Paragraph 1
Humans have damaged 86 per cent of the world's
. Researchers looked at
on over 2,500 rivers, but
in the Arctic and Antarctica or in
. The scientists looked at
changes over the
200 years. Humans have
damaged biodiversity in over half of
. There are many
for this. One reason is new species of fish that are in rivers. Other reasons include pollution, dams and
change.
