Biodiversity and No Net Loss

Biodiversity loss is a global challenge which requires extensive, long-term efforts. Biodiversity loss is caused by human activity which destroys habitats, fragments ecological networks and contaminates the environment. Global warming also has an impact on living conditions and makes survival more difficult for some species.In the Nature-wise Espoo project, we will determine how to better secure and increase biodiversity as the city’s population grows. Recovery of biodiversity is also a goal nationally as well as in the EU.

Biodiversity means the multitude and variability of habitats and species and their genes. This multifaceted nature makes advancing biodiversity-related goals challenging. Ecosystem services, i.e. the tangible and intangible benefits of nature to humans, and the quality of green spaces are also topics that should be discussed in a growing city. One approach for preserving nature and green spaces which is becoming established is “No Net Loss”.

The phrase “No Net Loss” appears in recent plans, background studies and reports concerning the protection and restoration of nature and ecosystem services. 

No net loss can be used to refer to various things remaining the same despite human activity. However, the term is most frequently used to refer to natural values, particularly the preservation of biodiversity. It is used in contexts such as green space surface area, carbon stocks and sinks or ecosystem services.

No net loss is a state where human activity should not decrease biodiversity or ecosystem services. The goal of the Nature-wise Espoo project is to avoid negative environmental impacts whenever possible based on this principle. Negative environmental impacts can also be minimised, or the state of nature can be improved by restoring natural areas. As a last resort, any other negative impacts can be offset by improving the state of nature elsewhere. 

Achieving a state of no net loss is based on a mitigation hierarchy where the goal is to always primarily avoid and minimise the loss of natural values. Negative environmental impacts can be avoided by, for example, directing construction away from valuable natural sites.

If this is not possible, attempts to minimise the negative impact can be made by e.g. planting trees and vegetation in the area which can be used to secure wildlife corridors, for example. Wildlife corridors include all areas covered by vegetation which form a network between nature’s core areas and allow various species to travel from one area to another.

If the negative environmental impact cannot be avoided or minimised, the last resort is to offset it by improving natural environments elsewhere. This is called ecological compensation. A negative environmental impact can be offset by, for example, restoring a degraded area closer to its natural state or protecting a valuable natural site. Offsetting a negative environmental impact is always primarily the responsibility of the one who caused it, for instance a developer. This method has been applied in Germany and England, for example.

To prove the preservation or improvement of biodiversity, it must be measured or compared against the starting point or target level. Biodiversity has several levels and is hard to measure. For this reason, simplified indicators which are known to reflect biodiversity well are frequently used.

The preservation or improvement of the quality and surface area of valuable habitat types is a fairly common indicator. Habitat types are areas with specific environmental conditions and characteristic flora and fauna. Determining the quality of a habitat type is not simple but such practices are fairly well established in Finland. Instructions on how to do this can be found in the Ecological Surveys and Ecological Impact Assessment guide(external link, opens in a new window) published recently by the Finnish Environment Institute.

The “No Net Loss” approach aims to guide activity in a way beneficial to nature. The method is effective at supporting the preservation of biodiversity even if achieving a total state of no net loss is impossible.

Espoo wants to preserve and increase biodiversity as the city grows and develops. Coordinating these somewhat conflicting goals requires information and knowledge of good practices. A better understanding of biodiversity is required when designing ways to support it. In order to apply the principle of no net loss, there has to be an agreement on what to preserve.