Dmitriy Vysotskyy Mar 10, 2013:

Г-н Васильев! А собственно в чем заключается Ваше затруднение? В переводе species turnover? Определения на русском имеются, в т. ч. приведенное ниже. Может быть, точнее будет написать не показатели (меры) бета-разнообразия, а их значения.

vasilev (asker) Mar 10, 2013:

расширяю контекст Wartenberg et al. (1987: p. 438) commented on the manner in which DCA has been adopted rather uncritically by plant ecologists, and they argued that there is 'no empirical justification for the method, since the DCA model is not consistent with the structure of the data... and ... there is no theoretical justification for the method, since DCA is, as Hill and Gauch (1980) point out, an ad hoc adjustment of CA/RA.' In relation to the 'arch effect', the position of points on the first axis is not changed, and all DCA does is to flatten the arch on the original plot. They continued '.. .This deception does not enhance our understanding of the data or help to identify the cause of the observed distortion' (p. 435). Concerning the end of axis compression problem, they also question the assumption that rates of species turnover are constant or even along gradients and axes and that all species can be treated equally. Also, Wartenberg et al. (1987) and Minchin (1987a) pointed out that the detrending and flattening of the arch may result in loss of ecological information if some of the arch form represents a real pattern in the original data.