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
e. Life-form spectrum, ecological spectrum Central European phytocoenology avers (especially after TÜXEN and ELLENBERG'S work, 1937) that the groups of species belonging to the several lifeforms in the association are not only indicators of the environment but, by their amount and mass, also its measuring instrument. Hungarian coenological literature contends the same. For istance, according to Soó (who, incidentally, applies the "bio-ecological" spectre already in 1927), "the per cent distribution of the lifeform in the composition of a given association is the ecological spectrum, invariably characteristic of the ecology of the association" (Soó, 1945). Or, as HORÁNSZKY (1963) writes: "the life-forms are the indicators of the ecological conditions of the association, and the complex effects of the ecological factors of the habitat is reflected by the ecological spectrum". It was the hydrobiologist THIENEMANN (1939) whose basic tenets influenced Hungarian authors —and presumably also the leading exponents of Central European phytocoenology. Concerning the life-forms of the phytocoenosis, these principles are as follows: 1. The more diverse the conditions of a habitat are, the more life-forms appear in it [BRAUN —BLANQUET (1951): "Der Vielfältigkeit der Lebensbedingungen innerhalb einer Pflanzengesellschaft entspricht auch die Mannigfaltigkeit der Lebensformen"]; 2. The more the life-conditions deviate from the normal and the optimum for most organisms, the poorer and more one-sided in life-forms the biocoenosis becomes (BRAUN —BLANQUET, I.e.: "Extremen Aussenbedingungen unterliegende Pflanzengesellschaften bestehen oft nur aus einer einzigen Lebensform.") In the Hungarian literature, FELFÖLDY ascribes a definite role as ecological indicator to the life-forms. He studied half-culture and weed associations (1942, 1943) and established that their life-form composition expresses so profoundly the rate of external intervention (manuring, treading, grazing, hoeing, etc.) that the associations can be aligned into a degradation sequence directly by the life-form spectrum (FELFÖLDY'S term is "ecological spectrum"). This author studied especially the degradation-indicator role of the Therophytes, and states (1951) that "the Therophyton life-form is a defense not so much against the winter cold but the cruel, irregular destruction". The struggle for life and the dynamism of the species depend, according to FELFÖLDY, principally on their life-form; this dynamism becomes displaced by anthopogeneous-zoogeneous effects so that the annuals will finally have an advantage and preponderance over the perennials, because the above effects decrease the competition of the very perennials (cf. also UBRIZSY, 1954). It cannot be questioned that the observations serving as the basis for these statements are correct. What should be censored is the following: Species of various life-forms possess, parallel with them, also diverse biological characteristics by which they also differ from one another. Thus, for instance, the majority of perennials (Ph, N, Ch, H life-forms) are able to form associations and to spread vegetatively, having evolved organs (stolos, runners, etc.) for this purpose. On the other hand, the Therophytes had, together with their most intensive climatic adaptation, reduced also some of their biological characteristics (among these: the length of their life-cycle, the vegetative spreading), hence a number of their requirements towards the environment (e.g. the essential demand for space) had also simplified. Owing to such biological traits, associated (but not identical!) with life-forms, the species with a Ph, N, Ch, H life-form are more sensitive against
