Comparative study of soil organic layers in two bilberry-spruce forest stands (Vaccinio-Piceetea). Relation to forest dynamics

Abstract

Morphologica1 features of twelve humus profiles demonstrating the diversity of vegetation types present in subalpine forests were compared, together with soil fauna. Two forest stands of spruce [Picea abies (L.) Karst.] in association with bilberry (Vaccinium myrtillus L.), located at 1630 and 1880 m altitude (Mâcot-La Plagne, Tarentaise valley, Savoy, France), were studied. Morphological observations of small soil volumes were made on disturbed samples by the method of Ponge, but here transformed into quantitative data. Analysis of the data gave evidence of a large degree of heterogeneity of the form of humus in a given forest stand, but most of the observed variation might be exp1ained by differences in vegetation, due to phases of the forest cycle and sylvicultural practices. Regeneration sites are characterized by the development of a herbaceous coyer under which a mull humus is built through the activity of burrowing earthworm species. During the phase of intense growth of spruce organic matter accumulates in the top few centimeters. At this stage, the Al horizon previously formed under the action of endogeous earthworms becomes inactive but its crumby structure remains stable.Anecic worms (earthworms with a high amplitude of vertical movements) appear again under adult trees. As a result, changes in the form of humus are observed, with seemingly mull formation (burying of litter) but without true incorporation of organic matter to mineral matter. This humus was named dysmull. Thus soil conditions that prevail in the regeneration sites were developed to some extent under pre-existing adult trees. A parallel the Macot-La Plagne commune, and belong to the same communal forest. The sites were studied for several years by the

Land use change affects earthworm communities in Eastern Maryland, USA

“…Similar results of his and our study are: (1) similar species richness regardless of successional stage; (2) decrease of earthworm biomass in the subclimax plant community; (3) increase in the proportion of epigeic species; (4) stable abundance in a short (5 year) period in the forest earthworm community; and (5) species associated only with oldest forests. Earthworm abundance was also lower in later stages of succession of an alpine spruce forest in France [1].…”

Earthworms, stand age, and species composition interact to influence particulate organic matter chemistry during forest succession

“…The patches of forests in various stages of succession are adjacent at SERC and there are no physical barriers between stands of different ages keeping earthworms from migrating, which suggest a natural decline in earthworm abundance occurs with stand maturation (Szlavecz and Csuzdi 2007). Further, other studies in France and the Czech Republic showed that earthworm abundance declines along a successional gradient (Pižl 1992;Bernier et al 1993). Historic land-use, propagule pressure, or small differences in pH may reduce populations in later successional forests.…”

The impact of parent material, climate, soil type and vegetation on Venetian forest humus forms: A direct gradient approach

“…Annelids create different structures according to their size, macro-(> 4 mm) and meso-structures (2-4 mm) of mull and amphi humus forms resulting from the burrowing and defecating activity of earthworms (Galvan et al, 2008), while microstructures (< 2 mm) of moder humus forms result mainly from the activity of enchytraeids (Didden, 1990;Dawod and FitzPatrick, 1993;Ponge, 1999). Enchytraeids, in particular the common, asexual Cognettia sphagnetorum, replace earthworms when conditions become more severe along latitudinal and altitudinal gradients (Bernier et al, 1993;Briones et al, 2007). Exclusion mechanisms between enchytraeids and earthworms, whether competitive or behavioral in advance of competition, have been demonstrated (Haukka, 1987;Ponge, 2003), in addition to abovementioned differences in tolerance, which might explain observed gradients of annelid composition and resulting changes in humus forms (Ponge, 2003).…”