ORIGINAL PAPER
Effects of microtopography on the spatial pattern of woody species
in West Iran
Zahra Azizi
1
&
Zahra Montazeri
2
Received: 10 August 2017 / Accepted: 1 May 2018 /Published online: 24 May 2018
#
Saudi Society for Geosciences 2018
Abstract
Habitat heterogeneity is a main factor determining the geographical distribution of species. For plant and particularly trees and
shrubs, topography (microtopography) is an applicable predictor of habitat, slope, and aspect that often correlate with distribution
of water and nutrients availability and spatial pattern of species. However, there is lack on exploring this relationship in different
plant communities through different environments. In this research, the spatial pattern of woody species in relation to
microtopography was investigated in Chahartagh forest, Chahar Mahal, and Bakhtiari province, Iran. The location of the trees
and shrubs of a 53-ha forest reserve in Chartagh was measured and the type of microtopography including (i) slope A without
microtopography and (ii) slope B composed of three microtopography types: crest (degree of tilt is≥60%), intermediate area (30–
40%), and gully (10–20%) were recorded. The effects of microtopography on the spatial pattern of species were analyzed using
O-ring statistic. The results showed that the main distribution pattern for the woodiest species in the study area in all platforms is
aggregated pattern, while for larger scales, the pattern tended to become random. Also, the pattern was strongly influenced by the
scale that the distribution type was assessed. From the other hand, our results revealed that for steeper platforms, the patterns tend
to be more aggregated which indicates the non-uniformity of water and nutrition distribution in steeper platforms. Also, this can
be a result of seed distribution behavior which is affected by microtopography in a way that in steep platforms, rolling of the seed
results in patchy accumulation of the seeds and finally patchy regeneration.
Keywords Habitat
.
Geographical distribution
.
Platform
Background
Reconnaissance of spatial pattern is an essential key in com-
prehension the ecological processes that structuring the distri-
bution of trees in forest. The obvious and purpose description
of spatial distribution is a consequential part of producing
hypotheses about environmental processes. The spatial pattern
is the geographically arrangement of individual plants in a
plant community. This concept is one of the basic quantitative
characteristics of plant ecology. There is a range of factors that
cause spatial pattern, and these can be classified into three
broad categories: (i) morphological factors, (ii) environmental
factors, and (iii) phytosociological factors (Kershaw 1964;
Dale 1999). Morphological factors are the most important
factors because tree cover is a result of interplay between
growth and microtopography (Dale 1999).
The grade to which dispersion restriction against habitat
specialty drives plants’ spatial patterns along physiography
gradients is currently an active topic of scientific investigation
(Ganbari 2008). At small scales (population level), the pat-
terns are not clear, due to the difficulty in distinguishing be-
tween the effects of environmental factors and the dispersal
limitation (Duivenvoorden and Svenning 2002; Gilbert and
Lechowicz 2004). Species distributes along the resource gra-
dients (i.e. temperature, soil chemistry, moisture) according to
their requirements (Pulliam 2000).
Generally, the spatial pattern can be classified into three
categories: random pattern, aggregate or clustering pattern,
and uniform pattern. Analysis of the spatial patterns of tree
species is important in gaining a better understanding of the
* Zahra Azizi
zazizi@srbiau.ac.ir
1
Department of Remote Sensing and GIS, Faculty of Natural
Resources and Environment, Islamic Azad University, Science and
Research Branch, Tehran, Iran
2
Forest Science Department, Faculty of Natural Resources and Earth
Sciences, Shahrekord University, Shahrekord, Iran
Arabian Journal of Geosciences (2018) 11: 244
https://doi.org/10.1007/s12517-018-3588-1
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