Charles Sturt University
Charles Sturt University

Treasure Islands

Treasure Islands

By Gary Luck

When I travel in a plane, I always ask for a window seat. I find the journey much more interesting when I am able to see the landscape below. Cars on busy highways look like ants scurrying along a trail. Their nests are the car parks of shopping malls that dot the suburbs. Outside the city, the plane flies over meandering rivers that resemble droplets of water slinking down a windowpane. Vast, continuous forests stretch across the landscape like carpets for clouds.

Noticeable when flying over the agricultural region of southwestern Australia is the dusty brown of the farmland dotted with patches of green (Photo 1). These patches of green are the remains or remnants of the once extensive woodlands and shrublands that covered much of this region prior to European settlement. Early settlers who called this area their home cleared much of the native vegetation to grow crops and graze sheep. In some districts, greater than 90% of the original vegetation was cleared. From the air, the vegetation remnants resemble islands in a sea of dust. I call these treasure islands because they house much of the rich bounty that is the biological heritage of this region.

Not all islands hold the same amount of treasure. Larger ones generally contain more plants and animals that smaller ones. Those protected from the surrounding sea may be less degraded. Fences around native vegetation islands help to keep out the rising tide of non-native plants and animals. This reduces the competition for native species and helps them to survive. Rows of trees that connect one island to another may act as a highway for animals to move between islands (Photo 2). Those not connected to other islands often contain fewer species because many animals find the journey across the open space between islands too difficult. The surrounding sea is a dangerous place if there is little protection from predators or other threats.

Recognising the value of these islands, many landowners have undertaken restoration efforts to try to protect the island's treasure. Revegetation of cleared land, fencing remaining vegetation, and planting rows of trees that connect islands are some of the strategies used by landowners to protect the islands occurring on their property. All of us can help in these activities by joining a local Landcare group or becoming a volunteer with a conservation organisation that is involved in the protection of native vegetation. Working together, we can ensure that the treasure these islands contain is enjoyed by future generations.

The next time you travel on a plane sit by the window and watch the landscape below unfold. See if you can spot any treasure islands. Remember that many of the plants and animals we share this planet with rely on these islands for survival. It is our responsibility to make sure these islands do not disappear under the rising sea of human expansion.

Further reading

  • AndrĂ©n, H. 1994. Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat. Oikos 47: 365–373.
  • Collinge, S. K. 1996. Ecological consequences of habitat fragmentation: implications for landscape architecture and planning. Landscape and Urban Planning 36: 59–77.
  • Hobbs, R. J. & Saunders, D. A. 1993. Effects of landscape fragmentation in agricultural areas. Pp. 77–95 in Conservation Biology in Australia and Oceania. C. Moritz & J. Kikkawa (Eds). Surrey Beatty and Sons, Chipping Norton.
  • Saunders, D. A., Hobbs, R. J. & Ehrlich, P. R. (Eds). 1993. Nature Conservation 3: Reconstruction of Fragmented Ecosystems. Surrey Beatty and Sons, Chipping Norton.
  • Saunders, D. A., Hobbs, R. J. & Margules, C. R. 1991. Biological consequences of ecosystem fragmentation: a review. Conservation Biology 5: 18–32. 

Key web sites