Sustenance

Sustenance according to the dictionary means the following:

• support, maintainance or substance
• food, provisions, nourishment
• maintaining someone or something, life or existence

Images that come to mind to reflect the meaning of sustenance are:

• trees, bread, water, food
• Japanese and Asian symbols 
• Aboriginal symbols - tree, sun, kangaroo, bush tucker, meeting, rain
• fabricanart

Environmental issues we face today

Environmental issues faced by Australia and the world

• climate change
• energy use
• conservation
• endangered animals and plants
• barrier reef and marine life are endangered
• whales
• oil spills
• land clearing
• transportation
• urbanisation
• population growth
• water 
• coal 
• biodiversity

http://en.wikipedia/wiki/environmental_issues_Australia

Research of the target audience - children