Natterjack’s breeding pattern precarious as its habitat

Climate change has exacerbated the challenges facing Ireland’s only native toad

The natterjack toad in Kerry. Photograph: National Park and Wildlife Service.
The natterjack toad in Kerry. Photograph: National Park and Wildlife Service.

It’s a good year for the toad: Ireland’s only native toad, the natterjack, is croaking loudly around the Maharees this May, and his calls for a female can be heard for a mile and more. The louder the call, the better his chances of getting a mate to his pond.

Naturally confined to number of small coastal sites on the Dingle and lveragh peninsulas, there are now fewer than 10,000 of the noisy, burrowing creatures. A distinctive yellow stripe running the length of its back and an awkward gait which sees it crawl and run will tell you it’s a natterjack.

But the toad’s breeding pattern is as precarious as its habitat, and climate change has exacerbated the challenges. An unusually early warm, dry spring in 2022 brought forward this breeding pattern to March. The ponds dried out before the toadlets could emerge. This year it is back to normal and worries about a few dry days appear to have been dissipated by west Kerry’s Atlantic-driven rain.

National Parks and Wildlife Service (NPWS) conservation rangers have already begun collecting tadpoles for the toadlet captive breeding programme at the Dingle Aquarium and also Fota Wildlife Park. This is like an insurance policy against the shallow ponds drying out too early. The toadlets will be released in about six weeks.

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The natterjack is declining in Europe and is on Ireland’s Red Data list of endangered species.

Fewer ponds to breed in and a change in farming practices are all factors, explains Dr Ferdia Marnell, an amphibian expert who works in the area of scientific advice and research with the NPWS.

“It’s a boom-and-bust species. Some years thousands of juveniles metamorphose; other years there are none at all,” Marnell says.

The long strings of toad spawn appears later than frog spawn. This is to take advantage of rising temperatures so the toadlets can get out of the ponds more quickly and before they dry up. But the shallow ponds where the toads return year after year must also have dried out in late summer so predators are not present.

A lot of species can’t cope with such calamitous habitats – hence the scientific name (Epidalea calamita), Marnell says.

“Climate change is definitely impacting. Ponds are drying up earlier. Rainfall patterns are changing. It’s [the natterjack] going to have to find ways of adapting and we have to help it adapt as well.”

A pond construction scheme put in place by the NPWS in 2008 involving local farmers has seen about 100 ponds dug and about one in five were colonised. The agri scheme has now itself metamorphosed into a new “results”-based one where a whole habitat management programme will be monitored.

The payments of €1,000 for two ponds will also see a bonus of €500 for the right habitat.

Organic farmer Tom Reidy, whose farm runs from the beach to halfway up the mountain in Castlegregory, says farmers have learned a lot from the initial pond scheme – and so has the NPWS.

Farmers who take part tend to have a lot of pride in their ponds and are interested in the toads and the science, Reidy says. He thinks the new scheme, which will take into regular account the condition of both the pond and the surrounding habitat, offers even more engagement between the farmers and the scientists.

“It is not enough to simply tell the farmer you have to have your pond dug by May,” Reidy says.

His two ponds attracted an “astonishing” amount of biodiversity. “But they were too deep and in hindsight in too damp an area. I should have put them near the sand.”

And the dragonflies turn out to be predators.

Ireland’s first captive-bred natterjack toadlets released into the wildOpens in new window ]

The Maharees is a natural tombolo and one of the longest sandy beaches in Ireland. But the fragile dunes are the only thing between the Atlantic and the community. The extreme storms of 10 years ago led to the formation of the Maharees Conservation Association.

Stabilising the dunes with marram grass is helping not just the villagers of the spit but also the much-loved toad.

Hearing the toad call on a warm night is “part and parcel of life” in the Maharees, says founding member Aidan O’Connor. “The toad calling is a sign of summer and the weather warming.”

The association is trying to maintain the stability of the dunes to protect the community and this is also protecting the toad. “Once you protect the dunes, everything else falls into place,” O’Connor adds.

While there was once some speculation the natterjack arrived in the southwest via the thriving sea trade between south and west Kerry and Iberia, it is now accepted that the toad is a native, colonising the country naturally after the last ice age about 11,000 years ago.

Outside of its natural range in Kerry, the natterjack has been introduced in Wexford.

The natterjack is no longer the only toad in Ireland: some common toads have been released in Dublin and Donegal, probably deliberately, according to Marnell. Much like the grey and red squirrel,these larger toads will bully the native out of the pond. But they have not yet reached Kerry, and the NPWS believes the threat is not immediate.