ISSN:
1573-5117
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract We tested the hypothesis that inorganic nutrients released fromwaterfowl feces would stimulate primary production, therebyaffecting microinvertebrate grazers, by making controlledadditions of waterfowl feces to fishless wetland enclosures andmeasuring the response of planktonic and phytophilouscladocerans, copepods, and rotifers. Feces were added in twopulses, four weeks apart, to duplicate enclosures at a ‘high’level (115 g m−2 wet feces), simulating the total P load(1.6 g m−2) applied in an earlier fertilizationexperiment, and a ‘low’ level (11.5 g m−2). Density ofmicrocrustacean grazers in the water column increased inresponse to both feces additions, although the response wasmore noticeable after the second feces addition. After eachaddition, cladocerans (predominantly Ceriodaphnia dubia)and copepodites in the water column (and associated withperiphyton on acrylic rods in the water column) were mostabundant in enclosures with high loading. In contrast, densityof microcrustacean grazers associated with macrophytes(predominantly Chydorus spp. and copepodites) increasedin response to the second feces addition only.Microinvertebrate density increased only slightly with lowfeces loading. Community composition showed similar changesover the season in all enclosures, and differences in relativeabundance were not attributable to treatment effects. Given thesmall effects produced by nutrient additions that greatlyexceed natural loadings, nutrients leaching from waterfowlfeces do not appear to have a significant impact on the foodwebof this wetland.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1003167219199
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