Decomposition of site-specific litter mixtures was monitored for 100 wk in
four floodplain communities: (i) a mixed oak community along the Cache River
in central Arkansas, (ii) a sweetgum (Liquidambar styraciflua L.)-cherrybark
oak (Quercus falcata var. pagodaefolia Ell.) community along Iatt Creek in central
Louisiana, (iii) a sweetgum-swamp tupelo [Nyssa sylvatica var. biflora (Walt.)
Sarg.] community, and (iv) a laurel oak (Quercus laurifolia Michx.) community
along the Coosawatchie River in southeastern South Carolina. Soil temperature,
hydroperiod, and litter quality (C:N, C:P, N:P, lignin:N) were used to interpret
differences in the rates of mass loss and nutrient dynamics. After 100 wk, litter
mixtures retained 33, 18, 8, and 5% of original mass on the Cache, Coosawatchie
(laurel oak community), Coosawatchie (sweetgum-swamp tupelo community), and
Iatt floodplains, respectively, and these differences appeared related to hydroperiod.
Decay rates were comparable to rates reported in similar floodplain environments.
Net mineralization of both N and P was observed after 100 wk, but both elements
accumulated in litter mixtures periodically. Differences in hydroperiod were
observed among the four floodplain communities and decomposition of and nutrient
mineralization from litter among them appeared to be inversely related to the
number and duration of flood events. Litterbags containing leaflitter of a single-species
(i.e., cherrybark oak) were also monitored on three of the four sites to compare
decay rates and nutrient dynamics with the litter mixtures. On the Cache River
floodplain, slower decay of poorer quality cherrybark oak litter suggested that
litter quality drove decomposition under similar edaphic conditions.