Abstract
Indonesian coral reefs are famous for their high number of species. Samples have been taken over more than 100 years resulting in valuable natural history collections in museums and herbaria. These scientific collections enable detection of alterations in the composition of Indonesian marine fauna and flora though time and in particular assess the effect of the important El Niño Southern Oscillation (ENSO) events on reef communities. For the recognition of global change signals and a rational choice of indicator taxa, a solid historical baseline is needed. This may be achieved by the compilation of reliable and validated Indonesian biodiversity data from as far back in time as possible. Model taxa are selected, based on their representation in museum and herbarium collections and their response to environmental change. Next to data base comparison, we will analyse CaCO3 secreting organisms, such as corals and mollusks from the collections to detect patterns in timing and intensity of past ENSO events. The skeletal growth band patterns of museum specimens collected in the course of the 20th Century can be compared. Fluorescent banding, correlated with rainfall, is exposed with the help of UV-light. Small samples of CaCO3 can be taken from the bands with the help of a computer-guided microdrill. Stable oxygen isotope and Sr/Ca analyses on these samples will provide time series on sea surface temperatures and precipitation / evaporation changes and can thus be used as a reference for observed changes in floral / faunal composition.
Netherlands