Many freshwater ecosystems throughout the world support a high number of waterbirds. Nutrient from droppings of these waterbirds may serve as an important source of nutrients to those systems. Previous works suggest that excess nutrients from waterbirds may lead to eutrophication. The excess nutrients also may induce nuisance growth of aquatic weeds in shallow lakes. However, the aquatic weeds serve as an important food for some avian species. The main objective of this work is to study how the waterbirds affect the dynamics of the aquatic ecosystem through a process-based modelling approach.

To understand this, a lake with negligible anthropogenic nutrient influx and the high winter-avian congregation is taken as study site. A process-based dynamic ecological model with six state variables has been developed. Phosphorus (P) is taken as model currency since it is the limiting nutrient in most shallow and present in high concentration in the dropping of waterbirds. Before the model calibration, sensitivity analysis is performed with the data collected during the first year of study. Model is validated with the data collected during the second year of study.

As per the model, P from the waterbird guano comprises 98.32% of P input to the lake. Parameters affecting the water-sediment exchange of P are most sensitive. P content in zooplankton is the most sensitive state variable. Nutrient budget analysis reveals that internal cycling of the nutrient is the main pathway to sustain productivity in the system. So far, no process-based modelling has been done on the impact of dropping of waterbird on nutrient dynamics of the aquatic system. This kind of model will be helpful to handle problems like eutrophication and macrophyte overgrowth due to eutrophication.

全世界许多淡水生态系统都支持大量水鸟。这些水鸟的粪便中的营养物可能是这些系统养分的重要来源。先前的研究表明，水鸟的过量养分可能导致富营养化。过多的养分还可能导致浅湖中水草的滋扰生长。但是，水草是某些鸟类的重要食物。这项工作的主要目的是通过基于过程的建模方法研究水鸟如何影响水生生态系统的动力学。

为了理解这一点，将人为营养素流入量可忽略不计且冬季禽类聚集度较高的湖泊作为研究地点。建立了基于过程的具有六个状态变量的动态生态模型。磷（P）被认为是标准货币，因为它是最浅处的限制性营养素，并以高浓度存在于水鸟的下落中。在模型校准之前，将使用研究的第一年收集的数据进行敏感性分析。使用第二年研究期间收集的数据对模型进行验证。

按照该模型，P从的水鸟鸟粪包括98.32％P输入到湖。影响P的水沙交换的参数最敏感。浮游动物中的磷含量是最敏感的状态变量。营养预算分析表明，养分的内部循环是维持系统生产力的主要途径。到目前为止，还没有基于过程的建模来研究水鸟掉落对水生系统养分动态的影响。这种模型将有助于解决诸如富营养化和由于富营养化导致的大型植物过度生长等问题。