Microbats in the Mangroves – Russell Island

Microbats are small, flying mammals which generally weigh between 4 and 30 grams. There are 70 species in Australia alone, and they inhabit almost every habitat on earth. Many people don’t realise that microbats exist or confuse them with flying foxes (fruit bats). The table below shows some of the differences between flying foxes and microbats.

Microbats are extremely important for insect control, many feed on mosquitoes eating anywhere between 25% and 100% of their own body weight in insects every night. They are certainly unsung heroes in Moreton Bay!

 

Background

Microbats comprise approximately twenty-five percent of all land mammal species in Australia, yet they remain the least studied. Severe population declines have been reported across many microbat species worldwide. The primary threat to microbats is habitat modification. In Australia, one of the main habitat modifications is land clearing and development. Currently there is very little information regarding the effects of habitat modification on microbats.

Mangrove communities in Australia are recognized as vital ecosystems; they act as coastal water filters, prevent erosion and provide essential habitat for wetland fauna. Recent studies across Australia indicate that mangroves may play an important role as microbat feeding, roosting and breeding habitat. To date, there have been no studies which have looked at the relationship between microbats and mangrove ecosystems in Queensland. Many microbat researchers believe that old growth mangrove forests support large microbat communities. This research project may provide useful ecological knowledge for conserving microbats in coastal mangrove ecosystems.

The aim of this project is to answer two main questions:

  1. Are microbats using Grey mangrove forests in south-east Queensland?
  2. Does the structure of the mangroves affect how microbats use the habitat?

Russell Island, like many of the islands in Moreton Bay, has large mangrove forests which could be important habitat for microbats. The mangroves on Russell and Macleay islands will be sampled as part of a larger project being conducted over south-east Queensland. Sampling consists of harp trapping microbats and recording their calls using detectors placed around the mangrove. Harp trapping causes no harm to the bats and once they are identified and measured they are released.

At this stage in the study it is obvious that mangroves are an important microbat habitat in south-east Queensland. Many mature and old growth mangroves support large maternal roosts where mothers raise and protect their babies. There have been a number of species found in the mangroves on Russell Island including the Chocolate wattled bat (Chalinolobus morio) and an undescribed Broadnosed bat species (Scotorepens sp).

This study is an Honours project with University of Queensland. It could not be completed without the generous assistance of the Australasian Bat Society, Long Grass Nature Refuge, Pink Heath Project and Bay Islands Conservation. For any further information please contact Julie at julie.brokenbrow@uqconnect.edu.au

 

 

Microbat

Flying Fox (Fruit Bat)

Eats mainly insects and other invertebrates

Eats predominantly fruit or blossoms

Small (4 – 30grams depending on species)

Large (weighing between 100 and 800grams)

70 species in Australia

9 species in Australia

Uses echolocation as main sense

Uses eyesight as main sense

Roosts in caves, hollows and tree bark

Roosts in tree branches

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