Decay of multiple species of seagrass detritus is dominated by species identity, with an important influence of mixing litters

Authors

  • Tim N. Moore,

  • Peter G. Fairweather


T. N. Moore and P. G. Fairweather, School of Biological Sciences, Flinders Univ., GPO Box 2100, Adelaide, South Australia 5001, Australia (tim.moore@flinders.edu.au).

Abstract

No studies of seagrass decay have examined effects of the number of species contained within the detrital pool. Given the importance of decay for nutrient cycling and long-term productivity, we tested how three seagrass species affected decay in litterbags. Experimental results clearly showed that species identity was the predominant driver of mass loss, with total loss not differing between bags containing one, two and three species. Furthermore, we show there were also non-additive effects of mixing litter that were not predicted from single-species decay rates. The nature of the non-predictable mass loss varied both through time and with the number of species in the mixtures. This indicates that species richness indeed plays a role in this important ecosystem function but one that is of less importance than species identity. The concordance of these results with terrestrial studies suggests that mechanisms responsible for mixed-species decay rates may be broadly applicable across ecosystems.

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