The concept of “Refuge” in Species survivorship
When you hear the word refuge, likely you think of a safe space, a haven from something to be avoided. Ecologists and paleontologists also use this word, but with parallel meanings. A predation refuge is a means for an animal to avoid being eaten by a predator, through specific attributes of the organism, like being too big to attack. A climate refuge is a place where the habitat is protected from present-day climate change and mimics the conditions of past climate - ice caves are examples of climate refuges, where ice-age plants can grow within the cold emanating from the cave. An extinction refuge is one where species might find protection from a global environmental crisis that would otherwise drive them to extinction.
Extinction refuges, or refugia in formal terminology (“refugium” is the singular form), were mechanisms for species to survive ancient mass extinctions. The fossil record for refugia isn’t great - the fossil record is full of major gaps in time and space - but from the ancient refugia that have been discovered, I have discovered a few key points. These are:
Refugia must be big enough for the species in them to have large enough populations to survive the environmental crisis. The longer and larger the crisis, the larger the refugium is needed. However, there is a threshold of refugium size relative to length of crisis: when an environmental crises becomes too long, refugia cannot be maintained because the environments within them eventually become too unstable. Then, species need to move between shorter-lived refugia as the environment shifts during the crisis - these are considered ephemeral refugia.
For small refugia and often for ephemeral refugia that overlap in time, species’ individual, isolated populations need to be connected for genetic exchange, in other words, for breeding.
When global environmental crises occur, as the habitat breaks down, it’s pretty much “every species for itself” - species will respond to their individual requirements by adapting or moving, or else they will go extinct. This means that ecosystems break down during a global environmental crisis as each species responds to their needs. Thus, an ecosystem in a refugium is not the same as the pre-extinction ecosystem; the new ecosystem will be made up of some of the pre-extinction species and some different species that have moved in.
Through past mass extinctions, species only needed refugia for their own survival; but in the present extinction, refugia need to not only support the species for their own sake, but also for ecosystem services and and as resources that are important to humanity.
What does this mean for our intervention, as scientists, in the “sixth” mass extinction? We need to be flexible in responding to species’ requirements during habitat deterioration and loss. We need to think ahead to see where species may move and what their habitat requirements might be. We likely will also have to allow ecosystems in refugia - in protected areas and reserves - to change naturally as species move and respond to environmental crises.
But what do refugia mean for the non-scientist? How can you help in creating man-made refugia, like protected areas and national parks, that will decrease the magnitude of the sixth mass extinction?
Use your voice, your actions, and your vote to support protected areas and reserves, along with their funding.
If you have the financial means, donate accordingly, even if it is a small amount - every dollar matters.
If you have the time, consider volunteering for citizen science activities, often offered by various environmental and ecological non-profit groups and universities.
Follow online posts by environmental groups about conservation areas so that you can keep up to date with what is going on.
Importantly, consider what you would like to support so that you don’t feel overwhelmed in trying to support too many causes. Would you like to support the conservation efforts in a local “refuge,” like a nearby park or wilderness area? Are you concerned about a specific species or ecosystem? Find the one thing that most moves you to action, where you care the deepest, and begin your efforts to help there. Years later, when you have gained experience with your chosen cause, you can consider adding another area or species - or not. A focused effort of assistance, no matter how great or small-seeming, on one conservation issue can have a greater impact than trying to contribute to too many causes.