Southern brown tree frog (Litoria ewingii) - eggs

​Application for Scientific Permit – Available for Public Comment

Public comment on the following application for a Scientific Research (Fauna) Permit is open until 28 May 2019.
 
Applicant: Monash University (VIC)
 
Species/Taxon: Southern brown tree frog (Litoria ewingii) - eggs
 
Location: Reserved land - Mount Direction Conservation Area, Meehan Range Nature Recreation Area, Tasman National Park, Hartz Mountains NP, Mount Field NP, South Bruny NP, Franklin-Gordon Wild Rivers NP, South West NP, Peter Murrell Reserve.
 
Title of research: Geographic variation in developmental strategies of frogs
 
Aim of project:
Developmental plasticity — the ability of organisms to modify their development in response to local environmental cues such as temperature — is a key evolutionary adaptation to environmental variability. Southern brown tree frogs are distributed along strong temperature gradients in eastern Australia, and previous studies hint at geographic variation in developmental strategies.
The overall objective of this project is to understand geographic variation in developmental strategies of frogs. Specifically we aim to:
(1) Determine whether there is significant variation in the developmental biology of frog populations that have been collected from different environments;
(2) Investigate whether variation among populations influences the species’ sensitivity to climate change.
 
Justification: 
Southern brown tree frogs are abundant in the suburban areas of Hobart, but we will also need to collect eggs from reserved land further afield to fully incorporate geographic variation of the species.
Developmental plasticity is a key process determining species’ sensitivities to climate change – a species that can respond to increasing temperatures or increasing temperature variability through plasticity may have a greater likelihood of persistence. 
Understanding the extent of developmental plasticity in frog populations from different environments can help inform targeted management practices in a changing climate for Litoria ewingii and other amphibian species.
 
Maximum likely numbers of individuals involved:
Litoria ewingii lay eggs in one or more clusters attached to vegetation. We will collect 5 clusters of eggs from 5 ponds in the Hobart area, i.e., 25 egg clusters in total. There can be anywhere from 20-100 eggs per cluster, i.e., a maximum of 2500 individual eggs.

 
Activities undertaken and methods:
Each cluster will be gently scooped into an individual plastic aquarium bag (used to sell pet fish) containing ~400 ml of RO water. Aquarium bags will be filled with oxygen, tied, and placed in a larger plastic tub with a lid. Eggs collected in Tasmania will be driven back to Monash University in a rental vehicle and placed in incubators within 24 hours of being collected.
 
Fate of animals:
Tadpoles will be raised to maturity in individual containers and bred >1 year after this project commences. Throughout this time, we will measure growth and development, temperature preferences and metabolic rate of each individual.
 
Likely impact on species involved (including any by-catch):
Removing 5 clusters of eggs from a pond would have minimal impact on the remaining egg clusters. Firstly, this species is highly fecund and females can lay up to 500 eggs per clutch. We would ensure that we do not take all egg clusters from a single pond. Secondly, tadpoles have extremely high mortality in the wild, partially due to competition. Removing some eggs may therefore increase the survivorship of the eggs remaining in the pond (decreased competition). There will be no by-catch.


Contact

Scientific Research Permits
Natural Values Conservation Branch
134 Macquarie Street
Hobart TAS 7000
Email: Scientific.Permits@dpipwe.tas.gov.au

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