dynamics [Vinogradov, 1988].
Monitoring of the Ecosystem Dynamics
The Amudarya delta was covered by space photography from manned spacecraft "Soyuz-9" in 1970, from
"Salyut-4" in 1975, from "Salyut-6" in 1980 and from "Salyut-7" in 1985 for long-term monitoring of the
ecosystem dynamics. Thus, the Amudarya delta was surveyed through equal time intervals each 5 years. All
space photographs were taken with photographic metric camera KATE with f= 140-210 mm on panchromatic
films with spatial resolution near 50-80 m. Thus, technical conditions of all photographic space surveys were
comparable. Then, natural conditions of photographic space surveys were unified also: dry weather and clear
air of late summer season (august-september). Simultaneously a range of test sites over the Lower Amudarya
delta was studied on the ground from 1975 during last 15 years.
Using repeated aerial and space photos tested by field works we could monitor the ecosystem changes of the
Lower Aanudarya delta for each 5 years.
1960-1965. Decrease of water flow of the Amudarya river was not marked before 1965. Variations of river
disharge was within the equilibrium state. Hydromorphic ecosystems (Hydr, HyMe, HyHa, see tabl.l)
dominated on the delta plain. Meadow and tree-scrub ecosystems were favourable and stretched along river
channels.
1965-1970. Aerial surveys and space photographs from "Soyuz-9" revealed beginning of drying over delta plain.
Although composition of ecological dominants in hydro- and mesoimorphic ecosystems is remained the
condominants could be changed and morphometric characteristics (such as decrease of soil humidity, plant
density, high, and fidelity and increase of soil salinity) became worse.
1970-1975. Space photographs from "Salyut-4" made evident the desertification process. As was revealed
on photographs the composition of ecological dominants was changed. Area of hydro- and mesomorphic
ecosystems began reduce and area of xero- and halomesomorphic ecosystems began growth.
1975-1980. Space photographs from "Salyut-6" indicated the critical level of desertification when they reach
of limit admissible size near 30% of area but they had a possibility of reverse successions. Area of forest-shrub
mesomorphic associations was chortened twice.
1980-1985. Finally, space photographs from "Salyut-7" showed catastrophic stade of desertification. Amudarya
river depleted and didn't fall into Aral sea. Desertification reaches 70% of the delta plain and is growing
disaster stade. In contrary, swamp, meadow-swamp and meadow-forest (tugai) ecosystem classes drop below
then 15% of area.
The Ecosystem Dynamics Forecasting
The analysis of the dynamic trends of area changes of the ecosystem classes within the Lower Amydarya delta
reveals the ecosystem dynamics through desertification using successive space photographs 1970, 1975, 1980,
and 1985. Comparison of areas of all ecosysytem classes with successive space photographs indicates the form
of trends. The dynamic trends of area changes of the most ecosystems are seen to be nonlinear. The nonlinear
trends have a curve of form:
& $
Y[n]= a + b(X[i] - X[o]) + c(X[i] - X[o]) ,
where Y is the area of delta occupied by n-th ecosystem classe, X[o] is the conventional year of the beginning
of the significant ecosystem area change, X[i] is the current year of the aerospace survey. At one case the
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