A Biological Study of a Temporary Pond in Western Canada

A temporary pond in southern Manitoba, Canada, situated at fifty degrees north latitude and ninety-seven degrees west longitude, was studied during the spring of the years 1925, 1926 and 1927. This pond was formed by the melting snows and spring rains in the month of April, and usually persisted until sometime in the month of June. The period of activity of the aquatic animals which are permanent residents of the pool, not merely migrants, is thus somewhat more than two months in each year. During the summer, after the pond has be come dry, the dormant organisms are subjected to severe desiccation and during the winter to low temperatures. The flora and fauna of this pond is quite extensive, and many of the species present occur in very large numbers. The phyllopods, Eubranchipus, Lepidurus and Limnetis, beetles and snails are the most numerous macroscopic forms. There is a well-marked seasonal succession in both plants and animal species. The alternation of moist and dry conditions plays an important part in the great productivity of the pond and has some possible applications to fish culture and fish-food culture.