Forest succession on landslides in the Fiord Ecological Region, southwestern New Zealand

Abstract

Primary succession to montanerain forest on the bare slip faces of landslides is described from three variously aged slides with plot and plotless data, 24 years after a previous study, and is related to adjacent mature forest. Over a 15-102 yr period striking successional changes occurred in both vegetation and flora.The dominant pioneer, Leptospermum scoparium, persists with decreasing importance in the canopy beyond a century, with regeneration falling completely from the seventh decade. Although some species persist throughout the succession and into the mature forest most characterise particular stages and several were recorded only in the mature forest. Among the 90 vascular plant taxa recorded, richness was variable (38-46 taxa) throughout the seral stages and greatest (52) in the mature forest.A total of 118 bryophyte taxa and 26 lichens were recorded from the succession. Bryophyte richness varied from 54 to 66 taxa, the highest being recorded from late seral (102 yr) forest. Ten to 15 species of lichen were recorded per sere with the greatest number in the youngest (39 yr) stage.Tree basal area increased while that of smalltrees declined after 40 yr. Tree and small-tree densities generally declined after c. 70 yr to values similar to those in the mature forest. Densities of shrubs, subshrubs, and herbs showed no consistent trends with time.The successional pattern can be explained by the facilitation (relay floristics, or autogenic) model. It also conforms with the recently proposed resourceratio model although more data are needed for its substantiation.

Landscape-Scale Geomorphic Influences on Vegetation Patterns in Four Environments

“…He also found higher light levels, more extreme temperatures, greater moisture stress due to enhanced evapotranspiration, and continuing substrate instability on the steep upper slopes of landslide scars. Numerous recent studies have similarly reported lower nutrient levels (Reddy and Singh, 1993;Dalling and Tanner, 1995), more extreme temperatures (Mark et al, 1989), and continuing substrate instability (Hunter and Parker, 1993) on landslides relative to terrain adjacent to landslide scars. Many have reported a predominance of pioneer species on landslide scars (e.g., Miles and Swanson, 1986;Guariguata, 1990;Simon et al, 1990;Mark et al, 1989); on sites characterized by repeated failure, pioneers may dominate indefinitely (Orme, 1990;cf.…”

“…These findings suggest that revegetated landslides may greatly affect the land scape-scale diversity of forested mountain environments. Most scholars tracking revegetation of scars over time have reported predictable successional changes in composition and structure (Johnson, 1976;Hupp, 1983;Mark et al, 1989). Because of inherent variation among different scars (Flaccus, 1959;Miles and Swanson, 1986;Guariguata, 1990), however, revegetation patterns revealed by chronosequences of landslide scars often are less detailed and predictable.…”

“…Contrasts in plant species composition and physical charac teristics are often apparent between landslide scars and the surrounding vegeta tion (e.g., Mark et al, 1989;Veblen and Ashton, 1978;Miles et al, 1984;Simon et al, 1990;Reddy and Singh, 1993), although considerable spatial variation in plant cover and physical variables also is evident within landslide scars. In the White Mountains of the northeastern United States, Flaccus (1959) reported lower organic matter content and available calcium, magnesium, and potassium in soils on landslide scars than in the adjacent forest.…”

Structure and regeneration of canopy species in an old-growth evergreen broad-leaved forest in Aya district, southwestern Japan

“…Landslides are more infrequent than tree fall disturbances (Garwood 1979), but the scale is larger. After landslides, pioneer tree species may colonize immediately and remain for a century or more (Mark et al 1989). Brokaw (1987) showed that uncommon pioneer species, some of which are tall, long-lived species, may be vestiges of previous patterns of secondary succession.…”

Evidence of widespread, synchronous, disturbance‐initiated forest establishment in Westland, New Zealand.

“…Consequently the time between disturbance and the establishment of the first tree in a cohort could vary considerably. Observations of vegetation colonisation on over twenty surfaces of known age since disturbance indicate that the first appearance of the species we include in this study takes from 3^0 years (Baxter & Norton 1989;Bray 1989;Mark et al 1989;A. Wells, unpubl.…”