Salt marsh communities provide numerous, valuable ecosystem services such as flood and erosion prevention, providing essential habitat for coastal wildlife, soil accretion, and carbon storage. It is likely that salt marsh communities will be vulnerable to the impacts of anthropogenic climate change, but little research has been done to investigate how they will respond to these impacts. The goal of this study was to compare plant functional traits of a dominant salt marsh sedge species, Schoenoplectus americanus, grown under four temperature regimes: ambient, +1.7 ºC, +3.4 ºC and +5.1 ºC. In a laboratory setting, we grew plants from rhizomes in lighted environmental chambers that mimicked the conditions of the Salt Marsh Accretion Response to Temperature eXperiment (SMARTX) in Edgewater, Maryland, where the same temperature treatments are applied through aboveground infrared lamps and belowground cables. Here we present data on growth rates, gas exchange rates, and tissue nutrients of sedges planted and grown in experimental chambers in Fall 2017 .
Results/Conclusions
Elevated warming had a significant effect on plant growth rates. Plants grown in +3.4 ºC and +5.1 ºC treatments initially showed faster height growth than plants grown in ambient and +1.7 ºC treatments. However, growth cessation and senescence began to occur earliest in +3.4 ºC and +5.1 ºC treatments, allowing plants in the ambient treatment to catch up and even outgrow the warmed plants near the end of the 4-month-long experiment. Rates of photosynthesis were not significantly affected by the warming treatments, thought there was a trend toward reduced rates of stomatal conductance as growing temperature increased. The results from this experiment are important in illumining how climate change will alter the function and growth of an essential salt marsh plant species. A better understanding of how this and other salt marsh species will respond to future climate conditions will be necessary to guide policy and land management decisions.