Spatial Variability in Decomposition Rates in a Desert Scrub of Northwestern Mexico |
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Authors: | Laura Arriaga Yolanda Maya |
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Institution: | (1) Centro de Investigaciones Biológicas del Noroeste (CIBNOR), S.C., Mar Bermejo 195, Col. Playa Palo de Santa Rita, La Paz, 23090, Baja California Sur, México |
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Abstract: | The decomposition of leaf litter for five dominant plant species of a desert scrub in Baja California Sur, Mexico was investigated.
We designed a factorial decomposition experiment using decomposition bags and the collected leaf-litter from Prosopis articulata, Jatropha cinerea, J. cuneata, Cyrtocarpa edulis, and Fouquieria diguetti. Factors, such as radiation exposure, rainfall, and the size of litter-consuming organisms were considered. The rates of
litter decomposition were calculated for these plant species and the environmental conditions by using single exponential
models. The initial concentration of nutrients (C, N, P, K, and Ca) and crude-fiber content of the leaf litter were determined.
Our results show that the environmental heterogeneity generated by different conditions of radiation exposure and short-term
rainfall patterns are the most relevant factors affecting decomposition processes in this Sonoran desert community. A species-specific
pattern was observed in decay rates and mass-loss patterns. Decomposition rates varied from 0.0027 to 0.0201 depending on
the species and exposure to different ecological conditions. The decay rates were higher under bare-soil conditions and during
a wet year than under the shade provided by the canopy of nurse trees and during a dry year. The leaf litter of J. cuneata reincorporated to the soil more rapidly than that of P. articulata and C. edulis. Termites were the more important macroarthropods associated with litter decomposition, and their harvest distribution was
independent of the resources distribution. The ecological significance of these results is discussed considering the extreme
climatic conditions prevailing in this region. |
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Keywords: | Baja California Sur Decomposition rates El Ni?o-Southern Oscillation Radiation exposure Rainfall fluctuations Sarcocaulescent scrub |
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