Aloes and Lilies of Ethiopia and Eritrea

Fig. 18. Riverine
vegetation along
the Abay River
S of Mankush in
Wellega floristic
region.
INTRODUCTION
33
map represented by shown in darker blue lines, but
represented as shown in Fig. 18.
11. Fresh-water lakes, lake shores, marsh and
floodplain vegetation (FLV)
For freshwater, the generally accepted upper limit of
dissolved salts in the water is c. 1000 ppm.
However, authors like Wood & Talling (1988), who
carried out field studies of the plankton flora in a wide
range of Ethiopian lakes followed the classification
proposed by Williams (1964), with an upper limit for what
is classified as fresh water higher than 1000 ppm i.e up to
3000 ppm. This vegetation type is found in fresh­water
lakes with open water, on lake shores, in marshes and
Floodplains. Two subtypes are recognized in this major
vegetation type. The details of the differences between
the two subtypes and the definitions are presented in Friis
et al. (2010).
Subtype 11a. Freshwater lakes – Open water vegetation
(FLV/OW)
This includes lakes which have a concentration of salts
below 3000 ppm. This vegetation type is found in the
open water. The characteristic species include floating
aquatics such as Eichornia natans and the invasive E.
crassipes, native Lemna aequinoctalis, L. gibba, L.
minor, Pistia stratiotes, Spirodela polyrrhiza and Wolffia
arrhiza.