Topic Introduction

Humid tropical forests provide very favourable conditions for amphibians, being warm and humid. In contrast, drier forests provide conditions that are very favourable to reptiles, although reptiles can also do extremely well in warm, humid conditions.

The diversity of amphibians is not as great as in some of the other vertebrate groups, although there are still significant numbers, and with about 7,200 species so far described, they easily outnumber mammals. There are three main groups: the newts and salamanders, the caecilians, and the frogs and toads. Many, but by no means all, are closely associated with water.

Of the three groups, it is the toads and frogs that have garnered the greatest amount of attention. The Cane Toad (Rhinella marina), a Neotropical species, was introduced into Australia and elsewhere in an attempt to control a pest of sugar cane, the cane beetle (Dermolepida albohirtum). It has proven to be an ecological disaster, and Australia has many predators that feed on amphibians but which are killed by the toxic skin of the Cane Toad.

Tropical frogs have also received a lot of attention because of the apparent recent extinction of many species. This was first apparent in the decline in abundance of many species, followed by local extirpations. This in turn seems to have been followed by extinctions. The most famous example of this phenomenon was the loss of the Golden Toad (Incilius periglenes), a species that occupied a very small range in tropical cloud forest at Monteverde in Costa Rica. It was last seen in 1989, and has now been classified as extinct by the International Union for the Conservation of Nature (IUCN).

The causes of the extinction are uncertain, and the subject of vigorous debate. Climate change has been invoked as have another of other factors. One that is clearly involved in many of the amphibian declines, although not necessarily the loss of the Golden Toad, is the pathogenic chytrid fungus Batrachochytrium dendrobatidis, which causes chytridiomycosis, a lethal disease of amphibians. Other lethal diseases exist, and some of these remain unidentified, such as the disease killing the endangered Archey’s Frog (Leiopelma archeyi) in New Zealand.

By the end of this topic, you should be able to:

• Describe the range of amphibians that you might encounter in a tropical forest.
• Identify the amphibian groups found in particular regions.
• Assess the role that different groups of amphibians play in tropical forests.
• Assess the habitat needs of different groups of amphibians.
• Determine which groups of amphibians might be benefited or adversely affected by forest management decisions.

Topic Readings

Required Readings

• Ghazoul, J. and Sheil, D. 2010. Tropical Rain Forest Ecology, Diversity, and Conservation. Oxford, Oxford University Press, 516 pp. Section 4.3.1.

Optional Readings

• For amphibians and reptiles, I strongly recommend: Pough, F.H., Andrews, R.M., Crump, M.L., Savitzky, A.H., Wells, D.D. and Brandley, M.C. 2018. Herpetology. 4^th New York, USA: Oxford University Press and Sinauer Associates.
• Mattison, C. 1988. Frogs and Toads of the World. Princeton, New Jersey, USA: Princeton University Press. 192 pp.

Further Readings

Regional Guides

Australia and New Guinea

• Anstis, M. 2018. Tadpoles and Frogs of Australia. 2^nd London, UK: New Holland Publishers. 843 pp.
• Barker, J., Grigg, G.C. and Tyler, M.J. 1995. A Field Guide to Australian Frogs. Chipping Norton, New South Wales, Australia: Surrey Beatty & Sons. 407 pp.
• Culow, S. and Swan, M. A Complete Guide to Australian Frogs. Australian Geographic Pty Ltd. 304 pp.
• Griffiths, K. 2006. Frogs and Reptiles of the Sydney Region. Sydney, Australia: New Holland Publishers. 128 pp.
• Hoskin, C. and Hero, J.-M. 2008. Rainforest Frogs of the Wet Tropics, North-East Australia. Griffith University. 90 pp.
• Tyler, M.J. and Knight, F. 2009. Field Guide to the Frogs of Australia. Collingwood, Victoria, Australia: CSIRO Publishing. 188 pp.
• Vanderduys, E. 2013. Field Guide to the Frogs of Queensland. Collingwood, Victoria, Australia: CSIRO Publishing. 192 pp.

South and Southeast Asia

• Alcala, A. and Brown, W.C. 1998. Philippine Amphibians. An Illustrated Field Guide. Bookmark. 116 pp.
• Daniel, J.C. 2002. The Book of Indian Reptiles and Amphibians. Oxford, UK: Oxford University Press. 238 pp.
• Das, I., Pui, Y.M., Pang, S.-T., Wahab, T., Mokhtar, S., Hertwig, S.T., Haas, A. and Grafe, T.U. Amphibians of Western Sarawak (Borneo). Universiti Malaysia Sarawak. 102 pp.
• Inger, R.F., Stuebing, R.B., Grafe, T.U., and Dehling, J.M. 2017. A Field Guide to the Frogs of Borneo. Natural History Publications Borneo. 228 pp.
• Vassilieva, A.B., Galoyan, E.A., Poyarkov, N.A., and Geissler, P. 2016. A Photographic Field Guide to the Amphibians and Reptiles of the Lowland Monsoon Forests of Southern Vietnam. Frankfurt am Main, Germany: Edition Chimaira. 324 pp.

Africa

• Channing, A. 2001. Amphibians of Central and Southern Africa. Ithaca, New York, USA: Cornell University Press. 470 pp.
• Channing, A. and Rödel, M.-O. 2019. Field Guide to the Frogs and Other Amphibians of Africa. Penguin Random House South Africa. 408 pp.
• Channing, A. and Howell, K.M. 2006. Amphibians of East Africa. Frankfurt am Main, Germany: Edition Chimaira. 442 pp.
• Harper, E.B., Measey, G.J., Patrick, D.A., Menegon, M., and Vonesh, J.R. Field Guide to Amphibians of the Eastern Arc Mountains and Coastal Forests of Tanzania and Kenya. Nairobi, Kenya: Camerapix. 320 pp.
• Mercurio, V. 2011. Amphibians of Malawi. Frankfurt am Main, Germany: Edition Chimaira. 393 pp.
• du Preez, L.H. and Carruthers, V.C. 2018. Frogs of Southern Africa. A Complete Guide. Penguin Random House South Africa. 520 pp.
• Schiøtz, A. 1999. Treefrogs of Africa. Frankfurt am Main, Germany: Edition Chimaira. 350 pp.
• Spawls, S., Howell, K.M. and Drewes, R.C. 2006. Reptiles and Amphibians of East Africa. Princeton, New Jersey, USA: Princeton University Pres. 240 pp.
• Spawls, S., Wasonga, D.V. and Drewes, R.C. The Amphibians of Kenya. Stephen Spawls. 55 pp.

Madagascar

• Glaw, F. and Vences, M. 2006. A Field Guide to the Amphibians and Reptiles of Madagascar. Frosch Verlag. 496 pp.
• Henkel, F.W. and Schmidt, W. 2000. Amphibians and Reptiles of Madagascar, and the Mascarene, Seychelles and Comoro Islands. Krieger Pub Co.

Central and South America

• Guyer, C. and Donnelly, M.A. 2004. Amphibians and Reptiles of La Selva, Costa Rica, and the Caribbean Slope. University of California Press. 299 pp.
• Henderson, R.W. and Powell, R. 2018. Amphibians and Reptiles of the St. Vincent and Grenada Banks, West Indies. Frankfurt am Main, Germany: Edition Chimaira. 448 pp.
• Kahn, T.R., La Marca, E., Lotters, S., Brown, J.L., Twomey, E. and Amézquita, A. 2016. Aposematic Poison Frogs (Dendrobatidae) of the Andean Countries. Washington DC, USA: Conservation International. 588 pp.
• Lee, J.C. 2000. A Field Guide to the Amphibians and Reptiles of the Maya World. The Lowlands of Mexico, Northern Guatemala, and Belize. Ithaca, New York, USA: Cornell University Press. 402 pp.
• Leenders, T. 2016. Amphibians of Costa Rica. A Field Guide. Ithaca, New York, USA: Comstock Publishing Associates. 531 pp.
• Muñoz Chacón, F. and Johnston, R.D. 2013. Amphibians and Reptiles of Costa Rica. A Pocket Guide. Ithaca, New York, USA: Cornell University Press. 172 pp.
• Powell, R., Henderson, R.W. and Parmerlee, J.S., Jr. 2005. The Reptiles and Amphibians of the Dutch Caribbean. Dutch Caribbean Nature Alliance. 343 pp.
• Savage, J.M. 2005. The Amphibians and Reptiles of Costa Rica. A Herpetofauna Between Two Continents, Between Two Seas. University of Chicago Press. 934 pp.

Global

• Beltz, E. 2005. Frogs: Inside Their Remarkable World. Buffalo, New York, USA: Firefly Books. 175 pp.
• Mattison, C. 1988. Frogs and Toads of the World. London, UK: Natural History Museum. 192 pp.

Fundamental Concepts

PPT Presentations

4.4. Amphibians.pptx Download 4.4. Amphibians.pptx

Self-check Quiz

After viewing topic presentations, take this self-check quiz to check your own progress. This quiz is designed to see how well you remember some of the more important issues presented in the topic. There are five questions, and each has a potential of 4 answers, only one of which is correct. When you are ready, click the link Self-check Quiz 4.4 to start taking the quiz.

Pre-readings & Discussion (For certification)

Once you have read Section 4.3.1 of Ghazoul, J. and Sheil, D. 2010. Tropical Rain Forest Ecology, Diversity, and Conservation, choose to post one thought provoking question related to the material that you have read, and remember to answer/respond to at least one other student’s question on the discussion board Online Discussion Module 4.

Graded Assignment (For certification)

• There is no graded assignment associated with this topic.

Topic Summary

In this topic, you have learnt about the variety of amphibians that can be found in tropical forests. Many are concentrated in the lowest strata: on the ground or in the lowermost vegetation. However many species exist only in the upper canopy, making use of damp habitats such as moss and bromeliad tanks. A few species occur in both, moving between the different habitats (which does however present the greater risk of encountering a predator).

Amphibians are very sensitive to changes in the environment, and the apparent loss of a number of species in different parts of the world has been taken to be a potential indication of the impact of climate change. Others suggest that it is entirely due to the rapid spread of the invasive Chytrid fungus, also known as Batrachochytrium dendrobatidis. It is possible that these two explanations are both appropriate, with climate change enabling the fungus to spread more easily, or making amphibians more susceptible to it.

The sensitivity of amphibians to the environment means that changes in the environment induced by forest management activities, such as selective felling, will need to be accounted for. A much greater priority is to stop the loss of tropical forests altogether, particular in areas of high species endemism.

Topic Self-review (For self learning)

To review what you have learned in the topic, you are encouraged to use the following reflection questions as a study guide to do a self-review for the topic:

• Where would expect to encounter amphibians in a tropical forest?
• Which amphibian families would you expect to find in Madagascar and nowhere else?
• What roles do the different groups of amphibians play in tropical forests?
• Are the habitat needs of all amphibians the same? If not, how do they differ?
• What are the likely effects of forest clearance on caecilians, frogs, and salamanders? Are the responses different?
• Why should some species of male frogs hesitate before calling for a mate in their chosen habitat?