Variation in Plant Litter Decomposition Rates across Extreme Dry Environments in Qatar

Decomposition of plant litter is a key process for transfer of carbon and nutrients in
ecosystems. Carbon contained in decaying biomass is released to the atmosphere as
respired CO2, a greenhouse gas that contributes to global warming. To our knowledge,
there have been no studies on litter decomposition in terrestrial ecosystems in
the Arabian peninsula. Here we used commercial teabags (green tea, rooibos tea)
as standard substrates to study decomposition rates across contrasting ecosystems
in Qatar.
Teabags were buried under and beside Acacia tortilis trees, in depressions with
abundant grass vegetation, in saltmarsh without and with vegetation, under
Zygophyllum qatarense in drylands, in natural mangrove and in planted mangrove.
There were signifcant site effects across ecosystems on decomposition rate (k),
litter stabilisation factor (S), fnal weight of green tea and fnal weight of rooibos
tea. Mangrove and depressions with grassland had the smallest amounts of
remaining green and rooibos tea after the incubation period (69-82 days), while
teabags buried under A. tortilis and in saltmarsh without vegetation had the largest
amounts. Thus decomposition rates differ among ecosystems in the desert environment.
Further multi-year and site studies are needed to identify factorsthatinfuence
decomposition rates across sites in extreme environments.