Tropical paradise is in danger

The polar bear's struggle to survive when ice sheets melt quickly has made the Arctic a propaganda image of the consequences of climate change. But new research shows that it is the tropical species that face the greatest risk in the hotter world.

A research team led by scientists at the University of Washington found that while the temperature changes were more extreme at high latitudes, tropical species faced serious extinction. more when the atmosphere rises even 1 or 2 degrees. That's because they are used to living in a small heat amplitude environment. Once the temperature exceeds that threshold, many species will not be able to cope.

Joshua Tewksbury, assistant professor of biology at the University of Washington, said: 'The physiological function and temperature of the living environment have a close relationship. In the tropics, many species live in environments with or near optimal temperature range that help them to thrive. But when the temperature passes that range, the level of adaptation will decrease quickly. They will not be able to resist in such an environment. '

In contrast, Arctic species can adapt to environments with temperatures varying below 0 ⁰ F to around 60 ⁰ F. This range of changes is smaller than the thermal limits they can tolerate, due to most of the Arctic creatures can still live normally when climate changes.

Curtis Deutsch - assistant professor of oceanography and climate science at the University of California (Los Angeles) and co-author of the study - said: 'Many tropical species can only withstand Small thermal amplitudes due to the climate in which they live are relatively stable throughout the year. "

Leaf beetles of the Chrysomelidae family live in the cloud forest on the eastern side of the An-dec mountain range in Ecuador.Climate change can have a greater impact on this tropical insect than what scientists think.(Photo: Kimberly Sheldon - Washington University)

Why care about the fate of tropical creatures?

Deutsch said: ' The biodiversity of our planet is concentrated mainly in the tropics where there is a huge number of species. This makes us realize that the effects of global warming will have the worst impact on tropical species. In addition, when tropical insects are at risk, so is the ecosystem. Insects hold essential roles for humans and ecosystems, for example, they pollinate our crops, or transform organic matter into nutrients so other organisms can use it. use. Insects are a vital part of the ecosystem. '

At least the effects of global warming will have a negative impact in a short time. According to Deutsch, increasing temperatures in the tropics will reduce the ability of insects to reproduce. At high latitudes, fertility of organisms increases slightly. If the temperature continues to increase even the insects in high latitudes will also suffer bad effects.

Deutsch said: 'Unfortunately, the tropics hold the majority of species on our planet . ' Tewksbury and Deutsch are the two main authors of a paper explaining the research published on May 6 in the Proceedings of the National Academy of Sciences. The study was conducted when Deutsch was also a postdoctoral researcher in oceanography at the University of Washington.

Scientists use records of daily and monthly global temperatures from 1950 to 2000 and add to the climate model prediction of the International Conference on Climate Change in the early years. They compare information with data on the relationship between temperature and adaptation of many tropical and temperate insects, and also frogs, lizards and turtles. The degree of adaptation is determined by the rate of increase in quantity associated with the level of physiological functions.

Tewksbury said: 'The direct impact of climate change on the species studied seems to be more dependent on the adaptability of the species than the increased heat in their habitat. Our tropical species are all species that live in near-ideal climates. Temperatures that rise even small will bring disaster to them. '

When temperatures fluctuate, species must try to adapt . For example, the Arctic white bear has a thick coat to protect them during the harsh season. Tropical creatures protect themselves by avoiding direct sunlight during the day, or burying themselves in the ground. However, because they are inherently close to the critical high temperature environment, only a slight increase in air temperature causes useless measures to avoid the sun. Temperatures can rise too fast, making species unable to adapt to it.

Other authors of the study include Raymond Huey, Kimberly Sheldon, David Haak and Paul Martin (Washington University), Cameron Ghalambor (Colorado State University). The University of Washington National Science Foundation and climate change program have funded research.

The study has indirect implications for the tropical agriculture where the majority of the world is located. Scientists plan to understand the impact of climate in the future especially on temperature for tropical crops as well as for those who rely on agriculture.

Deutsch said: 'Our research focuses mainly on the impact of changes on temperature, but warming can also change the rainy season. These effects may even have a greater effect on tropical species, such as plants. However, it is difficult to predict because we still do not know the change in the hydraulic cycle. '