The future of coastal wetlands and their ecological value depend on their capacity to adapt to the interacting effects of human impacts and sea-level rise. Even though extensive wetland loss due to submergence is a possible scenario, its magnitude is highly uncertain due to limited understanding of hydrodynamic and bio-geomorphic interactions over time. In particular, the effect of man-made drainage modifications on hydrodynamic attenuation and consequent wetland evolution is poorly understood. Predictions are further complicated by the presence of a number of vegetation types that change over time and also contribute to flow attenuation. Here, we show that flow attenuation affects wetland vegetation by modifying its wetting-drying regime and inundation depth, increasing its vulnerability to sea-level rise. Our simulations for an Australian subtropical wetland predict much faster wetland loss than commonly used models that do not consider flow attenuation.
Dryland wetlands are resilient ecosystems that can adapt to extreme periodic drought–flood episodes. Climate change projections show increased drought severity in drylands that could compromise wetland resilience and reduce important habitat services. These recognized risks have been difficult to evaluate due to our limited capacity to establish comprehensive relationships between flood–drought episodes and vegetation responses at the relevant spatiotemporal scales. We address this issue by integrating detailed spatiotemporal flood–drought simulations with remotely sensed vegetation responses to water regimes in a dryland wetland known for its highly variable inundation. We show that a combination of drought tolerance and dormancy strategies allow wetland vegetation to recover after droughts and recolonize areas invaded by terrestrial species. However, climate change scenarios show widespread degradation during drought and limited recovery after floods. Importantly, the combination of degradation extent and increase in drought duration is critical for the habitat services wetland systems provide for waterbirds and fish.
4 August 2021 in Philosophical Transactions of the Royal Society B: Biological Sciences
The frequency and intensity of natural hazards and extreme events has increased throughout the last century, resulting in adverse socioeconomic and ecological impacts worldwide. Key factors driving this increase include climate change, the growing world population, anthropogenic activities and ecosystem degradation. One ecologically focused approach that has shown potential towards the mitigation of these hazard events is the concept of nature's contributions to people (or NCP), which focuses on enhancing the material and non-material benefits of an ecosystem to reduce hazard vulnerability and enhance overall human well-being. Soils, in particular, have been identified as a key ecosystem component that may offer critical hazard regulating functionality. Thus, this review investigates the modulating role of soils in the regulation of natural hazards and extreme events, with a focus on floods, droughts, landslides and sand/dust storms, within the context of NCP. This article is part of the theme issue ‘The role of soils in delivering Nature's Contributions to People’.