Danell Kjell
Department of Ecological Zoology, University of Umeå, S-901 87, Umeå, Sweden.
Oecologia. 1979 Jan;38(1):101-106. doi: 10.1007/BF00347828.
The muskrat (Ondatra zibethica (L.)) utilizes emergent hydrophytes both for housebuilding and for food. The impact of these activities on stands of Equisetum fluviatile L. in a northern Swedish lake was investigated. The areas of open water created by the muskrats were estimated from infrared air photographs, taken in July, on three occasions during a five-year period. During the first three years, with low muskrat densities, the areas of open water were estimated to represent removal of about one percent of the Equisetum stands. In the summer following a population peak the total area of open water had increased to about four percent. In that summer there were, on average, about 160 such areas per hectare and their combined perimeter length was about 1.5 km. The many small areas created by the muskrats were mostly very irregular in shape, each with a long perimeter in relation to its area. If not too numerous, the muskrats have a positive effect on the waterfowl population in well-vegetated lakes, by increasing the feeding areas available for both adults and young birds.
麝鼠（Ondatra zibethica (L.)）利用挺水植物来建造巢穴和获取食物。本研究调查了这些活动对瑞典北部一个湖泊中木贼（Equisetum fluviatile L.）群落的影响。通过在五年期间三次于7月拍摄的红外航空照片，估算了麝鼠创造的开阔水域面积。在最初的三年里，麝鼠密度较低，估算出的开阔水域面积约占木贼群落面积的1%。在麝鼠种群数量达到峰值后的那个夏天，开阔水域总面积增加到了约4%。在那个夏天，每公顷平均约有160个这样的区域，它们的总周长约为1.5千米。麝鼠创造的许多小区域形状大多非常不规则，相对于其面积而言，每个区域都有很长的周长。如果数量不过多，麝鼠会通过增加成年和幼鸟的觅食区域，对植被良好的湖泊中的水鸟种群产生积极影响。
