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AEROSPACE MONITORING OF ECOSYSTEM DYNAMICS 
IN DANUBE DELTA 
I. Noaje , L. Turdeanu 
Geodetic and Photogrammetric Department, Technical University of Civil Engineering Bucharest, 
Bd. Lacul Tei 124, Sect 2, Bucharest, Cod 020396, O.P. 38, ROMANIA, 
E-mail: noaje@pcnet.ro; srft@pcnet.ro 
Commission VII, WG VII/3 
KEY WORDS: Remote Sensing, Ecology, Change Detection, Monitoring, Dynamic, Multisensor 
ABSTRACT: 
Authentic barometers of environment health status, delta and coast wetlands represent research subjects for remote sensing 
applications. The Danube Delta contains a wide variety of ecosystems and species, many of them are seriously threatened 
throughout the rest of Western Europe, making an area of unique ecological significance. Efforts to exploit the Danube Delta for 
mechanized agriculture and aquaculture have reduced or eliminated natural water flow in many areas, severely disturbing aquatic 
ecosystems. 
The paper presents aerospace monitoring of simple ecosystem dynamics based on a comparison of aerial and Landsat-MSS 
(acquired on July 24, 1975), Landsat-TM (acquired on June 28, 1984) and Spot-HRV (acquired on April 27, 1993) space 
multispectral images, over an eighteen years period, between 1975 and 1993. During this period, the environmental stresses on 
delta’s ecosystems have increased markedly, caused by man’s intervention over the entire hydrographical basin of Danube and inner 
Danube Delta. 
After an individual preprocessing, a hybrid classification has been realized for each of the three multispectral images. Firstly, an 
unsupervised classification based on classic composite images (near IR, red, green - MSS 7, 5, 4; TM 4, 3, 2; XS 3, 2, 1) have been 
made, followed by a supervised hybrid classification process using a parallelepiped and maximum likelihood method for eight major 
classes. The dynamics of single ecosystems are described by linear or more commonly, non-linear exponential or parabolic 
functions. The study highlighted accentuated dynamics of alteration in Danube Delta’s ecosystems and proved that medium 
resolution Landsat-TM and Spot-HRV are efficient means for ecosystem dynamics estimation. Old Landsat images revealed their 
utility for early times of remote sensing. 
I. INTRODUCTION principal morphohydrological elements and vegetation in the 
delta's ecosystems. 
Although second in Europe and the twenty-third in the world, 
the Danube Delta contains a wide variety of ecosystems and 
bird species, many of which are seriously threatened throughout 2. STUDY ZONE AND DATA SOURCE 
“the rest of Western Europe, making an area of unique ecological 
and phaunistique significance. In addition to providing 2.1 Aerospace monitoring of the ecosystems 
transportation and drinking water for inhabitants along its 
course, the Danube's water is tapped for hydroelectric power, The reasonably extended ecological facies, the land use classes 
industrial processes, irrigation of agricultural land, and disposal and areas with destroyed ecosystems are also successfully 
of municipal and industrial waste. The complex and varied identified on space photographs with a spatial resolution of 50m 
ecosystems of the Danube Delta have remained unspoiled for or better. From these imageries, aerospace monitoring of the 
centuries, natives integrating in the maintenance of natural dynamics of areas can be realized, but only for those 
balance. Environmental stresses on delta wetlands have ecosystems where the probability of correct recognition 
increased markedly in the past 3 - 4 decades, caused by man's approaches 98-100% (as a rule not below 96%, as otherwise the 
errors of identification can exceed the dynamics of change. 
intervention, which became more and more actively over entire à £ 
Stable ecosystems, that is, with area changes of less than 0.5% 
hydrographical basin of Danube and inner delta. 
After 1990, the romanian region of Danube Delta, together with per year, require a revision not less than once in 8-10 years. 
: : M ; 3 BODSUS Ims o "8. 07 che ae redire 
the lacustrine complex Razim-Sinoie has been declared a Highly dynamic ecosystems (more than 4% changes) require 
y: : . > . 1 >t c» a j ^ J 
Biosphere Reserve. First of all, any agricultural and inspection every year (Vinogradov, 1988). 
hydrological developments have been stopped. Over 50% of the There are several developed technologies that can be used for 
reservation has been declared World Heritage Site by comparing successive photographs for the detection of the 
UNESCO. Experts of UNESCO among well-known ecosystem changes. The compatisons ais executed either 
commander Jacques Yves Cousteau (in 1991) have visited and visually or usme digital processing. By visual comparison, 
studied Danube Delta. Due to their specific techniques for data using known identification keys, the identification of images 
recording and analysis, photogrammetry and especially remote from two different date missions and the results are then 
sensing are exquisite means in change detection at the level of compared. The main advantages of this visual method are the 
possibility of using all the tone, texture and other photographic 
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