How have ecosystems changed?
Under the intervention of human hands, almost all ecosystems on earth have been transformed. In particular, in the past 50 years, ecosystems have changed at a faster rate than ever before. Today, this rapid change is clearly taking place in developing countries. For example, the depletion of fisheries resources on a large scale or the abuse of water resources for agricultural production have affected ecosystems.
Ecosystems depend on the fundamental cycles of life, such as the water, carbon, and nutrient cycles. Human activities have altered these cycles through the depletion of freshwater resources, the release of CO 2 , and the overuse of fertilizers. This not only damages the ecosystems themselves, but also affects the benefits they provide to humans.
Populations of plants and animals have declined and their habitats have shrunk. A quarter of the world’s mammal species are now threatened with extinction. Human activity has caused 50 to 1,000 times more extinctions in the past 100 years than natural processes. Archaeological evidence increasingly shows that many of the same species that once roamed different parts of the world no longer exist. Rare species have disappeared and common species have spread to new areas, and the genetic specificity of species has decreased, particularly in crops and livestock.
Leading to the decline of ecosystem services
Ecosystem services are the diverse benefits that ecosystems provide to people. However, when natural diversity is disrupted, it affects the ability of ecosystems to provide services and recover from disturbances.
Human well-being is measured in terms of prosperity, health, material wealth, good social relationships, security and freedom. Changes in ecosystem services affect all of these factors.
Ecosystem services, particularly food, timber and fisheries production, are important for employment and economic activity. Intensive use of ecosystems often provides the most efficient short-term benefits, but often leads to overuse and catastrophic long-term losses. A country can achieve high GDP by destroying forests and “milking” fisheries to achieve economic growth. However, this is unsustainable development, and in the long term, resources and people’s livelihoods will be lost. If the full economic value of ecosystems were taken into account in management decisions, degradation would be significantly reduced, and even reversed.
Today, poverty levels remain high. The world has about 1 billion people living on less than $1 a day, and they rely heavily on ecosystems for their livelihoods through activities such as agriculture, herding and hunting. The regions facing the greatest challenges tend to be those with the most ecosystem-related problems, currently Africa, Asia and Latin America.
Mass food production has lifted hundreds of millions of people out of poverty, but it has also had negative impacts. The loss of ecosystem services is hurting many of the world’s poorest people, and is sometimes a major factor in poverty because it increases dependence on ecosystem services. And this adds to the pressures on ecosystems, poverty reduction efforts, and ecosystem degradation.
Review the cause
Human or natural factors that change ecosystems are called drivers. For example, habitat change and overexploitation are direct drivers that clearly affect ecosystem processes. Indirect drivers affect ecosystems by influencing direct drivers.
Indirect drivers are often changes in population, economic activity, and technology, as well as cultural and sociopolitical factors. For example, the world’s population has doubled in the past 40 years, with most of the increase occurring in developing countries. The world’s urban population increased from about 200 million in 1900 to 2.9 billion in 2000, and the number of cities with populations exceeding 1 million increased from 17 in 1900 to 388 in 2000. This puts pressure on resources and sometimes leads to conflict.
Meanwhile, the direct drivers are habitat change, climate change, invasive species, overexploitation and pollution. Currently, the direct drivers leading to ecosystem degradation are increasing steadily.
Scenarios for the future of the ecosystem
According to the scenarios, the direct and indirect drivers of ecosystems in the next 50 years will be similar to those that drive them today. However, their importance will change. Climate change and eutrophication (too many nutrients) in water will become serious problems, while population growth will become less important.
The scenarios also predict that rapid transformation of ecosystems for agriculture, urbanization, and infrastructure will continue. Habitat loss will lead to a loss of biodiversity by the 2050s.
In some scenarios, human exploitation of ecosystems will increase but in a more sustainable manner, while overall human well-being will improve. Only one scenario predicts negative poverty, declining human health, and degraded ecosystems in developing countries.
One might ask: So, how do ecosystems change over time? In general, humans tend to use ecosystems for immediate benefit rather than for the long term. Meanwhile, the consequences of human impacts on ecosystems are often not immediately apparent. This means that the costs incurred today will be passed on to future generations.
Left to nature, most changes in ecosystems are slow, detectable, and predictable. Some species, especially plants, may take an extremely long time to become extinct. This delay provides opportunities for habitat restoration and species rescue.
But when human intervention occurs, ecosystems are at risk of abrupt change and are difficult to recover from. Once an ecosystem undergoes abrupt change, recovery to its original state is slow, costly, and sometimes impossible.
Sustainable Management
Reversing the degradation of ecosystems while requiring them to meet growing human needs is a major challenge. Policy changes could mitigate many of the negative consequences of increased pressure on ecosystems. However, what humans have already done seems modest.
We all know that ecosystems are being severely damaged and that ecosystem services will continue to be lost unless we take effective action. Actions such as strengthening international coordination, developing and disseminating technology, and improving the use of information are expected to have positive effects on the protection of ecosystems and human well-being. In addition, it is believed that it is necessary to shorten the information gap, increase transparency in information, call for community participation and build good reference models for decision-makers.
