Wetland selection by American Green-winged Teal breeding in British Columbia

Abstract

We examined wetland selection by breeding Green-winged Teal (Anas crecca carolinensis) in terms of wetland fertility near Riske Creek, British Columbia, Canada. We conducted 12 breeding-pair surveys to classify use of 96 wetlands. We evaluated wetland fertility by analyzing water chemistry (pH, conductivity, alkalinity [CaCO3], total phosphorus, chlorophyll a) and physical characteristics (percent emergent cover, area of wetland 0-1 m depth, wetland size). There was significant variation in chemical and physical variables between unused (n = 47) and used (n = 49) wetlands (MANOVA, Wilks' lambda = 0.8054, P = 0.0126). On average water chemistry measurements, total area (m2) and area 0-1 m (m2) depth were greater in used wetlands, whereas percent cover was lower. Also, there was significant variation in chemical and physical variables between unused (n = 47), infrequently used (n = 26), and frequently used (n = 23) wetlands (MANOVA, Wilks' lambda = 0.6951, P = 0.0085). On average, water chemistry measurements, total area (m2) and area 0-1 m (m2) were positively correlated with wetland use, whereas percent cover was negatively correlated. We conclude that wetland fertility is an important factor influencing landscape and geographic distribution of breeding Green-winged Teal.