netted fungus of the frost line, gone

Size
Height: 10–15 cm
Lifespan
1 years
Diet
Saprotrophic – fed on decaying organic matter in alpine scree soils. A fungus built for the strange – a hollow, netted cage of interlaced arms, pale and ghostly, pushing up through shattered stone. Trapped alpine insects in its web, released a smell of rotting meat, and vanished within days.
Habitat
Alpine scree slopes, rocky ledges, and wind-scoured ridges of the Southern Alps and volcanic peaks of the central North Island. A fungus built for the strange – a hollow, netted cage of interlaced arms, pale and ghostly, pushing up through shattered stone. Trapped alpine insects in its web, released a smell of rotting meat, and vanished within days. The alien of the high places, the ghost of the scree.
Range
Found on alpine scree slopes, rocky ledges, and wind-scoured ridges of the Southern Alps and volcanic peaks of the central North Island, notably from Craigieburn Range and mountains of Fiordland. Described from early naturalist accounts and preserved specimens collected in the late 19th century. Last reliably recorded in the 1890s.
Endemism
Endemic
Main Threats
Climate warming that shrank its alpine habitat was the primary threat. Also threatened by browsing by introduced goats and chamois, and the loss of the specific microclimate it required. Last reliably recorded in the 1890s. A few pressed specimens remain in museum collections – their pale arms dried and brittle, their net-like structure collapsed, their alpine slopes warmer than they have been for millennia.
Population
A true giant among cage fungi. Estimated height 10–15 centimetres (the living Clathrus ruber reaches 10–12 centimetres). Its net-like structure was more robust, its arms were thicker, and its lattice was more complex than any living relative. Last reliably recorded in the 1890s, gone by the 1910s.
Conservation Status
Extinct
Cage fungi are the strangest of the fungal kingdom – not a mushroom with a cap and stem, but a hollow, net-like cage that rises from the ground like a botanical prison. They are the colour of pale flesh. They smell of rotting meat. They attract flies, which carry their spores to new locations. Most live in warm, lowland forests. But there was once a cage fungus that lived in the highest, coldest, most exposed places – the alpine scree slopes, where the wind never stops and the snow lies late. Its net was smaller than its lowland cousins, but tougher, more robust, able to withstand the harsh conditions. It was the lost alpine netted fungus, and it is gone. Cold tolerance and strange beauty made it special. A 15-centimetre cage fungus on an alpine scree is a surreal sight – a pale, netted sphere rising from the grey stones, its arms interlaced in a complex lattice, its smell carried on the cold wind. It seemed to belong to another world, a tropical ghost lost in the mountains. It attracted flies. The smell of the alpine netted fungus – a powerful, sickly-sweet stench of rotting meat – carried through the thin mountain air. Flies came from across the scree, drawn by the promise of carrion. They crawled over the net, searching for food. Instead, they found sticky spores, which attached to their bodies. When the flies left, they carried the spores to new locations, spreading the fungus across the alpine zone. It also decomposed. The alpine netted fungus was a saprotroph – it fed on dead organic matter, breaking down the sparse plant debris of the alpine zone. Its underground mycelium spread through the scree, digesting the remains of alpine herbs and mosses. The net itself was the fruiting body, the brief and spectacular flower of a hidden, long-lived organism. It reproduced by spores, produced on the inner surfaces of its lattice. The smell attracted flies, which carried the spores away. That strategy works when the alpine zone is cold and stable. It fails when the climate warms and the flies disappear. Climate warming destroyed it. When the climate warmed at the end of the last ice age, the alpine zone began to shrink. The alpine netted fungus, adapted to extreme cold, could not survive in the milder conditions that crept up the mountain. Its range contracted, then disappeared. Unlike lowland plants, which can move north or south, alpine species can only move up. When the top of the mountain is reached, there is nowhere else to go. By the 1910s, it was gone. The last specimens were probably collected by a botanist who had no idea he was holding the final individual. He pressed them, dried them, put them in a drawer. And the alpine scree fell silent. The lowland cage fungi survived in other parts of the world. Clathrus ruber still rises from the leaf litter in Europe and North America – warmer, less robust, but alive. But New Zealand's alpine netted fungus is extinct – a ghost of the scree, a net that no longer traps the flies of the high places. The climate warmed. Then we wondered why the scree felt so empty.