35 research outputs found

    Probable Displacement of Riffle-Dwelling Invertebrates by the Introduced Rusty Crayfish, \u3ci\u3eOrconectes Rusticus\u3c/i\u3e (Decapoda: Cambaridae) in a North-Central Wisconsin Stream

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    The rapid northward range expansion of the rusty crayfish, Orconectes rusticus, and its negative effects on Wisconsin lakes have been the subjects of intense study throughout the last fifteen years. In this study, we investigated the possible impact of rusty crayfish on the benthic macroinvertebrate community structure of the Prairie River in north-central Wisconsin. Rusty crayfish and other invertebrates were collected during August and September, 1994, from three sections of the Prairie River. Rusty crayfish relative abundance increased significantly from the upper to middle, and middle to lower sections; and correlated negatively with a significant 77% decrease in total density of aquatic invertebrates between sections. Mean density of all important invertebrate families and trophic guilds decreased significantly between the upper and lower sections. Due to the similarity of most environmental conditions between river sections, decrease of invertebrates is attributed to the increased abundance of rusty crayfish and its interactions with the native rouna. Our results suggest that a high abundance of rusty crayfish may negatively impact Wisconsin lotic systems

    First Report of the Neoephemeridae (Ephemeroptera) in Wisconsin

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    The mayfly family Neoephemeridae was discovered in Wisconsin for the first time and is represented by the species Neoephemera bicolor. Nymphs were collected from three sites in two rivers in northern Wisconsin. Adults were reared from nymphs. Some physical and chemical characteristics of the sample locations are discussed

    Probable Displacement of Riffle-Dwelling Invertebrates by the Introduced Rusty Crayfish, \u3ci\u3eOrconectes Rusticus\u3c/i\u3e (Decapoda: Cambaridae) in a North-Central Wisconsin Stream

    Get PDF
    The rapid northward range expansion of the rusty crayfish, Orconectes rusticus, and its negative effects on Wisconsin lakes have been the subjects of intense study throughout the last fifteen years. In this study, we investigated the possible impact of rusty crayfish on the benthic macroinvertebrate community structure of the Prairie River in north-central Wisconsin. Rusty crayfish and other invertebrates were collected during August and September, 1994, from three sections of the Prairie River. Rusty crayfish relative abundance increased significantly from the upper to middle, and middle to lower sections; and correlated negatively with a significant 77% decrease in total density of aquatic invertebrates between sections. Mean density of all important invertebrate families and trophic guilds decreased significantly between the upper and lower sections. Due to the similarity of most environmental conditions between river sections, decrease of invertebrates is attributed to the increased abundance of rusty crayfish and its interactions with the native rouna. Our results suggest that a high abundance of rusty crayfish may negatively impact Wisconsin lotic systems

    First Report of the Neoephemeridae (Ephemeroptera) in Wisconsin

    Get PDF
    The mayfly family Neoephemeridae was discovered in Wisconsin for the first time and is represented by the species Neoephemera bicolor. Nymphs were collected from three sites in two rivers in northern Wisconsin. Adults were reared from nymphs. Some physical and chemical characteristics of the sample locations are discussed
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