Pulse frequency and soil-litter mixing alter the control of cumulative precipitation over litter decomposition



Joly F, Kurupas KL & Throop HL (2017) Pulse frequency and soil-litter mixing alter the control of cumulative precipitation over litter decomposition. Ecology, 98 (9), pp. 2255-2260.

Macroclimate has traditionally been considered the predominant driver of litter decomposition. However, in drylands, cumulative monthly or annual precipitation typically fails to predict decomposition. In these systems, the windows of opportunity for decomposer activity may rather depend on the precipitation frequency and local factors affecting litter desiccation, such as soil-litter mixing. We used a full-factorial microcosm experiment to disentangle the relative importance of cumulative precipitation, pulse frequency, and soil-litter mixing on litter decomposition. Decomposition, measured as litter carbon loss, saturated with increasing cumulative precipitation when pulses were large and infrequent, suggesting that litter moisture no longer increased and/or microbial activity was no longer limited by water availability above a certain pulse size. More frequent precipitation pulses led to increased decomposition at high levels of cumulative precipitation. Soil-litter mixing consistently increased decomposition, with greatest relative increase (+194%) under the driest conditions. Collectively, our results highlight the need to consider precipitation at finer temporal scale and incorporate soil-litter mixing as key driver of decomposition in drylands.

arid ecosystem; carbon cycle; Chihuahuan Desert; global change; litter moisture; precipitation regime; water pulses

Ecology: Volume 98, Issue 9

Publication date30/09/2017
Publication date online19/06/2017
Date accepted by journal08/06/2017
PublisherWiley-Blackwell for the Ecological Society of America

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Dr Francois-Xavier Joly

Dr Francois-Xavier Joly

Lecturer in Soil, Biological and Environmental Sciences