Biological Corridors 101: Building Resilience in Times of Crisis

How did it all start?

In the 1970s, island biogeography was properly constituted as a field that sought to respond to how and under what means the islands of the planet were populated, as well as to understand the factors that affected organisms that live in isolated areas. As understanding on the subject grew, a reality became evident: on our planet there are islands that are not embedded in oceans, since a good part of them, at present, are isolated within continental masses. These islands are the remnants of vegetation that remain in the midst of so much transformation of the Earth's surface as a result of human activities, and finding a way to stop fragmentation and promote its connectivity has become a more urgent race day by day. This is when, conceptually, biological corridors are born as a solution to this problem.

Biological corridors, also known as wildlife corridors or habitat corridors, consist of linear extensions of natural or semi-natural habitats that promote the movement of flora and fauna between ecosystems with a good state of conservation. Returning to island biogeography, and to the premise that isolation between habitat remnants can be reduced through connectors that maintain the movement of species, the incorporation of corridors as essential components within modern biological conservation strategies has become an increasingly common tool.

Beyond a Path: From Ecological Relevance to Survival

Perhaps the logical question that arises right now is: why would the isolation of species be a negative thing? Why does it represent a problem for the conservation of biodiversity? The function of biological corridors lies in maintaining the processes of genetic exchange and migration between populations -processes essential for the survival of species-, resulting in greater genetic diversity, and therefore, the variability necessary for life, which improves the capacity of species to develop traits that allow them to adapt to changing conditions. The above is essential: in a world that is governed by dynamism and change, especially in the face of the adverse effects of the climate crisis, having the benefit of genetic diversity is decisive for adaptation and survival.

Let's dive deeper into adaptation: biological corridors can also act as an adaptation strategy to climate change. As temperatures rise and habitats change, many species are forced to move in search of suitable conditions. Biological corridors provide the necessary routes for these migrations: they allow species to follow their preferred temperature and precipitation zones, reducing the risk of isolation and extinction. In turn, this movement also maintains crucial ecological interactions for ecosystems, such as pollination (which allows plant reproduction) and seed dispersion; fundamental situations for maintaining vegetation regeneration and, therefore, the resilience of ecosystems to natural and human disturbance.

Navigating extinction and conserving biodiversity

The connectivity provided by biological corridors is essential to preserve endangered species, whose populations are often fragmented and isolated between different habitats. By promoting connectivity, these originally isolated species can find mates, reproduce and maintain their genetic diversity, reducing the risk of hereditary diseases and death by inbreeding, allowing healthy and viable populations to be maintained for decades or centuries.

Among the successful cases of recovery of endangered species, the Mexican spotted owl stand out (Strix occidentalis lucida) in highly fragmented forests in New Mexico, where effective forest restoration actions were identified and implemented within federal lands, as well as identifying those remaining priorities for movement along the landscape. In turn, biological corridors also make it possible to identify critical conservation and monitoring areas for the recovery of threatened species such as the gray wolf (Canis lupus) in northern Pakistan, where not only key areas have been identified for their movement, but also those that are priorities for their natural prey and those where there are situations of human conflict with the region's shepherds.

Resilient Adaptation: How Biological Corridors Tackle Climate Change

Biological corridors also increase the resilience of ecosystems to climate disturbances. Habitats connected by corridors recover more easily from wildfires, storms, or disease outbreaks. In turn, these connecting spaces also mitigate the effects of habitat loss and degradation by providing alternative movement routes that allow species to move to less disturbed areas, reducing pressure on major habitat areas, which can be kept more intact and stable. Corridors diversify the landscape, which is a key benefit in the face of a planet that tends to monotony ecosystems as a result of climate change.

Beyond Ecosystems: Connecting Nature and Society

Biological corridors, among all the virtues mentioned above, also serve as tools for territorial planning, since it is possible to zone areas with different categories of intervention under a common goal of achieving sustainable management of territories, an objective that, beyond benefiting the organisms that inhabit them, allows the communities that live them to develop a more equitable relationship with their lands:

- The identification of priority conservation areas not only allows them to be prioritized for their contribution to the functioning of the corridor, it also allows planners to direct the development of management activities away from critical habitats and migration routes, thus minimizing conflicts between human activities and wildlife.

- Many biological corridors cross areas of scenic importance, which can offer low-impact productive activity such as nature-based tourism and recreational opportunities, generating economic benefits and promoting the importance of conservation to the public.

- In regions with water scarcity or flood risks, biological corridors can help in natural flood control, groundwater recharge and preserve coastal ecosystems that maintain water quality and flow. This service is indispensable for societies: promoting access to and safe supply of water vastly improves the quality of life of communities, since in addition, water is a human right.

- The involvement of local communities in the planning and management of biological corridors promotes the sense of identity and ownership of their natural resources, as well as strengthens governance within the community, promoting more effective and sustainable conservation efforts in the medium and long term.

- By designating conservation and restoration areas within land use plans, research and monitoring efforts for scientific research purposes are facilitated.

- In urban areas, the integration of biological corridors can help build sustainable cities while promoting cultural ecosystem services, which are rarely taken into account as indispensable to promote a nature/society relationship that works in the long term. Green corridors within urban landscapes not only improve residents' quality of life, but they also support urban biodiversity by providing habitats and connectivity for the wildlife that inhabits cities.

Connecting for a Future

As we can see, this tool is one of enormous scope because it is linked to several spheres that go beyond biodiversity only: biological corridors are the link that ecosystems and species require to adapt to a changing world; to a world crossed by a climate, social and environmental crisis that violates forms of life. In the midst of climate change, these corridors become indispensable solutions for the conservation of biodiversity and for promoting the future of our planet's ecosystems.

Many of the global challenges we face begin to be solved by promoting a way of life for all the biodiversity that lives next to us. Beyond allowing the free movement, adaptation and evolution of organisms, of being essential instruments for territorial planning, urban development and the management of natural resources, as well as being a secure investment both in the well-being of our ecosystems and in the long-term sustainability of human societies, biological corridors are a reminder, and at the same time a teaching, that the ties that physically unite us are fragmented as well as the profound interconnection between nature and societies humane.

The implementation of biological corridors on a planet that increasingly isolates its organisms from their environment every day is not only an act of conservation of biodiversity, it is an act of responsibility for the benefit of a future for all.

Credits:

Photograph provided by the project “Diagnosis of wild meat consumption and the establishment of management units for wildlife conservation (UMA)” executed by ECOBIOSFERA EL TRIUNFO, S.C., with the support of ENDESU, A.C. and WWF

Bibliography

• Cuvillard, O. & Gillod, A. (2022). “Biodiversity Corridors: Strengthening Ecological Connectivity to Adapt Ecosystems to Climate Change.” In Global Synthesis Report on Climate Action by Sector 2022, 153-60. France: Climate Action Chance Association. Available at: https://www.climate-chance.org/wp-content/uploads/2023/01/bs2022_en_utcatf_tendance_biodiv.pdf.
• Damschen, E. (2013).. “Landscape Corridors.” In Encyclopedia of Biodiversity, 467-75. Elsevier. http://dx.doi.org/10.1016/b978-0-12-384719-5.00385-3.
• Fraser, B. (2013). “Biological Corridors Help Plants Adapt to Climate Change - Study.” CIFOR Forests News. Available at: https://forestsnews.cifor.org/20217/biological-corridors-help-plants-adapt-to-climate-change-study?fnl=en.
• Hoffner, E. (2020). “In the Fight against Biodiversity Loss, Connectivity Is Key (Commentary).” Mongabay Environmental News. Available at: https://news.mongabay.com/2020/08/in-the-fight-against-biodiversity-loss-connectivity-is-key-commentary/.

• Imbach, A., et al. (2013).. “Climate Change and Plant Dispersal along Corridors in Fragmented Landscapes of Mesoamerica.” Ecology and Evolution 3, no. 9:2917-32. https://doi.org/10.1002/ece3.672.
• Muhammad, K. et al. , (2017). “Habitat Suitability and Movement Corridors of Grey Wolf (Canis Lupus) in Northern Pakistan.” PLOS ONE 12, no. 11: e0187027. https://doi.org/10.1371/journal.pone.0187027.
• Merenlender, Adina M., Annika T. H. Keeley, and Jodi A. Hilty. “Ecological Corridors for Which Species?” Therya 13, no. 1 (January 30, 2022): 45-55. https://doi.org/10.12933/therya-22-1162.
• Rudnick, Deborah A., Sadie J. Ryan, Paul Beier, Samuel A. Cushman, Fred Dieffenbach, Clinton W. Epps, Leah R. Gerber, et al. (2012). “The Role of Landscape Connectivity in Planning and Implementing Conservation and Restoration Priorities.” Issues in Ecology. 16 (Fall): 1-20.
• Wan, Ho, Samuel Cushman, and Joseph Ganey. “Habitat Fragmentation Reduces Genetic Diversity and Connectivity of the Mexican Spotted Owl: A Simulation Study Using Empirical Resistance Models.” Genes 9, no. 8 (August 10, 2018): 403. https://doi.org/10.3390/genes9080403.