Juniper: passport to prehistory. It survived in a Surrey that people have forgotten except when pollen is teased from fossil deposits. Juniper was here when woolly mammoths came trampling, growing alongside plantain and birch, and Arctic foxes sheltered under it. It was one of the first trees to recolonise after the ice sheets thawed, growing slowly, smelling sweetly.

People found it later, and wrapped many stories around its sharp spines.

Is nature a fixed state? Juniper says no. Its range retreated as the ice grew, and expanded as it died. The same is true of red foxes, roe deer and fungi. It is a pattern – a re-weaving of the tapestry – that occurs on scales so grand and slow that we struggle to visualise them.

It is true, of course, that entirely natural change is now vastly overshadowed by the humans in the equation. Juniper is listed as near-threatened, not because a new ice age looms but as a casualty of the farming revolution. Overgrazing by livestock is its bane – or alternatively, not enough grazing, for this child of mammoth-country needs some disturbance by herbivores to protect it against competing plants, and yet cannot survive where that pressure is too high.

In Riddlesdown, ‘Goldilocks’ grazing is provided by Hebridean sheep, a primitive breed from the Scottish north. Conservation groups often use rare breeds to support these kinds of ecosystems.

While we worry about losing some species, certain newcomers have made themselves less than welcome. Grey squirrels, Japanese knotweed and floating pennywort are major threats to our native wildlife, and all were introduced by rash or careless games of humanity.

But that doesn’t mean that all new species are here because of us. Juniper was a pioneer ten thousand years ago, and a few – a very few – species still spread quite naturally. Our meadows know this, for they now host something big and striped!

It’s large, it’s dramatic, it’s harmless – it’s a wasp spider, a dazzling newcomer to the British wild. It was first recorded in 1922 at Rye on the south coast, and has gradually spread northwards. Unlike the noble false widow, which hitched a lift on bananas and has now colonised much of southern England, the wasp spider seems to have floated over the channel entirely on its own threads.

Spiders can exploit airborne currents, but many other species don’t have that option. Fragmenting nature into tiny, isolated reserves hurts the chances of wildlife that should be on the move. Let’s try to keep our wild habitats linked together so they can continue to write their changing stories.