The effect of sea shore displacement on population age structure of coastal Alnus glutinosa (L.) Gaertn.

Wolfgang Cramer (1)

1 Uppsala Universitet [Uppsala]

The age structure of A/nus glutinosa (L.) Gaertn. populations was studied in two areas on the coast of the Baltic Sea. One area, situated in Uppland, eastern central Sweden, at 60°07'N, has a relative land uplift of 5.3 mm yr '; the other area, situated in Blekinge, southeastern Sweden, at 56° 10'N, is nearly stable. The spatial distribu­tion of 200 A/nus individuals of various age classes at nine sites was analyzed in order to reconstruct establishment history. fn the land uplift area, the youngest individuals were found in the lowest parts of the sites. and age and elevation were significantly correlated. ln the area without land uplift, no such pattern was found. Regression analysis of the time/space pattern of establishment in the land uplift area showed that the zone where individuals establish follows the moving shore line with roughly con­stant speed. A/nus g/r1tinosa uses two different regenerative strategies: ( 1) continuous colonization of emerging land from seeds (with subsequent mortality of the older trees) in the land uplift area, and (2) regeneration from old stem bases, forming multistemmed trees, in the area without land uplift.

Domaines: Sciences de l'environnement

Wolfgang Cramer. The effect of sea shore displacement on population age structure of coastal Alnus glutinosa (L.) Gaertn.. Ecography, 1985, 8 (4), pp.265 - 272. ⟨10.1111/j.1600-0587.1985.tb01178.x⟩. ⟨hal-01758327⟩