Effects of experimental sedimentation on the phenological dynamics and leaf traits of replanted mangroves at Gazi bay, Kenya

Abstract

Sedimentation results in the creation of new mudflats for mangroves to colonize among other benefits. However, large sediment input in mangrove areas may be detrimental to these forests. The dynamics of phenological events of three mangrove tree species (Avicennia marina, Ceriops tagal, and Rhizophora mucronata) were evaluated under experimental sediment burial simulating sedimentation levels of 15, 30, and 45 cm. While there was generally no shift in timing of phenological events with sedimentation, the three mangrove tree species each responded differently to the treatments. Partially buried A. marina trees produced more leaves than the controls during the wet season and less during the dry season. Ceriops tagal on the other hand had higher leaf loss and low replacement rates in the partially buried trees during the first 6 months of the experiment but adapted with time, resulting in either equal or higher leaf emergence rates than the controls. Rhizophora mucronata maintained leaf emergence and loss patterns as the unaffected controls but had a higher fecundity and productivity in the 15-cm sedimentation level. The results suggest that under incidences of large sedimentation events (which could be witnessed as a result of climate change impacts coupled with anthropogenic disturbances), mangrove trees may capitalize on "advantages" associated with terrestrial sediment brought into the biotope, thus maintaining the pattern of phenological events. © 2014 The Authors.