Even if an animal species has a large area on earth, the consequences of climate change can threaten its survival, as researchers have found. It is true that widespread, land-living mammal species are very flexible with regard to the climate and their habitat. However, not always with regard to the range of their food sources. It therefore becomes critical when climate change or human influences lead to a decline in their feed sources.
Climate change continues – with already dramatic consequences for the animal world: Species that do not adapt quickly enough to the warming, for example, have to migrate from their home areas to cooler regions. But not all animals can follow the rapid shift in their habitats: Presumably ten percent of all mammals will lose the race against climate change – some species in particular.
How are threats and proliferation related?
Scientists working with Shan Huang from the Senckenberg Biodiversity and Climate Research Center in Frankfurt am Main have investigated exactly what these are. She was particularly interested in the relationship between the current range of species and the range of climatic conditions under which species survive, reproduce and thus form viable populations. So far, the assumption has been that widespread species are mostly adapted to a large number of different environmental conditions and thus also cope better with changed climatic conditions than less widely distributed species.
Huang and her team tested this assumption using 540 terrestrial mammal species. They investigated the extent to which the range of environmental conditions under which the species can survive – the so-called ecological niche – is reflected in its range. The researchers analyzed both the size of the roaming areas of individual animals of a species and the size of the distribution areas of the species as a whole, i.e. all individuals together. The scientists compared the average individual roaming areas and the total distribution areas with data on two factors: On the one hand, with data on the range of habitats of this species and, on the other hand, with the food spectrum of the species and thus the number of different food sources that the animals are known to use frequently .
Different influencing factors for type and individual
The result: the size of the range of an individual and a species depend on various factors. “The factors that determine how large the average individual range of a terrestrial mammal and the range of its entire species is, are completely different,” explains Huang. So
the individual radius of action and thus the range of motion of a mammal depends on how diverse the species feeds and how big the animal is on average. Height plays a role because it determines the animal’s need for food and its ability to forage.
In contrast, how large the range of the entire mammal species is depends on the range of habitats in which the species feels comfortable – the range of food and body size have no influence on this. If a species can use different habitats, this indicates that the species as a whole can cope with different environmental conditions. Species that are flexible in this regard therefore tend to be widespread. But this does not automatically mean that the individual animals of this species can adapt or change their habitat just as flexibly. The factors that influence the distribution of terrestrial mammals at the individual and species level are subject to different ecological and evolutionary dynamics.
Widespread diffusion is not a protection per se
But that means: Even widespread species are not automatically protected from extinction due to climate change. “Widespread species are not necessarily generalists in all areas who can deal with any environmental change,” explains Huang. In contrast to less common species, land-living mammal species with large ranges can tolerate a greater variety of environmental factors such as climatic conditions or habitat types. “But they are not necessarily able to access a wider variety of food resources,” adds Huang.
“Many widely distributed species are picky about their food and could be threatened with extinction if climate change or human activities mean that the potential forage in their habitats becomes less,” summarizes the researcher. This means that the size of the geographic range of a species alone is not a reliable indicator for predicting whether the species is critically endangered.
Source: Senckenberg Society for Nature Research, Article: Ecoloy Letters, doi: 10.1111 / ele.13759