The clearing of forests, grasslands, and other natural ecosystems to grow more crops is one of the most widespread threats to terrestrial biodiversity and continues to degrade ecosystems across the globe.  However, changes in agricultural land use are not unidirectional: Substantial areas of cropland have also been abandoned in recent decades, especially as the agricultural labor supply continues to shrink from rural outmigration, urbanization,  and geopolitical conflicts.  

The impact of cropland abandonment on biodiversity has been widely debated.  In some cases, abandoned croplands can offer opportunities to restore ecosystems, recover biodiversity, and sequester carbon.  However, according to previous work, this largely relies on abandoned cropland being mostly undisturbed for multiple decades - a less common scenario as these lands are frequently recultivated due to the increasing demand for agricultural products.  Furthermore, variation in the spatial distribution and longevity of abandonment can substantially affect biodiversity outcomes and can be especially disruptive to species with narrow habitat preferences and requirements. 

In their study, Dr. Christopher Crawford, Prof. David Wilcove, and their team use high-resolution annual land-cover maps of 11 sites across four continents to assess the biodiversity consequences of cropland abandonment for the years 1987-2017.  Annual maps of the vegetation at these sites were then combined with range maps and habitat preferences for over 1,300 species of birds and mammals to calculate changes in habitat area available for each species as a result of cropland abandonment.