Data from: The legacy of large regime shifts in shallow lakes

Ecological shifts in shallow lakes from clear-water macrophyte-dominated to turbid-water phytoplankton-dominated are generally thought of as rapid short-term transitions. Diatom remains in sediment records from shallow lakes in the Prairie Pothole Region of North America provide new evidence that the long-term ecological stability of these lakes is defined by the legacy of large regime shifts. Here we examine the modern and historical stability of eleven shallow lakes. Currently, four of the lakes are in a clear-water state, three are consistently turbid-water, and four have been observed to change state from year to year (transitional). Lake sediment records spanning the past 150-200 years suggest that: 1) the diatom assemblage is characteristic of either clear or turbid lakes; 2) prior to significant landscape alteration, all of the lakes existed in a regime of a stable clear-water state; 3) lakes that are currently classified as turbid or transitional have experienced one strong regime shift over the past 150-200 years, and have since remained in a regime where turbid-water predominates; and 4) top-down impacts to the lake food web from fish introductions appear to be the dominant driver of strong regime shifts, and not increased nutrient availability. Based on our findings we demonstrate a method that could be used by lake managers to identify lakes that have an ecological history close to the clear-turbid regime threshold; such lakes might more easily be returned to a clear-water state through biomanipulation. The unfortunate reality is that many of these lakes are now part of a managed landscape and will likely require continued intervention.学界普遍认为，浅水湖泊由清水型大型水生植物主导态向浊水型浮游植物主导态的生态跃迁，通常属于短期快速转变过程。北美草原坑洼地带（Prairie Pothole Region）的浅水湖泊沉积记录中的硅藻（diatom）遗存，为这类湖泊的长期生态稳定性由大规模生态状态转变的遗留效应所决定这一观点提供了新的实证依据。本研究对11个浅水湖泊的现代与历史生态稳定性展开了考察。当前，其中4个湖泊处于清水稳态，3个始终维持浊水稳态，另有4个被观测到在年度间发生状态转换（过渡态）。对覆盖过去150至200年的湖泊沉积记录的分析显示：1) 硅藻群落特征对应清水或浊水湖泊的典型组合；2) 在大规模景观改造发生之前，所有湖泊均稳定处于清水主导的生态状态；3) 当前被归类为浊水态或过渡态的湖泊，在过去150至200年间均经历过一次强烈的生态状态转变，且此后长期维持浊水主导的状态；4) 鱼类引种对湖泊食物网产生的下行调控效应，是引发强烈生态状态转变的主导驱动因子，而非营养盐供给的增加。基于本研究结果，我们提出了一套可供湖泊管理者使用的方法，用于识别生态历史接近清水-浊水状态转换阈值的湖泊；此类湖泊可通过生物调控手段更高效地恢复至清水态。令人遗憾的是，这类湖泊如今大多已处于人工管理的景观中，大概率需要持续的干预措施才能维持其生态稳态。