Artificial ecosystems
Artificial ecosystems are made by humans for their own purposes and managed continuously: fields, orchards, cities, an aquarium, a spacecraft. They cannot regulate themselves and do not last long without human intervention. In an agroecosystem one or a few crop or livestock species dominate, species diversity is low, selection is mainly artificial; extra energy (fuel, fertiliser, irrigation) is used on top of solar energy; part of the product is removed, so the cycling of matter is incomplete and soil fertility falls. Large-scale monoculture leads to mass multiplication of pests and diseases, soil salinisation and structural damage; remedies are crop rotation, legumes, organic fertiliser, drip irrigation, biological control instead of chemicals (entomophages, Trichogramma) and protecting pollinating bees. An urban ecosystem (cities, villages) contains natural and human-made components; problems of air, noise and waste arise, while green plants trap dust and improve the air. A spacecraft is a closed mini-ecosystem: water and air are regenerated by physical and chemical methods.
Class table «Natural – artificial»: compare a tugai and a wheat field in species diversity, energy sources, self-regulation, nutrient cycling and stability. Do not go onto fields where pesticides were applied; do not handle chemicals.