The importance of bryophytes in the classification of human‐disturbed high arctic vegetation

Abstract. Evidence is presented from a variety of tundra cover types under human disturbance at three sites in the Canadian High Arctic to indicate that higher plants may be insufficient to differentiate among the apparently distinct geobotanical signatures of discrete surface disturbances. Unlike in the Low Arctic, woody growth forms are often minimal or lacking on heavily disturbed ground and several prominent species of ruderal herbs and especially graminoids occur on a wide variety of substrates. Therefore, cryptogams, particularly bryophytes, are important indicator taxa. Presence‐absence data on bryophytes from minerotrophic and oligotrophic soils, combined with vascular cover‐abundance data, enhanced detection of patch‐level floristic gradients within and among disjunct coastal lowlands. However, the pool of ruderal bryophytes is limited, and ultimately factors such as frequency and abundance should be considered. 1994 IAVS ‐ the International Association of Vegetation Science