Bryophytes have many economic and biological uses. Direct uses include as fuel sources from peat/Sphagnum, in medicine such as wound dressings, and as pollution indicators by absorbing heavy metals. Indirect uses are in soil conservation by preventing erosion, forming soil as minerals precipitate around them, and as rock builders. Bryophytes also serve important roles in research, horticulture, biotechnology, and as food and shelter for some animals.