One Million Under Threat

“The evidence is crystal clear: Nature is in trouble. Therefore we are in trouble.”

Professor Sandra Díaz, co-chair of the United Nations’ Global Assessment Report on Biodiversity and Ecosystem Services.

One million species of animals, insects, plants and the places they live are currently under threat and we are undermining the entire infrastructure on which human life depends. From the smallest of creatures to entire ecosystems, we destroy them at our peril.

Bees are in drastic decline, disappearing at rates consistent with a mass extinction. In 2014, the first-ever assessment of all European wild bees (nearly 2,000 species), prepared by the IUCN and published by the European Commission, found that nearly one in ten species were threatened with extinction. Population decline, they said, was mainly due to habitat loss because of agriculture intensification and the increasing use of pesticides and fertilisers. However, the report warned that 80 per cent of European bees have unknown population trends and some are suspected to be in a critical state of decline. The lack of information about these species meant that a threat category could not be assigned and the situation could be much worse than reported (Nieto et al., 2014).

Bumblebees

Of all the wild bees in Europe, bumblebees are the best studied group. There are about 19 different species of bumblebee in the UK, 68 in Europe and around 250 in the world. Well-suited to cooler weather, bumblebees’ fluffy hair and ability to generate heat while flying often permits them to be the first bees out in spring. They are among the most important pollinators of food crops and play a key role in pollinating tomatoes, peppers, squash and berries amongst other crops important to humans. But they are living under threat, due to the rise of industrial agriculture, habitat loss, deforestation, increased pesticide use and climate change. According to the European Red List of bees, around a quarter of bumblebee species in Europe are threatened with extinction (Nieto et al., 2014).

Common UK bumblebee

A study from the University of Ottawa in Canada, looking at 66 different bumblebee species across Europe and North America over a 115-year period (from 1900 to 2015), found evidence of rapid and widespread decline (Soroye et al., 2020). Lead author, Peter Soroye, PhD student at the University of Ottawa in Ontario, Canada, said: “Our results show that we face a future with many less bumblebees and much less diversity, both in the outdoors and on our plates.” Soroye warns: “If declines continue at this pace, many of these species could vanish forever within a few decades.”

Bees are just part of a much wider picture of population declines. By comparison, of groups that were comprehensively assessed in Europe; 59 per cent of freshwater molluscs, 40 per cent of freshwater fish, 23 per cent of amphibians, 20 per cent of reptiles, 17 per cent of mammals, 16 per cent of dragonflies, 13 per cent of birds, nine per cent of butterflies and eight per cent of aquatic plants were considered threatened (Nieto et al., 2014).

When discussing threatened species, most attention tends to focus on larger animals but conservation scientists are equally, if not more, concerned about smaller creatures. A study published in the journal Biological Conservation described the state of insect biodiversity in the world as “dreadful”, warning that 40 per cent of all insect species are in decline and could die out in the coming decades. They say that moths, butterflies, bees and dung beetles are particularly threatened along with other insects that help decompose faeces and detritus. Habitat loss by conversion to intensive agriculture over the last six decades, they say, is the main driver of the declines along with the widespread, relentless use of synthetic pesticides in recent times. Unless we change our ways of producing food, they warn, insects will go down the path of extinction in a few decades (Sanchez-Bayo and Wyckhuys, 2019).

Insect apocalypse

The sixth mass extinction that we are currently experiencing includes what has been described as an “insect apocalypse.” In 2018, English naturalist, television presenter and author Chris Packham said: “I’ve been in my garden in Hampshire for the last couple of days. Sunny, plenty of wildflowers. Not a single butterfly. Not one. Nothing. And in the woods a handful of Speckled Woods. I think we are at a point of absolute crisis in our countryside.”

Anyone who grew up in the 1970s will remember the splattering of dead insects all over the car windscreen that would happen during long journeys – it was carnage. Nowadays, there is hardly anything like as many splattered flies, gnats, moths and wasps. Entomologists call this the “windscreen phenomenon” and experts blame intensive agriculture and the increased use of pesticides over the past 50 years for the massive decline in insect populations.

There are over 23,008 protected areas in Germany including 5,205 Natura2000 sites, 742 Special Protection Areas (Birds Directive), 4,549 Sites of Community Importance (Habitat Directive) and 17,803 sites designated under national laws. A study looking at populations of flying insects in 63 protected areas in Germany found that they have declined by more than 75 per cent over the last 30 years, despite measures in place to preserve ecosystem functions and biodiversity (Hallmann et al., 2017). Butterflies are key indicators of the health of the environment. Across Europe, populations of European grassland butterflies are estimated to have halved between 1990 and 2011 with bees and moths following the same trend (European Environment Agency, 2013).

To really understand the potential negative impacts of what is happening to biodiversity we need to appreciate how the small and often unseen organisms do most of the work that keep ecosystems ticking over: insects, fungi, algae, crustaceans, molluscs and so on.

Earthworms

Often overlooked, as they lack the appeal of larger animals, earthworms have been referred to as “ecosystem engineers” because they play an important role in breaking down organic matter (decomposition) freeing up nutrients which help plants and trees grow faster. As a bonus, this process locks carbon in too. Charles Darwin referred to them as “nature’s ploughs” saying: “It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures” (Darwin, 1881).

But earthworms are on the decline too; one study found that 42 per cent of fields in England surveyed by farmers were seriously deficient in earthworms – in some fields they were missing altogether (Stroud, 2019). Globally, of the 222 species (out of around 7,000 worldwide) assessed by the IUCN, two are already extinct, six critically endangered, 13 endangered, eight vulnerable, 12 near threatened, 74 considered at lower risk and there was insufficient data on 107 to make an assessment. Habitat loss to agriculture, including land clearance for grazing and animal feed cropland, is one of the main reasons for their demise. Life could become very difficult without earthworms; we would have less food, more pollution and more flooding.

Earthworms

However, earthworms are not so welcome in boreal forests, which circle the northern hemisphere of the globe, passing through North America, northern Europe and northern Russia – rather like a ring of hair around a balding head. The boreal forest is the world’s largest and most intact ecosystem on the planet and holds one-third of the world’s terrestrial carbon (Watson et al., 2018).

Native earthworms disappeared from this region during the last ice age. The forest floor has adapted to thrive in their absence by accumulating a thick layer of rotting leaves, mosses and fallen wood over mineral soil. These layers of slowly decomposing matter, deposited over years, have created a home for insects, birds and native plants. Invasive earthworms, from Europe and Asia, are now wreaking havoc, devouring this mulchy layer and releasing nutrients that have been stored up over decades. Although generally seen as highly beneficial to soil fertility, scientists say earthworms in this region may increase net soil greenhouse gas emissions (Lubbers et al., 2013). In other words, they are upsetting the balance, such that more carbon is released than stored from this vital asset.

This shows how there is simply not a one-size-fits-all approach to biodiversity. The world’s natural ecosystems have all developed in their own unique way and disrupting any part of them can have devastating effects, the full consequences of which are unclear.

Seed dispersal

We depend on nature for the important task of seed dispersal. For animals that help in this essential activity, some plant species such as fruit-bearing trees, for example, offer a tasty reward. The indigestible seed coating protects the seed as it travels through the animal’s digestive system and is then deposited, at a new location away from the parent tree, in a dollop of natural fertiliser!

A black-and-white ruffed lemur in Madagascar

Black-and-white ruffed lemurs in Madagascar are capable of dispersing big tree species and as such may play a significant role in carbon sequestration. Listed by the IUCN as critically endangered, the principal threat to their survival is habitat loss due to slash-and-burn agriculture as well as hunting, logging and mining. Ring-tailed lemurs, also in Madagascar, are important seed dispersers and their numbers have declined by 45 per cent over the past 40 years (Brinkmann et al., 2014). Deforestation for small-scale but widespread charcoal production, slash-and-burn agriculture and livestock grazing, are all impacting the remaining forests throughout southern Madagascar (Waeber et al., 2015).

Elephants contribute to forest ecosystems by distributing seeds and nutrients, but they also help forests store a substantial amount of carbon. By trampling and grazing on young, smaller plants, elephants in west and central African forests (but not in the Amazon) create space for surviving trees to grow larger and therefore store more carbon.

A study published in the journal Nature Geoscience says that if elephants were to go extinct, the amount of carbon stored in central African rainforests could fall by seven per cent. They say the loss of elephants would reduce the biomass of African forests by about three gigatonnes of carbon – equivalent to 14 years’ worth of carbon emissions from the UK (Berzaghi et al., 2019). Co-author of the study, Dr Stephen Blake, Assistant Professor of Biology from Saint Louis University in Missouri in the US, says: “The sad reality is that humanity is doing its best to rid the planet of elephants as quickly as it can. Forest elephants are rapidly declining and facing extinction. From a climate perspective, all of their positive effect on carbon and their myriad other ecological roles as forest gardeners and engineers will be lost.” There were around a million elephants in central African rainforests in the early 19th century, now there are only about 100,000. Forest elephant conservation could halt and even reverse this tragic loss.

African forest elephants

Sumatran elephants are also critically endangered largely due to oil palm plantations destroying their home. From ice cream and instant noodles, to shampoo, lipstick and animal feed, palm oil is the most widely consumed vegetable oil worldwide and half of all packaged products contain it (WWF, 2018). The oil used in foods is derived from the reddish part of the fruit, while the oil in non-edible products, such as soaps, cosmetics and detergents, is extracted from the seed or kernel. A third product made from oil palms is palm kernel expeller (PKE) or palm kernel cake, which is used as animal feed. Around half of global PKE exports are sent to Europe and more than 80 per cent of that is used for animal feed, while the rest is used in power stations as biomass for co-firing with coal. The beef industries in several Asian economies (notably South Korea, Thailand and Vietnam) took over 20 per cent of PKE exports in 2012 and are emerging as significant PKE consumers (Virah-Sawmy, 2014).

Taken together, palm oil is big business; between 1980 and 2014, global production increased 15-fold; from 4.5 million tonnes to 70 million tonnes and demand is expected to grow by 1.7 per cent per year between now and 2050 (IUCN, 2018). The use of PKE in animal feed illustrates the direct links between elephants and other animals dying and the consumption of meat.

Wilderness areas – going, going, gone!

Wilderness areas are the last places on Earth to contain groups of different species of plants and animals at near-natural levels. They are the only areas left that support ecological processes that can sustain biodiversity, providing the last sanctuary for species that are declining. In the seas, they are the last regions that still contain viable populations of certain predators such as tuna, marlins and sharks (Watson et al., 2018a).

Around a fifth of the world’s land area is wilderness – mostly in North America, North Asia, North Africa and the Australian continent (Watson et al., 2016). However, despite their critical role in humanity’s survival, wilderness areas are disappearing at an unprecedented rate. Between 1993 and 2009, an area of terrestrial wilderness larger than India – a staggering 3.3 million square kilometres – was lost (Watson et al., 2018a).

Biodiversity in the extremes

In August 2019, a memorial plaque marking Okjökull, the first glacier lost to the climate crisis, was unveiled in Iceland. It will certainly not be the last glacier to be lost and scientists believe that the 400-plus glaciers in Iceland will all be gone by 2200.

Iceberg calving

Biologists use the term biome to describe a large, naturally occurring community of flora and fauna occupying a major habitat. For example, a biome may include a forest or a treeless frozen tundra. Glaciers are often regarded as a part of polar or mountain ecosystems, but scientists now say that they should be considered as a new biome in their own right. Far from being barren, they host a whole ecosystem of unlikely creatures including tiny insects, worms, fungi, algae, bacteria and microscopic animals called tardigrades or water bears.

How did these unlikely microbial hotspots develop? The answer lies in a combination of dust, wind and heat. The most biologically active part of a glacier is its surface, where during summer, interaction between bacteria, algae and wind-blown dust form a layer of cryoconite (from the Greek kryos meaning cold and konis meaning dust). Because the dust is darker than ice, it absorbs more heat from the sun and causes the ice under it to melt, creating water-filled reservoirs called cryoconite holes (Zawierucha et al., 2019). The surface of glaciers can be riddled with these holes, some needle-thin – others much wider. These sheltered reservoirs provide the perfect refuge for a hub of activity in which secret ecosystems can thrive.

In 2014, a team of researchers, led by Dr Krzysztof Zawierucha, from the Adam Mickiewicz University in Poznań in Poland, conducted the first worldwide survey of invertebrates inhabiting cryoconite holes in Alpine, Antarctic, Arctic, Himalayan and Patagonian glaciers. They found many new species, some of which are unique to their habitat (Zawierucha et al., 2014). Zawierucha said: “In Arctic regions the big predator is the polar bear, but in cryoconite holes it is the water bear, which feeds on bacteria and algae. They are the toughest organisms on Earth.”

A tardigrade

Tardigrades survive the long winter by drastically slowing their metabolism and they may even possess antifreeze proteins. They enjoy a reputation as being the toughest, most resilient creatures on Earth. In fact, hardy tardigrades have survived all five mass extinctions on Earth since they evolved about 500 million years ago and could survive after humans are long gone, if we don’t kill them all first. We might even learn some important climate resilience lessons from these tiny water bears. However, scientists are racing against time as the ice is melting due to the climate crisis – and animal agriculture is one of the main contributors.

Human activity has condemned vast numbers of mammals, birds, amphibians, reptiles, insects and microorganisms to an early grave. Ecosystems on which our economies, livelihoods, food security, health and quality of life depend are deteriorating more rapidly than ever. We are destroying the foundations of life worldwide with little or no regard for the consequences for us and the other species with which we share the planet.

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