Native grasslands have been termed the United States’ most imperiled ecosystem, with losses ranging from 70–99 % since the turn of the 20th century (Johnson 2000). A major driver of these losses has been the proliferation of intensive agriculture with >70% of all remaining U.S. grasslands dedicated to agriculture and other human land uses, such as haying and rangeland (Perlut et al. 2008a). Furthermore, irrigated and pasture lands worldwide are expected to double in area by 2050, with a net loss of ~1 billion ha of wildlands (Perrings et al. 2006). A large proportion of this loss can be expected to come from productive natural grassland habitat.
Declines in grasslands have a direct impact on ecosystem services such as soil conservation, flood mitigation, and wildlife habitat (Sala and Paruelo 1997). These losses of habitat have been accompanied by devastating declines in the wildlife species that depend on them, particularly birds. No other avian guild has as many declining populations as do grassland birds (Peterjohn and Sauer 1999). This is troubling due to the variety of ecological services provided by birds, such as seed dispersal, controlling populations of invertebrates through predation, and serving as prey for higher trophic species (Sekercioglu 2006), as well as cultural, recreational, and aesthetic values.
What do we do to mitigate and possibly reverse some of the effects of grassland habitat loss and the accompanying loss of wildlife, such as birds? In an attempt to ameliorate the continued decline of grassland bird populations, a number of federal and state agencies have developed programs (agri-environment schemes) to encourage farmers to conserve and restore their grassland habitat. These agri-environmental schemes (AES), have been developed in North America and in Europe, and have been shown to have positive effects for birds on both continents (Herkert 2009, Gillings et al. 2010). AES programs seek to increase the value of farmland for native species while maintaining the profitability of the land for the landowners. This goal is accomplished by pay-for-services initiatives that seek to provide financial and technical assistance to the farmers by direct payments or indirectly with subsidies used to purchase supplies or other expenses (USDA 2012).
One important form of an AES is the use of perennial grasses in restored grasslands as a feedstock, or source, for cellulosic biofuel. The energy landscape (the portfolio of various ways fuel is produced) is changing rapidly and restored grasslands can provide a unique opportunity if they also can be utilized as a source of feedstock for next-generation cellulosic biofuels. Moreover, the use of restored grassland habitat to provide fuel should be seen as an integral part of mitigating global climate change (Tilman et al. 2009). Recent reports indicate that the potential for mitigating increasing atmospheric carbon dioxide through the use of terrestrial biological sequestration is substantial in restored grasslands soils (Gelfand et al. 2011, Post et al. 2012). This possibility is heavily predicated upon the type of land used for biofuel production. Perennial grasslands utilized for biofuel production have the advantage of being able to be grown on degraded/abandoned agricultural land or other marginal lands (Tilman et al. 2009). This presents opportunities for both restoration scientists and those involved in biofuel production.
There are a number of factors that go into making an AES arrangement a successful habitat for birds. Because grassland birds are attracted to a range of microhabitat conditions, restored areas that have greater structural complexity are better suited for supporting diverse avian communities (Robertson et al. 2011). A more complex and diverse habitat will ensure greater food supplies for birds, which has been shown to be an important determinant of grassland bird distribution (Zanette et al. 2000). Patch size is also important for many grassland birds. The requirements can vary by species, so when setting wildlife restoration goals it is important to be realistic in terms of the species expected within the restored areas, based upon patch size alone (Winter et al. 2006). Finally, the structure and composition of the surrounding landscape will play a critical role in whether or not grassland birds will settle in restored grasslands...