Correlation between abiotic variables and diversity of birds

The present study was conducted at Saco da Fazenda Estuary, state of Santa Catarina, Brazil. The relationship between the abiotic variables and the diversity of birds at that site was evaluated over a period of ten months (July 2006 – April 2007). The diversity and equitability indices showed similar fluctuations over the study period, with significant differences between sampling months (F11-132 =17,061, p<0.001) and (F11-132= 7,789, p< 0.001). These values were affected by the lower average scores between October and December, in contrast with the higher ones recorded in August, September and July, probably influenced by the dominance of P. brasilianus and L. dominicanus. The diversity and evenness indices presented similar oscillations over the study months, with significant differences between the sampling months (F11-132=17,061; p<0.001) and (F11-132=7,789; p<0.001) respectively. The Spearman’s correlation analysis revealed a significant negative correlation (r = - 0.317, n= 135, p<0.05) between diversity of the aquatic birds and air temperature, but no correlation with wind speed or intensity or height of the tides. In relation to winds, the highest numbers of individuals were recorded in the easterly and east-northeasterly directions and the smallest for the southeasterly winds.