Invasive alien species

Historically, the area of San Paolo in Cagliari has suffered from environmental degradation and illegal dumping, making it an unsightly entrance to the city. In 2022, the Città Metropolitana di Cagliari, initiated a project to transform this degraded area into a urban park featuring 7,000 new plants, including olive trees, junipers, lentisks, myrtle, rosemary, tamarisks, and Aleppo pines. Managed by the municiplaity of Cagliari, and funded by a €500,000 grant from the Ministry of Ecological Transition, this initiative will cover 4.7 hectares between Via San Paolo and the Santa Gilla Lagoon, creating a natural corridor connecting the city to the lagoon. The project aims not only to restore the land but also to enhance both metropolitan and municipal environmental requalification plans.
A multidisciplinary team, including a forestry technician, agronomist, and biologist, developed the project to ensure it is environmentally sustainable and suited to the local ecosystem.
The work on the project began in June of 2022 with land preparation, removal of invasive species, and waste collection, resulting in the clearing of over 5 tons of rubbish. By December, around 3,000 plants had already been planted, with the remaining work, including the installation of an irrigation system, scheduled for completion by January 2023. The selected plant species are fast-growing, and within two years, the shrubs are expected to reach a height of about two meters. The park is planned to open to the public in 2024, providing a new green space for walking and outdoor activities.
The San Paolo urban park project has encountered obstacles, mainly due to the expropriation of buildings, leading to legal disputes, permit delays, and a temporary halt caused by a tender-related issue. The site is currently overgrown and unused, showing clear signs of neglect. (Refs. 1, 2, 3, 4 & 5).

The Lower Salt River Restoration Project (LSRRP) is a riparian restoration initiative located along the Lower Salt River within the Mesa Ranger District of the Tonto National Forest. This collaborative project seeks to restore a section of the Lower Salt River Recreation Area that was severely impacted by the 2017 Cactus Fire. The Cactus Fire was a significant wildfire that caused extensive damage to vegetation and habitat in the area, highlighting the need for targeted restoration efforts to rebuild the ecosystem and mitigate future fire risks.
The LSRRP’s primary activities focus on removing invasive tamarisk trees, which are highly flammable and contribute to the intensity of wildfires, and planting native seedlings to reestablish local flora. By removing tamarisk trees, the project aims to create a landscape that is more resistant to fire, reducing the wildfire risk for the region. Additionally, the project supports the abundance and diversity of native plant species by removing invasive plants and planting thousands of native riparian tree species.
The restoration efforts also aim to enhance the riparian habitat by expanding two critical vegetation communities—the mesquite bosque and the cottonwood-willow gallery forest. These communities support rich biodiversity and offer essential habitats for local wildlife.
Beyond ecological restoration, the project emphasizes community involvement and awareness. It provides opportunities for the local community to participate in the project through environmental education events for K-12 students and ongoing volunteer involvement in monitoring and maintaining restored areas.
Overall, the Lower Salt River Restoration Project is a proactive effort to protect and revitalize the Lower Salt River Recreation Area, enhancing its ecological resilience and engaging the community in long-term conservation. (2-4, 6, 8, 11)

In Lisbon's Areeiro district, Urbem, a non-profit organization, is leading the creation of a 2500m2 Miyawaki mini-forest in Casal Vistoso Urban Park. This initiative involves densely planting native species to rapidly establish a diverse, self-sustaining forest ecosystem. Supported by the Lisbon City Council, the project aims to enhance urban biodiversity, improve air quality, and contribute to climate resilience. Volunteers from the local community play a crucial role in every stage, from preparing the land to planting and maintaining the forest. Despite initial challenges, such as a 40-50% plant survival rate, the forest is expected to become self-sustaining within three years. The project focuses on environmental restoration and seeks to engage and educate the community, fostering a sense of ownership and connection to these new green spaces (Ref 1; Ref 2; Ref 3; Ref 4).

The Three Mile Creek Watershed project is part of the City Council watershed management plans (Ref 2) to stabilize the banks and the stream along the Twelve Mile Creek and Langan Park Lake, both of which drain into Three Mile Creek and Mobile Bay (Ref 1). The project aims to address the issues of degradation of the banks and destabilization of the creek, undercutting of sanitary sewer crossings and sedimentation in the creek and Langan Park Lake because of the increased water flow speed due to stormwater conveyance (Ref 2). Besides, major pollutants from run-off and sewage water contribute to the degradation of Three Mile Creek (Ref 5). Key initiatives include stabilizing the banks and streambed of the Twelve Mile Creek, dredging and restoring Langan Park Lake, and implementing instream structures to reduce erosion and protect infrastructure (Ref 2). The project also emphasizes reducing pollutants from stormwater runoff, improving water quality, and helping to protect the area’s estuarine and marine water resources (Ref 1). The project will increase natural habitat and contribute to regulating biodiversity by aiding in the abatement of invasive species such as the apple snail (Ref 2). It is expected to contribute to enhancing recreational access through the development of trails, educational programs, and water sports facilities. The overall goal is to restore ecological health, support flood control, improve the quality of life in the Mobile and Prichard communities and make the Three Mile Creek a recreational destination (Ref 6).

Sourced from Northern Worcestershire, the River Stour has played a significant role in the industrial heritage of Birmingham and the Black Country (Ref 1). It consists of 11 Water Framework Directive water bodies and multiple tributaries, spanning 200 km in length (Ref 2, 3). Once a pristine Salmonid river that powered the Industrial Revolution, rapid industrialization severely impacted the river, leaving it heavily polluted with sewage (ibid.).
Initiated by the Birmingham and Black Country Wildlife Trust (BBCWT) in 2021, the Love Your River Stour (LYRS) project focuses on Dudley and Wolverhampton, aiming to transform the River Stour and its surrounding green spaces into a beautiful, wildlife-rich source of pride for local communities and to create a corridor for wildlife to thrive through the heart of the Black Country (Ref 4).
Phase 1 of the project was completed in June 2023, bringing significant improvements along the river (Ref 5, 6, 7, 8). In Phase 2, the project will extend to a stretch running through Cradley Heath and Lye (Ref 7, 8). This initiative is funded by the UK Government's Green Recovery Challenge Fund.

The Martinican Marine Natural Park (MMNP) was established in 2018 to protect key marine habitats, including coral reefs, mangroves, seagrass beds, and open waters. These areas are home to important species like sea turtles, dolphins, and tropical fish. The park’s conservation efforts focus on addressing threats from human activities such as pollution and overfishing. It also collaborates with ocean-related industries, such as tourism and fishing, by recommending, funding, or conducting research aimed at promoting more sustainable practices within the MMNP.

To support its work, the park operates a growing fleet of boats that raise public awareness, resolve conflicts, and enforce the protection of designated areas. The MMNP spans an area of 47,340 km², extending from Martinique's coast to the boundary of the French Exclusive Economic Zone. The park's management board, which includes diverse stakeholders, must be consulted for advice on development activities that impact the marine environment. Their goal is to balance competing interests within the region.

The park receives funding from the French Office for Biodiversity (OBF) to carry out initiatives that protect the marine environment, promote sustainability, and raise public awareness. Notable efforts include creating or restoring habitats for species such as sea turtles and sea urchins, managing invasive species like sargassum algae, restoring coral reefs, and training resource users such as whale-watching companies and diving clubs. Other initiatives include reducing plastic pollution through clean-ups, supporting sustainable fishing practices (e.g., artisanal coastal fishing), installing eco-friendly moorings, funding Marine Educational Areas (MEAs), and sponsoring cultural events that promote marine conservation (Ref 1; 2; 3).

The Dublin Urban Rivers LIFE (DURL) project incorporates two interconnected wetlands in Griffeen Park as part of its broader initiative to improve water quality, natural water management and aquatic biodiversity in urban areas. These wetlands were specifically designed as a natural sewage system to treat wastewater from the surrounding areas, addressing a significant environmental issue known as "domestic misconnection." Domestic misconnection occurs when household appliances, such as washing machines, dishwashers, and kitchen sinks, are incorrectly linked to surface water drains rather than the sewage system. This leads to untreated wastewater being directly discharged into local waterways, contributing to contamination.
In the River Griffeen catchment, which includes approximately 12,000 dwellings and associated infrastructure, domestic misconnections are a considerable threat to water quality. The DURL project focuses on identifying and rectifying these misconnected appliances to ensure that wastewater is properly treated before entering the river. This process will not only improve water quality but will also provide flood alleviation and support healthier aquatic ecosystems in the area.
The project is aligned with broader environmental policies, including the River Basin Management Plan 2022-2027, the Water Framework Directive, the Climate Change Action Plan, the Floods Directive, and the draft Biodiversity Plan. One of the key strategies is to use a Geographic Information System (GIS) to streamline inspections for domestic misconnections, making the process faster and more cost-effective.
The constructed wetlands in Griffeen Park, with a standing water depth of approximately 30 cm, are planted with a variety of native Irish species. These wetlands offer a natural, sustainable solution to wastewater treatment, with the potential for similar applications across Europe. (Ref. 2, 4)

In September 2018, a new didactic itinerary on invasive alien species was inaugurated in Cagliari's botanic garden. The initiative has been initiated in order to raise awareness and share important legislative and scientific knowledge on the matter (Refs. 1, 2 & 3). It has been curated by Life ASAP, which is an EU co-funded project focused on targeting the introduction of animal and vegetal alien species in Italian territory (Refs. 4 & 5). The initiative in the botanic garden focuses on a 13-pannels pathway through the garden, which will guide visitors towards the discovery of the issue of the introduction of alien invasive species on the territory. The goal is to attract the population's attention to the topic through a sensorial and interactive experience. In fact, the panels are easy to understand, colorful, and accompanied by explanatory images and bas reliefs. Children and youngsters can also participate in a laboratory called "the alien's identikit," according to which they have to recognize the newly learned alien species around the garden (Refs. 1, 2 & 3). This Path represents the first (and only) permanent space dedicated to biological invasion processes and invasive alien species in the network of Italian Botanical Gardens. (Ref.2).
Therefore, the project, in collaboration with the University of Cagliari, promotes education for all ages on the risks and consequences of such an underestimated problem and aims to educate citizens on how their actions can prevent the phenomenon from spreading further (Refs. 1, 2 & 3).

The mangrove area of Morne Cabri, located in the municipality of Le Lamentin and sharing the bay of Fort-deFrance, is the largest mangrove area in Martinique. Since 2011, the municipality has led efforts to understand and better manage the area (Ref 1). The natural regeneration of the mangrove is threatened by fresh water run-off (from waste and rainwater), invasive species and pollution. However, it is an important protection against extreme weather events, operates as a carbon sink for the island and provides recreational activities (Ref 1). The municipality has led several initiatives supported by volunteers, local businesses, national subsidies and private donations (See: Ref 2, 3, 4, 11).

The Tbilisi Urban Forest is an ecological restoration project of 5,5 ha spanning two pilot areas initiated in 2020. Located on Mtatsminda ridge around Tbilisi, it is part of a larger reforestation effort within the 700-ha forest territory (Ref. 1,2). The project is funded by the Cartu Foundation and led by the Development and Environment Foundation along with Tbilisi City Hall. Restoration is undertaken to addresses significant challenges such as forest dieback caused by pest infestations, climate change adaptation as well as the creation of recreational infrastructure (Ref. 3,5). Through collaboration among interdisciplinary scientists and urban planners, a novel reforestation strategy has been developed that integrates patches of locally sourced plant communities tailored to diverse soil and slope conditions. This approach incorporates existing trees with new saplings, carefully grafted into existing soil pockets, and focuses on a biodiverse palette of endemic and climate-adapted species (Ref. 1,5). While the project implementation could not be carried out as planned, lacking public participartory due to Covid 19, still 100 jobs were created locally (Ref. 2). Ultimately, the Urban Forest project will enhance ecological connectivity, biodiversity and tourism and also serve the public as an improtant recreational site (Ref. 1,2).