Bat habitat use of restored jarrah eucalypt forests in south-western Australia
Burgar, Joanna (2014) Bat habitat use of restored jarrah eucalypt forests in south-western Australia. PhD thesis, Murdoch University.
Restoration is an important tool in conserving biodiversity, yet passive faunal recolonisation may take decades, or longer, to occur. This is of particular conservation importance in biodiversity hotspots, such as south@western Australia, which are experiencing increasing fragmentation and rapidly drying climates. Within this hotspot, I investigated the response of nine insectivorous tree@dwelling bat species to restored mine@pits in jarrah (Eucalyptus marginata) forests. I assessed bat activity in restored, relative to unmined, forests and the suitability of restoration as foraging and roosting habitat. Bat echolocation call surveys measured bat activity in varying ages of restoration and unmined forest across two years (2010@2012) during both maternity and mating seasons. Although all bat species were detected in both forest types, restored mine@pits of all ages had significantly different bat communities and lower overall activity compared to unmined forest. Habitat filters to bat use of restoration were evident for the more manoeuvrable bat species and were predominantly related to midstorey forest structure. Tree density was the most important predictor of bat use of restoration for less manoeuvrable bat species. To determine the suitability of restored forest as foraging habitat I investigated the diet of three species (Chalinolobus gouldii, Nyctophilus gouldi and Vespadelus regulus) over maternity and mating seasons (2010/2011) by examining prey remains in faecal samples. I used high@throughput sequencing and bioinformatics analyses to phylogenetically group prey DNA and found that niche partitioning occurred, with dietary divergence positively related to bat ecomorphological divergence. In addition, I assessed the foraging potential of restored forest and found that prey occurrence did not necessarily equate to prey accessibility for all bat species. There was a synergistic effect of vegetation structure and insect biomass for edge foraging bat species. To determine the suitability of restoration as roosting habitat I used telemetry to radio@track 36 bats from two species (N. gouldi and V. regulus) to 59 distinct roosts. Not one bat was found roosting in restored forest and individuals preferred roosting in mature, tall trees in intermediate to late stages of decay. My research clearly shows that restored forest does not yet provide suitable foraging or roosting habitat for all jarrah forest bats. Improving habitat suitability through management manipulations, such as thinning and burning, may accelerate bat recolonisation of restored forest. In the interim, retention of mature forest patches is necessary for conserving and maintaining bat populations across restored landscapes.
|Publication Type:||Thesis (PhD)|
|Murdoch Affiliation:||School of Veterinary and Life Sciences|
|Supervisor:||Craig, Michael and Stokes, Vicki|
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