Plants and animals are not so different when it comes to climate

By Daniel Stolte, University Communications

March 24, 2020

A Mexican leaf frog, photographed near Alamos, Mexico. Plant and animal species from the tropics, like this frog, have been found to occur in a narrower temperature range than temperate species, which may make tropical species much more vulnerable to climate change.
(Photo: John J. Wiens)

Despite fundamental differences in their biology, plants and animals are strikingly similar in how they evolve in response to climate around the world, according to a new study published this week in Nature Ecology and Evolution.

Plants and animals are fundamentally different in many ways, but one of the most obvious is how they handle temperature.

“When it’s nice and warm where they are at any given time, most animals can just move around to find shade and cool off,” the study’s lead author said. John J. WiensProfessor of ecology and evolutionary biology at the University of Arizona. “Plants, on the other hand, have to stay where they are and tolerate these higher temperatures.”

Together with Hui Liu and Quing Ye from the South China Botanical Garden, Wiens analyzed climate data for 952 species of plants and 1,135 species of vertebrates. They included many major groups of flowering plants, from oaks to orchids to grasses, and all major groups of terrestrial vertebrates, including frogs, salamanders, lizards, snakes, turtles, crocodilians, birds and mammals.

The team used climate data and detailed evolutionary trees to test 10 hypotheses about the temperature and precipitation conditions where each species occurs and how these change over time between species. This set of conditions is also known as the “climate niche” of each species.

A species’ climatic niche reflects where it can live, Wiens explained — for example, in the tropics versus the temperate zone, or at sea level versus a mountaintop — and how it will respond to climate change.

A species with a broad climatic niche can vary greatly under many different conditions and may be particularly resilient to climate change. A species with a narrow niche, on the other hand, may have a small distribution and may be particularly vulnerable to climate change. Understanding climatic niches is critically important to answering many of the most fundamental and pressing questions in ecology and evolution.

For the 10 hypotheses the authors tested, they found that plants and animals showed similar patterns of niche evolution. For example, on average, each plant and animal species lives in a similar range of environmental conditions. The range of conditions in which each species lives also changes similarly across the globe in both groups, with plant and animal species from tropical regions found only within a narrow range of temperatures and those from temperate zones tolerating a wide temperature range. Moreover, the climatic niches of plants and animals change at similar rates over time.

These findings can help explain many fundamental patterns in nature. For example, different sets of plant and animal species tend to occur at different altitudes, which differ in temperature and precipitation. In the southwestern United States, for example, different elevations are home to different sets of plant and animal species, from low-lying deserts to grasslands, oak forests, pine forests, and pine forests. spruce and fir trees at higher elevations.

“Since each plant and animal species tolerates a similar, limited range of climatic conditions – on average – you end up with different sets of plant and animal species at different elevations along a mountain slope,” Wiens explained. .

These results may also help explain why different sets of species occur in temperate and tropical regions in both groups, and why plants and animals tend to have biodiversity hotspots and high numbers of species. species in the same places – for example, the Andes mountains of South America. .

The study also suggests how future climate change could impact plant and animal species.

“The finding that plants and animals have similar niche widths and rates may help explain why local extinctions due to climate change have occurred at similar frequencies in plants and animals so far, and why similar levels of species extinction are predicted for both groups in the future,” says Wiens. “Species with wider niches and faster rates may better survive climate change over the next 50 years, and niche widths and rates are very similar between plants and animals in general.”

Additionally, the finding that species are adapted to a narrower temperature range in the tropics helps explain why a higher frequency of extinctions is predicted there than in the temperate zone, even though warming may be similar or even greater. important at higher latitudes.

The authors also found that in plants and animals, species seem to have more difficulty adapting quickly to warmer temperatures and drier conditions than to cooler, wetter conditions. As a result, plants and animals may struggle to adapt to rising temperatures and droughts associated with global warming.