Pasture puddles are small basins of water created by farmers for watering cattle and sheep and situated close to an alpine hut. These basins were built using natural depressions and dolines and made waterproof by coating the bottom with pressed clay. Puddles are distinctive also for their shallowness (which is normally no deeper than 50 cm), round shape, limited size, standing water (since there is no current to move it), considerable changes in water temperature throughout the day (caused by the shallowness of the basin), lack of thermal stratification (from surface to the bottom there are no great differences of temperature) and turbidity.
Normally, during the time they are used, these puddles are characterized by a complete or almost complete absence of aquatic plants that do not survive trampling by livestock, nor thrive in water contaminated by animal droppings. In vast areas of Mount Baldo, puddles are the only aquatic ecosystems found at high altitudes (as a consequence of the karstic substrata) where life is possible for amphibians (frogs and newts) and for insects that are specialized to live in such environments (water beetles, dragonflies, etc).
Many puddles have been abandoned, so that grass has gradually grown into them; others have become increasingly restricted because of the lack of maintenance. Even the waterproofing of the bottom is maintained only thanks to the continuous trampling of livestock: an unused puddle slowly disappears and grasses over.