Amphibian Arrivals

A little earlier than last year, the first frogs, toads, and newts arrived in our wildlife pond on Valentine’s Day – 14th February. Not many clumps of frog spawn so far but a group of three toads were still gripped together even in the bright sunlight when I visited in the morning. We are hoping for more similar visitors and also praying that no-one removes any of the frog spawn like they did last year. Or interfere with it in any way. All the official conservation bodies warn that moving spawn from the place where it has been deposited is potentially disastrous.

There are many reasons given for not moving spawn from one location to another, however well intentioned the activity. Spawn survives and thrives only when it remains in the same place that it was laid. Small changes in water chemistry from one pond to another can affect survival and development. Water temperature differences due to a change of location and a difference in water depth can cause thermal shock to the spawn. Then there is the danger of transferring pathological viruses and bacteria from one pond to another, as well as spreading alien invasive aquatic plants.

Some people might think that taking a small amount of spawn to observe development in a jar, aquarium, or garden pond does not matter if there is an abundant natural source of the eggs. But it does matter. A superabundance or over-production of amphibian eggs has evolved to protect and aid the survival of the eggs. It allows for superficial layers of eggs to be predated while conserving the lower layers; and takes into account the wastage from predation and other causes. Extra spawn provides a food source for the rapid growth of the early hatched tadpoles. Cannibalism in amphibians is normal. There can be lots of spawn but – even when left in the best of natural circumstances – relatively few eggs will survive to adulthood. Let’s not make it harder for them to exist. Numbers of all amphibian species are already declining due to disease, reduction of habitat, and water pollution. It is important to remember that frogs and toads in their turn provide food for many other creatures such as birds, mammals and reptiles. They are part of a vast food matrix of interdependence.

And finally it surely goes without saying that interfering with the spawn in any way such as stirring it up with sticks, keeping it in a jam jar, or similar activity is a bad idea. Previous years have unfortunately seen spawn fished out of the water and left to die on the grass. It is tough enough for the eggs to survive and develop into adults with all that Nature has to throw at it in terms of predators, fluctuating water levels, contamination, and extreme temperature changes. Please spread the word and protect our local amphibians.