Lateral Hydrological Connectivity Driven by Tidal Flooding Regulates Range-Expansion of Invasive Spartina alterniflora in Tidal Channel-Salt Marsh Systems

• Published in: Journal of environmental informatics Vol. 41; no. 1; pp. 16 - 26
• Main Authors: Ning, Z. H., Chen, C., Zhang, S. Y., Wang, A. D., Wang, Q., Xie, T., Bai, J. H., Cui, B. S.
• Format: Journal Article
• Language: English
• Published: Regina International Society for Environmental Information Sciences 01-03-2023
• Subjects: Aquatic plants; Channels; Ditches; Ecological risk assessment; Flats (landforms); Floods; Geomorphology; Grasses; Habitats; Hydrologic analysis; Hydrology; Introduced species; Invasive plants; Invasive species; Moisture effects; Nonnative species; Plant species; Risk assessment; Risk management; Salt marshes; Soil hardness; Soil moisture; Soil salinity; Soil stresses; Spartina alterniflora; Tidal flooding; Tidal floods; Wetlands
• ISSN: 1726-2135; 1684-8799
• DOI: 10.3808/jei.202300484

Understanding how hydrological features affect habitat invasibility is crucial for predicting whether variations of such hydrological features may act as important inducement regulating range-expansion of invasive species in tidal channel-salt marsh systems. Although lateral hydrological connectivity (LC), or the hydrological connections between tidal channels and adjacent marsh flats, is an important hydrological feature, its effect on plant invasion has rarely been studied in depth. Here, we examined the effects of lateral hydrological connectivity on range-expansion of Spartina alterniflora (S. alterniflora) in tidal channel margins of a typical tidal channelsalt marsh system, in the Yellow River Delta, China. Field surveys and transplanting experiments showed that high LC greatly favors S. alterniflora to expand its invasion ranges along tidal channel margins by mediating such habitat physical forms of stress as soil salinity, soil moisture and soil hardness. In contrast, low LC, exacerbates those forms of stress, thereby significantly checking the lateral expansion of S. alterniflora. Moreover, human-made and naturally formed geomorphic structures in salt marshes (e.g., artificial ditches, pools, and hollow microtopography), particularly at high elevations, could potentially enhance LC over time, thereby making such sites prone to invasion by S. alterniflora. These results highlight the importance of lateral hydrological connectivity as an essential driver to regulate S. alterniflora lateral expansion along with the tidal channels. Our results imply that considering the relationships between hydrological processes and spread processes of exotic species should be incorporated into future management frameworks for risk assessment and ecological control of invasive plant species.