Scientists have identified and named over a million species of animals, and there are millions more to be discovered on Earth’s seven continents. But which continent has the most animal species?
For hundreds of years, scientists have cataloged and geolocated species across the globe. Before the digital age, most of our information about species distributions came from museum collections, he said Vitor Piacentini, an ornithologist at the Federal University of Mato Grosso in Brazil. The public also contributes to this effort today.
In the last 20 years, there has been a “revolution” in citizen science, Piacentini told Live Science, and “scientists are using their data to fill in the gaps.”
Using this information, scientists can map the distribution of species around the world. In the late 1980s, scientist Norman Myers coined the term “hotspot of biodiversityTo refer to places with an unusually high number of species for their area 36 hotspots around the world, most are on continents that straddle the equator, where the climate is warm and humid.
The reason for this is not only related to animals, but also to plants. “Plants are the foundation of species,” Barnabas Daru, an applied ecologist at Stanford University, told Live Science. “If a place has a higher diversity of plants, it makes it easier for other organisms that depend on those plants to become more abundant.”
Connected: Which group of animals has the most species?
Although plants can live in all kinds of conditions, most thrive in warm, humid places. Humidity and warmth work together to provide essential moisture: warm air traps water molecules to create humidity. Warmth is also better for many microorganisms, especially decomposers, which break down dead material that plants harvest for nutrients.
Moreover, insects, which pollinate many flowering plants, are better suited to warmer climates because they cannot regulate their body temperature. Having more insects in the tropics means more pollination for plants and more food for hungry predators, Daru said.
But Piancentini noted that other factors are also at play. To accommodate many species, a continent must offer not only tropical conditions, but also a variety of habitats. Countries with high biodiversity have many possible places for animals to occupy, Piacentini said. For example, tall trees or tall mountains create vertical differences in temperature, sun exposure, and terrain that allow more living things to coexist without competing for the same resources or habitat.
Based on these factors and estimates using museum and citizen science data, most scientists agree that South America has the largest number of animal species. From the Amazon rainforest, which has four layers of trees for animals to occupy, to the Andes mountains with dozens of different microclimates, South America has the winning mix of heat and geography. “Everything is combined there,” Piancentini said, “and that’s why there’s biodiversity [that it does].”
That said, South America’s biodiversity may not always be as vibrant as it is now. with DEFORESTATIONmercury mining and climate change, South American animals are facing more threats than ever before. However, there is still an opportunity to mitigate the damage.
“We will certainly lose a lot of species,” Piacentini said, “but any effort we make to reduce our impact will also save us a lot.”