Eucalyptus wandoo crown decline and its influence on wildlife
Moore, Tracey (2013) Eucalyptus wandoo crown decline and its influence on wildlife. PhD thesis, Murdoch University.
A decline in the condition of forests and woodlands is a worldwide phenomenon. In the south west of Western Australia, declines of Eucalyptus wandoo have been noted since the 1980s and more recently in the 2000s. There is a knowledge gap regarding the relationship between the effects of tree decline and wildlife. This study aimed to help close this knowledge gap and provide insight to the effects of tree decline on fauna. At two reserves in Western Australia (Dryandra Woodland and Wandoo Conservation Park) 24 sites of pure E. wandoo stands were used to investigate this relationship.
Firstly, on-ground and remotely sensed methods of canopy assessment in E. wandoo were compared. The open canopy of E. wandoo, the spatial heterogeneity and cyclic decline, as well as the expression of recovery symptoms (e.g. epicormic growth) has meant that remote sensing methods are limited in their ability to reflect the on-ground changes noted and were not used in the following chapters.
Reptiles, mammals, birds, vertebrate foraging activities and reproductive efforts of E. wandoo were related to E. wandoo condition and the changes in the surrounding habitat. Healthier patches of E. wandoo that were longer unburnt with higher levels of site litter had more reptile species and higher abundances. Site litter cover, crown dieback, understorey vegetation cover and tree density influenced the abundance and species richness of small mammals. Three focal bird species weebills (Smicrornis brevirostris), rufous tree creepers (Climacteris rufa) and yellow-plumed honeyeaters (Lichenostomus ornatus) were influenced by E. wandoo condition according to their individual ecology. Vertebrate activities and the tree and habitat characteristics were related, with more diggings and scats present underneath healthier E. wandoo trees. Lastly, E. wandoo condition, weather, time since last fire and tree size were factors related to the reproductive cycle of E. wandoo trees from this study.
Eucalyptus wandoo decline aetiology differs to other eucalypt species in Western Australia such as Eucalyptus marginata and Eucalyptus gomphocephala by its lack of severity, cyclic recovery and spatially heterogeneous nature. These features of E. wandoo decline meant that wildlife were influenced by the changes in their habitat as a result of the decline but no species were absent from declining sites. It is not certain that E. wandoo declines will maintain a heterogeneous, cyclic pattern, particularly as the causes of the decline are undetermined and many exacerbating factors such as a warming climate, reduced rainfall, land clearing and competing land uses are ever present.
|Publication Type:||Thesis (PhD)|
|Murdoch Affiliation:||School of Veterinary and Life Sciences|
|Supervisor:||Fleming, Trish, Valentine, Leonie, Craig, Michael and Hardy, Giles|
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