Vol. 35 – 2009 - Ecologia Mediterranea - Université d'Avignon et des ...

Investigation on macrophyte development
in Litani River (Lebanon) subjected
to human disturbances
Abstract
Although several rivers in Lebanon have been
studied for hydrological, chemical, faunistic and
epithilic parameters, little attention has been
paid so far to the macrophytes. The present
study assesses aquatic plants growth in Litani
River in the Bekaa region (Lebanon). Investigations
of this river showed that Litani, in different
sites, was affected by anthropic disturbances.
Eleven sampling campaigns were carried
out from April 2005 to April 2006 at four stations
on Litani River from its source to the
Qaraoun Lake. In the first place, the abiotic
characteristics were measured. The inventory of
the species belonging to the macrophyte communities
were drawn up, and the spatio-temporal
variations in their patterns of distribution
were analysed and compared. The successive
species and the rates of cover of macrophyte
population depend on seasonal climatic changes
and anthropic disturbances. An exotic species,
potentially invasive was detected on the Litani.
Introduction
Macrophytes show a longitudinal pattern of
zonation in rivers (Butcher 1933; Haury &
Muller 1991), provide useful biotypological
tools (Haury 1988) and can indicate the quality
of river environments (Bernez 1999;
Abou-Hamdan et al. 2005). They are often
used for monitoring heavy metals and other
Keywords: Mediterranean rivers, community
dynamics, biodiversity, macrophytes, disturbances.
ecologia mediterranea – Vol. 35 – 2009
Hanadi ISMAÏL 1,3* , Hussein ABOU-HAMDAN 1,2,3 ,
Ahmad KOUBAYSSI 2 , Stéphanie FAYOLLE 3 , Gaby KHALAF 2 ,
Arlette CAZAUBON 3 & Jacques HAURY 4
1. National Council for Scientific Research, National Center
for Marine Sciences, Batroun, North Lebanon
2. Lebanese University, Faculty of Sciences I, Hadath, Beirut, Lebanon
3. Paul-Cezanne University – IMEP, CNRS, UMR 6116,
Écologie des eaux continentales méditerranéennes, Marseille, France
4. Agrocampus Rennes, CS 85215, 35042, Rennes cedex, France
Correspondence: ihanadi@yahoo.fr
pollutants present in the water and bottom
sediments (Sawidis et al. 1995). The macrophytic
communities affect processes such as
the sedimentation, the hydrological and
underwater light regimes, as well as depend
on these processes (Khedr et al. 1997; Westlake
1996; Daniel & Haury 1996; Haury &
Peltre 1993). Crowder and Painter (1991)
indicate that the lack of macrophytes in a system
where they are expected to grow may
suggest a reduced population of living beings.
In Lebanese freshwater environments, as far
as we know, besides some physico-chemistry
study (Halawani et al. 1999; Oulabi et al.
1999; Saad 2005; Saad et al. 2006; Shaban &
Nassif 2007) very little attention has been
paid so far to the macrophytes and to our
knowledge only a few rather fragmentary data
are available (Abou-Chaar 1991; Tohmé &
Thomé 2001, 2002). It is therefore necessary
to attempt to fill this gap by carrying out biological
and ecological studies on the aquatic
plants growing in this type of environment.
The aim of the present study on a single river
with different study sites is:
– to draw up a first inventory of the macrophyte
species living in the Litani River;
– to study the changes in the spatial patterns
of distribution of the plant communities during
a seasonal cycle;
– to study the effects of human disturbances
on the aquatic plant communities, and the
description of any local specificity will be
assessed.
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