In 1990, the wolves came back.
In a controversial ruling, the US Wildlife Department imported a load of them from Canada into Yellowstone National Park, where they had gone extinct. There’s now about 15 packs of them, possibly totaling 400 in all. It is what they have inadvertently done that is so surprising.
By predating on elk, which they do, they have kept the elk lively. Lively elk do not have time to pause by the riverside and over-graze the willow. If the willow is allowed to grow, beavers, who are very partial to it, come back into the area and build dams. The dams create pools and depths that then attract a huge variety of river plants and insects, who attract fish, and on it goes. You’ve seen it all on your TV, and much more eloquently explained than I can.
The phenomenon goes under the rather wonderful name of Apex Predator Trophic Cascade, and rather more often, the damage is done when the apex predator is removed, or goes away. Red deer preventing tree growth all over the highlands, for example, or absent sea otters no longer eating the sea urchins, who themselves eat the kelp and kill of local biodiversity.
I am proud to say that we have established our own Apex Predator Trophic Cascade at Upperton and, whilst not necessarily awaiting the imminent call from the Nobel committee, I now offer it to you for its improving potential.
In the beginning, we had a bird table. It had a hanging container for nuts, another one for bird mix and a third for nijer seed for the goldfinches. Occasionally, it had lard balls for anything that flies and likes its food on the fatty side.
For years, events at the table were dominated by jackdaws, pigeons and scirius carolinensis, better known as the grey squirrel. Granted, we had our share of assorted tits (and who doesn’t in this life?), but the constant presence of one squirrel after another hanging off the nut feeder kept anything more interesting away.
Enter the apex predator. Actually enter two of them.
They are called Millie and Boris, two mid-intellect, cross bred bit-Jack-Russell-bit-Fox-terrier-bit-god knows what else. For a decade, events on the bird table went unseen by them, as their place in the vertical ecosystem was at ground level and, from there, and with the sofa in the way, it was impossible for them to see what was going on three metres away on the bird table. Nature, them included, continued in its unchallenging way.
Then one day, like the US Wildlife Department, we took the decision to spice things up around the bird table, and we did it by the simple trick of allowing –encouraging even- the dogs to climb up onto the back of the sofa to see what was going on in their immediate territory. For a week or so, the squirrels went on feeding contentedly, whilst the mid-intellect apex predators inside were doing their nut in protest.
For phase two, we decided to give the squirrels fair warning, by knocking on the window, and then letting the dogs bomb burst out of the kitchen door in search of some long-gone prey. And to say that they were strangely interested is perhaps an understatement.
The final phase was, of course, much more lively. Razzing them up into a state of near hysteria, we would let the apex predators out with no warning at all, giving the resident squirrel around 0.822 seconds to finish what it was doing, wipe the crumbs from its face, descend down to the ground, run across three metres of lawn and over the gate into the ecosystem beyond.
Over time, the squirrels, none of whom were harmed in the making of this documentary, have come to see our bird table as rather hazardous, and they have largely disappeared.
In their place have come nuthatches, great-spotted woodpeckers, goldfinches and all manner of new species- our equivalent of the beaver and the riparian insects in Yellowstone.
We are happy. The dogs, who are admittedly easily pleased, are happy, and even the squirrel has had its humdrum living made more exciting.
Apex Predator Trophic Cascade, before your very eyes.
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