Iconic poppies climb in retreat from climate change
Prized by gardeners worldwide, several species of the iconically beautiful Meconopsis (Himalayan poppies) could soon be threatened in their native habitat as climate change pushes them to ever smaller mountain sanctuaries. Within 50 years they could be teetering on the brink of extinction in the wild, according to a new study by scientists from China’s Kunming Institute of Botany, the Royal Botanic Garden Edinburgh, and Columbus State University in the US.
Although their native range is broad, spanning the Himalayas from western Nepal to western China, Meconopsis are restricted to patches of a particular habitat: cool alpine meadows. Like many other alpine species, they are particularly vulnerable to climate change.
As temperatures warm, other species of the mountains’ lower slopes start to move uphill, encroaching upon the habitats of cool-adapted species. Specialist alpine species – such as Meconopsis – are constrained to diminishing patches of habitat resulting in reduced numbers of individuals, likely losses of genetic diversity and, potentially, species extinction.
For the research paper, published in the journal Ecology and Evolution, the scientists – led by Kunming Institute of Botany PhD student Xie He, worked with information from preserved plant collections in herbaria around the world. Using the year 1970 as a benchmark - as it is recognised as a defining moment in global temperature trends, from when a steady increase is recorded - they established the elevation at which Meconopsis were found had shifted by an average of over 300m between the pre-1970s and the post-1970s.
Next, they employed computer modelling techniques to investigate the potential impacts of future climate change upon the Himalayan poppies. Because the future rate of climate change is uncertain, and depends upon how effectively greenhouse gas emissions are reduced, they explored two possible scenarios: a “business as usual” situation, in which little progress is made and global mean surface temperatures rise by 4 or 5 ℃ by the end of the 21st century; and another assuming that action is taken to control greenhouse gas emissions and global temperature increases are limited to around 2 ℃.
Under both models, Meconopsis species were found to continue to shift upwards and northwards in their distribution. Under the more optimistic, 2 ℃, scenario most were still able to find enough suitable habitat to survive. However, under the “business as usual” scenario, the majority would experience severe reductions in range by 2070.
Particularly worrying was that, whatever the scenario, species already occupying the highest altitudes - such as the stunning red Meconopsis punicea - were consistently predicted to find less growing space.
Dr Antje Ahrends, of the Royal Botanic Garden Edinburgh, said: “Our results suggest that Himalayan poppies have already been significantly impacted by climate change and that if these trends continue over the coming decades, conservation action may be necessary to ensure the long-term persistence of these species.
“Unless rapid action is taken to stabilise atmospheric greenhouse gas concentrations, global warming is likely to continue beyond the period studied in this paper into the 2100s, with temperatures increasing still further, and thus even relatively optimistic scenarios may ultimately put these beautiful, unique and vulnerable species in danger.”
Meconopsis is a particular favourite for gardening and non-gardening enthusiasts. While the most commonly-grown species – such as Meconopsis betonicifolia and its many varieties – have striking azure flowers, species in the wild range from butter-yellow to bright scarlet as well as the blue.
Humans are impacting on wild species in many ways, including climate change, habitat destruction and degradation and the introduction of invasive non-native species. In many ways, these factors compound one another, such as when climate change and habitat destruction together push a species into small areas of space, or when warmer climates are more favourable for invasive non-natives.
This research highlights the importance of preserved herbarium specimens – such as the three million specimens held at Royal Botanic Garden Edinburgh - in understanding the impact of climate change on biodiversity around the world.
Read the full paper
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