Diversity patterns and seasonal variation of the waterbird community in Mediterranean wetlands of Northeastern Algeria
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Date
2016-03-23
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Zoology and Ecology
Abstract
During two annual cycles (from September 2012 to August 2014), we analysed structural
patterns (provided and compared data on diversity metrics) of bird assemblages in coastal
wetlands of Northeastern Algeria. Annual and seasonal differences in relative species abundance
were analysed from the viewpoint of diversity/dominance. Bird assemblages vary only in the
number of species (35 recorded species during the wintering season against 23 during the
breeding season). Values of the relative abundance in both seasons were similar, curves in the
diversity/dominance diagram were analogous (not significantly different; both p > 0.05). Indeed,
the seasonal structure of waterbird communities indicates highly dominated assemblages
manifesting themselves in reduced species diversity and increased dominance of certain species.
Simpson’s index was never recorded below 0.50, thus indicating evidently lower evenness. The
Eurasian Coot Fulica atra and the Little Grebe Tachybaptus ruficollis were highly dominant species
together accounting for more than 50% of waterbird communities. This atypical organisation
(highly dominated structure) is mainly due to anthropogenic or natural stresses. The marked
decline in bird species diversity recorded during the study period (approximately two years
long) may be of concern to wetland managers as causes and consequences of the increased
number of widespread species and factors behind the increasing species diversity are likely to
be felt in both seasons.