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 240

Land degradation of desert and semidesert rangelands throughout the whole
Central Asian region has reached an alarming level, calling for prompt action. It
was estimated that out of more than 16.4 Mha, 73 % are affected by degradation
(Nordblom et al. 1997 ). of various origins, including anthropogenic impact and
climate fluctuation. The anthropogenic disturbances alone are estimated to affect
7.4 Mha (UNCCD 2006 ). Grazing induced rangeland degradation is common
across large desert zones of Uzbekistan and causing major ecological transforma-
tions resulting in biodiversity loss and occurrence of nonequilibrial ecosystems
(Gintzburger et al. 2003 ). Yusupov ( 2003 ) estimated that of all disturbances,
overgrazing by livestock was the most serious, accounting ting for 44 % of the
total degradation, followed by uprooting and cutting of vital shrubs for fuel (25 %).
All other disturbances, including all abiotic disturbances such as drought and wind
erosion, accounted for only one-third of the disturbances. The effect of grazing is
often localized and is ubiquitous around watering points and settlements. Changes
in vegetation cover and composition have led to the disappearance of many native
fodder species. Gradual reduction in biomass, changes of, for example, species
composition from palatable plants into unpalatable, increased trampling and soil
compaction are frequently observed. At the present time the area of degraded desert
rangelands continues to grow due to overgrazing. A typical impact covers a radius
of 2-5 km around watering points, with the most intense degradation occurring
closest to the wells. Grazing occurs throughout the year. The animals are kept half
of the year in the mountains or other distant regions, but they are brought back to
the settlements as winter approaches. It is during this winter grazing seasons that
most of the degradation occurs, as grazing pressure is high due to low vegetative
production.
According to Salmanov ( 1996 ), the area of rangeland occupied by ex-
otic/unpalatable plant species is now 1.5 million hectares (Mha). The original
vegetation was completely removed because of the heavy grazing pressure. Mostly
of anthropogenic origin (Ashurmetov et al. 1998 ). The degradation process has
become severe and needs urgent measures to avoid the loss of phytogenetic
resources and botanic diversity of the rangelands.
An understanding of the degradation processes currently ongoing in Uzbekistan
rangelands is limited as traditional research has mostly focused on optimizing
livestock fodder production (e.g. Shamsutdinov 1975 ). Since livestock production
in Uzbekistan in arid and semi-arid zones is based on rangeland vegetation,
current studies have focused on improvement of low productive grazing lands and
rehabilitation of degraded rangelands. Less interest has been given to the driving
factors of land degradation and their interaction with other ecosystem components
e.g. response of vegetation to organizational changes, institutional transition from
former Soviet system, and grazing induced disturbances. In recent years, due
to poor localized grazing management, rangeland degradation has increased. An
understanding of the current trend of vegetation changes due to ecological and
anthropogenic factors gives the potential of sustainable management of natural
rangelands. Driving factors of grazing induced rangeland degradation and their
interaction with other ecosystem components were not often studied in previous