Theoretical ecology

El techo poblacional del medio is the carrying capacity of the habitat, and el medio is where Spanish keeps four English words in one. It is the environment, which is what it means here — el medio ambiente, un medio acuático. It is the means by which something is done: un medio de pago, por medio de. It is the middle: en medio de la calle. And in the plural, los medios are the press. English hears nothing joining environment, means, middle and media; Spanish hears one word going about its work.