Abstract

Ginn BK, Dias EFS, Fleischaker T. 2021. Trends in submersed aquatic plant communities in a large, inland lake: impacts of an invasion by starry stonewort (Nitellopsis obtusa). Lake Reserv Manage. 37:199–213.

Aquatic plant and macroalgae (collectively, macrophyte) communities from Lake Simcoe (Ontario, Canada) were studied in lakewide, >200 site surveys in 2008, 2013, and 2018. Over this period, mean macrophyte biomass increased 5-fold, from 29.9 g (dry)/m² in 2008 to 153.9 g (dry)/m² in 2018, due to the arrival and expansion of invasive starry stonewort (Nitellopsis obtusa). First recorded in Lake Simcoe in 2009, starry stonewort has greatly altered the macrophyte community, particularly in shallow (<3 m) water where it outcompeted invasive Eurasian watermilfoil (Myriophyllum spicatum). By 2018, starry stonewort comprised 67.6% of the total macrophyte biomass in Lake Simcoe. In shallow, mesotrophic Cook’s Bay, comparison to studies from the 1980s shows an increased plant biomass due to increased water clarity, from phosphorus (P) abatement and invasive dreissenid mussels, with further increases after 2011 due to starry stonewort. Starry stonewort may continue to impact nearshore ecology, with shallow-water fish species losing habitat and refugia as the “forest-like” structure of the plant community is replaced by large, dense aggregations of starry stonewort. Recreational uses will also be impaired and landowner complaints of macrophyte wash-ups will increase, with municipalities and lake-based businesses bearing the cost of mitigation and control strategies. Future research should consider the impacts of starry stonewort to P cycling as, unlike aquatic plants that uptake sediment P, macroalgae use dissolved P as a nutrient source. A lack of communication and reporting on starry stonewort has enabled its spread through south-central Ontario and the Great Lakes Region. Moving forward, we need a better understanding of starry stonewort biology and need to develop effective control and management strategies.

摘要

Ginn BK，Dias EFS，Fleischaker T.2021。一个大型内陆湖中水生植物群落的趋势：星状石麦入侵的影响（Nitellopsis obtusa）。湖后备管理。37：199–213。

在2008年，2013年和2018年，在全湖范围内进行了200多次现场调查，研究了西湖（加拿大安大略省）的水生植物和大型藻类（统称大型植物）群落。在此期间，大型植物的平均生物量从29.9克增加了5倍。 （干）/ m ²在2008年达到153.9 g（干）/ m ²在2018年，这是由于侵入性星状石麦（Nitellopsis obtusa）的到来和扩展。最早记录于2009年的西姆科湖（Simcoe），星状石麦极大地改变了大型植物群落，特别是在浅水（<3 m）水域中，它胜过了入侵性的欧亚水母（Myriophyllum spicatum）。）。到2018年，星光麦草占Simcoe湖大型植物总生物量的67.6％。与1980年代以来的研究相比，在中度营养丰富的库克湾浅水区，由于水的透明度提高了植物的生物量增加，这归因于磷（P）的消除和侵入性杜鹃花贻贝的繁殖，2011年以后由于星状麦芽汁而进一步增加。繁星点缀的石may可能会继续影响近岸生态，随着大型，密集的繁星点缀的石w被植物群落的“森林状”结构所取代，浅水鱼类丧失了栖息地和避难所。娱乐用途也将受到损害，土地所有人对大型植物污染的投诉将增加，市政当局和以湖为基础的企业将承担缓解和控制策略的费用。未来的研究应考虑繁星状石麦对磷循环的影响，因为与吸收沉积物P的水生植物不同，大型藻类利用溶解的P作为营养源。缺乏对繁星满天的石w的交流和报道，致使其传播遍及安大略省中南部和大湖区。展望未来，我们需要更好地了解星空石蒿生物学，并需要制定有效的控制和管理策略。