Amphibians: Manipulate larval density within the enclosure

How is the evidence assessed?
  • Effectiveness
    88%
  • Certainty
    28%
  • Harms
    0%

Source countries

Key messages

  • A replicated study in the USA found that reducing larval density of spotted salamanders increased larval survival and body mass.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated study in 2010 of spotted salamanders Ambystoma maculatum in the USA found that housing larvae at low densities resulted in bigger salamanders, higher survival and lower stress levels, similar to larvae in the wild. At different larval densities there were significant differences in body mass (6/tank: 1.8 g; 12/tank: 1.6 g; 30/tank: 0.9 g), survival (94%; 67%; 33% respectively) and stress levels (white blood cell ratios: 0.4; 1.5; 2.2 respectively). At medium larval densities, increased food or habitat complexity had no significant effect on body mass (food: 1.4 g; environment: 1.7 g), survival (89%; 50% respectively), or stress levels (1.3; 0.7 respectively). Egg masses were collected from the wild. Larvae were reared in three replicates of five treatments: starting densities of six, 12 or 30 larvae/1,000 l tank, increased food (12 larvae/tank with triple the zooplankton) or increased habitat complexity (tank filled with sticks and refugia). All tanks had leaf litter on the bottom. Metamorphs were weighed and blood sampled for stress hormone levels.

    Study and other actions tested
Please cite as:

Jonas, C.S., Timbrell, L.L., Young, F., Petrovan, S.O., Bowkett, A.E. & Smith, R.K. (2019) Management of Captive Animals. Pages 539-567 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.

 

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Management of Captive Animals

This Action forms part of the Action Synopsis:

Management of Captive Animals
Management of Captive Animals

Management of Captive Animals - Published 2018

Captive Animal Synopsis

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read latest volume: Volume 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust