| |
Presented at the NABS Annual meeting, La Crosse, Wisconsin, 2001
FISH ASSEMBLAGES IN ISOLATED BEAVER PONDS
H. L. Ray1, A. M. Ray1, and A. J. Rebertus2. 1Department of Biological Sciences, Idaho State University, Pocatello, Idaho 83209, 2Biology Department, Northern Michigan University, Marquette, Michigan, 49855
Beavers (Castor canadensis) have been described as "keystone species", because their impoundments and cutting activities dramatically alter nutrient cycles and food chains in both aquatic and terrestrial systems. We documented colonization and development patterns of fish in 17 isolated beaver ponds using a biogeographical perspective. The ponds sampled were impounded peatlands and represented relatively stable aquatic patches ranging from 4 to >40 years in age. The number of fish captured per pond increases with maximum pond depth. The maximum number of species identified in a single pond was 5. Simpson’s diversity index increases with increasing percent abundance of submersed macrophytes (p = 0.037). Relative frequency and total abundance of species captured were high among Phoxinus eos, P. neogaeus, Culaea inconstans, and Umbra limi. The average length of fish captured was 60.6 mm. The largest average length of fish species captured was Umbra limi (72.4 mm) and the smallest average lengths of fish species’ captured were Lepomis gibbosus (43.0 mm) and Culea inconstans (48.1 mm). Trends in fish community assembly impact a number of aquatic organisms and ecosystem processes within beaver ponds, and our results may contribute to better understanding the dynamics of these regionally abundant habitats.
|
|
