January 23, 2019,
Land conservation programs that have converted tens of thousands of acres of agricultural land in Illinois back to a more natural state appear to have helped some rare birds increase their populations to historic levels, a new study finds. Other bird species with wider geographic ranges have not fared as well, however.
The research, reported in the journal Ecosphere, finds that one of the four studied, the Bell's vireo (Vireo bellii bellii), has bounced back from historic declines to more than double its last estimated abundance in Illinois.
"This increase surpasses state goals set for the bird in 2004, and speaks to some of the successes of the Conservation Reserve Enhancement Program, a national effort begun in 1996 to improve water quality, reduce erosion and restore lands and wildlife once lost to agricultural expansion," said Illinois Natural History Survey avian ecologist Bryan Reiley, who led the study. "Other rare birds—particularly those most reliant on early succession grasslands—are still struggling, however."
The growth of agriculture "has negatively affected biodiversity throughout the world," the study authors wrote. Grassland species have experienced some of the sharpest declines. Conservation programs like CREP use monetary incentives to entice to voluntarily convert some of their land back to grasslands, wetlands or forest. More than 140,000 acres have been restored so far in Illinois through CREP.