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Where have all the flowers gone? The global biodiversity crisis

Updated: Feb 23, 2023

By Mark Nicholson

Eurasian Bee-Eater

Or should it be: Where have all the birds gone? Or the non-human animals? Four months ago, I was walking with my dogs near my home in Kenya when I heard a soft but familiar bubbling in the sky. I looked up and saw a solitary Eurasian Bee-Eater flying about 100 m above my head. One?! In former years, it was always at least fifty on their way south from the Mediterranean (and occasionally Kent) to South Africa. The call is unmistakable but very difficult to describe. It is a far-carrying, rolling liquid call, quite unlike our nine other Bee-Eater species. I had to look it up in our local bird book in which the voice was given as klroop-klroop or chrreep-eep. If you try that, I can guarantee I will not confuse you with a Merops apiaster. Like swallows, maybe one observation does not make the summer it was heading towards, but Europe has suffered a huge decline in insect numbers, which I suppose partly explains the decline in the numbers of insectivorous birds. I will listen out for it/ them in a month when they return north.

A few weeks later, a Willow Warbler fell out of the sky in front of our garage. I weighed and measured it: 10g and 11 cm. Yet another miracle of life on this planet…to think that a creature that small can fly from Siberia (1) to South Africa twice a year, a return trip of 18,000km.

Willow Warbler

Last year 20,000 people convened in Montreal for one of those annual UN meetings, rather pompously named Conference of Parties (COP). This was the UN Biodiversity conference (COP 15), where governments and others around the world (dis)agree on policies to guide global action to halt and reverse nature loss. After much wringing of hands and numerous clichés such as tipping points, last chances for humanity etc., hasty last-minute compromises were made in order to arrive at new sets of clear targets, landmark goals, bold frameworks and historic agreements. The sad reality of course is that few of the previous goals, frameworks and agreements have led to any reversal of biodiversity loss.

The dramatic decline in biodiversity is increasingly conflated with anthropogenic climate change. This is not always fair or accurate. Yes, warmer seas threaten corals, which can only tolerate a narrow range of water temperature. A domino effect then ensues because fish and other species are symbiotically attached to certain species of coral. Likewise, as terrestrial ecosystems change, shade plants from tropical forests cannot live once the rain forest trees have been removed. Conversely, melting of glaciers and of permafrost provides larger areas for cultivation or natural plant regeneration. So, although climate change can, and will, effect biodiversity, loss of the latter is mainly the result of direct human activities. These include urbanization, construction, pollution, conversion of natural forests and grasslands to smallholder farms or mono-culture. In the drier parts of the globe, overgrazing or cutting trees for charcoal leads to land degradation. In the oceans, it is over-fishing. Yet the main question at COP 15 was neither asked nor answered. Is the conservation of biodiversity compatible with eight billion humans? Sir David Attenborough thinks not. He reckoned publicly some time ago that the Earth’s carrying capacity in relation to global human population is around one billion, which was the world population in 1800. In 1950, the population was still a reasonable 2.5bn. It then started to rise exponentially in 1970, which was the start of the Anthropocene extinction.

Is biodiversity doomed? First, it needs defining. When discussing it, we normally mean macro-biodiversity, or the sum and variety of all species that we can see. Micro-biodiversity is a different issue. The human body is host to far more species of microorganisms than the total number of large species found on Earth. We have absolutely no idea how many species of bacteria and other micro-organisms there are on this planet. It is also necessary to distinguish biodiversity from genetic diversity, which refers to diversity within (intraspecific) a species. Last month I was working on a fruit farm with 54 varieties of mangoes (2), an example of genetic diversity. Rice has high genetic diversity with over 120,000 varieties.

Genetic diversity within mangos (Mangifera indica). The small green one on the left is the best, full of sweet juice with a tiny stone and fetches four times the price of the others. The centre one weighed 1.7kg, the heaviest I have ever picked (or seen).

Biodiversity can often be the enemy of progress and profitability. Elephants break fences and destroy crops; lions kill cattle; leopards devour sheep, goats and dogs; bats, buffaloes and badgers transmit disease to both humans and livestock; locusts eat all vegetation. A flock of Red-billed Queleas can comprise several million individuals, which can consume well over 1000 tonnes of wheat in one day (3). Farmers hate this bird, the most populous (and least popular) bird on earth; conservationists regard them as an example of a super successful avian species.

Red-billed Quelea enjoying some wheat

Whose responsibility is it to restore biodiversity? Governments or individuals? Can it be achieved anyway? There is a plethora of information about the dangers of losing biodiversity but how many of us are in a position to do anything? If we are worried about climate change, at least we can try to reduce our dependence on fossil fuels. I suspect that far fewer of us lose sleep over declining biodiversity.

Farmers are in the best position to reverse biodiversity loss. In Europe, restoring hedges has a marked beneficial effect on biodiversity. In Kenya, the main plantation crops are tea, coffee, sisal and pineapples, all crops associated with low biodiversity.

Farmers have a choice. They can plant trees, which provide shade and habitat for other species, but planting trees will reduce crop yields.

Tea: low biodiversity

versus higher biodiversity

Low biodiversity: Pineapple farming in Kenya

Why should large-scale producers be bothered about biodiversity? Mechanization and trees are not good bedfellows; trees in large wheat fields are an obstruction. At the other end of the scale, many small farmers, especially in the developing world, are amongst the poorest in society. Why would they want birds to eat their crops, or civet cats or snakes to eat their chickens? I can guarantee that the champions of biodiversity protection are the well-off, unless they directly benefit from biodiversity, like bird guides.

The problem with biodiversity is that this planet now has one species of highly rapacious primate that has invaded the habitat of other species and competes for resources. We are intelligent enough to recognize our effect on biodiversity but not clever enough to reverse the trend. On a personal level, I appreciate what a privilege it is to enjoy our morning chorus. I have been in so many towns and villages in modern-day Africa where dawn arrives with no bird song at all, only the noise of internal combustion engines.

Recording of dawn chorus in rural Kenya, including cockerel

I returned last week from farming friends who for many years farmed in the Mara Region, close to the Mara-Serengeti, ecologically the richest large mammal ecosystem on Earth. They gave up wheat farming because the rainfall is too erratic. The soils have dried up and become less fertile. Chasing away zebras and quelea also just got too much. Huge areas are now fenced so wildebeest can no longer migrate. On the final night after a thunderstorm, I heard the mournful call of a hyena. My friends told me the next morning they had not heard a hyena in their area for years since all the fencing was constructed. For me, it was a sad, valedictory howl.

1 The two east African races of Willow Warblers mostly migrate between here and central or eastern Siberia.

2 Worldwide there are around 500-1000 types of mangoes, of which about 350 have been selected and bred commercially (known as cultivars).

3 The only control methods of these queleas to date are aerial spraying of pesticide or bombing the roosting sites. Spraying kills the birds, but also poisons the animals that eat the corpses and adulterates the grain. Apparently, the birds are a delicious snack and widely sold in southern Africa, but try shooting 100,000 birds.



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