Night Spotting, Valla Nature Reserve

‘Were it not for shadows, there would be no beauty.” Junichiro Tanizaki, In Praise of Shadows (1933).

From the ubiquitous campfire to Romans using oil lamps filled with vegetable oil – to candles, fine beeswax or spermaceti for the rich, or foul smelling smoky tallow candles for the rest. Cities and towns burnt parts regularly from naked flames until the 1800s, when gas lamps reduced the fire risk. Electric streetlights using arc lamps were introduced in 1878 in Paris. Now our dusk, evenings and nights are dazzled and dazed by high-pressure sodium lighting that is blinding and creates sharp contrasting shadows – nothing subtle about darkness any more.

Half of the world can’t see the stars. The Greeks could count 10,000 stars without a lens. Skyglow, the combination of all the reflected light and upward-directed light escaping from populated areas into the sky, now obscures the Milky Way. A large city like Sydney has a huge skyglow wasting many millions of dollars and many thousands of tons of carbon dioxide emissions from the wasted energy.

We live in an electric world. Electric light affects the natural day-night cycle of our wildlife, as well as our own circadian rhythms. Hundreds of thousands of migrating birds navigate by the moon and the stars and are hurt by city lights. Insects swarm to lights until they die of exhaustion or are picked off by predators. Light pollution in Europe and the United States is severe, in Australia it is confined to the south east and south east Queensland.

Many Australian mammals, reptiles, insects and arachnids coming out at night. In fact, 70% of our wildlife is nocturnal, so night-spotting is important to understand what is happening in the bush.

Wednesday 18 Feb, 2015, we undertook a survey of Valla Nature Reserve with the keen eyes of National Parks and Wildlife Officer, Andrew Turbill. There is a disturbing decline of large mammals, Fifteen years ago yellow-bellied gliders were here and in Jagun Nature Reserve to the north. They need very large territories and Valla has been gradually cut into piecemeal by development.

Greater Gliders need much smaller territories and were in both reserves in large numbers until recently. I heard a Powerful owl in Jagun yesterday; they can have a major but temporary impact on glider populations and have been known to take an adult koala. An adult owl weighs around 1.5 kilos, an adult koala can weigh up to 15 kilos.

Andrew said fresh scat smelt of Eucalyptus which I had heard before. So I picked a piece, surprisingly hard, broke it up and smelt. My fingers stank of poo  all evening.

The evening found one Ringtail Possum, one Greater Glider, one Feather-tail Glider, about a dozen Brushtail Possums  and one female koala. Andrew suggests the Greater  Glider population has crashed here and Brushtails have taken over their nesting sites. There are more old trees here than in Jagun, and so more chance of Gliders. It is a great shame. Gliders are not common in coastal wet sclerophyll forests.

Our coastal development appears inexorable and destructive.

According to the Australian Museum our population is the biggest threat top coastal biodiversity.

The greatest threat to biodiversity is the size and rate of growth of human population. Everyday, more people need more space, consume more resources and generate more waste as world population continues to grow at an alarming rate.

Human population growth is reducing biodiversity in the following ways:

• We cause habitat change through agricultural, urban and industrial development, and the exploitation of natural resources.
• We pollute soil, water and air.
• We overharvest resources which reduces both population sizes and genetic diversity of commercial species, such as fish.
• We introduce exotic species which damage land and water resources and sometimes bring diseases with them. In addition, they may compete with native plants and animals for food and shelter. Some animals, such as cats and foxes, directly destroy native species.
• We cause global warming by releasing increasing amounts of carbon dioxide and other gases into the atmosphere, which will alter the nature of ecosystems everywhere. One of the causes of increased levels of carbon dioxide is the burning of carbon-based fuels such as coal, oil and gas.

Loss of habitat

Many ecosystems have been lost during the past 200 years.

Some of these ecosystems include:

• 75% of rainforests and nearly 50% of all forests;
• over 60% of coastal wetlands in southern and eastern Australia;
• nearly 90% of temperate woodlands and mallee;
• more than 99% of south-eastern Australia’s temperate lowland grasslands.