Contribution of microtopography and hydroperiod to the natural regeneration of Avicennia germinans in a restored mangrove forest

Abstract

We evaluated the success of the ecological restoration of a degraded mangrove forest by monitoring the natural regeneration of Avicennia germinans (black mangrove). The restoration actions focused on hydrological rehabilitation by desilting tidal channels and modifying the microtopography to enhance or restore water flow. As a result of these efforts, a population of black mangrove established naturally. Six sampling sites including restored and reference areas were established. We measured seedling survival; tree density, height, and growth rate; and the physical and chemical characteristics of soil and water. According to a redundancy analysis, microtopography and hydroperiod contributed the most to the establishment and development of the black mangrove. Microtopography ranged from 0.08 to 0.14 m above sea level. In the case of the hydroperiod, water level ranged from 0.11 to 0.14 m, flooding duration ranged from 439 to 529 h per month, and frequency was 7 to 8 floods per month. Our results highlight the contribution of microtopography and hydroperiod to the natural establishment of black mangrove. It is important to consider these 2 variables in mangrove ecological restoration.