Rainbows in the swamp

In 1983, two new frog species were discovered in the high rainfall region of south-western Australia. The white-bellied frog (Geocrinia alba – Plate 24.1) was found to occur over about 100 square kilometres, much of which had been cleared for agriculture. Fortunately, many sections of creek on private land remain uncleared and some of these sites retain populations of white-bellied frogs (Plate 24.2). The orange-bellied frog (G. vitellina) (Plate 24.3) was even more restricted, limited to only 6 square kilometres in just six adjacent creek systems in State Forest to the north of the Blackwood River. Within this range, there are only about 20 ha of suitable habitat. These two frog species are among the most geographically restricted vertebrates on mainland Australia. Their restricted distributions, low population densities and high habitat specificity mean that they are particularly prone to extinction.

Are such rare species unusual? Are the G. alba and G. vitellina populations stable or in decline? If they are in decline, what is the cause and can management lead to population recovery? How can their habitat be protected, including, for example, the threatened Reedia spathacea ecological community, which occurs in the same areas (Plate 24.4)? These types of questions are addressed by conservation biology.

Chapter aims

This chapter covers the science and biology required for conserving species and ecological communities that are rare and threatened, or declining.