Rapid peat development beneath created, maturing mangrove forests: ecosystem changes across a 25-yr chronosequence.

Area of Science:

• Ecology
• Soil Science
• Coastal Ecosystems

Background:

• Mangrove forests are highly productive, carbon-rich ecosystems vital for coastal protection.
• Understanding soil carbon dynamics is key, especially in restored mangroves aiming to replicate lost functions.
• Peat development rates in maturing and restored mangroves require further quantification.

Purpose of the Study:

• To quantify the rate of soil organic matter development in created, maturing mangrove forests.
• To compare ecosystem properties in created mangroves with adjacent natural forests.
• To estimate the time for created mangroves to reach ecological equivalency with natural systems.

Main Methods:

• A 25-year chronosequence study was used to measure ecosystem changes.
• Ecosystem properties were compared between created and natural mangrove forests.
• Site-specific changes were quantified between 2010 and 2016.

Main Results:

• Rapid soil organic matter accumulation occurred, forming a 20-cm peat layer within 25 years.
• Created mangroves reached ecological equivalency: <15 years (vegetation), ~55 years (trees), ~25-80 years (soil layers).
• Soil elevation gain in created mangroves matched or exceeded natural ones within 5 years.

Conclusions:

• Mangrove peat formation is exceptionally rapid, occurring within decades, unlike centuries in other peatlands.
• Rapid peat development, driven by root accumulation, supports carbon sequestration and coastal adaptation.
• Findings improve predictions for mangrove restoration success and resilience to climate change and sea-level rise.