Limnological factors influencing bird abundance and species richness on florida lakes

Abstract

Forty-six bird species were observed on 33 Florida lakes with some species occurring on only one lake and others on as many as 26 lakes. Average annual bird abundance ranged from seven to 750 bird/km2and total species richness ranged from two to 30 species per lake. Regression analyses were used to examine the effects of lake trophic status, aquatic macrophyte abundance, and lake morphology on average annual bird abundance and total species richness. All trophic state parameters (total phosphorus, total chlorophyll a, etc.) accounted for significant portions of the variance in average annual bird abundance, but total chlorophyll a concentrations (μg/L) accounted for the highest percentage (47 percent) of the variance. The best fit regression equation was: Log Bird Abundance = 1.35 + 0.56 Log Total Chlorophyll a. Lake area, shoreline length, and all trophic state parameters accounted for significant portions of the variance in total species richness. Multiple regression analyses indicated that lake area (km2) and total chlorophyll a (μg/L accounted for the highest percentage (87 percent) of the variance in total species richness (species/lake). The best-fit multiple regression equation was: Log Species Richness = 1.10 + 0.47 Log Lake Area + 0.17 Log Total Chlorophyll a. After accounting for lake trophic status and lake area, neither aquatic macrophyte abundance nor lake morphology accounted for additional variances in average annual bird abundance or total species richness. © 1990 Taylor and Francis Group, LLC.