Litter Fall From Shrubs in the Northern Mojave Desert

Strojan, Carl; Turner, Frederick; Castetter, Richard

Plant litter was collected in traps from 8-10 replicates each of Ambrosia dumosa, Ephedra nevadensis, Krameria parvifolia, Larrea tridentata, Lycium andersonii and L. pallidum in Rock Valley, southern Nevada. Collections were made at biweekly to monthly intervals from 1975-1977 and handsorted into leaves, stem, flowers and fruites. L. pallidum produced the most litter, with annual means ranging from 52-173 g/shrub. Annual means per shrub for other species ranged from 39-89 g (L. andersonii), 27-77 g (L. tridentata), 20-29 g (E. nevadensis), 6-18 g (K. parvifolia) and 3-21 g (A. dumosa). Litter fall was generally correlated with annual rainfall, which was low in 1975 (62 mm), high in 1976 (223 mm), and close to the long-term mean in 1977 (141 mm). Leaves were generally the largest litter category, followed by stems, fruits and flowers. Large sample variations were found, particularly for reproductive parts. Aboveground litter fall from the 6 spp., which comprise approx/= 82% of perennial plant biomass and approx/= 81% of shrub cover in Rock Valley, was about 117 kg/ha in 1975 and 318 kg/ha in 1976. Total aboveground litter fall for Rock Valley (all perennial and annual plants) was 194 kg/ha in 1975 and 530 kg/ha in 1976. Distinct litter fall patterns occurred for shrub species and litter categories. Most litter fell during the summer months, with individual species peaks reflecting particular phenologies. Significant amounts of live aboveground biomass were shed as litter. Amounts of litter from the 6 spp. ranged from 7-83% of their respective live aboveground biomass.

Litter Fall From Shrubs in the Northern Mojave Desert

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