| Titre : | Structure and composition of grassland habitats used by wintering Smith's Longspurs: the importance of native grasses |
| Auteurs : | William C. Holimon, Auteur ; Jennifer A. Akin, Auteur ; William H. Baltosser, Auteur ; Catherine W. Rideout, Auteur ; C. Theo Witsell, Auteur |
| Type de document : | Article |
| Dans : | Journal of Field Ornithology (83(4) DEC 2012) |
| Article en page(s) : | 351-361 |
| Langues: | Anglais |
| Résumé : | Smith's Longspurs (Calcarius pictus) are a species of concern in North America because of their limited range and apparent low population size. To better understand winter habitat needs and guide management of this species, we examined habitat associations of Smith's Longspurs in eastern Arkansas by comparing grassland patches where Smith's Longspurs flushed to randomly located patches in the same area. Smith's Longspurs were found in sparse grassland patches of relatively low height adjacent to airport runways where the native grass prairie three-awn (Aristida oligantha) dominated ground cover and vertical structure. Smith's Longspurs were not found in vegetation plots dominated by non-native Bermuda grass (Cynodon dactylon). Prairie three-awn grass may provide concealment from predators and their seeds may be an important food source. Occurrence of Smith's Longspurs was also correlated with less litter, perhaps because deeper litter could make walking and searching for seeds more difficult. Availability of suitable habitat for Smith's Longspurs along airport runways may be declining due to natural succession of grassland habitat in the absence of disturbance and recent changes in management that favor Bermuda grass. Conversion and degradation of native prairie has resulted in the decline in abundance and distribution of Chestnut-collared Longspurs (C. ornatus) and McCown's Longspurs (Rhynchophanes mccownii). Our findings suggest that conversion of native grasslands to non-native grasslands results in loss and degradation of habitat for wintering populations of Smith's Longspurs. |



