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Predation By Ermine And Long-Tailed Weasels On Duck Eggs, Joseph P. Fleskes

Journal of the Iowa Academy of Science: JIAS

Ermine (Mustela erminea) and long-tailed weasel (M. frenata) predation on duck eggs was studied at Union Slough National Wildlife Refuge, Kossuth County, Iowa, 1984-85. Captive individuals of both species ate 2-4 duck eggs at a rate of 0.5-2 eggs per trial day. All eggs were moved but some were not opened. One hole, ringed with small fragments and "bite-outs'', was made in all eggs opened by captive weasels. In the field, the appearance of opened eggs, the pattern of egg loss and the amount of nest bowl disturbance were used to determine the number of nests depreciated by weasels. Egg …

Using Life History And Ecology As Tools To Manage A Threatened Salamander Species, Scott R. Mcwilliams, Marilyn D. Bachmann

Journal of the Iowa Academy of Science: JIAS

Selected aspects of the life history and ecology of the small-mouthed salamander (Ambystoma texanum Matthes) relevant to the management of this threatened species in Iowa are presented. The population studied utilizes flooded woodland habitat during courtship, breeding and egg laying, and during the entire larval period. Larval foraging strategies in this habitat included ontogenetic but no diel shifts in prey selection. Synchronous, nocturnal breeding migration allowed effective use of drift fences fur capture of adults used in captive breeding, courtship behavior studies, and the estimation of breeding population size. Large numbers of spennatophores, apparently indiscriminate mate choice, and the relatively …

Seasonal Composition Of Benthic Diatom Associations In The Cedar River Basin (Iowa), Stephen P. Main

Journal of the Iowa Academy of Science: JIAS

This is the first detailed report on the taxonomy and ecology of diatoms in the portion of the upper reaches of the Cedar River basin in Iowa. This paper describes the diatom taxa from shallow benthic substrata collected quarterly between 11 October 1975 and 19 February 1977 at 14 sampling stations. Just over 500 frustules were counted from each of the 216 samples obtained. Analysis of water samples collected at the same time as the diatoms indicates these screams have alkaline hard waters rich in nutrients with extreme turbidity level fluctuation at irregular intervals.

The 281 diatom taxa identified represented …

The Status Of Three Uncommon Salamanders (Amphibia: Caudata) In Iowa, Jeffery D. Camper

Journal of the Iowa Academy of Science: JIAS

The smallmouth salamander [Ambystoma texanum (Matthes)], blue-spotted salamander (Ambystoma laterale Hallowell), and central newt [Notophthalmus viridescens louisianensis (Wolterstorff)] were studied in Iowa from fall 1982 through summer 1984. All three species have declined in abundance in Iowa. A. texanum is more abundant and widespread than was previously suspected, but is declining due to habitat destruction. Apparently, only two populations of A. laterale remain in Iowa. N. v. louisianensis has also declined due to habitat destruction, with only three populations known. All three species require ponds in or adjacent to forest. A. ta was found primarily in riparian …

Evaluation Of Fish Eradication And Game-Fish Restocking In A Central Iowa Pond, Dennis L. Scarnecchia

Journal of the Iowa Academy of Science: JIAS

Changes in fish community and population structure associated with fish eradication and subsequent restocking were investigated in a small (0. 25 ha) impoundment in Boone County, Iowa. In September 1985, when fish were eradicated with rotenone, the fish community consisted of eight species. Large numbers of small bluegills (Lepomis macrochirus), green sunfish (Lepomis ryanellus), and stunted crappies (Pomoxis spp.) dominated the pond numerically, but seven large carp (Cyprinus carpio) and 18 large bigmouth buffalo (lctiobus ryprinellus) constituted 80% of the total biomass. The only quality angling (popular species of desirable size) was for a few largemouth bass (Micropterus salmoides) and …