A comparison of fynbos and non-fynbos coenoclines in the lower Gamtoos River Valley, southeastern Cape, South Africa

摘要: Patterns in the relative importance of structural attributes and growth forms along fynbos non-fynbos coenoclines were studied to test hypothesis that there would be less variation former because overriding influence low levels soil nutrients manifest a great deal convergence fynbos. The ranged identical environmental gradients increasing altitude, rainfall moisture decreasing climatic variability. Results showed entire coenocline vegetation was structurally small-leaved sclerophyllous shrubland with graminoid understorey and, usually, large-leaved (proteoid) shrub overstorey. Fynbos structure interpreted largely as response nutrients. Non-fynbos from mixed succulent-sclerophyllous spiny thicket at lower altitudes tall mesic forest upper end gradient. explained terms variations climate. An analysis biogeographical affinities sample floras sites dominated by taxa endemic Cape phytochorion, although phytochorological mixing pronounced altitude sites. level local endemism relatively high; nearly all endemics their incidence increased altitude. These data indicate has had lengthy history southeastern high have comprised refuge for during unfavourable periods. dry subtropical Tongaland-Pondoland strong Karoo-Namib component temperate Afromontane forest. Levels than decreased number karroid found both suggests been more widespread past, probably last glacial which considerably drier present Holocene interglacial.