Ombrotrophic ("cloud-fed") refers to soil or vegetation which receive all of their water and nutrients from precipitation, rather than from streams or springs. Such environments are
hydrologically isolated from the surrounding landscape, and since rain is
acidic and very low in
nutrients, they are home to organisms tolerant of acidic, low-nutrient environments. The vegetation of ombrotrophic
peatlands is often
bog, dominated by
Sphagnum mosses.
Ombrotrophic circumstances may occur even in landscapes composed of limestone or other nutrient-rich substrates – for example, in high-rainfall areas limestone boulders may be capped by acidic ombrotrophic bog vegetation. Epiphytic vegetation (plants growing on other plants) is of course ombrotrophic.
In contrast to ombrotrophic environments, minerotrophic environments are those where the water supply comes mainly from streams or springs. This water has flowed over or through rocks or other minerals, often acquiring dissolved chemicals which raise the nutrient levels and reduce the acidity. It leads to different vegetation such as fen or poor fen.
Charman, D., Peatlands and Environmental Change. John Wiley & Sons, 2002. ISBN 0-471-96990-7
