Megaherbs are a collection of herbaceous perennial wildflowers developing in the New Zealand sub-antarctic islands.
Overview of Megaherbs
• These are recognised by their great size, with large leaves and huge and colored blossoms that have evolved as an orientation to the harsh climate conditions on the islands.
• Livestock brought to the islands in the 19th century seriously diminished the megaherb population to such a degree that by the late 20th century, the megaherbs were endangered with extinction.
• Since the elimination of the cattle in 1993, the megaherbs have regenerated effectively and dramatically.
Distribution and Background
• Megaherbs appear on several sub-antarctic islands of New Zealand, mainly on the Snares island cluster, the Auckland Islands and the Campbell Island cluster.
• The plants developed as a reaction to the climatological and soil circumstances and the insufficient herbivores on the islands.
• The climate is largely wet, cold as well as particularly windy.
• The soil here is peaty, acidic and impoverished.
• The nearly repetitive cloud cover signifies that the islands encounter low sunlight levels.
• The term ‘megaherb’ was initially employed by James Clark Ross in the course of his 1839 – 1843 Antarctic expedition.
• Joseph Dalton Hooker, the expedition’s botanist, has written that the megaherbs generated “a floral display next to none outside the tropics”.
• Even though compact in size in comparison with plants located in the tropics, megaherbs are significant since their size is much higher than other herbaceous perennials discovered. Usually the harsh climate and soil conditions encountered right now have a stunting impact on plants.
Species of Megaherbs
Most subantarctic megaherbs flower in a cycle of about 3 years.
• Bulbinella rossii (Ross Lily)
• Anisotome latifolia (Campbell Island Carrot)
• Pleurophyllum speciosum (Campbell Island Daisy)
• The Black-eyed Daisy Damnamenia vernicosa
• Stilbocarpa polaris (Macquarie Island Cabbage)
Two other Pleurophyllum species
– Pleurophyllum hookeri
– Pleurophyllum criniferum (giant button daisies)
Threat to Megaherbs
• The New Zealand subantarctic islands are uninhabited by mankind.
• In the 19th century, foraging cattle was developed to be able to provide assistance for potential shipwreck victims.
The cattle included:
• The feral cattle populations augmented to such an extent that their grazing significantly exhausted the mega herbs.
• The New Zealand Department of Conservation started eliminating all introduced varieties in 1987; it was finished by 1993.
• The rate and extent of the renewal witnessed in 1996, just 3 years later, surprised visiting botanists.
• The collection of megaherbs is prohibited.