MorrisbyÕs gum is a small tree or mallee that grows to between 6 Ð 12 m, generally with a
stocking of rough bark at the base of the trunk, the upper trunk and branches have smooth bark
that is brown, white-grey or pink-grey in colour (TSS 2006). MorrisbyÕs gum is ÒheteroblasticÓ,
meaning younger (juvenile) trees have markedly different structures to adult trees. As a juvenile,
MorrisbyÕs gum has bluish-green leaves are covered with a whitish, waxy (or ÒglaucousÓ),
unstalked and rounded, 2 to 3 cm long and 2 to 4 cm wide, arranged in opposite pairs (TSS
2006). As an adult, MorrisbyÕs gumÕs leaves are stalked, less waxy, and arranged alternately
(TSS 2006).
Morrisby gumÕs flowers are 5 to 10 cm long and 1.5 to 4 cm wide, short-stalked and white/waxy
in appearance. Its flower buds have a pointed flower cap (or ÒoperculumÓ) (TSS 2006). They
arise in clusters of three from the points at which the leaves connect to a branch (the Òleaf axilÓ).
The woody capsules are cylindrical and glaucous, measuring from 9 to 11 mm long, and 6 mm
wide (TSS 2006).
Morrisby's gum |
Eucalyptus morrisbyi
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
Close all
-
Australian Government, Conservation Advice, Eucalyptus morrisbyi
Threat factor Threat type Evidence base and status Climate climate change Drought drying known There are indications that the range of Morrisby s gum has conditions current future been contracting to wetter gullies since the last glaciation (TSS 2006).
Fire related damage also represents a potentially critical threat; eliminating juveniles before they can produce viable seed and further exacerbating competition with fire stimulated species.
Although more recent indications are that fire has not occurred in the gully for at least the last decade (Gilfedder pers. comm. 2016); the poor condition of the populations; (most of which are juveniles); means that any fire event would have a significant negative impact.
Poor recruitment has been attributed to a combination of threats including high frequency of arson events lack of appropriately timed disturbance events; drought stress; grazing pressures; agricultural and other human activities including the maintenance of roadside vegetation.
Threats Morrisby s gum is drought sensitive drying conditions may exacerbate other threat factors for this species including poor seed production; out competition by other plant species; and or ability to cope with stresses such as defoliation; browsing; grazing or other damage by native and introduced species.
Drought stress in response to a series of drought events were observed in the populations in 2006; and indicate that Morrisby s gum is drought sensitive (TSS 2006).
In light of this; conservationists should advocate continued strong commitments to emissions reduction and offset activities in Australia; which; if implemented; would contribute to the continued survival of the Morrisby s gum by mitigating the advance of warming; drying conditions and its impact on suitable habitat for the species.
Grazing browsing and defoliation by natives o Grazing and browsing by native species should be understood as a threat only in the context of the cumulative impact of a range of other threats that have impacted on the resilience of the Morrisby s gum population (especially drought stress and contraction of suitable habitat).
Download