Implications of Marsh Size and Isolation for Marsh Bird Management

Abstract
The number of breeding bird species in 30 Iowa prairie marshes ranged from 2 to 17/marsh during 1983 and 1984. All marshes were similar in physical characteristics, except for size and isolation from other marshes. A 2-variable regression model containing size and isolation accounted for 75% of the variation in species richness. Ten of 25 species did not occur in marshes < 5 ha. Species richness often was greater in wetland complexes than in larger isolated marshes. Marsh size and isolation are important management considerations.