For isolated communities, muscle, water, wind-power, firewood, and charcoal were their only energy sources. The bulk of their food and energy supplies had to be obtained from their own immediate hinterland, whose productivity had to be maintained by crop rotations, and by returning appropriate amounts of manures and compost to it. This traditional settlement type could be called 'Agropolis'. The arrangements for utilising local land and resources practiced across the world were the basis for resilient urban communities. As the industrial revolution progressed and as vast areas of farmland and forest were gobbled up by Europe's burgeoning cities, lack of access to local food supplies and to recreational areas became a major concern. In Germany they were called Schrebergarten, after Dr. Moritz Schreber, a prominent physician working in Leipzig in the mid-19th century, who linked the occurrence of ill health in people to urban pollution, to inadequate diets and to lack of access and exposure to the living world.