Ecological significance of standing dead phytomass: Marcescence as a puzzle piece to the nutrient cycle in temperate ecosystems
Abstrakt
1. The plant economics spectrum (PES) drives nutrient cycling through effects on soil decomposers. However, dead phytomass may remain standing or unshed (marcescent), hardly accessible to decomposers and be photodegraded. In arid zones, the significant part of marcescent phytomass can be decomposed with- out touching the ground. In temperate zones, photodegradation of marcescent phytomass is low but prompts important chemical changes, which affect its sub- sequent decomposability in the soil and alters the surrounding environment. It is unknown, however, how common marcescence is among different taxa and in which habitats, and how it is coordinated by PES traits.2. We sampled standing (marcescent) and lying (shed) dead phytomass from a broad spectrum of 127 herbaceous temperate species in a common garden experiment and related these parameters to PES traits, species ecological preferences and phylogeny.3. Nearly all species (97%) kept their phytomass marcescent. Tall species with a small leaf area and high leaf carbon had a high level of marcescence. Marcescent species also preferred sites affected by severe (but not necessarily frequent) disturbance. The degree of marcescence was considerably conserved in phylogeny.4. Synthesis. Marcescence extends PES trait effects on ecosystems, particularly in immature habitats, being a common but overlooked phenomenon of the temper- ate flora.