C.2.7 Stochastic eventsC.2.7 Stochastic events

C.2.7 Stochastic events

Because of the tropical location of the island, severe rainfall events associated with the monsoon are common in the wet season, although the extent and impacts of these cannot be predicted. Severe dry seasons tend to coincide with the El Niño effect in the Pacific (CofA 2002), and these events may be increasing in frequency and severity.

Confident assessment of the impact of stochastic events (as for other potential impacts) requires further study of the life cycle, longevity and regeneration requirements of the species - information which is currently not available (Reddell pers. comm.).

However, applying the precautionary principle, it is reasonable to expect that Asplenium listeri could be affected by severe rainfall events through scouring and transport of soils and mulch from rock crevices to expose the rhizome, and/or by severe dry seasons through desiccation.

In view of the exposed nature of the species’ cliff-top habitat, such events have the potential to be significant factors in limiting its occurrence and potentially in threatening its continued survival. These events were seen as the most concerning threat at the time of initial listing (TSSC 2002).