Mangrove ecosystems function at the edge of land and sea, often covering large intertidal areasalong (sub)tropical coastal regions worldwide but also in a wide array of other topographical settings. Once or twice a day, tides move seawater in and out, consecutively submerging and exposing the intertidal surface, while freshwater now and then, at moments of heavy rainfall, may enter the system from the land. Mangroves can live in these highly dynamic and demanding environmental conditions via a series of remarkable adaptations such as aerial roots (pneumatophores), specialized cells in their leaves to excrete salt and the production of buoyant seeds and fruits (propagules) that disperse at the ocean surface (i.e. hydrochory). With their dense root networks, mangroves present a natural breeding ground and nursery for juvenile fish and provide shelter to many other animal species, rendering mangrove systems ecologically invaluable. From a socio-economical point of view, these forests sustain fisheries, provide firewood and wood for charcoal and construction. They may offer coastal protection to natural disasters such as storm surges and under certain conditions against tsunami. Despite their ecological and economical value, about 40 % of original mangroves have been lost worldwide during the last 50 years due to excessive exploitation and development. Deforestation, degradation and conversion to other land uses like intensive shrimp farming and agriculture have reduced and fragmented these ecosystems at an alarming rate. Climate change, probably most pronouncedly via changes in sea level, poses another important threat. In this dissertation we investigate some understudied but important aspects of the dispersal process in mangroves, with as the main objective the reduction of parameter and model uncertainty. In this way more reliable predictions of dispersal patterns and long-term population dynamics under different climate change scenarios can be expected. |
