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International Journal of Marine Science 2014, Vol.4, No.54, 1-10
http://ijms.biopublisher.ca
8
3 Discussion
Wetlands provide ecological functions such as
protective nursery habitat for fish and shellfish,
erosion prevention, flood protection, and water
filtration[13, 31]. They also provide vital feeding,
resting, and breeding habitat for resident and
migrating birds[31]
.
Marsh birds and colonial
waterbirds face threats to the habitats and sites on
which they depend. Conservation of marsh birds and
colonial waterbirds is a local matter. Nesting and
roosting marsh birds and colonial waterbirds are
particularly affected by local conditions. Diversity and
number of waterbirds indicate environmental pollution
[13]. Inland wetlands are essential parts of wetland
systems and provide breeding and foraging habitat for
many marsh birds in Iran. The Miangaran wetland is
one of the important marsh in the southwestern
foothills of the Zagros Mountains, and south part of
the marsh directly received domestic, industrial and
agricultural wastewater from
Izeh city. The border
between more polluted and north part (low-polluted)
is not very clear, but the water color in more polluted
part is darker than low-polluted (Figure 1).
Water
pollution was identified as the main threats at polluted
part, because the wastewater of Izeh runoff to south
part of marsh. The Miangaran wetland is the most
important habitat for waterbirds in south of Iran [7,
28]. The distribution and population of waterbirds in
Miangaran wetland, especially in its shores and
around has become better understood in recent years
(7, 27, 28]. More information has been gathered
through waterbirds count. Over 86 bird species occur
in Miangaran wetland in winter (7, 28], of these, about
90% are waterbirds, of these 30% are present in
summer (Table 1). Along the south part coast survey
on July 2011, most of the waterbirds habitat were
polluted (Table 1), and therefore unavailable as
feeding grounds (Killing of invertebrate and aquatic
vertabrate food supplies). Census data counted less
than half of the expected number of waterbirds at
south part (Table 1). Many species of marsh birds
spend the winter feeding on benthic invertebrates on
wetlands coasts. Many species of gulls are highly
opportunistic feeders, and exploit a wide range of
habitats as well as taking many kinds of food [17]. In
tow part of Miangharan wetland waterbird numbers
correlated over month with salinity, EC, COD, BOD,
NO3, SO4.(Table 6). The marsh bird's community
influenced by water quality because, the Average of
Shannon-Weaver Index of diversity was greater (H'
=2.20 in north part and 1.16 in south part)
Shannon-Weaver Index values in north part revealed
that this part had the greater diversity in terms of
both species richness and evenness. Average
Simpson’s Index of dominance revealed that south
part of marsh was greater dominance (C =0.49 in
south and 0.14 in south) Simpson’s dominance varies
inversely with diversity which is in consonance to
the present observations. Marglef’s richness Index
was greater and varied between 1.23-1.72 with
average 1.85 in south and 1.90-1.97 with average
1.94 in north. Evenness in bird communities was
greater (E = 0.58) in north and (E = 0.32) in south
(Figure 4 and Table 4).
Table 6 Correlation between bird communities and water chemistry parameters in Izeh marsh in 2011
PH
DO
Sal.
T
EC
Tur.
BOD
COD
SO4
NO3
Birds Pearson Correlation 0.37
-
332
-
877*
0.352
-
0.848*
-
0.381
-
0.915**
-
0.795*
-
0.968**
-
0.298
Sig. (2-tailed)
0.473
0.260
0.011
0.247
0.016
0.228
0.005
0.29
0.001
0.283
Note: ** correlation is significant at the 0.01 level (2-taild) * correlation is significant at the 0.05 level (2-taild)
Number, species diversity, evenness and richness in
north part of marsh was more than south part,
inversely the physicochemical parameters in south
were more than north part, except dissolved oxygen
(Table 5). Correlation coefficients between different
diversity indices revealed significant negative
correlation between Dominance-D , Shannon-H,
Evenness and Margalef’s with PH, DO, T, BOD, COD
(r =- 0.955, p<0.05), In south and north part. T- test
recorded that species richness was dependent on the
amount of pollution ( 15 in north >10 in south p<0.05).
Many studies have been documented how habitat
components and human activities in and around the
wetland habitat have influenced waterbirds [4, 5, 25,
30, 32]. However, threats to wetlands are growing
rapidly in Khuzestan. The main factor is habitat
alteration, which is fuelled by a very high rate of
human population growth and unwise development