Abstract. Litter decomposition plays a vital role in wetland carbon cycling.
However, the contribution of aboveground litter decomposition to the wetland
soil organic carbon (SOC) pool has not yet been quantified. Here, we
conducted a Carex brevicuspis leaf litter input experiment to clarify the intrinsic factors
controlling litter decomposition and quantify its contribution to the SOC
pool at different water levels. The Carex genus is ubiquitous in global
freshwater wetlands. We sampled this plant leaf litter at −25, 0, and +25 cm relative to the soil surface over 280 d and analysed leaf litter
decomposition and its contribution to the SOC pool. The percentage litter
dry weight loss and the instantaneous litter dry weight decomposition rate
were the highest at +25 cm water level (61.8 %, 0.01307 d−1),
followed by the 0 cm water level (49.8 %, 0.00908 d−1), and the
lowest at −25 cm water level (32.4 %, 0.00527 d−1). Significant
amounts of litter carbon, nitrogen, and phosphorus were released at all
three water levels. Litter input significantly increased the soil microbial
biomass and fungal density but had nonsignificant impacts on soil bacteria,
actinomycetes, and the fungal∕bacterial concentrations at all three water
levels. Compared with litter removal, litter addition increased the SOC by
16.93 %, 9.44 %, and 2.51 % at the +25, 0, and −25 cm water
levels, respectively. Hence, higher water levels facilitate the release of
organic carbon from leaf litter into the soil via water leaching. In this
way, they increase the soil carbon pool. At lower water levels, soil carbon
is lost due to the slower litter decomposition rate and active microbial
(actinomycete) respiration. Our results revealed that the water level in
natural wetlands influenced litter decomposition mainly by leaching and
microbial activity, by extension, and affected the wetland surface carbon
pool.
Seasonal variation in the leaf-litter frog community (Amphibia: Anura) from an Atlantic Forest Area in the Salto Morato Natural Reserve, southern Brazil
