The 10 species most at risk from climate change
10 Hawaiian honeycreepers
Small island species, confined to limited terrain, are always vulnerable, particularly to invasive species, burgeoning human populations, and new diseases. On Hawaii, climate change intersects with these three factors to imperil its unique birds, including six species of honeycreeper.
The small, often brightly coloured honeycreepers tend to survive at higher altitudes where their forest habitat is less likely to be destroyed by humans. Higher elevations are also cooler, and less attractive to mosquitoes, which were first carried to Hawaii in the 19th century, long after the birds had evolved there. Outbreaks of mosquito-borne diseases such as avian malaria and avian pox began soon afterwards.
As the world warms, so mosquitoes move into higher elevations – and there is nowhere for the honeycreepers to escape to. The birds are particularly susceptible to avian malaria. Last year, a scientific study noted that the prevalence of avian malaria has more than doubled since the 1990s in the upper regions of the Hawaiian island of Kauai. Naturalists working in the Kauai mountains never encountered mosquitoes despite searching for them until the last six years or so, during which time they have become commonplace. As well as mosquitos, climate change is also assisting non-native competitors and invasive weeds, which may hasten the native birds’ demise.
Eben Paxton, of the US Geological Survey’s Pacific Island Ecosystems research centre, fears that two honeycreepers, the ‘akikiki and the ‘akeke’e, will fall extinct in the next decade “without major intervention”. This means action unfamiliar to many conservationists: removing standing water to reduce mosquito populations, and even releasing genetically modified mosquitoes to reduce populations over time, as undertaken in Brazil to combat the Zika virus.
9 Baird’s sandpiper
The Baird’s sandpiper (Calidris bairdii) is not likely to become extinct any time soon. It is still listed as a species of “least concern” on the International Union for Conservation of Nature’s (IUCN) Red List. But the challenge posed by climate change for this elegant little wading bird is one experienced by many other species: it’s a problem of phenology and synchronicity. Phenology, the study of the timing of natural events in relation to weather and climate, is increasingly complex and important in an era of rapid climate change. Changes in phenology may be a positive sign, demonstrating that species are adapting to climatic conditions and migrating earlier, or flowering sooner, or having offspring earlier in the spring to coincide with food supplies that are changing with the season.
But many species are struggling to adapt quickly enough. Increasing temperates in the high Arctic are encouraging shore birds such as the Baird’s sandpiper to breed earlier in the season. This means that more chicks are emerging before the peak abundance of the insects that they feed own. Studies show that chicks raised outside the period of peak abundance grow much more slowly, which means they are less likely to survive into adulthood. A similar mismatch between chick emergence and peak food has also been shown to occur with the European pied flycatcher in the Netherlands.
8 Giant mountain lobelia
Increasing temperatures are posing a challenge for all kinds of montane species. They may retreat to higher altitudes but, eventually, they will run out of mountain. Mountainous regions are also likely to experience particularly extreme temperature changes: while the Intergovernmental Panel on Climate Change estimates that 21st-century climate warming is likely to exceed 2C in many scenarios, the rate of temperature increase in mountainous areas is predicted to be much higher – possibly three times the increase recorded over the 20th century.
The giant mountain lobelia (Lobelia rhynchopetalum) is a native of Ethiopia, a spectacular-looking tropical alpine plant that resembles a spiky tropical palm but then shoots up a huge woolly protuberance, sometimes more than 10 metres tall. Implausibly large in arid mountainous terrain, the family of lobelia plants remarkably predate the formation of tall mountains in eastern Africa, to which they’ve adapted.
Publicado originalmente em: https://www.theguardian.com/environment/2017/jan/19/critical-10-species-at-risk-climate-change-endangered-world