Cold Blooded Wildlife: The Gift of Nature

As our beautiful country is warming up in most regions, we will soon find many reptile and amphibian species becoming active hunters to play their important role in combating pests in gardens as well as to contribute to balanced ecosystems. Most gardens should be harboring various reptile and amphibian species. Many of you will find their presence disturbing, but fortunately most species found in gardens are harmless, play an important role in many ecosystems and are an integral part of the food chain.

Reptiles and amphibians both have three-chambered hearts and cold blood and have to rely on external heat, either direct sun or heat from rocks to speed up their metabolism.

Amphibians live on land and in water. Whereas the embryos of reptiles are encased in two fetal membranes which serve as protection during the development inside the egg, amphibians have a larval stage called tadpoles.

Amphibian vertebrates such as frogs and toads are under threat because of destruction to their natural habitats. There are as many as 130 known amphibian species of South Africa. They are important for controlling insects such as mosquitoes, crickets, cockroaches and termites. Some larger species also feed on crabs and smaller vertebrates. Most amphibians live for short periods where others, especially toads, can live for more than 40 years. The common platanna, Cape sand frog, bullfrog and red-banded frog have extremely long life spans.

Flap neck chameleon waiting patiently for prey on tomatoes

The most common reptiles that may be found in home gardens are various species of lizards and snakes. Chameleons, skinks, agamas, blind and legless burrowers and geckos are the most common species of lizards to be found in gardens and natural habitats. They play an important role in combating garden pests including ants, termites, moths, flies, mosquitoes and fungus gnats.

Common skink (garden lizard) found in most gardens

(Young ghecko found in house shown here on hand

If you are fortunate enough you might even have a rock monitor (common name leguaan) around hunting for anything from snails, millipedes to rats, mice and snakes. I have a resident leguaan in my garden as can seen on the photo below; a beauty of a giant lizard! Snakes help combat mice, rats, snails, slugs, moles and other unwanted pests in the garden. Many species can be found in African gardens, especially on smallholdings where urban activities haven't disturbed them. Advanced species include house snakes, mole and slug eater snakes, water snakes, sand and grass snakes, centipede eaters, tree snakes, cobras, mambas, adders, etc. More primitive species include blind snakes, thread snakes and pythons.

Resident leguaan ("rock monitor") in garden

Adult toad on land

The English language has bestowed the name 'toad' on bufonids, while other species known as 'anurins' are called frogs. Most frogs are nocturnal, have large eyes and wide pupils, and can sing and hear. Adults have lungs but they can also obtain oxygen through their skin. Frogs have many predators including fish, snakes, water birds and even invertebrates such as dragonflies (their larvae feed on tadpoles). Toads consume anything from cutworms to caterpillars and cockroaches. The loss of breeding sites such as marshes and ditches in urban areas has diminished their numbers. Large numbers are also killed by cars as they cross roads near the few natural breeding sites that still exist in urban areas. Ideally, all home gardens should have fish-ponds or water features to help protect their numbers. Many toad species such as the raucous and guttural toads take up residence in holes near dripping taps, under flower containers and even water drains from where they hunt for insects attracted by lights at night (information partially obtained from Everyone's guide to SNAKES other reptiles and amphibians of Southern Africa by Bill Branch).

Toad inside burrow in soil on dry land; holes will be visible in flower beds of gardens

Adult toads having a romantic moment in the water

Tadpoles in shallow water of dam

For some, frogs and toads singing are irritating while for others it is very soothing. Various species of frog and toad will breed in and around garden ponds. The absence of frogs and toads in gardens as well as in nature and farm land, is one of the first signs of possible pesticide damage. Frogs are extremely sensitive to most pesticides that are toxic to fish life and a healthy population in and around your pond and garden is an indication that you have not been using hazardous organic or chemical pesticides. Most pesticides containing organophosphates, carbamates, synthetic pyrethroids, natural pyrethrins, nicotine and many other substances such as household disinfectants (which should not be used as pesticides), are harmful to frogs.

If you are serious about identifying the reptile and amphibian species in your garden, I highly recommend that you obtain "Everyone's guide to SNAKES other reptiles and amphibians of Southern Africa by Bill Branch (Struik Publication); it has helped me a lot to know what is living in my garden.

Articles

Snail and Slug Control in Harmony with Nature / The Living World Within Roses / Inaugural IPM-endorsed training courses will commence this month. / Garden Plants Perfect for Attracting Beneficial Insect Parasites and Predators / The Living World of Conifers / Winter Garden Care: To Spray or Not to Spray? / Spiders and Pesticides / Cold Blooded Wildlife: The Gift of Nature / Predatory Ladybirds: Nature's Solution to Aphid Control

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	Johan Gerber
	083 631 9952		0866465406
	Plot 17, Middel Road, Leeuwfontein, DINOKENG		P.O. Box 220, DERDEPOORT PARK, 0035
	www.gardencare.co.za / www.gardenguardian.co.za

Garden care advice to consumers on the use of agricultural remedies ( pesticides). Biopesticide product development for registration with Act 36 of 1947, Department of Agriculture. Garden talks and editorial contributions to consumer magazines. GARDEN CARE PAGE