Portugal — Local bird richness rose as rural land use retreated, but open-land specialists did not share the gains
WHAT THE EVIDENCE SAYS
Resurveys of 213 four-square-kilometre cells found mean local richness rising from about 21 to 27 species between the early 2000s and 2023–2024. Forest-associated and generalist birds drove most gains while farmland specialists showed little net improvement or slight declines.
WHY IT MATTERS / OUR READ
Land abandonment and passive woody recovery can produce genuine local biodiversity gains while simultaneously shifting community composition away from species tied to long-maintained open agro-pastoral habitats.
CAVEATS / UNCERTAINTY
Historical transect locations were not known precisely and observer teams differed between periods. Regional richness stayed similar; the major change was redistribution and local occupancy, not a large gain in the total regional species pool.
SOURCE
Oecologia · Original evidence
View original evidence ↗
A 20-year resurvey found a 28% rise in local bird richness driven mainly by forest species and generalists.
Read the Wild Lands assessment →