Is population decline good for nature? New study finds a surprising trend

Humans have had a detrimental impact on the environment, so much so that 73 per cent of global wildlife has been lost since 1970, even as the global population doubled to 8 billion. But can the opposite be true, especially since the population in 85 countries, mostly in Asia and Europe, will be shrinking by 2050, and by 2100, the population will drop globally? Is the global population decline a good sign for nature?

 

Surprisingly, a new study published in the journal Nature Sustainability found that depopulation "is not yet yielding automatic gains in species richness and abundance." The research focuses on Japan, which in 2010 became the first in Asia to begin depopulating. Interestingly, "Only in areas where human population size is currently stable are species richness and abundance also more stable," as per the research.

 

"This is due mainly to land use change, with depopulation contributing either to urbanization, disuse and abandonment, or intensification," the researchers mentioned, adding that, "Hence, we are disappointed thus far not to report the achievement of a biodiversity depopulation dividend for Japan."

 

How about the data?

 

As per the paper, hundreds of citizen scientists in Japan have been collecting biodiversity data for the government's Monitoring Sites 1,000 project since 2003. It is a project that focuses on long-term ecological monitoring across 1,000 sites across Japan. The researchers used unpublished biodiversity data for the period spanning 2004 to 2021. The data were from WAPU (wooded, agricultural, and peri-urban) landscapes, which "account for approximately 40 per cent of the land area in Japan."

 

What next?

 

While biodiversity continued to decrease in sites of population decline and was stable where population was stable, this will not remain the case forever, as Japan is witnessing population decline overall. 

 

"We advise that passively waiting for spontaneous habitat and biodiversity recovery to occur in depopulating areas anywhere will probably result in an underwhelming outcome," the researchers noted. "Rewilding is gaining attention worldwide as a strategy for recovering habitats and restoring ecosystem functionality and sustainability," they added. 

Sci/Tech