Mangroves facing climate change: landward migration potential in response to projected scenarios of sea level rise

[摘要] Mangrove forests prominently occupy an intertidal boundary position wherethe effects of sea level rise will be fast and well visible. This study inEast Africa (Gazi Bay, Kenya) addresses the question of whether mangroves canbe resilient to a rise in sea level by focusing on their potential tomigrate towards landward areas. The combinatory analysis between remotesensing, DGPS-based ground truth and digital terrain models (DTM) unveilshow real vegetation assemblages can shift under different projected (minimum(+9 cm), relative (+20 cm), average (+48 cm) and maximum(+88 cm))scenarios of sea level rise (SLR). Under SLR scenarios up to 48 cm by theyear 2100, the landward extension remarkably implies an area increase foreach of the dominant mangrove assemblages except for Avicennia marina and Ceriops tagal, both on thelandward side. On the one hand, the increase in most species in the firstthree scenarios, including the socio-economically most important species in thisarea, Rhizophora mucronata and C. tagal on the seaward side, strongly depends on the colonisation rateof these species. On the other hand, a SLR scenario of +88 cm by the year2100 indicates that the area flooded only by equinoctial tides stronglydecreases due to the topographical settings at the edge of the inhabitedarea. Consequently, the landward Avicennia-dominated assemblages will furtherdecrease as a formation if they fail to adapt to a more frequent inundation.The topography is site-specific; however non-invadable areas can be typicalfor many mangrove settings.

[学科分类] 地球化学与岩石