The following is an extract from our nature newsletter Wild Wild Life. Sign up to receive it for free in your inbox every month.
To start off 2024, I’m proposing a shift in how we think about nature. I’ve been thinking a lot about bioabundance – the number of individual living organisms on Earth. Winter, typically, is a good time for a British nature-lover to get a taste of abundance. Large groups of birds from northern Europe overwinter here, and if you brave the cold you can enjoy seeing birds such as redwings and, in lucky years such as this one, Bohemian waxwings feeding in relatively large numbers. The need for food at a tough time can drive birds to fly around together, increasing their chances of spotting berries, while the cold pushes small birds like long-tailed tits to stick together for warmth. In some coastal areas, you may be able to see thousands of wading birds such as knots probing every inch of mud for food.
Today, such spectacles can be a special treat, but it wasn’t always this way. Before our current biodiversity crisis took hold, life was simply more abundant. An iconic North American example is the passenger pigeon, which humans drove to extinction throughout the 19th century. Before we did this, the bird was so abundant that, when flocks migrated overhead, they were described as darkening the sky for days at a time.
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Murmurations of starlings swirling around in their thousands during winter can give us a hint of what this might have looked like, but they’re also a good contemporary illustration of declining abundance. Starlings were common in the UK during my childhood, but their numbers dropped by 53 per cent between 1995 and 2020, and they are now on the UK’s red list of threatened species. Today, the UK is thought to have 73 million fewer birds than it did in 1970, while North America is estimated to have lost nearly 3 billion since then.
This bioabundance crisis is affecting all types of life on Earth. A 2022 report calculated that, on average, Earth’s populations of wild birds, fish, amphibians and reptiles declined by 69 per cent between 1970 and 2018. Insects have declined dramatically too. When I put the call out on social media for memories of bioabundance, US biologist Zen Faulkes replied: “As a kid, I did many summer road trips across the Canadian prairies. Stopping for gas often also meant wiping bug splatter off the windshields. Last summer’s trip across the prairies, bug splatter was practically unnoticeable.”
The scale and seriousness of this loss of abundance is often lost in discussions of biodiversity. There’s a tendency when examining the state of nature to focus on the number of different species, not the number of individuals within those species. We are wowed by countries with the largest numbers of endemic species, we are concerned about the vast numbers of species that are threatened with extinction. I wonder if that’s because the disappearance of an entire species forever is more easily recognised as a bad thing. The huge declines in bioabundance, however, have happened at a pace that is just slow enough to be not-quite-noticeable to busy humans living in an increasingly urbanised and intensively farmed world.
This phenomenon is known as shifting baseline syndrome, and it leaves me wondering what it was really like to live 100 or 200 years ago, when everything buzzed, fluttered, scurried that much more. I remember thinking this in the mid-2010s during a magical walk in rural Portugal. With every step I took, butterflies, grasshoppers and countless other insects leaped out from under my feet. Their abundance seemed fantastical but must once have been the norm.
In 2022, the COP15 United Nations Biodiversity Conference agreed on a range of targets designed to tackle both species extinction and the loss of bioabundance. If you’ve been following international efforts so far to halt both biodiversity loss and climate change, you’re allowed to feel sceptical of how much difference this will make. But we have to at least hope, while continuing to demand more from our governments.
I also think those of us who love nature could do more to appreciate bioabundance. The start of every new year, for example, sees many birders begin in earnest racking up as many species sightings as they can. The concept of a “big year” has become popular – the challenge of seeing as many different birds as possible in 12 months. I hope that, amidst this kind of competition, we can still appreciate species that we’ve seen countless times before, as well as enjoying the spectacle of seeing many individuals all at once, even if they don’t add anything extra to our lists.
While I was pleased to catch a quick sighting of a single Bohemian waxwing a few weeks ago, it wasn’t as fun as recently watching a large gang of adolescent starlings noisily foraging insects from my garden lawn.
