Mogumber bell   |  

The main factors that make the species eligible for listing in the Endangered category are restricted and fragmented distribution; small population size; and continuing decline due to climate change; invasive species; habitat loss; disturbance and modifications.

Table 2 Threats impacting Mogumber and Narrogin Bell Threat Status and severity a Evidence Climate change Increased Timing current The Mogumber and Narrogin Bell is thought to be severity frequency of Confidence inferred killed by fire and regenerate from soil stored bushfire seeds (Keighery 1985).

This type of event is increasingly likely to reoccur due to climate change.

Additionally; a drying climate will increase the extent of the fire season and lengthen the minimum fire interval required for self replacement of obligate seed regenerators; like the Mogumber and Narrogin Bell; to 15 years; due to higher seedling mortality and slower growth (Enright et al. 2014).

In many Myrtaceae species; including Mountain Bells; germination of dormant seeds is triggered by fire related cues; including heat; smoke and scarification (Keighery 1985 Dixon et al. 1995 Auld Ooi 2008).

The species is threatened by several fire related threats; including high frequency fire; fire drought interactions; and fire promoted weed invasion.

A high frequency fire Consequence regime ( 10 years) is likely to kill adult plants catastrophic before soil stored seed banks can be replenished Trend increasing (Brown et al. 1998).

Analysis and modelling predict that a 20 percent reduction in post fire winter rainfall would increase the minimum fire interval for this species to 15 years (Enright et al. 2014); further imperilling the Mogumber and Narrogin Bell.

The small population size and restricted distribution of the species may also increase population extinction risk; following stochastic events; such as fire (DEC 2009).

Fire intensity and severity varied across the bushfire extent; with many patches burning at extreme intensity and severity while others remained unburnt (DPIE 2020).

Under the current high frequency fire regime; the Mogumber and Narrogin Bell may not be able to replenish soil stored seed banks before the next fire; putting this species at serious risk of extinction.

In Trend static particular; grassy weeds can increase fuel load Extent across part of its and alter fire regimes (Milberg Lamont 1995 range Setterfield et al. 2013).

These altered fire regimes can create conditions that are detrimental to the maintenance of native species and favourable to the establishment and spread of weeds (D’Antonio Vitousek 1992 Grigulis et al. 2005).

The species is threatened by several fire related threats; including high frequency fire; fire drought interactions; and fire promoted weed invasion.

Drought threatens all Mogumber and Narrogin Bell subpopulations and contributed to the presumed extinction of subpopulation 2 (Table 1 DEC 2009).

Drought may also alter the habitat structure; by killing associated species and opening up the canopy and ground cover layers (DEC 2009).

The small population size and restricted distribution of the species may also increase population extinction; following stochastic events; such as drought (DEC 2009).