As terrestrial mammals, people often see land as separate from the sea. But the two are interconnected - as are all ecosystems on Earth - through the movements of water, air, nutrients, plants, animals and other living organisms. This is known as ecological connectivity.
Protecting, restoring and enhancing ecological connectivity underpins the survival of a wide range of species and is key to tackling the global nature and climate crises.
Connectivity occurs from local to global scales and is crucial to supporting life on Earth.
Many species need movement and connectivity to survive: seeds are carried by the wind to germinate where the temperature, light, and moisture are just right; elephants follow ancient paths passed down through generations to find the best routes for food, water and avoiding danger. People rely on ecological connectivity too, from the movement of pollinators that allows our food to grow, to the snow and rainfall that fill rivers and recharge aquifers as sources of fresh drinking water.
The importance of connectivity is exemplified by marine turtles, which rely on global connectivity. They begin their life on land, within a nest buried in the sand on a beach. When the turtles hatch, they crawl to the ocean and drift on oceanic currents for years before embarking on huge migrations between feeding sites, sometimes covering thousands of miles between continents. They then travel back to the area of their birth to mate, and the females lay their nests on the beach where they were born.
Despite its importance, ecological connectivity is often disrupted by human impact. Practices like habitat conversion and unsustainable development can have major impacts on connectivity.
Important migratory routes have been obstructed by infrastructure such as roads and fences, or impeded by activities such as fishing and shipping. Almost 10% of the world’s forests are now found in fragments with little or no connectivity between them, and less than 10% of the terrestrial protected area network can be considered structurally connected.
Losing connectivity negatively impacts on many species and damages ecological integrity. This, in turn, has an effect on people. For example, research has shown that fragmented habitats may stimulate more rapid evolutionary processes and diversification of diseases, posing a risk to human health.
Transforming the way land and seascapes are managed is key to rebalancing the relationship between people and nature.
Conserving connectivity requires nature-positive decision-making that considers ecosystems, and the connections between them, as a whole.
In doing so, there are policy and governance challenges to overcome, since political boundaries do not reflect the interconnectedness of nature. For example, some marine species travel through multiple national jurisdictions and are protected in some, but not others, which can potentially undermine protection efforts. Indeed, Leatherback turtles in the Pacific collectively travel through the jurisdictions of 32 countries as well as the High Seas, meaning they rely on 33 governance structures for protection.
The new IUCN Guidelines for Conserving Connectivity through Ecological Networks and Corridors were designed to address just this. The freely available guidelines, led by IUCN WCPA Connectivity Conservation Specialist Group (CCSG) with input from UNEP-WCMC, inform more consistent and coherent connectivity conservation practices. The guidelines provide common definitions, case studies from a wide range of applications globally, and recommendations on how to formalise ecological corridors and networks to maintain, enhance, and restore connectivity. These guidelines are particularly timely amid calls to improve Protected Area connectivity and as the international community looks to ramp up restoration efforts during the UN Decade on Ecosystem Restoration.
Connectivity also needs to be considered at the early stages of planning and designing infrastructure. Through the Development Corridors Partnership, UNEP-WCMC and our partners are analysing proposed development corridors in Kenya, Tanzania and Southern Sudan and finding proactive solutions for nature-positive infrastructure. For example, the partnership has explored the impact of railway development in Kenya on the movement wildlife in the area, leading to recommendations on how to account for nature in similar infrastructure projects.
By its very nature, global connectivity conservation depends on co-operation and collaboration. As the world looks ahead to the agreement of a post-2020 global biodiversity framework later this year and to delivering on the UN Decade on Restoration, protecting, restoring and enhancing ecological connectivity is an important consideration across all sectors of society.