The researchers studied how a type of underwater plant called fennel pondweed maintains its uneven distribution in a pond. They found that the plant's abundance varied due to factors like swan feeding, winter die-off, and summer regrowth. Despite swans eating plants evenly, they still created differences in plant density. After swan feeding, the plant distribution became more even, but then returned to its original pattern due to winter die-off and regrowth. This shows that different factors affect the plant's distribution in different ways, helping to keep the pond diverse.