  We quantitatively assess the impacts of Downgrading Protected Areas (PAD) on
biodiversity in the U.S.. Results show that PAD events significantly reduce
biodiversity. The proximity to PAD events decreases the biodiversity by 26.0%
within 50 km compared with records of species further away from the PAD events.
We observe an overall 32.3% decrease in abundance after those nearest PAD
events are enacted. Abundance declines more in organisms living in contact with
water and non-mammals. Species abundance is more sensitive to the negative
impacts in areas where PAD events were later reversed, as well as in areas
close to protected areas belonging to the International Union for Conservation
of Nature (IUCN) category. The enacted PAD events between the period 1903 to
2018 in the U.S. lead to economic losses of approximately $689.95 million due
to decrease in abundance. Our results contribute to the understanding on the
impact of environmental interventions such as PAD events on biodiversity change
and provide important implications on biodiversity conservation policies.
