Patterns and drivers of evapotranspiration in South American wetlands

Abstract

Evapotranspiration (ET) is a key process linking surface and atmospheric energy budgets, yet its drivers and patterns across wetlandscapes are poorly understood worldwide. Here we assess the ET dynamics in 12 wetlands complexes across South America, revealing major differences under temperate, tropical, and equatorial climates. While net radiation is a dominant driver of ET seasonality in most environments, flooding also contributes strongly to ET in tropical and equatorial wetlands, especially in meeting the evaporative demand. Moreover, significant water losses through wetlands and ET differences between wetlands and uplands occur in temperate, water-limited environments and in highly flooded areas such as the Pantanal, where slow river flood propagation drives the ET dynamics. Finally, floodplain forests produce the greatest ET in all environments except the Central Amazon, where upland forests sustain high rates year round. Our findings highlight the unique hydrological functioning and ecosystem services provided by wetlands on a continental scale.

Evapotranspiration in a subtropical wetland savanna using low‐cost lysimeter, eddy covariance and modelling approaches

“…These data also lie within the range of ET estimated by other studies in subtropical and tropical grasslands and wetlands. At the humid end, ET in the equatorial wetlands in the Amazon is 1300–1550 mm/year (Fleischmann et al, 2021) and around 1320 mm in a freshwater wetland in Central Florida (Dolan et al, 1984). The subtropical wetland savanna in the Everglades National Park has ET values around 1200 mm/year (Saha et al, 2012).…”