Seasonal release of propagules in mangroves - Assessment of current data

Phenology is often neglected in dispersal research, in spite of its potential effects on the patterns of propagule deposition. Based on peer-reviewed literature, we collated data on propagule release timing for mangroves and aimed at understanding the relation between mangrove propagule release timing and monthly average rainfall and temperature. There were data on 47 species of 25 genera, accounting for 67% of mangrove species, but most (35%) of the available data are related to Avicennia marina, Avicennia germinans and Rhizophora mangle. We found significant correlations (r > 0.8, P < 0.001) between mangrove propagule release and rainfall, with 72% of data reporting propagule release during the wet season, except in the southernmost latitudes. In the equatorial zone (10°N-10°S), propagules fall from parent trees throughout most of the year with no pronounced production peaks. At latitudes higher than the equatorial zone, propagule release was also significantly correlated with temperature (r > 0.6, P < 0.05). Our results show phenological complementarity between the northern and southern hemisphere, with a peak in propagule release corresponding to the boreal and austral summer, respectively. We encourage mangrove researchers to report data on propagule release and availability to render an increasingly accurate and precise interpretation of geographic patterns as the current dataset increases, both in terms of geographic and species coverage.