Fungal diversity and community structure on <i>Phragmites australis</i> (poaceae) along a salinity gradient in the scheldt estuary (belgium)

We examined fungal communities on stems and leaf sheaths of common reed (Phragmites australis) in four tidal marshes along a salinity gradient (mesohaline to freshwater) in the Scheldt estuary (Belgium) by direct observation. One hundred and fourteen taxa, the highest number of taxa ever recorded during a survey of phragmiticolous fungi, were found, with 56 taxa (49%) in the ascomycetes, 6 taxa (5%) in the basidiomycetes and 52 taxa (46%) of anamorphic fungi, the latter comprising 30 (26%) coelomycetes and 22 (19%) hyphomycetes. Fungal diversity in tidal marshes compared is lower than that in non-tidal reed marshes. Species distribution on reed litter, investigated by multivariate analysis, was strongly correlated with flooding frequency and salinity. Influences of salinity on the fungal community are discussed and tested by a culture experiment. Taxa were divided into three basic distributional types: taxa present only in the saline-brackish water zone, species present only in the freshwater zone, and a group of eurytopic species found over the entire salinity gradient sampled. Indicator species for each group were determined. In two sites, mesolialine brackish and freshwater, the vertical distribution of mycota was analysed. Higher similarities between the same vertical zones, especially in middle and apical parts of the culms, indicated that terrestrial fungi (no direct contact with tidal exchange water) were less influenced by site-specific characteristics. However, in both sites, a few common indicator species for standing Phragmites culms could be identified. Flooding height (and frequency) is demonstrated to influence vertical species distribution. Generally rather complicated interactions and a narrow niche differentiation among species are revealed for the phragmiticolous fungal community

Nature

The sluices of the Bergenmeersen FCA-CRT were opened for the first time on 25 April 2013. At the time of writing, the natural development of the area was still in a primordial stage. Therefore the actual observed nature development in Bergenmeersen could not be described in this book (although some actual results are given in Chapter 8). Therefore, this chapter explains the expected nature development with relation to similar environments along the river Scheldt.The nature target scenario was defined in the objective of the updated Sigma Plan. In this plan, just one coordinating objective was set out for Bergenmeersen: the development of 40 ha of estuarine nature. What this precisely implies is described below

The decomposition of reed leaves in the Scheldt-estuary: spotlight on the Fungi

The poster presents preliminary results on a decomposition-study of reed leaves (Phragmites australis) in one site (PQ 206, near ‘Schor van Doel’). In a brackish reed stand leaves make about 25 % of the above-ground reed biomass, being an important organic pool in the Scheldt-ecosystem and a potential substrate for phragmiticolous fungi. Fungal species composition and fungal biomass (and also some abiotic factors, not presented here) were followed during decomposition in litterbags on the sediment of a reed belt. Fungal biomass was measured using ergosterol quantification. During the survey 40 fungal taxa were found to colonize the leaves from standing green - to standing dead - to litterleaf-stage. Succession and vertical preference of fungal species is demonstrated during growth and decomposition. Leaves, although abscised from the culms, have an important standing dead decomposition with high fungal diversity and biomass (599 µg ergosterol/ g leave, n = 10 corresponding with ! 0.12 g fungus/ g leave) just before abscission. Leaves were almost totally fragmented after a 10 month incubation on the sediment. With fungal crop ranging from 142 µg ergo/ g leave to 346 µg ergo/ g leave showing a steep decline in fungal crop after leaf abscission, a gradual recovery followed by a final decline towards the final stage. Despite the fact that a serious amount of fungal biomass is developed, less species seem to be adapted to colonize the litter leaves