THE CLIMATIC CONTROL OF THE ALTITUDINAL DISTRIBUTION OF SEDUM ROSE A (L.) SCOP. AND S. TELEPHIUM L.

Abstract

SUMMARYWhen plants of Sedum rosea (L.) Scop, and S. telephium L. ssp. fabaria Syme are grown in competition at different altitudes it is found that the growth of the species is affected differentially. This effect is such that at low altitudes S. telephium is a larger plant than S. rosea, while the reverse is the case at high altitudes. The observed differences are caused by a marked sensitivity of the growth of S. telephium to differences in altitude, while S. rosea is very insensitive.The most probable cause of these responses would appear to be differences of climate. The influence of altitude in northern England on air temperature, saturation deficit and irradiance has been investigated in order to establish the magnitude of the differences which may cause these responses.

Predicting plant responses to global environmental change

“…9). Shortterm (less than one season) experiments (Woodward, 1975;Woodward & Pigott, 1975) clearly predicted that 5. rosea should be excluded from the low altitude site, while 5. telephium was expected to be excluded at the high altitude site. The prediction for S. rosea proved to be correct, although final competitive exclusion of this perennial species took 5 yr. After 15 yr S. telephium is still present at the high altitude, although its survival has been declining continuously through all of this time.…”

“…In a series of experiments on two closely related species of Sedum with contrasting geographical distributions. Woodward (1975Woodward ( , 1988 and Woodward & Pigott (1975) demonstrated that comparing the growth of individual plants of the two species over a wide range of temperatures was an effective approach for predicting the areal and height dominance of the species in competition (Fig. 8).…”

Alpines, trees, and refugia in Europe

“…Dryas octopetala, Sedum rosea), may have remained locally frequent over a broad altitudinal range in naturally open habitats (cryptic refugia) ( Figure 5). These species (see also Table 4) may thus be sensitive to competition from taller, faster-growing lowland species rather than to the direct physiological effects of summer warmth (Woodward and Pigott 1975;Pigott 1978). Between these extremes of varying direct sensitivities to warmth and varying sensitivities to competition, there will be all degrees of 'relictness' of alpines and hence their occurrence in open cryptic refugia within the potential forest zone.…”

“…When the growth of these more robust growth forms is depressed by severe wind exposure, many alpines descend to lower altitudes (McVean and Ratcliffe 1962) (see Table 4). Thus the lower limits of many alpines may be determined directly or indirectly by summer warmth and its close correlates, the most important of which may be competition from more vigorous, larger, and more competitive lowland species (Woodward 1975;Woodward and Pigott 1975;Pigott 1978).…”

The Past and Present Vegetation of the Caenlochan National Nature Reserve, Scotland Ii. Palaeoecological Investigations

“…F"urthermore, in order to carry out such controlled-environment work a further factor, that of inter-specific competition, is inevitably altered, and this may be of considerable importance in controlhng the effective range of a species [see, for example. Woodward and Pigott (1975) and Woodward (1975), on a comparison of two species of Sedurri\. One possible approach to the testing of this hypothesis is that of transplant experiments.…”