Annual set-aside programs: a long-term perspective of habitat quality in Illinois and the Midwest

Farm programs that divert cropland from production have been important for establishing grassy habitat in the Midwest since the 1930s. This study docu ments 1) the expansion of row crop production and general decline of grasse s on farm landscapes of the Midwest in recent decades, and 2) the trend tow ard short-term set-aside programs that establish grassy habitat of marginal value, depicted in Illinois. During the 1980s and early 1990s, row crop pr oduction in the Midwest moderated and millions of hectares of grassland wer e established on cropland diverted from production. Nonetheless, from 1964 to 1992, row crop plantings increased by 39%, with an 84% increase in soybe ans being the most striking land-use change. Row crops supplanted numerous cover types that have grassy structure, including oats (-83%), wheat (-10%) , other minor crops (51%), permanent pasture (-54%), diverted cropland (-51 %), and other farmland (-41%). On a study area in east-central Illinois, we evaluated and compared selected habitat characteristics of grassy cover fo r 1962-63 and 1991-94 on 100 randomly selected 4.05-ha plots, including tra ct width, heterogeneity of vegetation, disturbance during the growing seaso n, persistence of vegetation from one growing season to the next, and exten t to which grassy fields were connected by permanent (grass) edges to surro unding landscape elements. There was a diminution (P<0.05) in these habitat attributes in the 1990s compared to the 1960s. The conservation community has emphasized the potential benefits of the Con servation Reserve Program (CRP) for wildlife, while most of the grassland i n the Corn Belt has been established by annual set-aside programs. Although the most recent set-aside era ended in the late 1990s, programs of this na ture may reemerge. Our study underscores the need and opportunity for impro ving habitat conditions as part of future farm programs that would divert l and from production under short-term contract.