Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 53. (Budapest 1961)
Pócs, T.: The calculation of the quantitative grade of efficacy of collecting and extracting methods of materials used in zoocoenology
Summary The grade of efficacy of a collecting or selecting method can be calculated if the method can be repeated on the same material and in identical conditions. The amount received on the second occasion must be divided by the first, thus gaining quotient „^4". The unknown efficacy-grade constant (x) of the method, by the use of this experimentally gainable value A, is : x = 1 — A. The range of application of this calculation includes for example, collecting by singling, manual selecting, the computing of the quantitative grade of efficacy of netting. In cases where the collecting or selecting of the material cannot be repeated in identical conditions and by the same methods (e. g. floating, salting, desiccating), the material or the habitat under investigation must be divided into two arbitrary but possibly similarly composed parts, then two different methods will be used, but in a reverse order, on the two samples. For instance, one of the samples will first be floated then the residue selected ; while the other will first be selected and then floated. The number of individuals gained by the method applied as the second must be divided by the number of specimens received during the first treatment, thereby receiving, in the first sample, quotient „B", and in the second, quotient „C". Applying these experimentally gained and known values, the grade of efficacv (x and y) of the two methods can be calculated : However, this process cannot be used in cases if, in the course of the two subsequent investigations of the samples, the size of the sample cannot be fixed, or if the two methods do not refer to the same group of animals (e. g. light-trap and bait). The value of the grade of efficacy received by these calculations is suitable for the comparison of the different quantitative collecting and extracting methods as also for the selection of the most serviceable one (e. g. by a manual selecting of a sifted humos sample containing mollusks, 41% of the individuals can be extracted, while, by the fatty alcohol sulphonate process, the percentage is 77). Further, coenological investigations can be made exacter if the respective efficacy-grade constant be established for the animal group, habitat, and method in question, and then applied by multipliyng by its reciprocal value the number of individuals received, or if the grade of efficacy be at least theoretically taken into consideration. Our results will thus come nearer to reality. References : 1. Balogh, J.: A zoocönológia alapjai — Grundzüge der Zoozönologie (Budapest, 1953, pp. 248). — 2. Vágvölgyi, J. : A new sorting method for snails, applicable also for quantitative researches (Ann. Hist.-nat. Mus. Nat. Hung., S. n. 3, 1952, p. 101 — 104). РАСЧЕТ КОЛИЧЕСТВЕННОЙ ЭФФЕКТИВНОСТИ ПРИМЕНЯЕМЫХ В 300ЦЕН0Л0ГИ МЕТОДОВ СОБИРАНИЯ И ОТБОРА МАТЕРИАЛА Т. П о ч, Будапешт Расчет эффективности метода собирания или же отбора материала можно провести, если метод повторяется на одном и том же материале при одинаковых условиях. Полученное при втором сборе количество следует делить на количество первого сбора, причем получается коэффициент «А». Неизвестное постоянное эффективности (х) будет при использовании этого экспериментально получаемого
