Stochastic dynamics of wetlandscapes: Ecohydrological implications of shifts in hydro-climatic forcing and landscape configuration

Leonardo E Bertassello; James W Jawitz; Antoine F Aubeneau; Gianluca Botter; P Suresh C Rao

doi:10.1016/j.scitotenv.2019.133765

Stochastic dynamics of wetlandscapes: Ecohydrological implications of shifts in hydro-climatic forcing and landscape configuration

Sci Total Environ. 2019 Dec 1:694:133765. doi: 10.1016/j.scitotenv.2019.133765. Epub 2019 Aug 6.

Authors

Leonardo E Bertassello¹, James W Jawitz², Antoine F Aubeneau³, Gianluca Botter⁴, P Suresh C Rao⁵

Affiliations

¹ Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907-2051, USA. Electronic address: lbertass@purdue.edu.
² Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, USA.
³ Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907-2051, USA.
⁴ Department of Civil, Architectural and Environmental Engineering, University of Padua, Padua I-35100, Italy.
⁵ Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907-2051, USA; Agronomy Department, Purdue University, West Lafayette, IN 47907-2054, USA.

PMID: 31756814
DOI: 10.1016/j.scitotenv.2019.133765

Abstract

Wetlands are embedded in landscapes in fractal spatial patterns, and are characterized by highly dynamic, interlinked hydrological, biogeochemical, and ecological functions. We propose here a stochastic approach to evaluate and predict the spatiotemporal hydrologic variability of wetlands at landscape scale (100 km²). Stochastic hydro-climatic forcing (daily rainfall and evapotranspiration) and the landscape topographic setting (spatial structure of wetlands within the landscape) are key drivers of wetland eco-hydrologic functionality. The novelty of our approach lies in the quantification of the hydrological dynamics for all wetlands distributed in a given landscape, and in linking stochasticity of hydroclimatic forcing and ecologically meaningful wetland network metrics. We applied the modeling framework to investigate daily hydrologic dynamics in six landscapes across the U.S. that span gradients of hydroclimate and abundance of wetlands. We assess landscape-scale patterns using four key wetland hydrological attributes that have significance in terms of aquatic habitat suitability and dispersal: (1) Abundance (2) Diversity (3) Persistence, and (4) Accessibility. We observe that the hydrologic responses of each of the six landscapes are driven by the interactions between regional stochastic hydro-climatic forcing and landscape topographic setting. Despite differences in these features, similar scaling relations define diversity (area distributions) and accessibility (separation-distance distributions). Persistence of hydrologic regimes, defined by duration of inundation above thresholds, was least in more-arid settings, and higher in humid settings, consistent with intuitive understanding. These results can support assessments of the spatiotemporal variability of ecohydrological attributes in diverse wetlandscapes, including aquatic species dispersal and habitat suitability for unique flora and fauna.

Keywords: Hydrologic regimes; Landscape connectivity; Persistence; Wetlandscapes.