Patterns of decomposition and functional traits for flower and leaf litter in tropical woody species

The variation within and across species has afterlife effects on carbon and nutrient cycling through the alteration of litter decomposability. However, the focus on leaves may not reflect a whole-plant economic spectrum of strategies. Here, we assessed the patterns and predictors of flower and leaf-litter decomposition at the intra- (i.e., flowers and leaves of the same species) and inter-specific (i.e., flowers and leaves from different species) levels for 29 tropical woody species in northeast Brazil. We evaluated nine functional litter traits, including structural and chemical traits. Flower litter decomposed, on average, three times faster than leaf litter (11.9% and 39.4% mass remaining, respectively) and exhibited higher water-holding capacity (WHC), leaching (LEA), and N, P, and K content. Otherwise, leaf litter showed higher density (DEN) and Ca, Mg, and Na content. The average relative differences in decomposition rate and functional traits between flower and leaf litter did not differ at both intra- and inter-specific levels. The predictors of decomposition were mostly similar, explaining 39% and 37% of flower and leaf litter, respectively. Leaching, P, Ca, Mg, and Na predict both flower and leaf-litter decomposition. However, WHC exclusively predicted flower-litter decomposition, and DEN, N, and K exclusively predicted leaf-litter decomposition. The observed differences in decomposition rate and functional traits between flower and leaf litter indicate that the afterlife effects differ between these plant organs and leverage the role of flower litter and its secondary consequences to nutrient and carbon cycling on ecosystems.