Molecular Soil Biology
23
Where,
D
is Simpson evenness index;
S
is
invertebrate's group's number;
Pi
is average
abundance of per invertebrates groups.
3- Margalef richness
Where
R
is Margalef richness index;
S
is invertebrate's
group's number;
Ln
is natural logarithm;
N
is number
of populations.
3.5 Statistical analyses
The normality of the variables was checked by the
Kolmogorov - Smirnov test, while Levene’s test was
used to examine the equality of the variances.
Differences in macrofauna biodiversity and also soil
physico-chemical features among afforested stands
and depths were tested with two-way analysis
(ANOVA) using the General Linear Model (GLM)
procedure, with stands (Alder, Maple, Poplar, Cypress
and Natural forest) and depths (0~10 cm and 10~20
cm) as independent factors. Interactions between
independent factors were also tested. Duncan’s test
was used to separate the averages of the dependent
variables which were significantly affected by
treatment. Significant differences among treatment
averages for different parameters were tested at P ≤
0.05. SPSS v.16 software was used for all statistical
analysis. In addition, for evaluate the factors affecting
macrofauna biodiversity indices over the whole range
of stand and soil physico-chemical features, the data
for all stands were analyzed using Principal
Component Analysis (PCA) to find the most effective
factors on macrofauna distributed in areas.
4 Conclusions
The study showed that, the strong faunal effects on
decomposition argue for greater consideration of the
role of decomposer organisms in subtropical
ecosystems. If feedback between detritus food-webs
and ecosystem processes occur, this may affect
subtropical soil fertility. Therefore, it can be pointed
out that soil habitants play a significant role in
reviving and rebuilding destructed forests and
accelerating and reinforcing growth in natural forests.
This interacts with the genus type and, hence, species
must be planted and reinforced in forest habitats
which positively affect biomass and activity of soil
habitants and improve habitat conditions and
productivity. The present paper emphasizes the point
that forestation using native broad-leaf species
consistent with region's ecological conditions can act
as a proper method to revive and rebuild destructed
forests. Moreover, using various species for
forestation has different effects on abundance and
biomass of earthworm and hence species must be
selected carefully in order to improve soil conditions.
Considering an increase in productivity and soil
macrofauna, Acer and Alnus are among favorable
species to be used in forestation in this region.
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NL
S R
n
1
Molecular Sil Biology