Autor(es):
Graça, M. A. S. 
; Poquet, J. M.
Data: 2014
Identificador Persistente: http://hdl.handle.net/10316/25516
Origem: Estudo Geral - Universidade de Coimbra
Assunto(s): Litter breakdown; Detritivores; Headwaters; Leaf traits
Descrição
We tested the hypothesis that water stress and
soil nutrient availability drive leaf-litter quality for decomposers
and detritivores by relating chemical and physical
leaf-litter properties and decomposability of Alnus glutinosa
and Quercus robur, sampled together with edaphic
parameters, across wide European climatic gradients. By
regressing principal components analysis of leaf traits
[N, P, condensed tannins, lignin, specific leaf area (SLA)]
against environmental and soil parameters, we found that:
(1) In Q. robur the condensed tannin and lignin contents
increased and SLA decreased with precipitation, annual
range of temperature, and soil N content, whereas leaf P
increased with soil P and temperature; (2) In A. glutinosa
leaves N, P, and SLA decreased and condensed tannins
increased with temperature, annual range of temperature,
and decreasing soil P. On the other hand, leaf P and condensed
tannins increased and SLA decreased with minimum
annual precipitation and towards sites with low temperature.
We selected contrasting leaves in terms of quality
to test decomposition and invertebrate consumption. There
were intraspecific differences in microbial decomposition
rates (field, Q. robur) and consumption by shredders (laboratory,
A. glutinosa). We conclude that decomposition rates
across ecosystems could be partially governed by climate
and soil properties, affecting litter quality and therefore decomposers and detritivores. Under scenarios of global
warming and increased nutrients, these results suggest we
can expect species-specific changes in leaf-litter properties
most likely resulting in slow decomposition with increased
variance in temperatures and accelerated decomposition
with P increase. This
research was funded by the IMAR and the FCT through the project
POCI/BIA-BDE/58297/2004.
