Anthropogenic stress may affect aquatic hyphomycete diversity more than leaf decomposition in a low-order stream

Changes in dominance among species in aquatic hyphomycete assemblages do not affect litter decomposition rates

“…Despite the differences in dominance/evenness and/or identity of the dominant species among assemblages, there were no significant differences in litter-mass loss, which seems to indicate functional redundancy among aquatic hyphomycete assemblages, as suggested by some field experiments (Bär-locher & Graça 2002, Pascoal et al 2005, Ferreira et al 2006b). Still, because the identity of the dominant species changed in late assemblages, and the various species have been reported to differ in their abilities to decompose litter (Suberkropp & Klug 1980, Arsuffi & Suberkropp 1984, Butler & Suberkropp 1986), functional redundancy was not expected.…”

“…The importance of dominant species in driving ecosystem processes has been demonstrated previously (Hector et al 2000, Smith & Knapp 2003, Dangles & Malmqvist 2004, Ellison et al 2005, Hillebrand et al 2008. However, leaf litter incubated in streams with distinct aquatic hyphomycete communities (different species richness and identity) decomposes at similar rates, which suggests a certain level of functional redundancy among communities (Bärlocher & Graça 2002, Pascoal et al 2005, Ferreira et al 2006b, but see Baudoin et al 2008). Though different communities might decompose litter at similar rates, this probably results from the interaction between species number, identity (i.e.…”

“…Also, the hetero trophic nature of these small streams and their strong interaction with the terrestrial surroundings (Vannote et al 1980, Mulholland et al 2001) make them most sensitive to changes in the riparian vegetation, which can result from invasion by exotic species, conversion of diverse deciduous forests into tree monocultures or agricultural fields, vegetation re mo val by forestry practices or urban development (Chadwick et al 2006, Ferreira et al 2006b, Lecerf et al 2007, Castela et al 2008. All these threats have been shown to induce changes in the structure of aquatic communities (Bärlocher & Graça 2002, Pascoal et al 2005, Ferreira et al 2006b, Castela et al 2008, Dang et al 2009), which might have profound consequences for the maintenance of ecosystem processes.…”

Denaturing Gradient Gel Electrophoresis (DGGE) in Microbial Ecology - Insights from Freshwaters

“…Este 1 is at the spring of the stream while Este 2 is located ca. 5 Km downstream, near the industrial park of Braga (Duarte et al 2008a(Duarte et al , 2009aPascoal et al, 2005). At first glance, fingerprints of fungal communities from leaves decomposing at the two sites a p p e a r t o b e d i f f e r e n t , b u t v i s u a l i n s p e c t i o n i s n o t e n o u g h t o d r a w a n y p a r t i c u l a r conclusion (Fig.…”

Copper and zinc affect the activity of plasma membrane H+-ATPase and thiol content in aquatic fungi

“…Amongst fungi, aquatic hyphomycetes appear to have the greatest ecological role as decomposers of plant detritus in streams (Baldy et al, 2002; Pascoal & Cássio, 2004). Even though metal pollution lowers the biodiversity and activity of aquatic hyphomycetes, the occurrence of these groups of fungi has been consistently reported in metal-polluted streams (Pascoal et al, 2005a;Sridhar et al, 2005). This means that fungi, similar to other living organisms, have to tightly regulate the intracellular metal concentration in such a way that safe uptake of the required metal ions in the cytosol and organelles can occur without cellular damage due to metal toxicity (Kneer et al, 1992).…”