BIODIVERSIY OF HIGHER FRESHWATER IN THE NILE

Abstract

Biodive.-sity and distribution of fungi on subme.-ged wood in the Ri ve.- Nile wa te.-, Uppe.- Egypt.

The present investigation aimed to study the occurrence, distribution and seasonal variation of freshwater fungi on submerged wood i n River Nil e and irrigation canals i n Upper Egypt (Sohag, Qena and Aswan). Salini ty of water ra nged between 0.083 to 0.7%. The results obtained could be summ arized as follows.

(1) In the first part of the study:

A total of 64 fungal taxa, in clud ing 40 Ascomycetes,2.0 Mi tosporic fu ngi and 4 Basid iomycetes were identified from Sohag, Qena and Aswan. The average ratio of the two dominant fungal groups, Ascomycete taxa : Mitosporic taxa was 2 : 1. The diversity of fungi found on samples in Sohag was highest among these three collection sites a nd 50 taxa were recorded includi ng 36 Ascomy cetes, 3 Basidiomycetes, 11 Mi tosporic. The ratio of the two d om i nant fungi groups, Ascomycete taxa : Mitosporic taxa 3 : 1. The abundance of individual taxa was lower than 12 %, except for five dominant taxa, v iz. Botryodiplodia theobromae (15%), Leptosphaeria agnita (14.2%), Pleospora vagans (13.5%), Massarina australinesis (13%), Linocarpon sp (12%). The diversity of fungi found on sa mpl es i n Qena was hi gh an d 37 taxa recorded ,

including 27 Ascomycetes, 2 Basidiomycetes, 8 Mitosporic fungi. The ratio of the two dominant fungal groups Ascomycete taxa : Mitosporic taxa was 3.3 :1. The abundance of all taxa ranged from l to 12% seven taxa was abundant Botryodiplodia theobromae (12%) Pleospora vagans (11%), Herpotrichia sp (10.6%), Massarina bipolaris (9%) Linocmpon sp (8%), Dictyosporium elegans (8%), Phoma suaedae (7%). The diversity of fungi found on samples in Aswan was lowest among the three collection sites, and 25 taxa were recorded, including 9 Ascomycetes, 1 Basidiomycetes, 15 Mitosporic fungi. The ratio of the dominant fungal groups, Mitosporic taxa : Ascomycete taxa 1 .5 1 . The percentage abundance. Botryodiplodia theobromae (I0%), Dictyosporium cocophilum (8%).

Among the three collection sites in this study Botryodiplodia theobromae was frequently found in all three sites 15% in Sohag, 12% in Qena and 10% in Aswan. Leptosphaeria agnita 14.2% followed by Pleospora vagans 13.5% , Massarina australiensis 13% in Sohag.

(2) In the second part of the study:

High simi l arity in fungal communities between Sohag and Qena, where low simi l arity in fungal communities between Aswan and both Sohag and Qena.

(3) In the third part of the study:

Higher species diversities were recorded in winter season when compared to summer. Higher species richness were recorded in period between December 1998 and March 1999. More than 18 taxa appear on ly in winter season such as Linocarpon sp., Otthia sp.l, Otthia sp.2, Anthostomella aquatica, Nodulosphaeria sp., Nais aquatica, Bionectria sp., Arthrographis cuboiea, Callistospora gaudae, Urohendersonia subteranea, Tetracladium sp., Lulworthia sp. where only six taxa apper only in summer such as Lindra sp, Massarina bipolaris, Massarina sp.l,

Massariosphaeria vitalbae, Mycosphaerella aquatica where

Leptosphaeria luctuosa,

Massarina australiensis, Krschsteiniothelia elaterascus, Leptosphaeria agnita, Pleospora vagans, Aniptodera chesapeakensis, Zopifella latipus, Savoryella lignicola were genera lly abundant throughout the year

(4) In the fourth part of the study:

We observed substrate specificity in Ascomycetes occu rring. There was differences in dominance and/or colonization of these species on different substrates.

(5) In the fiveth parof the stud y:

In this study, higher species diversities were recorded on natural wood when compared to Casuarina, Eucalyptus and Salix baits. Dominant ta xa (with 10% abundance in at l east one collecting period) on Eucalyptus, Casuarina and Salix baits were Linocarpon sp., Nais aquatica, Aniptodera chesapeakensis, Botryodiplodia theobromae .