Processing of leaf litter in a northern jarrah forest stream, Western Australia: I. Seasonal differences

Abstract

Seasonal differences in the processing of jarrah (Eucalyptus marginata) leaves were examined in a small forest stream of the Darling Range, Western Australia . Processing rates in both summer and winter were very low, placing this species in the `slow' category (k<0 .005) of Petersen & Cummins (1974) .Macroinvertebrates did not contribute to the processing of jarrah leaves during summer and autumn, coincident with the period of peak litter fall . The low quality of detritus entering the streams, and possibly some adverse interactions with the physical and chemical environment, inhibits processing during the summer months. As a consequence, a significant proportion of the coarse-particle detritus entering these streams may be exported unprocessed at the onset of high winter flows .In contrast with previous studies, jarrah leaves were processed at a faster rate during winter than summer . This seasonal difference can, in part, be attributed to the increased density and proportion of shredders at this time. Despite this, the processing of jarrah leaves during winter was very slow and must reflect the poor quality of this detritus as food for invertebrate consumers .

Organic matter breakdown and ecosystem metabolism: functional indicators for assessing river ecosystem health

“…See ''Water temperature'' below Gessner et al 1998, Mathuriau and Chauvet 2002, but see Chergui and Pattee 1991 Depends on rate of invertebrate shredding Baldy et al 1995, Jonsson et al 2001, but see Grac¸a et al 2001Fabre and Chauvet 1998, Fleituch 2001 See ''Nutrients'' below Pozo 1993 Invertebrate density or leaf abrasion higher in riffles Meyer 1980, Smith 1986, Casas 1996 Invertebrate densities lower or anaerobic Reice 1974 Higher invertebrate density Rounick and Winterbourn 1983 Crayfish very important, but fish might reduce shredder activity Rosemond et al 1998, Usio 2000, Konishi et al 2001, Schofield et al 2001 Microorganisms most responsive to temperature; if invertebrate density is high in cold season, leaf decay is faster Webster and Benfield 1986, Bunn 1988, Garden and Davies 1988, 1989, McArthur et al 1988, Short and Smith 1989, Lopez et al 2001, Menendez et al 2003 Lower invertebrate density or anaerobic conditions Reice 1974, Triska and Buckley 1978, Herbst 1980, Meyer 1980, Chauvet 1988, Chergui and Pattee 1990, Rader et al 1994, Niyogi et al 2003 Reduced invertebrate or microorganism activity Allard and Moreau 1986, Collier and Winterbourn 1987, Garden and Davies 1989, Griffith and Perry 1994, Rowe et al 1996, Dangles and Gu...…”

Étude de la biodégradation des feuilles d’eucalyptus (Eucalyptus camaldulensis) et de laurier rose (Nerium oleander) dans l’eau de l’Oued Aïn Chkef au Maroc

“…La température augmente la vitesse de décomposition indirectement en agissant sur l'activité des microorganismes et en accélérant les processus enzymatiques intervenant dans le processus de décomposition des feuilles (CHERGUI et LEGSSYER, 1995). Par ailleurs, la faible vitesse de la décomposition des feuilles de certaines espèces d'eucalyptus serait liée à leur texture et leur faible teneur en composés azotés (BUNN, 1988;POZO, 1993;MOLINERO et al, 1996). PETERSEN et CUMMINS (1974) classent les feuilles en trois catégories en fonction de leur taux de décomposition dans les écosystèmes aquatiques : feuilles à dégradation lente, moyenne ou rapide.…”

“…Le lessivage : phénomène de dissolution physique des substances hydrosolubles des feuilles (NYKVIST, 1963;BUNN, 1988;WEBSTER et BENFIELD, 1986); 2. La décomposition microbienne : action des bactéries et champignons qui transforment la matière organique végétale en protéines microbiennes pour augmenter leur propre biomasse.…”

Leaf Litter Decomposition and Nutrient Dynamics in Woodland and Wetland Conditions along a Forest to Wetland Hillslope

“…There were few previous studies on the decomposition of jarrah and banksia leaf litter in the region. Jarrah (E. marginata) leaf litter was reported to have a half-life of 260-340 days in stream conditions [32] and to be more resistant than the river red gum (Eucalyptus camaldulensis) in the floodplain forest [16]. The half-life of the labile fraction for the leaf litter studied here was 2.6-3.2 weeks (E. marginata) and 1.0-1.7 weeks (B. menziesii) in two site conditions.…”