Human activity leads to environmental transformations, frequently on a large scale. There are places where anthropogenic consequences are unprecedented and disadvantageous to the extent that can be perceived in terms of an ecocatastrophe that goes beyond the local range. The article presents three anthropogenically degraded areas that pose danger for ecosystems in various parts of the world.
The Suchedniów water reservoir is located in the central section of the River Kamionka in the northern part of the Holy Cross Mountains of central Poland. This area once belonged to the Old Polish Industrial District that, during the Middle Ages, was very intensively developed by iron metallurgy. Many forges and mills along the rivers used water power, which led to the construction of an anthropogenic, small-scale water retention system. At the beginning of the twentieth century many of these reservoirs were drained after the collapse of metallurgical activities. The present-day reservoir was built in 1974 and drained in 2017. Research into the drained basin has documented various forms and sediments, some of which record present-day depositional processes (fire proof clay layer, inland fan delta), while others represent the historical period (lacustrine sediments of older reservoirs). Traces of catastrophic events have been preserved as well; an assemblage of megaripples marks the sudden drainage caused by a dam break in 1974.
Changes in the environment that are caused by the activity of beavers bring numerous advantages. They affect the increase in biodiversity, contribute to improving the condition of cleanliness of watercourses, improve local water relations and restore the natural landscape of river valleys.
Rapid increase in the European beaver population in Poland in 21st century determines and accelerates the process of renaturalization of the areas that have undergone partial degradation as a result of anthropopressure. A singular example is the river valleys populated by beavers that have been adapted to people’s needs in the last centuries, which has inevitably exerted an undesirable effect.