Disturbance effects on herbaceous layer vegetation and soil nutrients in Populus forests of northern lower Michigan

Abstract

Abstract. Recent disturbance models have identified changes in resource availability as factors that control plant community response. Soil nutrient resources typically are assumed to change following forest disturbance, usually with nutrient availablity increasing initially and subsequently decreasing through later stages of succession. We examined the effects of disturbance (clearcut harvesting with a brief recovery period) on soil organic matter, pH and extractable soil nutrients in successional aspen forests of northern lower Michigan to determine relationships of these variables to changes in herbaceous layer vegetation. Two site types were identified: drymesic (glacial outwash sands, low in organic matter) and mesic (calcareous clay till, high in organic matter). Extractable nutrient concentrations were 1.5 to 3 times higher in the A1 horizon of mesic sites than those of dry‐mesic sites. Soil pH and cations increased after disturbance on mesic sites, but not on dry‐mesic sites. Patterns of change with disturbance were less pronounced in lower horizons on both site types. Herblayer species diversity increased after disturbance on mesic sites, but with decreases in the importance of shade‐tolerant tree species and Maianthemum canadense. Species characteristic of open habitats (e.g. Pteridium aquilinum, Rubus spp., Fragaria virginiana, and Diervilla lonicera), increased in importance. Soil factors, species composition and diversity on dry‐mesic sites changed little after disturbance, with Pteridium aquilinum and ericaceous species remaining dominant in both mature (55–82 yr) and disturbed (≤ 15 yr) stands. These results suggest that soil nutrient resources do not always change through secondary succession and that patterns of change can be distinctly site‐dependent. Disturbance response patterns in the herbaceous layer of these aspen forests are also site‐dependent.

The dynamics of bodícka brána forest vegetation

“…Number of species observed in the year after deforestation of the oak-wood stand (Quercetum petreae-cerris) in Hungary increased twice; and it decreased in the following years (Papp, 1984). Our results are also comparable to findings of Roberts & Gilliam (1995) in the U.S.A, where the species diversity in an adult poplar stand was lower (26) than it was in a young stand (35). The average of 13 species was present in our adult stand, and 33 in the young one.…”

Vegetation responses to burning in a rain forest in Borneo

“…We, in fact, witnessed massive colonisation of ferns, probably by means of long-distance wind-mediated spores, in the burned forest. Dominant ferns included Blechnumorientale, Microlepia speluncae and the cosmopolitan Pteridium aquilinum (Dennstaedtiaceae), or bracken, a species noted for colonising extremely perturbed acidic environments (Roberts and Gilliam 1995). When dense, fern stands can exclude other plants (Whitmore 1984;Richards 1996).…”

Previous land use alters plant allocation and growth in forest herbs

“…In eastern North America and Europe, for example, agricultural practices abandoned more than 30 years ago have been shown to account for the loss or reduced abundance of at least 50 herbaceous species (Peterken & Game 1984;Dzwonko & Loster 1992;Motzkin et al 1996). The effect of clearcutting tends to be less straightforward, with some studies showing long-term detrimental impacts on the herb layer (Duffy & Meier 1992) and others finding short-lived or highly site-dependent changes (Roberts & Gilliam 1995). Empirical observations and models strongly support the hypothesis that many herbs are slow or unable to recolonize suitable habitat due to constraints associated with dispersal mode, clonal expansion, diaspore production or habitat isolation.…”