Functional shifts in the potential ecosystem services and disservices of Pontederia crassipes along a freshwater–marine continuum
TL;DR
These findings support the development of integrated, spatially explicit management approaches aimed at understanding the balance between the potential ecosystem services/disservices with the aim to mitigating the impacts of invasive macrophytes in transitional coastal systems.
Abstract
Wetland systems are key components of many coastal zone, playing a critical role in global ecological and economic sustainability. However, biological invasions represent a pervasive pressure in these environments, with significant impacts on biodiversity and socio-economic activities. Pontederia crassipes , one of the world’s worst invasive alien plant species, was introduced to Europe in the 18th century and continues to cause substantial ecological and economic impacts. As a freshwater macrophyte with limited tolerance to low salinity occurring in coastal lagoons, this species has been associated with multiple impacts across aquatic ecotones. Assessing the environmental effects of invasive species across coastal gradients requires integrated analytical frameworks. In this study, we apply the Drivers–Pressures–State–Impact–Response (DPSIR) framework to evaluate the impact of P. crassipes along a freshwater-estuarine continuum in a protected coastal lagoon in Portugal. We integrated existing seasonal environmental datasets with data from previously conducted in-situ and ex-situ experiments to assess biomass dynamics and ecosystem processes as decomposition and mineralisation associated with this invasive macrophyte. Our results indicate a salinity-driven functional shift, with P. crassipes acting as a nutrient sink in freshwater sectors and as a nutrient source in more saline environments, due to enhanced decomposition and mineralization processes. This shift alters ecosystem functioning and contributes to spatial variability in the potential ecosystem services and disservices provided by water hyacinth along the aquatic continuum. By combining process-based observations with a DPSIR framework, this study identifies key ecological mechanisms underlying invasion dynamics across salinity gradients and highlights critical limitations of current management strategies. These findings support the development of integrated, spatially explicit management approaches aimed at understanding the balance between the potential ecosystem services/disservices with the aim to mitigating the impacts of invasive macrophytes in transitional coastal systems.