Flowering patterns in three neotropical mangrove species: Evidence from a Caribbean island

The present study sought to identify the factors that drive flowering in the main neotropical mangrove species. We evaluated the effects of water regime variables and foliar meristematic activity on the flowering intensity of Rhizophora mangle, Laguncularia racemosa, and Avicennia germinans in three physiographic types of San Andres Island, Colombia. The results show that pore salinity regulates flowering intensity and periodicity in all three mangrove species. All species flowering showed significant correlations with water balance and air vapor pressure deficit (VPD). In the fringe and interior mangroves, R. mangle flowering was explained linearly by salinity (25%) and monthly change in salinity (47%), respectively. L. racemosa flowering was linked with stronger periods of foliar meristematic activity and occurred during months of relatively high water balance (54–233 mm) and low VPD (1.18–1.29 kPa). The flowering of A. germinans was triggered by water deficit conditions when the monthly pore salinity increased over 30 g L−1 and, with a month delay response, when the water column height (WCH) was below ground. The flowering of A. germinans was also explained by these variables at 65% and 39%, respectively. The flowering patterns of the studied mangrove species indicate that reproduction within the neotropical mangrove community depends on seasonally contrasting water conditions on an annual basis.

Research highlights
► Water regime and meristematic activity as drivers of neotropical mangroves flowering.
► Flowering was related to water balance and air vapor pressure deficit in all species.
► Pore salinity regulates flowering intensity and periodicity in all species.
► Reproduction in the community depends on seasonally contrasting water conditions.