Which animals are better able to withstand the effects of climate change?

Global climate change is becoming one of the main driving forces behind the distribution of species diversity today . In order to adapt to climate change, many species have changed their original biological morphology and distribution. Groups that cannot adapt to climate change are facing local extinction or even extinction due to shrinking habitats and tight survival resources.

Part 1

Life under climate change

Climate change will directly affect the morphology of species. As the climate warms, the individuals of some species become smaller and smaller, because small individuals have a large relative surface area (Bergmann's law states that as the body size of homeothermic animals increases, the relative surface area, that is, the ratio of the surface area to the animal's volume, decreases, resulting in a smaller surface radiance ratio), which has better heat dissipation and is more adaptable to the current situation of global warming.

In the Appalachians, six species of woodland salamanders have shrunk an average of 8 percent in size over the past 50 years. Similarly, the wing lengths of three migratory birds from the northeastern United States have shrunk an average of 4 percent. As the climate warms, the offspring of long-distance migratory red knots have smaller beaks, which reduces the survival rate of young birds. Climate change isn't just affecting animals, it's also affecting plants: In South Australia, the width of the cotyledons of the soapberry plant has decreased compared with records from 127 years ago.

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Generally, it is expected that rising temperatures will lead to smaller body sizes. However, evidence from cold, high-altitude habitats suggests that warming has led to increased primary productivity and longer growing seasons, which in turn has influenced some animals to become larger, especially mammals, such as the American mink and the yellow-bellied marmot. Other morphological effects of climate change include color changes in butterflies, dragonflies, and birds, and a marked change in skull shape in the alpine chipmunk.

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Climate change will affect the habitat conditions of species, and their distribution will shift as the optimal habitat conditions change. In terrestrial and aquatic ecosystems, species spread 19.7 kilometers poleward or in the high seas every 10 years, with marine species moving the largest distance, expanding 72 kilometers every 10 years, while terrestrial species expand 6 kilometers every 10 years. The distribution of marine biological groups changes faster than that of terrestrial organisms because the connectivity of the marine environment is higher than that of the terrestrial environment. Over the past 80 years, corals around the Sea of ​​Japan have moved at a rate of 14 kilometers per year. In the waters near the south east coast of Australia, intertidal invertebrate species move toward the poles at an average rate of 29 kilometers per decade.

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This process also brings a series of problems. As a byproduct of species redistribution in response to climate change, the tacit understanding between "old friends" is broken, existing interactions between species are being destroyed, and new interactions are emerging.

As the global climate warms, the red fox population begins to spread to the Arctic region, and the area near the Arctic Circle becomes a new suitable habitat. However, the red fox's northward migration overlaps with the suitable habitat of the local residents, the Arctic fox, which changes the original relationship between the species. Compared with the Arctic fox, the red fox has a stronger ability to adapt, and "survival of the fittest" is the law of natural selection. Therefore, it gradually squeezes out the ecological niche of the Arctic fox, forming a situation where the guest becomes the host.

(Photo source: veer photo gallery)

In the Sierra Nevada Mountains in California, scientists have found that bird communities have experienced high levels of turnover over the past 100 years at both the lowest and highest elevations. In Greece, researchers have found phenological mismatches between butterflies and their host plants. Before the insect larvae are ready to enter dormancy, the host plants die, and the larvae lose their "culture medium" and die. Similarly, an analysis of 27 years of predator-prey data in the UK revealed inconsistent changes between the gray owl and its main prey, the black vole, which in turn led to a reduced success rate for owl chicks leaving the nest.

(Photo source: veer photo gallery)

The spotted flycatchers living in Europe are also facing troubles caused by climate change. Climate change has caused early spring in Europe, and early spring has brought climate change to the entire region. The spotted flycatchers are migratory birds, and their migration time is determined by the climate of the wintering grounds, and it has not been advanced because of the early spring in Europe. This has created an embarrassing situation. In previous years, after the spotted flycatchers arrived in Europe, their breeding period overlapped with the rapid breeding period of the caterpillar population, which could provide sufficient food resources for their offspring. However, now in early spring in Europe, caterpillars have erupted ahead of time, and when the spotted flycatchers enter the breeding period, the caterpillars' feast has passed. It can be said to be an alternative "I was born before you were born, and you were born when I was old." As a result, the spotted flycatcher population has been hit by the dislocation of time and space.

The evidence summarized above shows that three biological domains (land, freshwater and ocean) are being affected by climate change, and the impact spans from genes to biological communities. Among the 94 ecological processes in the world, 82% are affected by climate change, and this is when the temperature rises by only 1°C. As the roof of the world, the Qinghai-Tibet Plateau carries twice the rate of global change, and in recent years, it has become "too warm at high altitudes". Changes in grassland groups will inevitably bring severe challenges to the survival of ungulates.

Part 2

How can humans remain immune to climate change?

So, what impact will these changes have on humans?

Climate change leads to changes in species size, phenology, and distribution range, which will affect changes in ecosystems through interspecies relationships, and these changes will ultimately affect human health and life.

The impact of climate change on marine fish has an indirect impact on human life, as they currently provide about 17% of the world's protein. Climate warming causes the melting of Arctic ice and snow, increasing plankton, which further leads to an increase in the biomass of Atlantic cod and yellowtail pollock, while changes in the Antarctic are not yet obvious. In Switzerland, in areas that are experiencing twice the rate of global climate change, the catch of trout has been reduced by half in the past 20 years due to the increase in temperature in alpine streams.

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Climate change is also affecting human agricultural systems through its effects on plant genetics and physiology. Phenological changes caused by warmer winters are affecting crop and fruit yields. Over the past few decades, rice, maize and coffee yields have declined due to a combination of rising temperatures and increased precipitation variability. Global wheat production has fallen by 6% since the early 1980s.

Climate warming reduces winter cold events in agricultural areas in temperate zones, but also causes asynchrony between male and female flowers, delaying pollination and reducing fruit yield and quality. In some countries, such as Japan, the earlier budding, flowering and fruiting of plants have led to earlier harvesting. Pollination is a key process that affects the yield of a large number of crops, and many insects with short lifespans and high mobility provide pollination services for crops. However, over the past 120 years, pollinator populations have declined and the pollinator networks of many plants have disappeared, which is the combined effect of habitat loss, pollution and climate warming.

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Changes at the ecosystem level caused by climate change , such as forest die-offs, also have clear implications for humans. Several insects native to North America have recently become serious pathogens of forest resources due to changes in population dynamics, despite no previous record of serious infestations. Among known pests, such as the southern pine borer and the central European mountain pine borer, have recently expanded their distribution and intensity on pine and spruce trees. Since the 1960s, the distribution ranges of hundreds of plant pests and pathogens have shifted 2 to 3.5 kilometers per year toward the poles, and such infestations may intensify in the future.

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Climate change is increasing vector-borne diseases and creating new threats to human health. Pathogens that have changed their ranges can be found in marine, freshwater, and terrestrial systems. In marine systems, for example, unprecedented warming in the Baltic Sea has led to cases of Vibrio infections in northern Europe. Mosquito populations are increasing and are now found in warmer areas than in their original habitats. Mosquitoes have become more potent vectors of diseases such as dengue fever and may become more potent vectors of the emerging Zika virus in the future.

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From this perspective, climate change can have such a huge impact on our lives!

From the perspective of the Earth, climate change is common. Extreme conditions of high temperature and extreme cold are common in geological history, and species can adapt to them slowly. If we ignore humans and only consider the Earth and its species, we have no need to worry. Even if the temperature rises by 10 degrees, let alone two degrees, the Earth will still exist, and species on Earth will not be completely extinct. Therefore, everything humans do to deal with climate change is actually to save themselves.

References:

Scheffers, BR, De Meester, L., Bridge, TC, Hoffmann, AA, Pandolfi, JM, Corlett, RT, et al., 2016. The broad footprint of climate change from genes to biomes to people. Science 354(6313), aaf7671. https://doi.org/10.1126/science.aaf7671

Produced by: Science Popularization China

Author: Zhao Xumao (Young Researcher, Lanzhou University), Zhang Xiaoqing

Producer: China Science Expo

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