CSIRO Special Seminar
A recently published review of 73 historical reports from across the globe has shown that biodiversity of insects is threatened worldwide. Dramatic rates of decline affect 41% of the world's insect species, while a third of them are threatened and may become extinct over the next few decades. In terrestrial ecosystems, Lepidoptera, Hymenoptera and dung beetles (Coleoptera) appear to be the taxa most affected, whereas four major aquatic taxa (Odonata, Plecoptera, Trichoptera and Ephemeroptera) have already lost a considerable proportion of species. In addition, insect biomass has decreased at a rate of 2.5% annually in the past four decades.
The main drivers of species declines appear to be in order of importance: i) habitat loss and conversion of natural landscapes to intensive agriculture and urbanisation; ii) pollution, mainly that by synthetic pesticides and fertilisers; iii) biological factors, including pathogens and introduced species; and iv) climate change, particularly in tropical regions and in mountain settings of temperate zones. The ecological implications of such declines and the priority actions needed to stem them will be discussed.