Responses of mangrove in Corpus Christi Bay after the Feb. 2021 hard freezes and implications for broader ecological theory

Since the last freeze in 1989, populations of black mangroves (Avicennia germinans) have rapidly increased throughout coastal Texas. Some sites are dense shrub thickets that reduce light penetration, lowering salt marsh abundance; causing large-scale ecological regime shifts along segments of the Texas coast. Two consecutive nights of below-freezing temperatures in Feb. 2021 provided an opportunity to study the effects of a catastrophic disturbance on the regime shift in Corpus Christi Bay. We are using observational data to test the hypothesis: that recovery of mangroves will be faster on Mustang Island than on Ward Island because Mustang is nearer the Gulf of Mexico which may provide for more mangrove propagule colonizers from locations outside the bay and also may have been a little warmer due to thermal buffering by the Gulf. We established paired 3x3 m plots on each Island near the seaward edge of the intertidal vegetation and 5-11 m further inland. We quantified shrub mortality, survivor resprouting, seedling recruitment, and marsh cover by species.