Introduction

The ecosystem approach entered international environmental practice as an attempt to move away from narrow sectoral management of natural resources. In Decision V/6 of the Conference of the Parties to the Convention on Biological Diversity, it is linked with the need to consider ecosystem structure, processes, functions and interactions, as well as the presence of humans as part of ecosystems [1]. Later, Decision VII/11 described the ecosystem approach as a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use [2].

Two principles are especially important for this article. Principle 6 states that ecosystems should be managed within the limits of their functioning. Behind this short formula there is a very practical idea: every natural system has boundaries. Water cannot be withdrawn endlessly; a coastal zone cannot endlessly absorb tourist and municipal pressure; biological communities cannot permanently compensate for managerial mistakes. Principle 11 adds another layer to this logic. It requires all relevant forms of information to be considered, including scientific, local and traditional knowledge. A territory, then, should not be treated as an empty technical scheme for development. It already has its ecology, history, people and limits of resilience.

At first sight, the Aral Sea and Lake Baikal are not obvious objects for comparison. The Aral Sea became a symbol of the almost catastrophic desiccation of an inland water body. Lake Baikal, by contrast, remains the largest and one of the most unique freshwater lakes of global importance. This contrast makes the comparison meaningful. In one case, the crisis became visible through the disappearance of water, fisheries and shoreline. In the other, it develops more slowly: through overloaded settlements, wastewater, tourist pressure and changes in littoral communities. The scale is different, the speed is different, but the governance question is similar: what happens when economic development becomes detached from the real carrying capacity of an ecosystem?

Materials and Methods

The article is based on a comparative case-study design. The empirical base includes open scientific publications, documents of the Convention on Biological Diversity, World Bank materials on the restoration of the Northern Aral Sea, UNESCO and IUCN information on Lake Baikal, and the state report on the condition of Lake Baikal for 2023. This set of sources was chosen deliberately. The ecosystem approach cannot be evaluated through one type of evidence only. It requires natural indicators, the governance context, socio-economic pressure and signs of biological response.

Methodologically, the article combines three procedures. The first is a quantitative comparison of key indicators: water-body area, commercial fish catch, wastewater discharge and tourist pressure. The second is a qualitative interpretation of these indicators through Principles 6 and 11 of the ecosystem approach. The third is data visualisation in tables, graphs and a locator scheme. This format makes it possible not only to describe environmental degradation but also to show its dynamics. It is particularly important for the Aral Sea, where ecosystem collapse is best understood through a time series, and for Lake Baikal, where risk is often hidden behind the external impression of vastness and natural stability.

Fig. 1. Locator scheme of the water systems analysed in the article

Table 1

Ecosystem-approach principles used in the analysis

The Aral Sea: Disrupted water balance and the functional limits of an ecosystem

The Aral Sea is one of the clearest examples of what can happen when a water system is managed for decades outside its natural limits. Before the period of intensive water withdrawal, it was one of the largest inland water bodies in the world. Most sources give an area of about 68,000 km² for 1960 [3; 5]. Afterwards, the sea began to shrink rapidly, mainly because the runoff of the Amu Darya and Syr Darya rivers was redirected for irrigation. The economic objective seemed understandable: to support agricultural production in an arid region. The management failure was that the water balance of the sea was treated almost as an external detail.

This is exactly where Principle 6 becomes not an abstract environmental norm but a strict analytical criterion. If more water is taken from a system than it can compensate for year after year, the system changes its state. It does not simply become a little worse. It moves into another regime. In the Aral Sea, this meant a fall in water level, increasing salinity, fragmentation of the single water body and the formation of a dry saline seabed. Under these conditions, the former fisheries, climatic and social functions of the sea could no longer be maintained.

Table 2

Key quantitative indicators of degradation and partial recovery in the Aral Sea

Fig. 2. Change in the surface area of the Aral Sea, 1960–2020

The dynamics of surface area are important because they make the governance problem visible. In 1960, the Aral Sea was still a large inland sea embedded in the social and economic life of Central Asia. By 2020, its area had fallen to a small fraction of its former extent. The numbers do not show the whole tragedy, of course. They do not convey dust storms from the exposed seabed, the loss of port towns, the disappearance of fishing settlements or the health effects of a transformed landscape. Yet they clearly show that the ecosystem crossed a functional threshold.

The collapse of commercial fishing is an even more concrete indicator. Before the crisis, the Aral region was an important fishing area. In 1960, fish catch was reported at 43,430 tonnes; by 1970 it had fallen to 17,460 tonnes, and by 1980 industrial fishing had effectively disappeared [3]. This means that the sea was shrinking not only spatially. It was losing its living functions. The loss of water was followed by the loss of fish, employment, local income and a familiar way of life. An ecosystem crisis very quickly became a social crisis.

Fig. 3. Dynamics of commercial fish catch in the Aral region

The partial restoration of the Northern Aral Sea is important because it complicates the picture. The Aral case is not only a story of destruction. The Kok-Aral Dam and the Syr Darya Control and Northern Aral Sea Project made it possible to raise the level of the Northern Aral, reduce salinity and bring water closer to the former port of Aralsk [4]. These results do not mean that the lost sea has been fully restored. The Southern Aral remains in a very difficult condition. Still, the Northern Aral demonstrates something essential: even a deeply damaged ecosystem may retain some recovery potential if management starts to work with hydrological reality rather than against it.

From the point of view of Principle 11, the Aral Sea also shows the cost of ignoring local socio-ecological knowledge. Large irrigation schemes were planned primarily through production targets. The territory itself was poorly heard. Water was not only a technical input for agriculture. It supported fisheries, microclimate, transport, employment, health and the everyday life of entire communities. The collapse of the Aral Sea therefore cannot be reduced to a “water-management mistake”. It was a failure to understand the sea as a connected socio-ecological system.

Lake Baikal: tourism, wastewater and littoral vulnerability

Lake Baikal represents a very different type of ecological risk. It is located in southern Eastern Siberia, between Irkutsk Oblast and the Republic of Buryatia. The lake is about 25 million years old, reaches a maximum depth of roughly 1,700 m and contains around 20 % of the world's unfrozen surface freshwater. In 1996, Lake Baikal was inscribed on the UNESCO World Heritage List [6]. These facts often create a sense of exceptional stability. Baikal appears so large, deep and ancient that its vulnerability is easy to underestimate.

The current pressure on Baikal is not expressed as a dramatic disappearance of the water body. The lake is not “shrinking” in the Aral sense. Its problem is more subtle and, for that reason, sometimes more difficult to communicate. Pressure accumulates in the coastal zone where settlements, tourist centres, roads, beaches, piers and insufficiently modernised municipal infrastructure meet the lake. The littoral zone is especially sensitive because it is where human activity and aquatic biological communities come into direct contact.

Table 3

Key indicators of environmental pressure on Lake Baikal

Tourism is one of the most visible drivers of pressure. Studies of overtourism in the Baikal natural territory note that tourist flow to the lake almost doubled in 2010–2014. Particularly high pressure falls on Olkhon Island and the Small Sea area. For the Khuzhir municipality, estimates range from 200,000 to 500,000 tourists and holidaymakers per year, while the permanent population is about 2,000 people [9]. The arithmetic is simple and quite alarming: seasonal pressure may exceed the number of local residents by 100–250 times.

Fig. 4. Seasonal tourist pressure in the Khuzhir municipality

Such pressure is not automatically destructive. Tourism can support local income, services and regional visibility. The problem begins when the number of visitors grows faster than wastewater treatment, waste collection, land-use control and environmental monitoring. A small settlement cannot function as a large tourist centre without major changes in infrastructure. If those changes lag behind, the lake receives the hidden costs of recreation.

The municipal factor is one of the weakest points in the Baikal case. According to the state report on the condition of Lake Baikal for 2023, wastewater discharge in the central ecological zone of the Baikal natural territory in the Republic of Buryatia increased from 2.04 million m³ in 2022 to 2.65 million m³ in 2023. This is a 30.4 % increase in a single year [7]. The same report identifies outdated municipal wastewater treatment facilities as a major source of polluted water entering first-order tributaries of Lake Baikal [7].

Fig. 5. Growth of wastewater discharge in the central ecological zone of the Baikal natural territory

The biological response is already visible in nearshore indicators. L. S. Kravtsova and co-authors reported that species of the genus Spirogyra, which are not typical of open nearshore waters of Baikal, formed algal mats together with Ulothrix near the settlement of Listvyanka [8]. For an oligotrophic lake, this is a serious signal. Baikal historically developed under conditions of low nutrient concentration. Local inputs of nitrogen and phosphorus may therefore alter benthic communities faster than the external image of the lake suggests.

The IUCN assessment also shows that the problem cannot be reduced to isolated episodes. In the World Heritage Outlook materials, the conservation outlook for Lake Baikal is described as “of concern” because of pollution, tourism development, insufficient wastewater treatment, coastal eutrophication and climate change [10]. This wording is important. It does not mean that Lake Baikal has already lost its outstanding universal value. It means that the protection of a large ecosystem cannot be confused with its infinite resilience.

In the Baikal case, Principle 6 appears in a more delicate form than in the Aral Sea story. There is no single dramatic diversion of water. There is, however, an exceedance of the local carrying capacity of coastal territories. A settlement designed for several thousand residents cannot receive hundreds of thousands of visitors without consequences if treatment systems, waste management and land-use regulation do not grow with the pressure. Principle 11 is also relevant here. Decisions about tourism and coastal development cannot be made without local experience, monitoring data, knowledge of littoral sensitivity and a realistic understanding of municipal infrastructure.

Comparative analysis of the cases

The Aral Sea and Lake Baikal demonstrate two different forms of one governance failure. The Aral Sea is a case of direct disruption of water balance. Lake Baikal is a case of gradually accumulated pressure in the most sensitive part of the ecosystem. In the first case, the system was damaged through the redistribution of river runoff. In the second, risk is produced by many relatively small but persistent impacts. They do not look like one large catastrophe until they begin to form a systemic problem.

Table 4

Comparison of the Aral Sea and Lake Baikal through the ecosystem approach

The main shared conclusion is that the ecosystem approach requires seeing connections rather than isolated indicators. In the Aral region, cotton production and the sea could not be calculated separately. In the Baikal region, tourism cannot be developed separately from wastewater treatment and then be expected to leave the lake unchanged. Water, shores, settlements, treatment facilities, fisheries, biota, human health and local economies are parts of one chain. When governance breaks this chain, environmental damage eventually returns as social and economic loss.

Both cases also show that a change in governance direction is possible. The Northern Aral Sea after the Kok-Aral Dam did not return to its former state, but it proved that a well-targeted hydrotechnical and water-management intervention can restore part of ecosystem functions. For Lake Baikal, it would be dangerous to wait for such a dramatic turning point. The more important task is to act before irreversible degradation occurs: modernise treatment facilities, restrict chaotic development, distribute tourist flows, strengthen littoral monitoring, and take local knowledge and scientific evidence seriously before conflicts become acute.

Conclusion

The Aral Sea and Lake Baikal differ strongly in scale, natural history and present condition. Yet in the logic of the ecosystem approach they can be read together. The Aral Sea shows that ignoring water balance can destroy an entire region as a socio-ecological system. Lake Baikal shows that even the largest freshwater ecosystem of global importance becomes vulnerable when coastal pressure grows faster than governance, infrastructure and monitoring.

Principle 6 in these examples sounds almost like a warning. An ecosystem is not required to adapt endlessly to an economic project. It has limits in terms of water, nutrient loading, recovery and the stability of biological communities. Principle 11 adds the human dimension: a water system cannot be managed only from offices and only through large economic targets. Scientific data, local experience, long-term monitoring and an understanding of how environmental change enters people's lives are all needed.

For the Aral Sea, the cost of error has already become a historical fact. For Lake Baikal, much of that cost can still be reduced. This is the practical meaning of the comparison. The ecosystem approach is needed not for elegant terminology but for preventing economic decisions from falling behind natural consequences. Where management begins to see ecosystem limits, nature has a chance to recover. Where those limits continue to be ignored, even the largest and most unique water body gradually loses resilience.

References:

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