Urban lakes and waterbirds: effects of shoreline development on avian distribution

Abstract

The need to understand how wildlife responds to the broad-ranging impacts of development is becoming increasingly important as human populations around the globe continue to increase and urbanize. We examined waterbird distributional associations with shoreline development, and with littoral and onshore habitat elements on four partially developed urban lakes in central Florida. A total of 34 waterbird species were observed over the summer and winter seasons. Wading bird, marsh bird, and duck abundance was significantly greater than expected along developed shoreline in both seasons on all lakes. Diving bird abundance was significantly greater along developed shoreline in the winter. Species richness was not associated with shoreline development, while species evenness varied by season, being greater along undeveloped shoreline in the summer and along developed shoreline in the winter. Tall-emergent vegetation, open shore, lawn, and canopy appeared to be the primary habitat elements determining waterbird distribution. All guilds were negatively associated with tall-emergent vegetation on two or more lakes over both seasons, whereas wading birds, marsh birds, and ducks were positively associated with open shore in the summer, and wading birds, marsh birds, and diving birds were positively associated with lawn and canopy in the winter. Results showed that a wide range of waterbirds can use urban lakes during the summer and winter seasons, and many individuals can utilize developed shoreline in particular. However, the lack of birds observed along undeveloped shoreline may be explained by the abundance of dense tall-emergent vegetation found along this shoreline. Both littoral and onshore habitat elements should be managed to improve waterbird habitat on urban lakes.