Earlier this year I had the pleasure of attending Wildlife Queensland’s 50th Anniversary conference and was very taken with Professor Roger Kitching’s presentation on insects and other invertebrates. Around the same time a short article appeared in the Courier Mail warning of the likely extinction of 1/5th of the world’s invertebrates (creatures without backbones).
Professor Kitching told us that insects and other invertebrates vastly outweigh all other animals in terms of diversity and even sheer weight in ecosystems. They form between 87-99% of all living creatures on the planet and are essential to the survival of humans and other species. They play vital roles in driving processes such as decomposition- have you ever considered what an unpleasant place the world would be if dead animals and plants did not decompose – pollination, herbivory and natural pest control within ecosystems.
Imagine too if we had no bees, moths or other invertebrates to pollinate our crops or beautiful trees and flowers. Organic farmers (and even non-organic ones) rely on invertebrates to pollinate their crops.
Many of those invertebrates threatened with extinction are being put forward to the International Union for the Conservation of Nature for listing on the Red List of Threatened Species. ICUN Scientist Simon Stuart said that he hoped it would lead to invertebrates winning a much higher conservation profile.
Professor Kitching spoke also about the impact of fire management regimes on invertebrates, an issue that few people give thought to when confronted by a bushfire. We are familiar with images of koalas seeking water after bushfires and wild care volunteers nursing possums and other creatures back to health, but what of those that creep through the litter, or live underground or fly from plant to plant?
Following devastating fires such as Black Saturday in Victoria there has been an increased emphasis on reducing “fuel” loads in the bush and even now we hear of concern about bushfires following the two wet summers which produced lots of vegetation. It is important to protect lives and property, but we also
We need to consider the protection of the smallest biodiversity as they are essential to the continuation of life on the planet.
The current emphasis is on reduction burns over large areas without consideration of the type of ecosystem and the need for some areas to be protected from fire.
Invertebrates demonstrate extraordinary ecological variety and are found in every ecosystem and they are poorly described. Many are high specialised with a narrow range of endemism (area in which they are able to live – ed.) leaving them very vulnerable to habitat loss. They are often difficult to detect and evaluate because they are short lived, highly seasonal and often have different life stages. An example given by Professor Kitching was the common butterfly, which needs a different habitat with nectar-giving plants for the adult stage and leaves for its caterpillar to chew on.
Fire results in direct mortality of invertebrates and those that survive have to cope with a destroyed habitat and food sources which have changed in structure and composition. When “cool” burns are planned it is essential that invertebrate survival is considered and refuges are set aside in both time and place.
A mosaic plan for burning is better for all creatures than burning of vast areas and factors such as season, intensity of the burn, frequency of burns and the area all must be part of the plan.
An example was given of a particular caterpillar which has a habit of living underground in an ants nest in a symbiotic relationship.
The caterpillar was able to survive a fire which was done in late summer when it was fat and could manage a period when there was no foliage.