Local Storage Dynamics of Individual Wetlands Predict Wetlandscape Discharge

Abstract

Wetlands provide valuable hydrological, ecological, and biogeochemical functions, both alone and in combination with other elements comprising the wetlandscape. Understanding the processes and mechanisms that drive wetlandscape functions, as well as their sensitivity to natural and man-made alterations, requires a sound physical understanding of wetland hydrodynamics. Here, we develop and apply a single reservoir hydrologic model to a low-relief karst wetlandscape in southwest Florida (≈10 3 km 2 of Big Cypress National Preserve) using precipitation P and potential evapotranspiration PET as climatic drivers. This simple approach captures the dynamics of storage for individual wetlands across the entire wetlandscape and accurately predicts landscape discharge. Key model insights are the importance of depth-dependent extinction of evapotranspiration ET and the negligible effects of depth-dependent specific yield, the effects of which are diluted by landscape relief. We identify three phases of the wetlandscape hydrological regime: dry, wet-stagnant, and wet-flowing. The model allowed a simple steady-state analysis, which demonstrated the sudden seasonal shift between wet-stagnant and wet-flowing states, indicating a consistent threshold at P ≈ PET. Notably, stage data from any single wetland appears sufficient for accurate whole-landscape discharge prediction because of the relative homogeneity in timing and duration of local wetland hydrologic connectivity in this landscape. We also show that this method will be transferable to other wetlandscapes, where individual storage elements respond hydrologically synchronously, whereas model performance is expected to deteriorate for hydrologically more heterogeneous wetlandscapes.

Wetlandscape (dis)connectivity and fragmentation in a large wetland (Haiderpur) in west Ganga plains, India

“…Most of the time, seemingly isolated wetlands in a floodplain may not be isolated and there might exist a hydrological connectivity among them (Thorslund et al, 2017). The connectivity in such wetlands can be subsurface or episodic (Klammler et al, 2020; Rains et al, 2016). Therefore, understanding the role of hydrological connectivity is essential to decipher the impact of land‐use and climate change on wetland degradation (Golden et al, 2014; Klammler et al, 2020; Singh et al, 2021).…”

“…The connectivity in such wetlands can be subsurface or episodic (Klammler et al, 2020; Rains et al, 2016). Therefore, understanding the role of hydrological connectivity is essential to decipher the impact of land‐use and climate change on wetland degradation (Golden et al, 2014; Klammler et al, 2020; Singh et al, 2021). Wetland managers may not be able to mitigate the effects of climate change, but they can deploy local measures to counteract such effects by managing anthropogenic stressors such as nutrient loading and water abstraction (Green et al, 2017).…”

Role of small wetlands on the regime shift of ecological network in a wetlandscape

“…A wetlandscape, as an aggregate, supports additional emergent and dynamic ecosystem services which cannot be generated by an individual wetland. That is, a wetlandscape is a complex system composed of numerous components with their own traits and interactions (Thorslund et al 2017, Klammler et al 2020. Also, a wetlandscape and systems that depend on this often show dynamic and non-linear behavior originating from any change in its components.…”

The Baker Creek Research Watershed: Streamflow data highlighting the behaviour of an intermittent Canadian Shield stream through a wet–dry–wet cycle

“…The predominant first‐order controls that dictate stream network expansion and contraction vary by region, and this can dictate research questions and analyses. In some regions, topography is considered most important (Godsey & Kirchner, 2014; Prancevic & Kirchner, 2019), but in others it is geology (Devito et al, 2005; Lovill et al, 2018) or the distribution of surface storage capacity (Klammler et al, 2020; Rains et al, 2016). In many instances, these studies focus on short term changes in stream networks (i.e., weeks to months) to determine how physiography and meteorology control network dynamics.…”