Water chestnut (Trapa natans L.) is a notorious aquatic invasive species invading wetlands and waterways of the northeastern United States. In the Great Lakes watershed, specifically Lake Ontario coastal wetlands, water chestnut grows in areas similar to the native white water lily (Nymphaea odorata Aiton). To understand better the competitive interactions these species may have, they were grown in mesocosms in a factorial design to simulate varying levels of invasion. Biomass, percent cover, number of rosettes or leaves, and specific leaf area of both species, and seed production of T. natans were measured and analyzed. Relative growth rate (RGR) was also calculated. These data were analyzed using Spitters’ reciprocal-yield model to explore inter-specific and intra-specific effects. Regressions of T. natans percent cover, N. odorata percent cover, number of T. natans rosettes, and number of N. odorata leaves against planting density were statistically significant. Inter-specific competition from N. odorata was 2.27 times more effective than intra-specific competition on T. natans percent cover. These analyses indicate that N. odorata exerts more competitive pressure on T. natans than T. natans on N. odorata or either species intra-specifically. However, these analyses also indicate that N. odorata may facilitate T. natans seed production. Understanding competitive interactions between T. natans and other species can help inform management decisions.

（Trapa natans L.）是一种臭名昭著的水生入侵物种，入侵美国东北部的湿地和水道。在大湖流域，特别是安大略湖沿海湿地中，water生长在与本地白睡莲（Nymphaea odorata Aiton）相似的地区。为了更好地了解这些物种可能具有的竞争性相互作用，它们以因子设计在中胚层中生长，以模拟不同程度的入侵。生物量，覆盖率，莲座丛或叶片的数量，两种物种的比叶面积以及纳豆的种子产量被测量和分析。还计算了相对增长率（RGR）。使用Spitters的互惠产量模型分析了这些数据，以探索种间和种内效应。的回归T.叶萍％的覆盖，N.飞机草％的覆盖，数T.苹花环，以及数N.飞机草对种植密度叶均有统计学显著。来自异味猪笼草的种间竞争比用内生丁香球菌覆盖率进行的种内竞争要高出2.27倍。这些分析表明，香气烟草对纳丹茶的竞争压力比纳丹茶更大。上N.飞机草或任一种帧内特异性。但是，这些分析还表明，香叶猪笼草可能有助于纳丹猪笼草种子的生产。了解纳豆和其他物种之间的竞争性相互作用可以帮助指导管理决策。