Evolution of Heavy Metal Tolerance in Bryophytes Ii. An Ecological and Experimental Investigation of the “Copper Moss,” Scopelophila Cataractae (Pottiaceae)

Abstract

About six bryophyte species (including both mosses and liverworts) are generally thought to be restricted to copper‐enriched substrates and are consequently known as “copper mosses.” One of these, Scopelophila cataractae (Pottiaceae), is known from several sites in southern Arizona and occurs at six localities in the eastern United States. Chemical analyses of substrates from the eastern U.S. localities showed that all but one population grew on copper‐enriched soil. The one substrate sample low in copper was very high in iron. Plants from five of the six eastern U.S. localities for S. cataractae were grown experimentally on four soil types ranging from highly to not contaminated, and all grew best on the soil contaminated with copper, lead, and zinc. There was no significant variation in growth between populations on the four soil treatments. This lack of population differentiation is in contrast to flowering plants and may be related to the absence of sexual reproduction in S. cataractae in North America.

Bryophyte communities as biomonitors of environmental factors in the Goujiang karst bauxite, southwestern China

“…Jules and Shaw (1994) found that populations of Ceratodon purpureus growing on heavy metalcontaminated soils near mine and smelter sites were significantly more tolerant of heavy metals than those growing on uncontaminated soils. Many studies have found that bryophytes with high levels of tolerance to heavy metals are often restricted to contaminated environments (Jules and Shaw, 1994;Økland et al, 1999;Shaw, 1987Shaw, , 1994. Therefore, just as the presence of copper moss indicates copper reserves so also can the appearance of different bryophyte communities and their distribution patterns associated with environmental factors be utilized to monitor heavy metals in karst bauxite.…”

Adaptation to metals in widespread and endemic plants.

“…The two best known copper mosses are Mielichhoferia elongata and Scopelophila cataractae. M. elongata was described as a new species from an abandoned Austrian copper mine in 1817; and it has subsequently been reported from naturally occurring copperenriched substrates elsewhere in the Alps (20) (15,24). Plants from five North American populations were equally tolerant of contaminated mine soil despite that fact that one of those included in the experiment originated at a rare site for the species where the soil was not enriched with metals.…”

Contents of heavy metal elements in copper mosses:Scopelophila ligulata, Scopelophila cataractae, andMielichhoferia japonicaand their substrates

“…So far, studies on the heavy metal contents in the moss bodies and in their substrates of "copper mosses" have been done limited (Brown 1982;Shaw 1987;Nagano et al 1999). Leaching procedures to estimate the amounts of exchangeable or extractable elements in the substrates of several bryophytes have been developed by some researchers, since total analyses would overestimate the amount of elements available to the bryophytes.…”