摘要：We described the distribution of aquatic macrophytes sampled from 130 lakes (1997-2005) across Iowa and estimated the number of samples required to determine species richness at various detection levels. Sago pondweed (Stuckenia pectinatus), cattails (Typha spp.), reed canarygrass (Phalaris arundinacea), longleaf pondweed (Potamogeton nodusus), and coontail (Ceratophyllum demersum) were generally the most common species sampled, but several exceptions were observed. For instance, bulrushes (Schnoenoplectus spp.) were among the most common taxa in natural lakes, and American water lotus (Nelumbo lutea) was one of the most common species in oxbow lakes. Sample size estimates were closely related to lake size, with larger systems requiring more samples. Our analysis suggests that lakes smaller than 10 ha require about 12 vegetated transects to have a 95% probability of detecting all of the species present in the lake. Lakes between 10.1 and 40 ha require 13 transects, those between 40.1 and 101 ha require 19 transects, lakes between 101.1 and 202 ha require 25 transects, lakes between 202.1 and 404 ha require 29 transects, and lakes greater than 404.1 ha require 35 transects.
