Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 63. (Budapest 1971)
Fekete, G. ; Szujkó-Lacza, J.: A survey of the plant life-form systems and the respective research approaches III. Rankiaer's life-form conception. The application of life-forms in the characterization of phytoclimate and in vegetation analysis
nean organs during the vegetational period. The population of the species having the former life-form characteristic will, owing to its heredity and the now unfavourable season, retreat, become hypogeous, cease to function. There occurs an also physiognomically discernible aspect, and at the same time, a structural change. In such a case, aspect change can be characterized also by such a specific character as the life-form (principally the Cryptophyton and Therophyton life-forms). In a case, however, when, in the identical layer, the populations of two species of a Hemicryptophyton life-form become physiognomically characteristic (or indeed characterless owing to the more conspicuous phenophasis of the other species) due to a different developmental cycle, then the presence —-absence ISC —in the favourable season above or below, respectively, of the soil surface —must be nearly identical and strongly positive. The adequate application of the ISC affords the possibility of objectively judging the aspect change of the given population (and also the other way round : the existence and acknowledgement of aspect changes are important for the coenologist examining the joint distribution of the species !).— At the same time, the phenophases cannot be regarded (contrarily to RÜBEL'S and others' interpretation) as aspect changes. The problem of aspects have also other quantitative coenological sides. For instance, the life-form homogeneity of the same association living in different areas cannot be demonstrated if the coenological survey is conducted at different times, owing to the very aspect change (SZUJKÓ-LACZA, 1968). c. Life-form frequency or life-form mass? To express the life-form mass values, the Central European sociological school calculates (on TÜXEN and ELLENBERG'S advice, 1937) life-form group mass ("Gruppenmenge") values, based on the mass values (abundance —dominance values) of the coenological tables. But CAIN and CASTRO (1959, founded on their own and KILBURN'S, 1957, material) apply cover —cover-classes of identical extension contrarily to the usage of the Central European school —for the weighing of the several life-forms. According to TÍÍXEN and ELLENBERG (I.e.), the life-form spectrum, calculated on the basis of the life-form group-mass, reflects best community-physiognomy (better than the group-participation — "Gruppenanteil" —calculated by frequency values = constancy). Our opinion on the two kinds of quantitative (descriptive statistical) approaches of the life-form distribution within the association is as follows : It is known that it was RAUNKIAER (1909—1910) who used the life-forms also for the analysis of formations. (He characterizes a given formation or facies by the valency-method, establishing the presence and thereby the valency of the given life-forms, and finally the biological spectrum of the formation, on small, mainly 0.1 m 2 sample plots. He used no estimated cover values.) —The life-form groups ("Gruppenanteil"), weighed on the basis of frequency ("constancy"), and the spectra founded on these, of the Central European sociological school stand the nearest to RAUNKIAER'S biological spectra. The dimensions of the investigated areas are, however, essentially different in the two cases, partly owing to the community conceptions partly following from the RAUNKIAER formation approach; also, the influence of dimensions and the number of surveys on the frequency of the dominant species are well known. In spite of these difficulties, we hold lifeform frequency the more generally usable one for coenological purposes, by the following considerations :
