The Sydney Basin (which includes the Illawarra) is a ‘biodiversity hotspot’ in Australia. This means that it has relatively high diversity of animals and plants, relatively high uniqueness of animals and plants and relatively high level of threat to these animals and plants (the ‘hot’ bit). The threats are land clearing, other human-mitigated landscape changes (reservoirs, commercial forestry, all the other things we do to directly manipulate our environment) and, of course, climate change, which involves natural processes (rain, drought, fire etc) but with changed frequencies and intensities.
OK, phew, that’s enough of the long words for a while.
I was just thinking about all this after returning from a holiday in Scotland. The UK has the strongest evidence for rapid biodiversity loss occurring in our lifetimes, because of its 250-year history of naturalists observing, listing and collecting. Recent studies suggest 70-80% declines in numbers and species of insects (particularly moths) and birds since the 1960s.
What is going on and are we experiencing the same issues? Finally, does it matter?
The UK biodiversity loss is due to a combination of factors. One is obvious, the impact of increasingly intensive agriculture. The fields in south-west Scotland are bright, perhaps lurid, green, not unlike plastic lawns. They have been heavily fertilised, often with farm slurry (so the countryside has a notable pong), herbicided and grass-seeded. They are almost sterile, not unlike plastic lawns, and wildflowers don’t have a chance.
Hence, no insects, no birds. Another factor is climate change – dry spells are longer – Scotch mist is becoming something only experienced in a bar. On my recent trip there were fire bans in the hills, previously unheard of in spring. Drought has profound impacts on flowering times, insect emergence and the ability of birds to feed their nestlings, for example.
But south-west Scotland has relatively low biodiversity and no unique species. Here we have the opposite. There are numerous species of plants and animals (mostly insects) that are unique to the Sydney Basin and its diversity is phenomenal – we are certainly blessed to be living here.
Due to lack of historical observations in the Sydney Basin it’s hard to be definite about changes.
There are certainly plenty of new weeds and a few native species that are extending their ranges southwards. We need more observations, lists, records. In my 23 years in Helensburgh, I’ve seen a decline in small bird species (wrens, honeyeaters) and some insects (Christmas beetles). But 23 years is not that long and may only show natural fluctuations – we need longer term data than that.
Why does it matter? Extinction of species is a natural process. But rapid, large-scale extinctions are like an avalanche, collapsing whole ecosystems through loss of species.
And one of those species is us.
