Mycorrhizal Plants’ Accelerated Revegetation on Coal Mine Overburden in the Dry Steppes of Kazakhstan - Environmental Sustainability: Role of Green Technologies - page 262

F i g . 3 a - c Changes in self-organized vegetation on plots I ( a ), II ( b ), and III ( c ) of the dump in proportion to species
of different mycotrophic status ( 1 non-mycorrhizal, 2 facultative mycorrhizal, 3 mycorrhizal)

portion of non-mycorrhizal plant species over
time is reduced but to the value of the Spearman
correlation coeffi cient is insignifi cant
( r SP = -0.23, P = 0.4657). Satisfactory approxi-
mation of dependence of the logistic curve
(Fig. 4a ; R 2 = 0.61; P = 0.0034) indicates the non-
linear nature of the process. Stabilization of the
share of non-mycorrhizal species occurs at
7-8 years of overgrowth (abscissa of lower criti-
cal point x lower = 7.5). A proportion of optional
mycorrhizal species along the succession is
reduced statistically signifi cant ( r SP = -0.76,
P = 0.0039) and is expressed nonlinearly (Fig. 4b ;
for the logistic curve R 2 = 0.61; P < 0.0001). In this
case the stabilization of the share of non-mycor-
rhizal species occurs at 4-5 years of overgrowth
( x lower = 4.2). The proportion of obligate mycor-
rhizal species increases during succession statis-

tically signifi cant ( r SP = +0.84, P = 0.0007) and is
expressed nonlinearly (Fig. 4b ; for the logistic
curve R 2 = 0.80; P < 0.0001). In this case, the
stabilization of the share of optional non-mycor-
rhizal species occurs at 3-4 years of overgrowth
(x upper = 3.5).

4 Discussion

The obtained data indicate that the increase in
proportion of mycorrhizal plant species observed
in natural endoecogenetic successions (Miller
1979 ; Gemma and Koske 1990 ; Ahulu et al.
2005 ; Püschel et al. 2007a , b ), is well reproduced
and statistically confi rmed in the course of suc-
cession in unfavorable man-made habitats. Our
observations of the development communities for