Along with the growing speed of urbanization, the increase of human activities, and the spread of invasive species, distributed ecological habitats and communities are becoming similar to each other over time. This phenomenon is called biotic homogenization, a process whereby the genetic and functional characteristics of two or more living organisms become similar over time [1].
One of the main causes of biotic homogenization is rapid urbanization. The development of the city replaces natural habitats, eliminating the spaces for living organisms. For example, 66% of the red-listed birds, or critically endangered birds, are more probable to live in rural areas. Due to the increase in urbanization, the size of their habitat is shrinking, leading to habitat isolation, and additionally, because of the decreasing capacity of the surrounding landscape to provide resources due to human disturbance. Hence, species are lost without being replaced, leading to more homogenous groups of birds [2].
Furthermore, as the cities are expanding, species that adapt to urban areas are appearing, which increases biotic homogenization. The cities, because of resources and energy, are in a disequilibrium state unlike the natural environment [3].
Biotic homogenization threatens the ecosystem by limiting the diversity of species. This can lead to a destabilized ecosystem that decreases its productivity and makes the areas more vulnerable to droughts or heatwaves [4]. Especially, it also impacts soil. Soil accounts for 59% of terrestrial biodiversity, covering bacteria, fungi, and protists, which is crucial in ecosystem processes like nutrient cycling and plant-soil interaction. However, forest conversion, or deforestation, is replacing the forest with spaces for human activities. This disrupts soil habitats, reduces resource accessibility, and changes microbial community composition. Therefore, the increase of man-made land significantly decreases the diversity and efficiency of the land [5].
To avoid these environmental consequences, it is important to slow down biotic homogenization, or even reverse it. One of the ways is to connect the habitats. Remaining natural areas, including parks, forests, and wetlands, should be protected, including microhabitats that seem small but are crucial. These habitats should remain undamaged. Even though these actions can be subtle, small actions can become practiced and lead to long-term benefits for the ecosystem.
People can also advocate for ecological corridors. Ecological corridors are spaces connecting the natural area to restore effective ecological connectivity, which include hedgerows, greenways, or street trees. These serve as a connection between protected areas, which strengthen diversity, which contrasts with highways, roads, and buildings that isolate the habitats. Since it is about incorporating nature into the city, the support of the citizens is essential to create ecological corridors [6].
Ending biotic homogenization starts from preserving the ecosystem and natural habitats through protecting the local native and endangered species. If the communities and individuals take responsibility for protecting natural habitats through conserving and reconnecting ecosystems, societies will be able to maintain their diversity.