Interacting Effects of Plant Invasion, Climate, and Soils on Soil Organic Carbon Storage in Coastal Wetlands

Abstract

Coastal wetland soils store large amounts of organic carbon, which is becoming vulnerable to environmental changes such as exotic species invasion and climate change. Soil organic carbon (SOC) is also related to soil biogeochemical factors. To understand the mechanisms of these changes in regulating SOC, it is necessary to characterize the direct and indirect effects of exotic species invasion, climate, and soil variables on SOC. We used a structural equation model to identify the key driving mechanisms of SOC storage to a depth of 1 m at 15 sites on the East China coast, where Spartina alterniflora Loisel. (S. alterniflora) invasion has significantly influenced SOC storage. The model revealed several patterns that are expected to explain the enhanced SOC storage. Spartina alterniflora invasion had a direct effect on SOC storage mainly due to its impacts on biomass production. Temperature had an important influence on SOC storage and the subsurface SOC content. SOC storage was also related to the interacting effects of S. alterniflora invasion and soil biogeochemical properties such as soil salinity, fine soil fraction, and bulk density. The relative contribution of SOC in the topsoil to SOC storage at a depth of 1 m decreased over time, while the contribution increased for the SOC below the surface. These results highlight the interactions among S. alterniflora invasion, climate, and soil properties in regulating SOC dynamics. Our results imply that the relative importance of vertical patterns to SOC storage associated with S. alterniflora invasion and temperature fluctuations will change over time.Plain Language Summary The world's largest invasion of S. alterniflora is occurring in the coastal wetlands of China. Coastal wetland soils, which are vulnerable to exotic species invasions, contain large amounts of organic carbon. The controlling mechanisms of soil organic carbon (SOC) associated with S. alterniflora invasion and climate change may be complex due to the interrelationships that exist among ecological factors. In our study, we investigated the effects of plant invasion, climate, and soils on SOC storage and its vertical distribution. We found that SOC storage was enhanced over time. Spartina alterniflora invasion had a direct effect on SOC storage mainly due to its impacts on biomass production. Temperature had an important influence on SOC storage and the subsurface SOC content. The interacting effects of S. alterniflora invasion and soil biogeochemical properties such as soil salinity, fine soil fractions, pH, and bulk density were also identified as having crucial impacts on SOC storage. Our results suggest an interesting possibility that the relative contribution of vertical patterns to the SOC pool is likely to change over the invasion period. Citation: Yang, R.-M. (2019). Interacting effects of plant invasion, climate, and soils on soil organic carbon storage in coastal wetlands.

Spartina alterniflora invasion controls organic carbon stocks in coastal marsh and mangrove soils across tropics and subtropics

“…Many studies (Stagg et al, 2017; Williams & Rosenheim, 2015) only investigate one or some fundamental factors that control SOC dynamics. However, S. alterniflora invasion is dependent on a complex series of responses from coastal wetlands (Osland et al, 2018; Yang, 2019a). Factors influencing this invasion may include (i) climate factors: global precipitation and temperature affect coverage distribution and NPP of S. alterniflora .…”

The Case for a Critical Zone Science Approach to Research on Estuarine and Coastal Wetlands in the Anthropocene

“…Indeed, the world lost around half of its coastal wetlands altogether during the twentieth century (Li et al 2018). Examples of human impact on coastal wetlands from the recent literature indicate that the processes of disruption are at once diverse and widespread and include sea level rise (Haywood et al 2020), higher salinities (Yu et al 2019), lower sediment fluxes due to reduced freshwater inflows (Cheng et al 2019), pollution by heavy metals (Ye et al 2020), organic compounds (Tang et al 2020) and microplastics (Zhou et al 2020), the introduction of invasive species (Yang 2019) and habitat loss and fragmentation (Bryan-Brown et al 2020). Land reclamation projects have been especially prominent around the major coastal cities in Asia over the last two decades with considerable impact on coastal wetlands (Hu et al 2018;Sengupta et al 2020).…”

Salinity Affects Topsoil Organic Carbon Concentrations Through Regulating Vegetation Structure and Productivity

“…Soil texture has been reported to affect SOC stocks in coastal salt marshes (Bai et al, ; Yang, ), mainly by two ways (Yang et al, ): First, increasing clay and silt contents reduces microbial decomposition via stabilizing the SOC and decreasing carbon leaching, thus leading to accumulation of SOC, and second, increasing clay and silt contents stimulates plant production by increasing the water holding capacity, thereby increasing carbon inputs to soil. Our results also highlighted the importance of soil texture in controlling SOC concentrations, as indicated by the significant negative relationship between SOC concentrations and median grain size (Figure e), which could at least partly explain the spatial variability of SOC concentrations in the Chongming Dongtan salt marsh.…”

“…An elemental analyzer (Vario Macro, Elementar Analysensysteme GmbH, Hanau, Germany) was used to measure SOC concentration (g kg −1 ). SOC stock (kg m −2 ) in the 0‐30 cm soil depth at each site was then estimated using equation , according to Yang (): …”