A review of sediment carbon sampling methods in mangroves and their broader impacts on stock estimates for blue carbon ecosystems
- Authors: Fest, Benedikt , Swearer, Stephen , Arndt, Stefan
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Science of the Total Environment Vol. 816, no. (2022), p.
- Full Text:
- Reviewed:
- Description: Blue carbon ecosystems (BCEs), such as mangroves, tidal marshes, and seagrasses, are attracting interest for their potential to mitigate climate change arising from their high rates of carbon accumulation and the significant carbon stocks in their sediments. However, current sediment carbon sampling methods present a mixture of approaches adopted from paleoenvironmental methods focused on historical reconstruction of carbon accumulation, and from soil science methods developed to provide highly accurate and spatially representative carbon stock measurements. Currently, no international standard method for sediment carbon stock analysis exists. Consequently, current estimates of sediment carbon stock values for BCEs may have large uncertainties due to variable methodology. We reviewed and analysed the methods used 217 studies included in two recent global syntheses of carbon stocks in mangrove forest ecosystems to illustrate a lack of consistency in sediment sampling. We then outline how the choice of study design and field sampling methods can introduce inaccuracies and uncertainties in sediment carbon stock analysis. We conclude with examples of how each of these challenges can be resolved and how greater carbon stock quantification accuracy and higher spatial integration can be achieved for blue carbon ecosystems in the future. © 2021 Elsevier B.V.
Fine-scale spatial variability in organic carbon in a temperate mangrove forest : implications for estimating carbon stocks in blue carbon ecosystems
- Authors: Hu, Yang , Fest, Benedikt , Swearer, Stephen , Arndt, Stefan
- Date: 2021
- Type: Text , Journal article
- Relation: Estuarine, Coastal and Shelf Science Vol. 259, no. (2021), p.
- Full Text: false
- Reviewed:
- Description: Mangrove ecosystems have the potential to store large amounts of carbon but detailed studies on the fine scale spatial variability of biomass components and sediment organic carbon (SOC) and their relationships are lacking. Here we investigated the fine-scale spatial variation of SOC, aboveground and belowground biomass using systematic grid sampling in a temperate Avicennia marina ((Forssk.) Vierh) forest in Australia. We estimated aboveground biomass in a 9 × 9 sampling grid within a 0.16 ha plot and measured SOC, fine root biomass and necromass down to 1 m at 81 sampling points in an A. marina forest in Western Port Bay near Melbourne, Australia. We detected large differences in all measured carbon pools. SOC increased from low to high intertidal position but showed no consistent trend with depth. Aboveground biomass carbon was highly variable (mean 84 ± 56 Mg C ha
Impacts of land management practices on blue carbon stocks and greenhouse gas fluxes in coastal ecosystems—a meta-analysis
- Authors: O’Connor, Jack , Fest, Benedikt , Sievers, Michael , Swearer, Stephen
- Date: 2020
- Type: Text , Journal article
- Relation: Global Change Biology Vol. 26, no. 3 (2020), p. 1354-1366
- Full Text:
- Reviewed:
- Description: Global recognition of climate change and its predicted consequences has created the need for practical management strategies for increasing the ability of natural ecosystems to capture and store atmospheric carbon. Mangrove forests, saltmarshes and seagrass meadows, referred to as blue carbon ecosystems (BCEs), are hotspots of atmospheric CO2 storage due to their capacity to sequester carbon at a far higher rate than terrestrial forests. Despite increased effort to understand the mechanisms underpinning blue carbon fluxes, there has been little synthesis of how management activities influence carbon stocks and greenhouse gas (GHG) fluxes in BCEs. Here, we present a global meta-analysis of 111 studies that measured how carbon stocks and GHG fluxes in BCEs respond to various coastal management strategies. Research effort has focused mainly on restoration approaches, which resulted in significant increases in blue carbon after 4 years compared to degraded sites, and the potential to reach parity with natural sites after 7–17 years. Lesser studied management alternatives, such as sediment manipulation and altered hydrology, showed only increases in biomass and weaker responses for soil carbon stocks and sequestration. The response of GHG emissions to management was complex, with managed sites emitting less than natural reference sites but emitting more compared to degraded sites. Individual GHGs also differed in their responses to management. To date, blue carbon management studies are underrepresented in the southern hemisphere and are usually limited in duration (61% of studies <3 years duration). Our meta-analysis describes the current state of blue carbon management from the available data and highlights recommendations for prioritizing conservation management, extending monitoring time frames of BCE carbon stocks, improving our understanding of GHG fluxes in open coastal systems and redistributing management and research effort into understudied, high-risk areas. © 2019 John Wiley & Sons Ltd
Developing a nature-based coastal defence strategy for Australia
- Authors: Morris, Rebecca , Strain, Elisabeth , Konlechner, Teresa , Fest, Benedikt , Kennedy, David , Arndt, Stefan , Swearer, Stephen
- Date: 2019
- Type: Text , Journal article
- Relation: Australian Journal of Civil Engineering Vol. 17, no. 2 (2019), p. 167-176
- Full Text:
- Reviewed:
- Description: Australia’s rapid coastal population growth coupled with the increased risk of hazards driven by climate change creates an urgent need to start adaptation planning for the future. The most common solutions for protecting the coast (seawalls, breakwaters) are expensive and non-adaptive (i.e., they need to be rebuilt, upgraded and maintained in response to a changing climate). There is international precedence for the development of nature-based solutions (i.e., the integration of natural habitats such as coastal vegetation and biogenic reefs) as a cost-effective and sustainable approach to shoreline protection from erosion and flooding. The development of nature-based approaches has been supported by large interdisciplinary teams to inform policy and decision-making. Nature-based coastal defence is currently not a tool widely used in Australia. Key to their wider implementation is: (1) improved scientific knowledge; (2) effective governance; and (3) social acceptance. Recently implemented pilot trials need to inform industry-accredited guidelines that can be integrated into coastal management and government policy. © 2019, © 2019 Engineers Australia.