What are the reasons for the sharp decline in biodiversity?

Lost its habitat； Human hunting.

There are many reasons: including those mentioned above, as well as the invasion of foreign species, the focused development of certain industries (such as papermaking, large-scale planting of the same tree species), severe environmental pollution, changes in climate conditions, and so on.

It’s simple: Earth’s living space is limited, and if there are too many people, something else has to be reduced.

The loss of biodiversity occurs both naturally and as a result of human activities, but at present, human actions (especially over the past two centuries) are undoubtedly the main cause of the sharp decline in biodiversity. Natural causes fall into two categories. On one hand, they are determined by the biological characteristics of the species themselves; the formation and extinction of species are natural processes. Fossil records show that the average lifespan of most species is between 1 million and 10 million years. Moreover, these species have limited ability to adapt to changes in their environment, or their variability and adaptability are poor, making it difficult for them to cope with significant environmental changes, which puts them at risk of extinction. On the other hand, there is a sharp decline in biodiversity caused by environmental disruptions (natural disasters), such as earthquakes, floods, fires, blizzards, droughts, and other natural calamities. Due to a lack of awareness among humans regarding the importance of biodiversity to humanity, coupled with an excessive focus on economic development and a weak sense of commitment to biodiversity conservation, various behaviors that damage the ecological environment are responsible for the sharp decline in biodiversity. These human-induced factors mainly include the following four aspects: 1. Habitat destruction. The destruction of habitats has become the main reason for the decline in population numbers, the reduction of distribution areas, and the threat of extinction for some mammal species in our country. Logging and land occupation are the two main causes of habitat destruction in China. The significant reduction of natural forests directly threatens the survival of species ranging from mosses and lichens to higher organisms. The occupation of forests, wetlands, and grasslands for agricultural and construction purposes is another cause of habitat destruction. It is estimated that one-third of China’s current farmland was originally virgin forest, and this problem is particularly severe in China’s tropical regions. Over the past half century, about half of the coastal wetlands have changed, and the wetlands surrounding plateau lakes have also suffered severe losses. Furthermore, between 1950 and 1980, the area of lakes in China decreased by 1/10. 2. Predatory overexploitation: Many biological resources hold direct economic value for humans. With the increase in population and the establishment and development of a global commercial system, human demand for these resources has risen rapidly, leading to their overexploitation and a decline in biodiversity. When the commercial market has a high demand for a certain wild species, it usually leads to overexploitation of that species, thereby pushing it to the brink of extinction. A typical example is the relationship between human hunting of marine whales and the fluctuations in whale populations. Many medicinal plants in our country, such as ginseng, gastrodia elata, amomum villosum, paris polyphylla, solidago, momordica grosvenori, etc., have very few wild specimens left. 3. Environmental pollution: Environmental pollution includes water pollution, soil pollution, and air pollution. Water pollution can have sublethal or lethal effects on aquatic organisms (especially fish) at any stage of their life cycle, affecting their feeding, foraging, and reproduction. Among these effects, eutrophication has a more pronounced, widespread, and long-lasting impact on aquatic biodiversity; Dianchi Lake in Kunming is an example of this. Soil pollution usually leads to the degradation of local vegetation, sometimes even turning the land into barren areas; at the same time, soil organisms become scarce or even disappear, resulting in a significantly lower biodiversity compared to unpolluted areas. In areas such as mining sites, tailing piles, abandoned mining lands, and landfills, there are few trees growing. Air pollution can cause varying degrees of damage to living organisms and pose a threat to ecosystems. Sulfur dioxide, ammonia, ozone, and other substances that enter the air through various means can directly kill living organisms, while toxic metals present in the exhaust gases from smelters can directly poison plants. The damage to biodiversity caused by issues such as the ozone hole, acid rain, and the greenhouse effect resulting from greenhouse gases like carbon dioxide is receiving increasing attention and concern from the international community, particularly the impact of global warming caused by the greenhouse effect and acid rain on biodiversity. 4. Invasive alien species: The invasion of invasive alien species poses a significant threat to biodiversity. There are three ways in which it invades: the first is through intentional introduction or improvement for purposes such as agriculture, forestry, animal husbandry, and fishery production, as well as for urban parks, landscaping, and aesthetic improvement; examples include water hyacinths that spread in Dian Lake and genetically modified organisms ； The second category consists of species that are introduced through activities such as trade, transportation, and tourism; in other words, they are introduced unintentionally, such as new species brought in by ballast water and soil from ships ； Third, they spread through their own propagative capabilities or with the help of natural forces, that is, through natural invasion; examples include Eupatorium adenophorum and Digitaria sanguinalis, which cause significant damage in the southwestern region. On the global list of endangered plant species, approximately 35% to 46% are caused partly or entirely by invasive alien species.

Law of conservation of energy: The rise of human dominance

Ultimately, it is the continuous progress of science and technology

Loss of living space: an expression of the law of survival of the fittest