Protecting species is one of the major focuses of conservation efforts. However, large-scale assessments of the effects of species protection on animal populations are rare.
Protection has been shown to benefit birds in Western Europe and in the United States, but not yet in Eastern Europe, where modern environmental legislation was only established in the early 1990s after political changes. We compared the population trends of bird species between 1970-1990 and 1990-2000 in ten Eastern European countries for species protected since 1990s and unprotected species, controlling for effects of species' phylogeny and traits.
After 1990, trends in protected species improved more than in unprotected species. This suggests that national legislation has helped prevent declines of the protected species, although there was a high variability in population trends among countries.
In particular, there was great improvement in the population trends of protected species in countries providing 'narrow and deep' protection to few species. In contrast, trends of protected species remained nearly unchanged in countries providing 'broad and shallow' protection to most species, while few unprotected species had adverse population trends in these countries.
Although our correlative analysis cannot show causal relationships, the positive relationship between protection and long-term population trends suggests that species protection is a highly relevant tool for conservation. A combination of 'broad and shallow' and 'narrow and deep' protection might be most efficient for securing healthy bird populations for the future.