months environmental growth chambers experimentally manipulated temperature, salinity, humidity treatments that reflected conditions these species experience field. measured variation physiological characteristics before, during, after exposure. For both species, resistance resilience stress were mediated by conditions. Chronic chilling at °C caused widespread seedling stem elongation rate, altered leaf gas exchange rates, increased mortality, particularly high Additional exposure an overnight (−4 °C) had relatively minor impacts. Five temperatures, some R. mangle exhibited capacity recover severe cold damage, but only optimal Although A. generally more resistant stress, severely damaged plants did not recover, even contend current future result including Consequently, modelling approaches predicting change need consider their interactions.