||Grassland bird populations have declined more than any other group of birds over the last 37 years, based on breeding bird survey (BBS) data. In Tennessee, significant effort is underway to restore native grasslands through partnerships between Tennessee Wildlife Resources Agency, US Department of Agriculture Natural Resource Conservation Service and private landowners. This partnership has put thousands of hectares of native grasslands back on the Tennessee landscape. It is unknown however whether there has been a positive response by grassland birds to this restored habitat. Furthermore, the restoration has proceeded on an opportunistic basis, with emphasis placed on willing landowners, rather than conducting the restoration where wildlife benefits might be maximized.
Forty-five and forty-three restored native warm season grass (NWSG) fields were evaluated in 2002 and 2003, respectively. Three native grassland fields at Fort Campbell Military Reservation (FCMR) where viable populations of grassland birds are reguarly found breeding were also evaluated for vegetative species composition and structure and avian use. Effects of management practices for each field (mowing and burning) were also evaluated.
Restored program and FCMR fields were predominately NWSG and forbs. Vegetative height in FCMR fields did not exceed 50 cm in either year while restored program fields exceeded 90 cm in both years. In restored program fields, bare ground cover was reduced from 16.7% in 2002 to 7.47% in 2003 (P<0.005). Burned fields had significantly less litter cover (x-bar = 7%) than fields being mowed (x-bar = 17.24%) or not being managed (x-bar = 13.7%) (P < 0.05). Litter depths were also greater in fields being mowed (x-bar =1.06 cm) and not being managed (x-bar = 0.45 cm) (P=0.0004). Forb cover was greater in burned fields (x-bar = 33.75%) than forb cover in fields being mowed (x-bar = 19.86%) or fields not being managed (x-bar = 22.95%) (P = 0.0006).
Eighty-eight species of birds were noted in and around restored NWSG fields in Tennessee. Field size was the best explanatory variable for observed species reichness of grassland species in restored NWSG fields in both years ( P < 0.005). Nearly all of the grassland species in this study were positively associated with larger (> 30 ha) field sizes. Many species showed a negative relationship with increased vegetative heights and increased cover by NWSG. Many species also showed a positive relatiobship to increased levels of bare ground in both years. Henslow’s sparrow showed a positive relationship with increased litter depths. Grasshopper sparrows, Henslow’s sparrows, eastern meadowlarks, dickcissels, and northern bobwhites were foind in fields where average vegetative height was < 52 cm. Northern bobwhites were found in restored fields where average litter depths were < 1 cm. Northern bobwhites were found in restored NWSG fields in all size classes; Grasshopper sparrows, henslow’s sparrows, eastern meadowlarks, and dickcissels occured more often in larger patches were available. Observed vegetative composition and structure were a result of management within the restored NWSG fields. Fields at FCMR are burned on a 1-3 year rotation, whereas 70% of the fields evaluated in this study were being managed by mowing or were not being managed. If the managing organizations in Tennessee do not coordinate their management efforts, then grassland management in Tennessee will probably never reach its full potential. Restored NWSG fields in Tennessee need to be managed using rotational (every three to four years) burning. In areas where burning is not an option, moderate discing could be used instead of mowing. With appropriate management, NWSG restoration in Tennesee could ultimately be more successful than previously though possible.