It won’t be long before amphibians and reptiles begin to wake from hibernation. Released from natural lockdown they face challenges that nowadays include habitat degradation and loss. These beleaguered animals need all the support they can get. That’s where gardeners can help by encouraging wild spaces for both ‘herptile’ groups, and creating breeding ponds for the former.
All our native amphibians and reptiles face threats in one form or another and few are thriving. Particularly at risk is the Common Toad and according to the conservation charity Froglife it has declined by 68% over past 30 years. The threats are almost all the result of human activity. The solution to the problem also lies with us and everyone can do their bit to help.
NATIVE SPECIES In mainland UK there 7 native species of amphibians and 6 native species of reptile. Depending on where you live, the most likely candidates for your garden are Common Toad, Common Frog, Palmate Newt, Smooth Newt, Great Crested Newt (if you’re lucky), Slow-worm and Grass Snake. Here’s a brief introduction to your potential garden tenants.
THE BIGGER PICTURE – GARDENS AS WILDLIFE HAVENS The importance of gardens for wildlife, including amphibians and reptiles, lies in their sheer size. An estimated 29% (520,000 hectares) of urban areas in Great Britain comprise residential gardens. So, on the basis of size alone, these potential sanctuaries clearly have a role to play in conservation if managed appropriately. Then there’s the notion of connectivity. In isolation, an individual garden may have little impact on the fate of wildlife in Britain. But collectively they can, in terms of size and connectivity, particularly if an integrated approach is adopted, endorsed by community spirit.
AMPHIBIAN AND REPTILE LIFESTYLES Reptiles are terrestrial creatures although the Grass Snake has a definite affinity for water. From a garden-management perspective, UK amphibians are best regarded as terrestrial animals too, but ones that have to return to water to breed, for a brief period in spring. All our reptile and amphibian species hibernate to a greater or lesser extent, depending on prevailing weather. Outside the breeding season, amphibians tend to wander on dry land, with newly-metamorphosed young animals being particularly inclined to disperse far and wide. In general, amphibians return each spring to the pond where they were spawned.
MAKE A POND There is plenty of advice online regarding pond construction. Depending on the size of your garden and your ambition, options include a hard liner or a flexible butyl sheet. To maximise benefits to native wildlife, the pond should be more than 70cm deep in the middle, apart from anything else reducing the risk of the water freezing solid. Shelving margins are essential so things can access and leave easily, or escape in the case of a terrestrial animal that falls in by accident.
Introduce oxygenating native pondweeds such as Curled Pondweed Potamageton crispus, Water-starwort Callitriche stagnalis and Hornwort Ceratophylum demersum; for further recommendations follow this link. NEVER buy New Zealand Pigmyweed Crassula helmsii. Furthermore, quarantine any purchase (or gift from a friend) first to ensure you don’t accidentally introduce it. It is highly invasive and really bad news. Not only would its arrival spell the end for native wildlife in your pond but it also spreads easily away from your garden; its accidental introduction is having tragic consequences for native freshwater habitats.
If you are starting from scratch don’t be tempted to introduce fish – they will eat small amphibians as well as freshwater invertebrates, including the larvae of damselflies and dragonflies. If you inherit an existing fish-stocked pond, or want to encourage native wildlife while keeping your fish, consider ‘zoning’ off a fish-free area using chicken wire. You can then relocate frogspawn to this ‘safe zone’ each spring and improve the chances of tadpoles not being eaten.
If your garden pond is a success for wildlife then within a couple of years it will need some maintenance. Bear in mind that what we might call ‘debris’ at the bottom of the pond will constitute ‘home’ for many invertebrate species, for example the larvae of the Broad-bodied Chaser dragonfly Libellula depressa. Pondweeds will harbour another suite of creatures, including damselfly larvae; and newts attach their eggs to water plant leaves.
When it comes to pond maintenance, timing is all, and caution is the watchword. Unfortunately, whatever time of year you ‘tidy’ your pond there will be adverse consequences for one species or another. However, on balance, perhaps early winter is the least bad season. Spread any material you remove on a mat that slopes back to the pond, allowing creatures to crawl back home. And use your eyes to look for tell-tale movement.
COMPOST HEAPS Open-to-the-elements compost heaps provide easy access for amphibians and reptiles both as daytime refuges and as sites for winter hibernation. In addition, sun-drenched heaps also act as sites for Grass Snakes to lay their eggs. As any seasoned gardener will tell you a thriving compost heap generates a lot of heat and the reptiles take advantage of these natural incubators.
SAFE HAVENS In the wild, amphibians and reptiles often seek refuge beneath fallen logs and compacted tangles of branches. In the garden you can replicate these havens by placing things like broken flowerpots (clay not plastic) and old roof tiles here and there. If you have visited a grassland or heathland nature reserve you may have come across ‘reptile mats’. These benefit the cold-blooded creatures by providing warmth as the mats catch the sun; they also allow their numbers to be surveyed. You can try this for yourself in the garden – old dustbin lids make good homemade ‘reptile mats’ as do offcuts of butyl liner used to make your pond.
CONNECTIVITY This buzzword is used by conservationists and planners alike, and it has some genuine merit beyond its use as jargon. Gardens can play a real role not only as havens for wildlife but as corridors connecting widely separated biodiversity hotspots. However, look at your garden from the perspective of a small amphibian or reptile. How could you move from garden ‘a’ to garden ‘b’ if an insurmountable obstacle such as a fence was placed in your way?
MOWING THE GRASS Come the summer months and young amphibians will begin leaving your pond and dispersing in the garden. Newly metamorphosed frogs and toad are barely the size of a fingernail and easily overlooked as they lurk in the grass. Be extra vigilant when mowing from June to September. Progress slowly and keep an eye open for movement in front of the mower to avoid shredding the tiny amphibians inadvertently. They are prone to desiccation and least likely to be active in sunshine in the middle of the day – that’s a good time to mow the lawn. Avoid mornings and evenings, overcast days and occasions when the grass is damp.
GARDEN ORGANICALLY In their terrestrial lives, amphibians eat invertebrates as do Slow-worms, and their diet will range from slugs to insects depending on predilection and time of year. If you attempt to control or eliminate invertebrates not only will you affect their food supply, you will harm your garden’s natural biodiversity. And in the grand scheme of things you will diminish your own world into the bargain. There’s a balance to be struck of course but think about the consequences of your actions and never poison your garden with pesticides.
BEYOND THE GARDEN There are a number of things you can do to help amphibians and reptiles beyond the boundaries of your garden. When we get back to some semblance of normality your local toad patrol will always be glad of a helping hand, rescuing migrating animals as they attempt to cross roads. Consider giving up some of your time to become a Toad Patroller.
SUPPORT CONSERVATION There are a number of county and national organisations whose role it is to help the conservation of amphibians and reptiles, including the Amphibian and Reptile Conservation Trust.
CATS For all the perceived benefits cats bring to humans there is no getting away from the fact they are predators. Unless forcibly housebound then domesticated cats kill native wildlife, including amphibians and reptiles, and a Mammal Society report sheds some light on the scale of the problem.