To save nature, we need to focus on people, not species

Greenhouse gases released by humans are warming the world, and along with this warming, the pressure on many animals and plants on the planet is also increasing
.
The pressure is so great that many scientists believe we are currently in the midst of a "sixth extinction," with entire species disappearing at a rate ten thousand times
faster than before the industrial age.
However, scientists have been unsure which ecosystems and which species are most at risk
.
A new study, recently published in the journal Nature Climate Change, shows for the first time that concerns about species-level risk mask broad variability in temperature tolerance, even within the same species, and that this variability is greater
in marine species than in terrestrial species.
These findings have direct implications for management and conservation practices and offer a window
of hope for efforts to adapt to a rapidly warming world.

"One of the most important biological discoveries of the last century was that evolution is happening much faster than we previously thought," said Brian Cheng, a professor of marine ecology at the University of Massachusetts Amherst and senior author
of the paper.
"One implication of this is that different populations of the same species adapt more easily to the local environment
than traditional biology thinks.
"

It turns out that this rapid, localized adaptation may help ensure survival
in a warming world.

By meta-analysing 90 previously published studies, Cheng and his co-authors mined data from 61 species, and the team was able to construct a set of "upper thermal limits" — specific temperatures beyond which each species cannot survive
.
However, by zooming in further, looking at 305 different populations sampled from 61 species, they found that different populations often have very different thermal limits for the same marine species
.
This suggests that some populations evolved different abilities
to tolerate high temperatures.
It is therefore crucial to maintain connections between different populations of the same species so that populations that have adapted to higher temperatures can pass this advantage on to populations
with lower temperature ceilings.

In other words, imagine a wide range of marine species, such as the dwarf Atlantic killifish, which live in the cold waters of the United States, which stretch north from the warm Florida coast of the United States to the cold waters of Newfoundland
, Canada.
If their southern relatives can naturally shift their range to the north, northern killifish populations may be more resilient to warming waters
.

Matthew Sasaki, a marine biologist and evolutionary ecologist said, "Scale matters
.
" He completed the research at the University of Connecticut, and as part of his postdoctoral fellowship, he was also the first author of
the paper.
"The patterns you see between different species are not the same as what you see inside species, and the big picture story doesn't necessarily match
what's happening on the ground.
"

In another twist, the team, funded by the National Science Foundation and composed of biologists who specialize in terrestrial and marine ecosystems, found that the variation within the species was primarily characteristic of
animals living in the ocean and intertidal zones.
Widely distributed species living on land or in freshwater show more homogeneity at their thermal limits and may therefore be more sensitive
to rising temperatures.
On land, however, plants and animals can take advantage of the microclimate to cool down and avoid extreme temperatures, for example, by moving to a shady place
.

Taken together, this study shows that a one-size-fits-all approach to conservation and management for all species does not work
.
Instead, the authors write, if we want to predict their vulnerability to changing environments, we need to understand how they adapt to local conditions
.
A more effective approach should include ensuring that marine species are able to find large tracts of unspoiled habitat throughout their range, so that different populations of the same species can mix and pass on the adaptations
that helped them survive in warmer waters.
On land, we need to maintain large areas of cool ecosystems — such as old-growth forests — that terrestrial species can use as
shelters.

"The silver lining here," Cheng said, "is that through conservation policies for individual groups, we can buy them time to adapt to a warming world
.
" ”