- flowering: many eucalypts basically stop flowering in severe droughts (see MacNally et al. for good evidence of this), so when it rains, flowering ramps up with important consequences for other biota such as honeyeaters (e.g. Wattlebirds) that rely on nectar.
- tree health / vigour: under severe moisture stress, many plants such as eucalypts reduce their canopy and, in extreme cases, die altogether. Rod Fensham's work illustrates that drought is an important determinant of tree mortality in savanna in Queensland. With recent rains, tree canopy health appears to have markedly improved in some places.
- recruitment / breeding: in drought periods, successful recruitment is likely to be limited for many species. Floodplain species like Black Box rely on flooding for regeneration, while the breeding of many woodland birds is tied to resource availability (again, see Mac Nally et al for evidence that).
The ability to 'bounce back' after stress has been termed ecosystem 'resilience'*. Indeed, one definition for resilience is "the speed with which a community returns to its former state after it has been disturbed". Hence, "resilient landscapes" might be considered those that have the capacity to rapidly return their ecological structure and function after disturbance. But perhaps this is an overly optimistic view of resilience when considering how ecosystems might respond to changing climate.
|The Murray River at Mildura|
* I think it is unfortunate that the term 'resilience' has become a policy goal (see the Australian Biodiversity Conservation Strategy as an example) rather than being seen as a property of a system, much like species diversity, NPP and beta diversity might be considered. In the context I use it here, resilience can be thought of as a 'catch-all' concept or explanation for long-term trends in biota that reflect impacts of climate change, disturbance and habitat quality.