Uzbekistan: Rehabilitation of Desert Rangelands Affected by Salinity, to Improve Food Security, Combat Desertification and Maintain the Natural Resource Base - Combating Desertification in Asia, Africa and the Middle East - page 253

a

% 100

80

60

% annual
% perennia

40

20

0

shrub plant community on
salt affected soils

halophyte plant community
on solonchak depression

semi shrub plant community
on non saline soil

b

% 100

80

60

% C4
% C3

40

20

0

a a a

P P P

semi shrub plant
community on non saline
soil

shrub plant community
on salt affected soils

halophyte plant
community on solonchak
depression

Fig. 13.8 Ratio of perennials and annuals among desert rangelands plant associations along
salinity gradient. ( a ) is displayed according to location in landscape and ( b ) is displayed according
to photosynthetic pathway (C 3 or C 4 )

Along the salinity gradient the ratio of C 3 :C 4 species (averaged over all seasons)
is represented as 10:1, 10:2 and 10:9 for xero-, xerohalo-, haloxerophyte plant
communities, respectively. Regular prevalence of C 3 species is observed, as pro-
portion of

´ 4 species in the flora of desert vegetation of Uzbekistan does not exceed
than 4 % (Pyankov et al. 2001 ; Toderich et al. 2007 ). Nevertheless, proportion
of C 4 species is increased along the salinity gradient and in haloxerophyte plant