Eight hundred years ago, when the prince-bishops of Durham enclosed Auckland Park as their private hunting ground, they preserved for posterity what has become one of the rarest of our managed wildlife habitats: wood pasture.
The ancient oaks and sweet chestnuts here are magnificent, but so too is the species-rich grassland, fertilised only by dung from grazing livestock and protected from the plough. The most numerous beneficiaries are yellow meadow ants (Lasius flavus), whose mounds have been built grain by grain, with earth mined from underground galleries and carried to the surface in tiny jaws. They are everywhere, sometimes so densely clustered as to be visible in aerial mapping images, but the beauty of this ant-engineered landscape is best appreciated from only a few inches away.
There is an annual floral cycle on the summits of this undulating ant hill metropolis, unbroken over centuries and maintained by millions of social insects that are rarely disturbed, except when hungry green woodpeckers hack into their nests and raid their underground galleries.
Now, at winter’s end, every ant-hill dome is capped by an emerald blanket of mosses, already giving way to new spring growth of wildflowers. Kneeling down, I could see the first barren strawberry flower buds opening. Unfurling leaves of pignut, heath bedstraw, speedwell, hawkweeds, bird’s-foot trefoil, creeping cinquefoil and dog violets (Viola riviniana) were forcing their way through. Spring comes early to the flora of these knee-high islands, exposed to the warmth of the sun and raised above a surrounding sea of competing pasture grasses.
Most wildflower species arrive here by chance, but the violets probably owe their presence to unwitting ant gardeners, because their seeds have a small, nutritious oily protuberance called an elaiosome, which ants find irresistible. They will eat these wherever they find them, but undoubtedly carry some back to the colony, where discarded seeds germinate on the mound.
By August, the ant excavators, hollowing out new nest chambers, will have partially buried some plants under a new layer of soil particles. Summer droughts take their toll, when parched soil leaves many hummocks with bald patches, only covered again with a revived wig of mosses when cool, wet autumn weather returns.