Biodiversity offsets

Located in the Eastern part of Tanzania's mainland, the city of Dar es Salaam has been a fast urbanising centre in Sub Saharan Africa. A steady population increase represents implications related to increased human activities, such as encroachment of hazardous land, poor urban planning, as well as lack of infrastructure, placing considerable pressure on the good functioning of the city and causing a rapid loss of green areas and of trees. In counterbalancing these aspects, peri-urban agriculture, artisanal fishing, and nature-based tourism contribute substantially to the well being and livelihoods of the inhabitants of Dar es Salaam. Understanding that nature plays a significant role in the sustainable development of the city and to address the issues above, the municipality of Dar es Salaam, alongside several stakeholders, elaborated a so-called "Thematic Atlas of Nature’s Benefits to Dar es Salaam", tailored specifically for the city. One of the aims of the atlas is to tackle climate change effects that are threatening Dar es Salaam by keeping urban and peri-urban ecosystems intact while implementing nature-based solutions. It is a balancing act coupled with the fact that Dar es Salaam is located in a globally important biodiversity hotspot, the ‘East African Coastal Forest’. (1,2,3)

The municipal government of the Yiwu city in China has launched the Green Lungs of the City Project (GLCP) in 2019. The overarching goal was to build a green lung, which will create more green spaces for residents in Yiwu, mitigate environmental pressures and improve the city's resilience to climate change. Under the project, a green corridor was created to reconnect the roads, rivers, ponds and lakes where different tree species were planted. Additionally, wetlands were constructed and restored to improve resilience against climate change disasters. The project is still in the ongoing phase, and a forest-wetland ecological park is under development in the city's central area. The GLCP aims to use different types of NBS elements to promote sustainable urban development and to provide multiple ecosystem services to the citizens in a highly urbanised area. [1]

Douala is the economic capital of Cameroon and one of its largest cities. The city is located on the banks of the Wouri River (hence a port city) and its climate is tropical. The marine and coastal biodiversity of Cameroon is rich and diverse, and it is highly endangered because of human activities including artisanal and industrial fishing and pollution generated from industries, accidental loss of crude oil in transit or during loading or unloading. In Douala, thousands of inhabitants have settled in and around the mangrove swamps, destroying the mangrove ecosystem and endangering biodiversity including snakes, birds, fish, trees and frogs. Biodiversity studies are rare, and even if they exist, they are done in part and do not give an overview of the real state of biodiversity in the city. The city of Douala is full of many ecosystems of various natures (micro-ecosystems), each of which has species adapted to the environment. Besides this, Douala confronts itself with seasonal flooding and high temperatures due to climate change. In response to some of these challenges, a local entity, the Association of academics and researchers for Biodiversity conservation, initiated in 2020 an action that focused on environmental education and biodiversity conservation. The initiative also provides a framework for reflection and exchange on biodiversity issues. (1,3,4)

Medellin is the second-largest city in Colombia. The city used to be one of the most dangerous in the world, as Pablo Escobar founded here the Medellin cartel. After the death of Escobar, the city's homicide rate has decreased by 95% and extreme poverty by 66%, thanks in part to a string of innovative mayors who laid out plans to integrate the poorest and most violent hillside neighbourhoods into the city centre in the valley below. The same innovative mayors realised that Columbia and its cities are very vulnerable to climate change being located in a tropical zone and is influenced by El Niño and the La Niña. In Medellin, the municipality has built upon a tradition of planning to become an urban lab for the construction of public life with the aim of inclusive, peaceful and sustainable development. As such starting in 2008 Medellin began implementing a green strategy whose goal was the creation of a green belt around the city as well as waste control. The intervention discussed in this case is one initiated in 2014 when the municipality carried out planting and reforestation projects for the protection of the eastern slopes of the city. (1,2,3)

From 1998-2002 Argentina went through an economic depression, which began after the Russian and Brazilian financial crises, caused widespread unemployment, riots, the fall of the government, and a default on the country's foreign debt. Rosario, the third-most populous city in the country, was not a stranger to the crisis' effects as many of its inhabitants were now living under the poverty line. Coupled with this, climate change was heating up the city and making rainfall more erratic, leading to both flooding in Rosario and fires in the nearby river delta. To tackle urban inequality and climate change the Municipality of Rosario developed a program called "Urban Agriculture Program" which aims to give low-income residents access to underutilized and abandoned public and private land to cultivate food. Over the years, the municipality evolved the program into a cornerstone of its inclusive climate action planning. (1)

Climate change has become the day-to-day struggle for this nation - an island nation that faces serious sea-level rise implications should the problem remain uncurbed. The impacts seen are related to rising temperature, sea-level rise (coastal erosion), and changes in rainfall (flooding). To reduce the vulnerability of the population of two regions next to its capital (Victoria), the Ministry of Environment and Energy of Seychelles initiated in 2012 a project aiming at improving the quality of life for the people of Seychelles and restore coastal zones as well as the ecological habitat related to them through nature-based solutions. The project will reduce these vulnerabilities by spearheading ecosystem-based adaptation as climate change risk management—restoring ecosystem functionality, and enhancing ecosystem resilience and sustainable watershed and coastal processes, in order to secure critical water provisioning and flood attenuation. (1)

In 2019 at the Gullele Botanical Garden in Addis Ababa, the Ethiopian government launched a historic tree planting campaign. Over 350 million trees were planted in an ambitious move to counter the effects of deforestation and climate change. The Gullele Botanical Garden was selected as one of the 1000 sites all over the country involved in the Green Legacy Initiative, a national campaign against the effects of climate change. The United Nations estimates that Ethiopia’s forest coverage has declined drastically to a low of just 4 per cent in the 2000s from 35 per cent a century earlier. (1,2) The Botanical Garden was not selected aleatory as it is Ethiopia's only botanical garden and it is a nursery for various indigenous plant species. Its mission is to conserve and promote the Ethiopian diverse plants and tree population and it is a conservation initiative located at the northwestern tip of the Addis Ababa City Administration. The site covers an area of 1000 ha which is representative of the central plateau of Ethiopia. (3)

The John Muir Pollinator Way is an initiative by the NGO Buglife to create and restore pollinator habitats along a 215 km long-distance active travel route – The John Muir Way – across the densely populated central belt of Scotland. The John Muir Pollinator Way is the first B-Line ‘pathway’ in Scotland and stretches from Helensburgh in the west to Dunbar in the east (Emilie). It is an ambitious project given the length (215 km) of this pathway. It connects nine different local authorities and 40 km of the total length falls within the Edinburgh local authority area (Burgess, 2016). This not only serves to halt the process of declining pollinator numbers providing crucial ecosystem services, but also helps people to connect with nature. Between July 2015 and March 2017, project partners and volunteers have transformed 19 sites into species-rich grassland. [ref 1]

GIFT-T (Green Infrastructure For Tomorrow - Together!) is a four-year European project of which Medway was one of five case studies. In this project communities, businesses and governments were brought together to facilitate bottom up planning and implementation of green infrastructure (Ref 1). The product of this is a general business plan, and the planned intervention of focus here is the "Thames Terrace Invertebrates - corridors for wildlife" (Ref 2). Hoo Island already has areas that serve well to sustain invertebra species, but as of yet also has underutilised potential in this respect. This intervention addresses the latter.

On the territory of the former train station Vohwinkel (including the train tracks) a brownfield site of 15 ha was turned into a commercial urban area which was created as an economic driver for Wuppertal. However, the site was inhabited by the highly endangered sand lizard, which is why a species conservation island was created as the commercial park was being built. As a habitat of the endangered sand lizard species, the conservation area in the South-West of the commercial park remained free from construction development, and an adequate conservation concept was elaborated and implemented. The nature conservation area is maintained by the environmental protection department of the city. (Ref. 1 and 6). The project succeeded in its goal of creating a commercial area on the former Vohwinkel marshalling yard while simultaneously paying attention to the protection of the endangered sand lizard. (Ref. 2) Additionally to the conservation area within and around the commercial zone, lizards have also been relocated beyond the city limits as a biodiversity offsetting measure. (Ref. 8) Furthermore, the dried out Krutscheider stream, forming part of an important biotope system with its gravel surfaces, was dug out again to serve as a green corridor for compensation against the habitat loss. (Ref. 1, 4 and 6)