As the global community advances toward ambitious conservation targets – such as protecting 30% of the planet by 2030 – the concept of ecological connectivity has emerged as a keystone of biodiversity preservation. Yet, “well connected” remains an ambiguous term lacking a unified, operational definition. What does it mean to be well connected, and how can the term be applied in a practical sense?
A new review tackles this challenge by offering a comprehensive framework for defining, measuring, and implementing connectivity across ecosystems and taxa. The authors argue that connectivity, or the ability of organisms to move freely across land- and seascapes, is essential for maintaining biodiversity, ecosystem services, and climate resilience.
Brodie, J.F., Gonzalez, A., Mohd-Azlan, J., Nelson, C.R., Tabor, G., Vasudev, D., Zeller, K.A. and Fletcher Jr, R.J. 2025. A well-connected Earth: The science and conservation of organismal movement. Science 388(6745): eadn2225.
However, habitat fragmentation, infrastructure development, and other anthropogenic pressures are rapidly eroding connectivity worldwide. These impacts not only threaten species survival but also disrupt vital ecological functions like pollination and nutrient cycling.
Recent technological advances in GPS tracking, remote sensing, and genomic tools have revolutionized how scientists assess connectivity at multiple scales. The review synthesizes this progress into an actionable definition: a landscape or protected area is “well connected” if it allows sufficient movement to sustain the long-term persistence of focal taxa, ecological functions, or ecosystem services when compared to a scenario with no movement barriers.
This definition forms the basis of a “theory of change” for achieving global conservation goals. The authors outline a multi-step process for mapping and monitoring connectivity, integrating data on structural (physical habitat layout) and functional (species-specific movement behaviors) connectivity. They emphasize that connectivity must be context-specific, varying by species, geography, and ecological role.
Case studies, such as India’s tiger corridors and marine larval dispersal in the Philippines, illustrate how connectivity science can be applied to real-world conservation challenges. Yet, only about 10% of protected areas are currently considered structurally connected. Without deliberate planning and monitoring, many isolated reserves risk becoming ecological dead ends.
The authors call for international coordination to share movement data, develop robust connectivity indicators, and align restoration and climate adaptation with connectivity goals. They stress that connectivity bridges conservation with broader societal values, including Indigenous land stewardship, food security, and climate adaptation.
Ultimately, what’s needed is a global movement to embed connectivity science into conservation practice – turning theoretical understanding into tangible outcomes for biodiversity and people alike. This framework provides both the roadmap and the rallying cry to ensure that the Earth remains a well-connected home for all species.
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