Author(s):
Sampaio, Ana 
; Rodriguez-Gonzalez, Patricia ; Varandas, Simone ; Cortes, Rui Manuel ; Ferreira, Maria Teresa
Date: 2008
Persistent ID: http://hdl.handle.net/10400.5/5138
Origin: Repositório da UTL
Subject(s): leaf litter; forested wetlands; decomposition; lotic; lentic; microorganisms; macroinvertebrates
Description
Leaf litter breakdown is frequently used to measure both structural and functional integrity in aquatic ecosystems. Forested
wetlands are interface systems that received little attention, especially in the Iberian Peninsula. The present study compares
the decomposition of alder and willow in two biotopes (lentic and lotic) located in two different sites (Caxarias and Alpiarc¸a).
Litterbags were used to compare decomposition among the different treatments. Throughout decay, dry weight loss, nitrogen
and phosphorus content, microbial community physiological profiles, microbial and macro-invertebrate colonization were
measured at days 2, 4, 8, 16, 32 and 64. Decomposition rates ranged from intermediate to rapid for alder (0.006 day−1 to
0.0338 day−1) and slow to rapid for willow (0.0024 day−1 to 0.0272 day−1), depending on site and biotopes type. The combined
effects biotope × time was significant for heterotrophs (P < 0.05), molds (P < 0.05) and yeasts (P < 0.001). The analysis
of average well colour development (AWCD), richness (R) and Shannon-Wiener index (H ) based on the oxidation of carbon
and nitrogen sources by the microbial community, showed differences between the two biotopes, lotic and lentic, and sites.
These differences were also shown by the principal component analysis (PCA). Moreover, the macroinvertebrate communities
clearly distinguished between lentic and lotic systems. The invertebrates belonging to Plecoptera, Ephemeroptera and
Trichoptera were absent from lentic habitats.
