Restoring Wetlands for Carbon Uptake and Climate Change Mitigation: The Impact of Site Conditions and Disturbance on Vegetation Growth and Carbon Budgets
Abstract
Wetlands are receiving attention as a natural solution to mitigate climate change. They not only preserve existing soil carbon stocks, but have the potential to remove carbon from the atmosphere and store it on geological timescales. With the rise of carbon offsetting as part of carbon cap and trade schemes, new funding may become available for projects to conserve existing or restore new wetlands for carbon uptake purposes. Often management strategies for wetland restoration focus on other ecological services, such as creating habitat and promoting biodiversity, rather than specifically addressing the climate benefits. Furthermore, wetland carbon monitoring studies are generally more prevalent in northern peatlands with only limited deployment of long-term carbon flux measurements from other types of wetlands. These studies have shown that wetlands vary hugely in their carbon cycle response to environmental drivers. In practice, these complexities and nuances can sometimes obscure the intended goal of carbon sequestration, if not addressed appropriately. Depending on the hydrological conditions, wetlands can emit other more potent greenhouse gases, such as methane. Furthermore, past and present site conditions, as well as disturbance events can greatly impact the carbon and greenhouse gas budgets on annual timescales. This site-to-site and year-to-year variability, as well as the metric used to determine a system's greenhouse gas balance, can introduce complications that seemingly reduce the effectiveness of the climate benefits.
We present measurements of carbon exchange using eddy covariance flux towers over five wetlands of varying ages amounting to 21 complete site-years of data to shed some light on the complexity of these systems and the implications as natural climate solutions. The wetlands experienced different land-use histories, soil chemistry, hydrology, and disturbances, which significantly affected their carbon budgets resulting in a range of outcomes from large carbon sinks to moderate sources. We discuss the long-term trends and trajectories of carbon uptake and the impact of various disturbance events on vegetation development and carbon budgets.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGC43A..09V
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCES;
- 0490 Trace gases;
- BIOGEOSCIENCES;
- 1630 Impacts of global change;
- GLOBAL CHANGE