Eiffel Over

Tag: MarineConservation

  • Desertification versus dessertification

    Desertification = a real word that refers to the process where fertile land becomes desert, typically due to drought, deforestation, or poor land management. It can also be used more broadly to describe when a population of living things becomes so small that it struggles to sustain itself.

    Dessertification = a word I’ve just made up to describe an abundance of cake.

    Yesterday I talked about overfishing leaving fish populations so sparse that they can barely survive. When a population is reduced to such small numbers, it may become almost invisible. The creatures that remain may live in small, isolated pockets that are vulnerable to disease, and don’t benefit from much genetic variation. Such populations are on the brink of local extinction. 

    But populations in a desertified state can slowly come back into a state of thriving. One way to help them do this is by finding ways to connect together isolated pockets. Connecting to smaller populations creates a larger one with the potential for greater genetic variation, and the ability to move further should environmental conditions change. Both of these increase the resilience of the population. 

    Here I am going to leap from talking about fish to butterflies and people.

    When I first visited Hazel Hill Wood in 2008, it was to take part in a butterfly conservation activity. Our task was creating open corridors through the wood that would allow populations of butterflies living on either side of the wood to mix. As we were told, butterflies don’t like flying through dense, dark, cold woodland. So the wood was effectively a barrier between these two populations. But creating wide openings in the wood lets sunlight in and provides a pathway that the butterflies can follow. Connecting the populations builds their resilience, and today the wood is rich with a wide range of species of butterflies fluttering by. 

    Doing the work of conservation also brings people together. During Covid, the wood was a place where people come together, out of isolation, to form community and build resilience. 

    It is pleasing to think that this work of countering desertification, be that of butterflies or sense of community, is fuelled at tea time by an abundance of cake. Dessertification indeed.

  • No more fish in the sea

    Somehow the topics of my posts have returned to the subject of the sea. It is apparently a rich subject to trawl.  Sorry, I couldn’t resist the pun, but it is exactly to trawling that I am heading. 

    Yesterday I used Donella Meadows’s fish stocks example to show how humans can harvest a living resource while enabling it to thrive. A key to enabling this system to work is the balancing feedback loop between supply and the people doing the harvest. When the catch gets too low, the boats go home, and the fish can restore their population.

    But what happens when that balancing feedback loop is broken? 

    Let us imagine an entrepreneurial fisher who, noticing that their catch was diminishing, decides to invest in a much bigger net. Now their catch goes up and it is worthwhile for them to stay at sea for longer. Other boat captains do the same, and the fleet stays out much longer. 

    Now, rather than the fish population having time to replenish itself, it is further depleted. When the fish are further apart, their rate of reproduction diminishes. 

    Here, trawling is breaking the balancing feedback loop between supply and harvesters. So, instead of stopping, fishing continues and the population becomes so low that it is not able to grow back. It has become what is known as a ‘desertified state’, a vulnerable situation in which a living system can no longer thrive. 

    Clearly, this is a simplified version of a much more complex system. But hopefully it serves to illustrate that in thinking about how we scale up options, we need to think about how we might inadvertently be breaking the feedback loops that enable our activities to operate within the living system’s limits.

  • Plenty more fish in the sea

    Yesterday’s post on the fish écluses on the Île de Ré speaks to the idea of creating straightforward connections between the resources that humans need to live and thrive. 

    As engineers (and other humans) we need to find ways to harvest the materials and energy we need in balance with what the living and mineral world can sustain. So to help us understand how this can work I’m sharing Donella Meadows’s example of fish stocks to help see how humans can live as part of a sustainable system of supply.

    Meadows’s model concerns the local fish population in an area of sea. Left to its own devices, the fish population is stable because there is only so much food to go around. Too many fish, less food per fish, some fish die. Too few fish, more food per fish, they reproduce more. This feedback loop stays in equilibrium around a mean.

    Now, the local fishing fleet gets involved. By harvesting a small number of fish, the population goes down, increasing the reproduction rate of the remaining fish, and the population returns to what it was. Fish too much, however, and the fish are further apart. Fish that are further apart take longer to reproduce! And so for a while, there are few fish, the nets are empty and the boats go back to port. During this time the fish population recovers, and eventually the boats can go back to sea.

    This simplified model beautifully illustrates how humans can harvest what they need while still living within the ecosystem’s limits.  The key characteristics here are a living system that regenerates itself – the fish; and a feedback loop between supply and those doing the harvest. Simply, when the catch is too low, the boats go home. 

    This feedback loop between supply and harvesting is what interests us in regenerative design. It is what allows us to harvest abundance, and even create abundance, all while living within the ecosystem’s limits. 

  • Stone circles on the beach

    Hundreds of years ago, the inhabitants of the Île de Ré, just off France’s Atlantic coast, developed an ingenious way to catch fish. At low tide, they built large stone circles, say 20 metres or more in diameter, and formed by a rock wall about 50cm high. At high tide these stone circles are completely submerged. But as the tide falls, water remains trapped in them, and so do the fish swimming in that water. At low tide the water eventually drains out of the walls, leaving the fish lying on the beach, for the local fishers to just pick up.

    These stone circles, or ‘écluses’ in French, were very effective in providing a local food supply. So much so that during the Napoleonic Wars, recruiting officers for the army tried to destroy the walls in an attempt to starve the local population and force them into joining the army. Later, the owners of commercial fishing fleets sought to have them shut down as they proved a risk to their own market domination.

    Through a regenerative lens, in this example we see:

    • A local population connected to a local source of supply. 
    • A low-tech method for harvest that the community itself can build and adapt.
    • The resilience that local supply can provide (and therefore why the army and larger commercial operations sought to remove it).
    • A scale of operation that is necessarily limited – they can only harvest fish that swim over the beach; there’s literally plenty more fish in the sea. This is in contrast to the super trawlers that can take far more than their fair share.

    Community, ecology, supply and resilience. These are the sorts of stacked, multiple benefits that we are seeking to create through regenerative design.

    Today, groups of volunteers are protecting and rebuilding the walls. Perhaps for posterity. And, or, perhaps they see a time in the future when harvesting in this way may return stacked, multiple benefits to their community and ecosystem.