Traits control the digestibility-decomposition relationship

Fibre concentration and dry matter content can be considered as good predictors of both digestibility and decomposability.

Forage quality for herbivores and litter quality for decomposers are two important plant properties affecting ecosystem carbon and nutrient cycling. In agreement with “afterlife” effect hypothesis, Bumb et al. find a positive relationship between digestibility and decomposition for both leaves and stems of 16 species from low productive Mediterranean rangelands.

Scheme showing the putative links between traits of leaves and stems and the two degradation processes studied
Scheme showing the putative links between traits of leaves and stems and the two degradation processes studied here: digestibility and decomposition. Bumb et al. tested the hypotheses that (1) digestibility and decomposability covary positively (bidirectional arrow 1); (2) digestibility is affected by traits measured only on living organs (arrow 2); (3) traits of living organs affect some traits of litter for all studied organs (arrow 3) and (4) decomposability is caused by traits measured on both living and litter organs (arrows 4 and 5).

The two degradation processes are shown to be strongly driven by the fibre concentration and the dry matter content of organs. This study demonstrates the key role of plant traits to link above and below ground processes, which involve different types of organisms in the ecosystem.