At least two approaches are possible to produce cellulosic bioenergy without having detri­mental impacts on wildlife: produce bioenergy crops from lands already in crop production and use land use practices that are compatible with wildlife to produce them [74]. In the case of cellulosic biofuel crops there are limited studies showing that perennial grasses such as switchgrass and M. x giganteus can have some benefits for bird species. In a modeling study, Murray et al. [75] projected that bird species which were management priorities in Iowa would be increased by converting row crops to switchgrass but that other, more com­mon birds that depended on annual crop fields would be diminished in population. Similarly, in a field study of M. x giganteus and row crop fields in the United Kingdom., Bellamy et al. [76] showed that recently planted M. x giganteus fields had higher populations of breeding birds but speculated that these advantages would be lost as the M. x giganteus matured and, especially, as weed populations decreased. Tilman et al. [77] postulated that low input, high diversity grasslands for biomass production would be beneficial because higher diversity would be favorable for insects and wildlife. Furthermore, compared to annual crops, limited use of pesticides on perennial bioenergy crops will also benefit wildlife.

Unlike most annual crops, there will be possibilities for multiple harvests and variable timing of harvest for many of the perennial cellulosic bioenergy crops. Wildlife benefits from bioenergy grasses will only be achieved if harvests are scheduled to avoid local nesting or rearing seasons. Biomass cropping systems that include multiple harvests during the summer months will provide little benefit to wildlife [78]. Standards for harvesting of Conservation Reserve Program (CRP) perennial grasses to benefit wildlife may be applicable to bioenergy grasses in the parts of the country where there is substantial land in CRP grasses. Stubble heights are critical to wildlife when harvesting herbaceous vegetation and leaving higher stubble can result in much better nesting success for grassland nesting ducks and other waterfowl. Higher stubble can also trap more snow, shade the soil, and decrease evaporation [78]. Of course stubble left in fields is unharvested biomass and experiments are needed to determine how much biomass is needed for wildlife and what the economic cost is. Recommended harvest heights for perennial bioenergy grasses should be examined based on wildlife needs as well as biomass harvest goals. The best harvest scenario on a landscape scale is one that provides a mosaic of harvested and unharvested fields, but this has to be economically feasible [74].

Wildlife effects of land conversion to SRWC will depend on the type of land converted and the landscape in which the conversion takes place [79]. In general, conversion of annual cropland to SRWC will increase biodiversity but conversion of mature grasslands or forest to SRWC will likely result in a decrease in wildlife biodiversity [80,81]. Compared to corn, or other row-crops, conversion to either SRWC (poplar or pine) or conversion to perennial grasses has a positive effect on bird biodiversity. Management practices that increase landscape heterogeneity, reduce chemical input, and delay biomass harvesting until after bird (or mammal) breeding will help increase biodiversity [80].