Green / wildlife corridors, bridges, belts

A creek flowing through an underpass, acting as an accidental wildlife tunnel between either side of a roadway. Photo by Brittney Le Blanc via Flickr CC BY-NC-SA 2.0

Green corridors, also known as wildlife corridors, are specifically conserved or created to facilitate the movement of animals through human-modified environments, mitigating the impacts of habitat fragmentation, urbanisation, and deforestation.

Wildlife corridors can take the form of patches of vegetation, wildlife bridges or tunnels under and over barriers like roads, stepping-stone habitats, greenbelts, coastal setback zones, riparian areas, pollination pathways, and urban street trees and transport and infrastructure corridor planting (Gregory et al., 2021; Zellmer & Goto, 2022), as well as larger connections between protected or conservation areas like wildlife sanctuaries and botanical gardens. They also might incorporate or complement other nature-based solutions such as biodiverse plantings, green roofs, and green walls

Primarily, wildlife corridors are vegetated areas that provide refuge and safe routes for wildlife between primary habitat areas, maintaining biodiversity and ecosystem health, as well as reducing conflict between human activities and animals. They also contribute to ecosystem services such as pollination, pest control, and carbon sequestration (Zellmer & Goto, 2022).

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Name of NbS

Green / wildlife corridors

Type of NbS

Ecosystem restoration; Ecosystem protection

Location

  • Urban,
  • Peri-urban,
  • Rural
Riparian Buffers as Wildlife Corridors. Photo by placeuvm via Flickr CC BY-NC-SA 2.0

Relationship to Indigenous knowledge

Indigenous knowledge frameworks, including those that exist in Te Moananui Oceania encourage a reciprocal, interconnected relationship that views humans as just one part of the natural world (Kiddle et al., 2021). Traditional ecological knowledge can inform deep understanding of ecosystems to help understand and enhance the need for balance and connectivity between fragmented ecosystems.

Culturally appropriate approaches to conservation and stewardship are required, especially where conservation policies can conflict with Indigenous land rights, including food and resource gathering (Conservation International, 2018). Collaborative processes often result in arrangements that are co-beneficial, allowing or uplifting Indigenous outcomes while also achieving biodiversity goals. Indigenous knowledge can inform design, provide information about native species or remote areas where scientific literature is limited, and holistic conservation and stewardship (Conservation International, 2018).

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Climate change benefits
  • Biomass cover loss
  • Changes in phenology
  • Increased pests or spread of weeds
  • Reduced air quality
  • Reduced water quality

Wildlife corridors and bridges can address the impacts of habitat loss by connecting disparate habitat areas, enabling geographic connections between populations of plant and animal species (Gregory et al., 2021). By mitigating the effect of human activities in the landscape on wildlife especially, wildlife corridors and bridges are a strategy that begins to address biodiversity decline as land uses intensify globally. This includes Te Moananui Oceania where populations are increasingly urbanising (Kiddle et al., 2021). Maintenance of untouched natural areas has climate change adaptation outcomes too, potentially reducing the effects of extreme weather such as flooding or increased temperatures, and improving air quality.

Planting native vegetation, incorporating green infrastructures, and maintaining habitat connectivity are all processes that present opportunities to engage local communities in tangible conservation outcomes (Lukies, 2020; Wang et al., 2022; Zellmer & Goto, 2022). Wildlife corridors and bridges are key to enhancing ecosystem resilience and adaptation as human-induced effects on the environment, and as climate change increases, pressures on ecosystems worldwide (Conservation International, 2018; Zellmer & Goto, 2022).

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Societal / socio-cultural benefits
  • Biodiversity health and conservation
  • Empowerment/equity

Fostering community engagement and stewardship can support local autonomy in the landscape and support education and awareness about conservation outcomes. Working with natural environments can strengthen the community and improve mental and physical well-being (Lukies, 2020; Wang et al., 2022; Zellmer & Goto, 2022). 

By supporting neighbouring landowners to take additional biodiversity measures, the effect of wildlife corridors can be extended to a broader area. Wildlife corridors can also enrich cultural connections through the integration of local heritage in what are often undisturbed natural areas with significance to many people.

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Ecological and biodiversity benefits
  • Biological control
  • Climate regulation
  • Genetic resources (diversity)
  • Habitat provision
  • Nutrient cycling
  • Purification
  • Species maintenance

Local extinctions can be reversed by establishing new connections between habitat areas, enabling species to recolonise natural spaces. It is understood that streams are favoured as corridors by terrestrial wildlife. Therefore, integrating considerations of connectivity into ecosystem restoration or protection strategies, such as riparian planting, presents new opportunities for wildlife corridor establishment. Conversely, large rivers or water bodies can serve as linear barriers to wildlife, akin to roads or human-made structures (Gregory et al., 2021).

Protecting or restoring ecosystems in urban or cleared areas, such as those used for farming, enhances habitat provision, pollination, and various ecological and biodiversity benefits (Wang et al., 2022). Connectivity provided by wildlife corridors and bridges fosters genetic diversity and species maintenance by preventing population isolation and increasing gene flow. Ecosystem resiliency is also increased through enhanced pest control and nutrient cycling in some corridor projects (Wang et al., 2022).

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Technical requirements

understand if spatial protection is enough to allow wildlife and plant movement, or if more active approaches might need to be taken with endangered species (Gregory et al., 2021).


Wildlife corridors and bridges are extremely dependent on site selection and should be designed for maximum connectivity in places where land ownership and use allow it. If an area is not representative of its natural state, projects might re-establish and maintain native habitats in these areas.

Following this, monitoring of outcomes can provide valuable data to advance knowledge on the relative success of this strategy. Additionally, it offers impact assessment and other feedback for stakeholder and community engagement. 

Adherence to local laws and regulations must occur, alongside recognition, adherence or incorporation of customary laws and traditional management practices.

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Diagram of habitat fragmentation. Image by LlacaUrbden1 via Wikimedia Commons CC BY-SA 4.0

Issues and Barriers

Spatial planning relating to wildlife corridors and bridges can bring complex challenges, especially in Te Moananui Oceania where land ownership boundaries might overlap with Indigenous land rights, regulatory and conservation boundaries. Boundaries of all kinds need to be understood and resolved for the successful implementation of wildlife corridors (Gregory et al., 2021).

Linear barriers, which can include power lines, canals, roads, railroads, and large rivers can form physical barriers to wildlife and plant connectivity (Gregory et al., 2021). However, riparian zones alongside rivers can also be ideal corridors because of the low likelihood that they are affected by intensified land use at their edges. Infrastructure for safe crossing of linear barriers like roads or railways can be expensive and slow to install or repair (Gregory et al., 2021). 

Disaster events like flooding can affect wildlife and plant populations, and also inhibit access and therefore the safety of people and infrastructure involved in conservation and restoration projects (Gregory et al., 2021). 

Predation and invasion from alien species are also additional significant concerns in some areas (Lukies, 2020). Monitoring over very long periods can be required to understand how conservation corridors affect wildlife and population outcomes. (Gregory et al., 2021). Funding though, might require shorter impact measurement timelines, creating barriers to project funding. In Te Moananui Oceania, the capacity especially of governmental organisations to fund and manage largescale conservation projects is often limited, with low budgets and human resources 

(Conservation International, 2018; Lukies, 2020; Wang et al., 2022).

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Opportunities

Opportunities exist to integrate coastal restoration and protection projects with broader conservation corridors, incorporating initiatives like mangrove and coral reef restoration (Conservation International, 2018; Hilty et al., 2019). This integration, coupled with efforts in riparian, peri-urban, and inland conservation areas, would establish comprehensive ‘ridge-to-reef’ connections, recognising the interconnectedness of these ecosystems.

As erosion processes and sea level rise occur, uninhabitable areas or those abandoned for managed retreat can transform into new spaces for wildlife conservation and connectivity. This may involve implementing water management strategies, protecting watersheds, or restoring and managing floodplains. 

Integration with sustainable agriculture and forestry, including Indigenous knowledge-based methods like the home garden agroforestry that occurs in many parts of Te Moananui, could provide complementary land use on the edges of wildlife corridors (Thaman et al., 2006). 

Wildlife corridors offer cultural and eco-tourism opportunities, as their formalisation and recognition for biodiversity significance enhance their touristic appeal.

Indigenous-led projects play a crucial role in Te Moananui Oceania, where the intersection of Western policy-making and Indigenous governance necessitates innovative solutions (Conservation International, 2018; Hilty et al., 2019). Advancements in GIS mapping and technology are underway, with the development of software aimed at facilitating the planning of wildlife corridors using spatial data (Ribeiro et al., 2017).

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Financial case

The cost of wildlife corridors varies depending on scale, location and project type. Some wildlife corridor projects are funded by regional and national governments, while many others in Te Moananui Oceania are funded by international conservation organisations and NGOs (Conservation International, 2018; Lukies, 2020). The financial case however is clear, with numerous biodiversity, climate change adaptation and societal benefits overall.

References
  • Conservation International (2018). Creating a conservation corridor: Fiji. Available online: https://www.thegef.org/sites/default/files/publications/CI%20Fiji_Conservation%20Corridors_CI%20Factsheet.pdf. Date accessed 15 May. 2024.
  • Gregory, A., Spence, E., Beier, P., & Garding, E. (2021). Toward best management practices for ecological corridors. Land, 10(2), 140. https://doi.org/10.3390/land10020140
  • Hilty, J.A., Keeley, A.T.H., Lidicker, W.Z., Merenlender, A.M., & Possingham, H. (2019). Corridor ecology: Linking landscapes for biodiversity conservation and climate adaptation (Second edition). Island Press.
  • Kiddle, G.L., Pedersen Zari, M., Blaschke, P., Chanse, V., & Kiddle, R. (2021). An Oceania urban design agenda linking ecosystem services, nature-based solutions, traditional ecological knowledge and wellbeing. Sustainability, 13(22), 12660. https://doi.org/10.3390/su132212660
  • Lukies, K. (2020). Ecological corridors—Facilitating the movement of native species throughout the Eastern Bays and beyond. https://doi.org/10.13140/RG.2.2.10457.85600
  • Ribeiro, J.W., Silveira Dos Santos, J., Dodonov, P., Martello, F., Brandão Niebuhr, B., & Ribeiro, M.C. (2017). LandScape Corridors (lscorridors): A new software package for modelling ecological corridors based on landscape patterns and species requirements. Methods in Ecology and Evolution, 8(11), 1425–1432. https://doi.org/10.1111/2041-210X.12750
  • Thaman, R.R., Elevitch, C.R., & Kennedy, J. (2006). Urban and homegarden agroforestry in the Pacific islands: Current status and future prospects. In Tropical Homegardens (Vol. 3, pp. 25–41). Springer Dordrecht. https://doi.org/10.1007/978-1-4020-4948-4_3
  • Wang, Y., Qin, P., & Önal, H. (2022). An optimisation approach for designing wildlife corridors with ecological and spatial considerations. Methods in Ecology and Evolution, 13(5), 1042–1051. https://doi.org/10.1111/2041-210X.13817
  • Zellmer, A.J., & Goto, B.S. (2022). Urban wildlife corridors: Building bridges for wildlife and people. Frontiers in Sustainable Cities, 4, 954089. https://doi.org/10.3389/frsc.2022.954089