The effect of big predators on the web of life makes the page in NewScientist (27 February 2016):
Predators don’t control populations of their prey just by killing them. They also paint what is termed a landscape of fear, inhibiting prey from feeding and turning parts of their habitat into no-go zones. Now it appears that this has far-reaching effects throughout the food web.
Domestic dogs are the main predators of raccoons on the Gulf Islands of British Columbia, Canada. Justin Suraci and his colleagues at the University of Victoria in Canada wondered what would happen if they stoked the raccoons’ fear of dogs without increasing predation. They set up speakers along the shoreline on two islands and played either the calls of dogs, or of seals and sea lions, which also live here but are not a threat to raccoons.
The dog sounds cut the raccoons’ foraging time by 66 per cent over the course of a month. They also led to a rise in the abundance of crabs, fish and worms that raccoons feed on in the intertidal areas, and in turn, to a decline in numbers of those animals’ prey and competitors (Nature Communications, DOI: 10.1038/ncomms10698).
It’s work like this, in which the logical chains of reaction, behavior, and its effects on population dynamics are explained in a logical manner, that does two things for me (besides giving me a thrill down my spine).
First, it documents how important the large predators are to a geographical area. Their presence, or absence, affects their prey, the resources their prey use, the physical nature of the land used by their prey, and then rinse and repeat with those prey, now as predators in their turn, as all those numbers change and resource usage changes. This understanding of the underpinnings of what poets dream about has its own magic, its own manifold, tangible meanings, and these central logical connections do not exist in a vacuum, but they instead affect us as well – because we are intimately connected to that landscape.
Second, it permits a more essential and understandable ecological advocacy. While some folks, with a superfluous understanding of ecology, may merely shrug and advance the notion of ‘circle of life’, and suggest that commerce must come before ecology, this sort of deep understanding permits the inversion of such arguments. How? By the important understanding that we are tied to the landscape we live on. Even us software engineers, we have to live somewhere, and if we do not put our understanding of our real-life surroundings into a central place in our society, we risk ending up like the folks who have – and are – building houses near the coastline (see the section on Science & Government). That is, doomed to lose our houses, our belongings, even our lives, to the subtle forces of Nature, and how we have changed her. Despite our attempts to live apart from Nature, she is always there, always around us – and, unless we want to live in the E. M. Forster’s Machine, giving up all control, then we need to think about how that ecology works, and give it prime place in our society – with commerce a good second. So when someone advances the notion of commerce first, suggest that perhaps their commerce will self-immolate if mature thought is not given to the effect they will and are having. If they’re exterminating big predators, for instance: what if this destroys half the town in 20 years? (What? Patience. I’ll let an expert cover this in a moment.)
But there’s one more reason I like this article, and that’s this: it reminds me of a wonderful video which really illustrates the entire effect of big predators. It’s logical, it’s full of facts, and it’s gorgeous. Not in a visual sense, but in the entire gestalt of senses, and with the added informational load and logical chains, it’s really a wonderful riposte to those who believe they can exist apart from Nature. Click and enjoy.
