Plant Decomposition in Wetlands: Effects of Hydrologic Variation in a Re-Created Everglades

Abstract

The effects of water depth and flow on marsh plant litter decomposition and soil chemistry were measured in the Loxahatchee Impoundment Landscape Assessment (LILA) facility (Boynton Beach, FL), where macrocosms mimic Everglades ridge-and-slough landscape features. Experiments were conducted in two macrocosms that differed in flow but had ridge, shallow slough, and deep slough habitats that differed in water depth. Decomposition of three common Everglades species, Crantz, Torr., and Aiton, were measured using litter bags incubated in the macrocosms under both wet and dry conditions. Litter decomposition was similar among flow treatments and habitats but differed by species and between wet and dry conditions. Decomposition rates from fastest to slowest were > > litter had more total P than the other two species, confirming the importance of P availability in controlling decomposition in the Everglades. Planted species had no effect on soil nutrient content during the ~4 yr of plant growth. Average water velocities of ~0.5 cm s attained in the flow treatment had no effect on decomposition or soil chemistry. The plant species used in this study are major contributors to Everglades' organic soils, so their decomposition rates can be used to parameterize models for how restoration manipulations will affect soil-building processes and to predict the temporal sequence of landscape responses to these manipulations. The results suggest that longer periods and flows greater than studied here may be necessary to see restoration effects on soil building processes.

A common‐mesocosm experiment recreates sawgrass (Cladium jamaicense) phenotypes from Everglades marl prairies and peat marshes

“…Water and soil analyses followed methods described in Serna et al. () and were based on EPA method 365.1 (US EPA, ), Nelson and Sommers (), and Solórzano and Sharp (). Air temperature for the duration of the study was downloaded from a weather station at FIU_MMc maintained by Dr. Rene Price (https://www.wunderground.com/history/monthly/us/fl/miami/KMIA/date/2019-8?cm_ven=localwx_history).…”

Carbon and Nutrient (N, P) Cycling of Created and Restored Wetlands

“…Once hydrology is restored, consistent periods of soil inundation reduce rates of microbial decomposition by creating anoxic soils. Increased duration of inundation further decreases decomposition rates, which can create heterogeneity of decomposition rates and carbon pools within or among wetlands (Serna et al 2013). Other factors that can affect decomposition rates include the quality and quantity of detritus additions, soil characteristics, and temperature which can vary both with season and with latitude.…”

Decomposition of Standing Litter Biomass in Newly Constructed Wetlands Associated with Direct Effects of Sediment and Water Characteristics and the Composition and Activity of the Decomposer Community Using Phragmites australis as a Single Standard Substrate

“…A high availability of nutrients from surface water or eutrophic sediments potentially leads to high biomass production and higher availability of nutrients in the litter (Tanner 1996;Hoagland et al 2001; Lee and Bukaveckas 2002;Fennessy et al 2008;Trinder et al 2009;Emsens et al 2016a, b). However, decomposition rates will also be high (Rejmánková and Houdková 2006;Sarneel et al 2010;Emsens et al 2016a), since high plant tissue nutrient levels will increase decomposition (Serna et al 2013) of the most easily degradable water-soluble compounds and nonlignified carbohydrates (Berg and Laskowski 2005). In contrast, high concentrations of N can also decrease decomposition rates of lignified carbohydrates and lignin, which are decomposed in later stages, due to their inhibiting effect on lignin degrading enzymes (Berg and Laskowski 2005).…”