. Actes du Colloque sur la gestion des forêts et des Habitats pour la gamme Gibier, du 6 au 9 mai 1975, Tucson, Arizona. La conservation des oiseaux Les oiseaux ; Congrès Congrès de l'habitat ; la gestion des parcours d'amélioration de l'habitat de la faune ; congrès congrès. La pruche-sapin Pruche de l'écotone (101 W LSp ESp ESu LSu SAISON F -1 r 11 r -r- W LSp ESp ESu LSu F Figure 6.-Les changements saisonniers de la densité et de la biomasse et de la composition écologique de quatre étapes de la forêt de conifères succès- ion dans l'ouest de l'Oregon : 3  = chêne vert écotone, 7  =  = 9, douglas fir-pruche de l'écotone, 10  = "climax" de la pruche.

• Contributeur: Book Worm / Alamy Banque D'Images
• ID de l’image: RFPPR3
• Taille du fichier: 7,2 MB (254,8 KB Téléchargement compressé)
• Autorisations: Modèle - non | Propriété - non
• Dimensions: 1784 x 1401 px | 30,2 x 23,7 cm | 11,9 x 9,3 inches | 150dpi

Informations supplémentaires

Cette image appartient au domaine public, ce qui signifie que le droit d’auteur a expiré ou que le titulaire du droit d’auteur a renoncé à ses droits. Les frais facturés par Alamy couvrent l’accès à la copie haute résolution de l’image.

Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.

. Proceedings of the Symposium on Management of Forest and Range Habitats for Nongame Birds, May 6-9, 1975, Tucson, Arizona. Birds Conservation Congresses; Birds Habitat Congresses; Range management Congresses; Wildlife habitat improvement Congresses. FIR-HEMLOCK ECOTONE HEMLOCK (101 W ESp LSp ESu LSu F SEASON -1 r 1 1 r -r- W ESp LSp ESu LSu F Figure 6.—Seasonal changes in avian density and biomass and in the ecological composition of four stages of coniferous forest success- ion in western Oregon: 3 = oak-fir ecotone, 7 = douglas fir, 9 = fir-hemlock ecotone, 10 = hemlock "climax". Seasons: W = winter (2 November - 1 March), ESp = early spring (2 March - 15 April), LSp = late spring (16 April - 1 June), ESu = early summer (2 June - 15 July), LSu = late summer (16 July 1 September). F = fall (2 September - 1 November). Ecological categories: F = foliage-feeding, G = ground-foraging, T = timber-foraging, A = air-feeding. From Anderson (1970). and then more than doubled by the late spring censuses. Peak densities were recorded in all stands at this time, no doubt because of the inclusion of a great many migrant individuals in the censuses. Densities decreased from this late spring peak to the breeding density levels characteristic of early summer, which were higher in all stands than the wintering densi- ties. There was a gradual decline in density from these breeding levels to the wintering levels. Trends in total standing crop biomass were similar, although the magnitude of fluctua- tion was greater. Total biomass was greatest during the late spring migratory period but in at least some stands wintering biomass was nearly as great as that recorded during the breeding season. The degree of dominance of the single most abundant- species was generally greatest in fall and winter and least during the late spring period. Anderson's data also permit evaluation of seasonal changes in the ecological structuring of these forest bird communities (figure 6). Here

Recherche dans la banque de photos par tags

• bookcentury1900
• bookpublis