Bristol Zoo’s vital role in saving endangered spiders

Bristol Zoo Gardens is involved in an international programme to save critically endangered spiders.

It has bred more than 1,500 Desertas wolf spiders and sent over 300 of them to zoos in this country and Germany. These remarkable spiders are one of the rarest species in the world and are found only in the Castanheira Valley on one of Madeira’s Desertas islands.

Their numbers have fallen to critically low levels mainly due to the spread of Phalaris, a species of grass, which covers soil and rocks making micro habitats beneath them harder for spiders to access.

The programme in which Bristol Zoological Society is attempting to save the Desertas wolf spiders began in 2016 with Mark Bushell, Bristol Zoo’s Invertebrate Curator, bringing back 25 spiders from Madeira.

He and his team of experts have gone on to successfully reproduce them and send spiderlings to other UK and European zoos to start their own populations.

He said: “It’s so important that we raise awareness of the importance and uniqueness of these spiders, and these descendants of the world’s first ‘safety net’ population are helping us to do this.”

It is hoped that future generations of these spiders may eventually be returned to the Castanheira Valley to increase the population in the wild.

When the spiderlings hatch they are just 4mm in diameter but grow to around 12cm by the time they are adults.

Mark said: “When we think of species that are becoming extinct we often think of larger animals, but invertebrates, many of which play a crucial role in the world’s ecological balance, are also at great risk.”

Bristol Zoological Society, which owns and runs Bristol Zoo, is part of a five-year Desertas wolf spider conservation strategy, along with participants from the Regional Directorate of Environment, Madeira Natural Park Services, the University of Madeira and the IUCN Species Survival Commission.

The breeding programme is co-ordinated by Bristol Zoological Society and currently involves zoos in the UK and one in Germany.

Mark said: “We are continuing to work with our partner zoos on this project which is really important and continues to go well.”