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Food Cycle

Invertebrates, the Food Cycle and Jarrah

Praying Mantis

Jarrah communities are all the species of organisms - plants, animals, bacteria and fungi - that live together with jarrah trees.

Groups of species that live together and make a community, interact with each other and their environment, to form ecosystems. Ecosystems interact to form systems, such as forests, grasslands, heaths and swamps.

Communities create the processes that keep all the different species within them supplied with energy, water, gases, (oxygen and carbon dioxide), minerals (eg calcium, potash and iron) and soil nutrients (eg nitrates, phosphates and sulphates).

Animals are the consumers. They get their energy and biomass from eating other organisms - either plants or other animals that have fed on plants.

The Food Cycle
Plants are called the food producers. They get their energy and biomass (body structure) from sun, air, water and soil.

Carab Beetle

Animals are the consumers. They get their energy and biomass from eating other organisms - either plants or other animals that have fed on plants.

Bacteria, fungi and some animals (mostly invertebrates) are decomposers. They get their energy and biomass from feeding on the excretions and dead bodies of other plants and animals. They decompose these complex plant and animal bodies back to gases, water, minerals and soil nutrients. This enables the food cycle to continue.

It is a self-organizing cycle that goes on and on, unless it experiences more disturbance than it can overcome. Too much disturbance can lead to breakdown.

Invertebrates are animals without a backbone. At least 95% of all animals are invertebrates. Among them were the first animals to appear on earth; first in water and later on land.

One group, the insects, probably appeared about 425 million years ago, when plants were spreading out from water and on to land.

Other land living invertebrates are the arachnids (spiders, scorpions and mites); crustaceans (slaters and springtails); myriapods (millipedes and centipedes); different sorts of worms and a variety of lesser known groups.

Invertebrates are immensely important as decomposers in the food cycle of all communities. Without them earth would find that essential elements for making new complex plant and animal bodies would run out and recycling would come to an end.

This is of special concern in jarrah communities where invertebrate species are often uniquely adapted to the unique assembly of plants.


A Creative System
The jarrah communities that live on the Darling Range make up a continuous creative system.

This has developed a patchwork of slowly changing plants and animals responding to changes in soils and landforms in an extraordinarily stable environment.

Invertebrates, together with vertebrates (reptiles, birds and mammals) had to make adjustments as their plant food producers and habitats changed.

Communities living in the system probably contain all sorts of weird and wonderful insects that have evolved over millions of years including many that no-one knows anything about yet.

A single marri, a tree that grows in association with jarrah, was recently found to be home to 446 species of invertebrates. About half had never been recorded.

Many invertebrates that feed on jarrah and marri have mouths specially adapted to chew the hard leaves. They have also become immune to the chemical poisons in eucalypt leaves.

Invertebrates are food for birds, reptiles, mammals and each other. In the Darling system it is not known which ones are food for which bats, lizards, birds etc nor how the consumers have adapted to the special characteristics of their invertebrate food supply.

Marri, or redgum, widely used for woodchips, is an important plant food for many invertebrates. If the supply of marri is reduced, food for many inhabitants of the jarrah system becomes scarce.

Remnant jarrah communities are exceptionally important in the food cycle.

They need protection from further clearing and other disturbances because any remnant may provide habitat for special invertebrates, such as big staghorn beetles and leaf-like cockroaches that are a major food for the Chuditch (native cat).

Chuditch, (and indeed people!) - all depend on food which, at some point, depends on the work of invertebrates, quite possibly those in our local remnant jarrah communities.

Can the jarrah system continue to create its own future?

Billions of years of creative evolution have formed the self- sustaining communities that make up the jarrah system. Human activity can destroy the life of the whole by disturbing any part of it too much.

So, what have invertebrates to do with self-sustaining jarrah communities?

To understand this we need to know the place of invertebrates in the food cycle.

Why are remnant jarrah communities so important?

Each jarrah remnant is a small part of an original whole and provides homes for essential members of the community.

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