352
Pilar Andres, Eduardo Mateos and Carlos Ascaso
nean species. The two species found at La Castanya are "spring carabids"
(Loreau 1985). The hibernating adult stage appears in autumn, and the reproductive period occurs in spring and continues until the summer, as long
as the soil temperature is higher than 5 dc.
24.5 The "Soil Arthropod Community"
The expression "soil arthropod community" is surely a misleading conceptual simplification in a spatially and temporally variable ecosystem in which
seasonal patterns are strongly defined by water availability. Even though
some taxa belong strictly to a given part of the vertical forest structure, a
great number of arthropods move across the different soil layers and even
across the epigeal and hypogeal environments. The litter marks the border
between the above- and belowground subsystems, and, here, the composition
of the fauna changes continuously according to a seasonal pattern. When
moisture conditions are advantageous, the litter is inhabited by arthropods
characteristic of the deeper soil layers. On the other hand, arthropods that
inhabit the aboveground parts of plants or temporary habitats (some
Hemiptera, larvae of Coleoptera or Diptera, and some Psocoptera species),
such as dung or decaying stumps, are mainly active on the ground surface
from July to September. Reproductive rhythms and food search define the
epigeal activity pattern.
Belowground, mycophages and detritivores account for most of the arthropods, and the humus layers are the focus from which colonization extends towards the upper and lower horizons. Here, the seasonal pattern is
strongly related to the organic matter decomposition rhythm and to the
evolution of the fungal colonies. For most of the mesofauna, the upper mineral soil is only an emergency shelter, to be occupied during summer
drought.
References
Andres P (1990) Descomposici6n de la materia organica en dos ecosistemas forestales del Macizo del Montseny (Barcelona): Papel de los acaros oribatidos (Acarina, Oribatei). PhD Thesis, Autonomous University of Barcelona, Bellaterra
Ascaso C (1986) Analisis cuantitativo de poblaciones a partir de muestreos indirectos: aplicaci6n a comunidades de artr6podos en dos bosques del Montseny. PhD Thesis, Autonomous
University of Barcelona, Bellaterra
Athias-Binche F (1987) Modalites de la cicatrisation des ecosystemes mediterraneens apres incendie: cas de certains arthropodes du sol. 3. Les acari ens Uropodides. Vie Milieu 37:39-52
Athias-Binche F, Briard J, Fons R, Sommer F (1987) Study of the ecological influence of fire on
fauna in Mediterranean ecosystems (soil and above-ground layer). Patterns of post-fire recovery. Ecol Mediterr 13:135-153
Pilar Andres, Eduardo Mateos and Carlos Ascaso
nean species. The two species found at La Castanya are "spring carabids"
(Loreau 1985). The hibernating adult stage appears in autumn, and the reproductive period occurs in spring and continues until the summer, as long
as the soil temperature is higher than 5 dc.
24.5 The "Soil Arthropod Community"
The expression "soil arthropod community" is surely a misleading conceptual simplification in a spatially and temporally variable ecosystem in which
seasonal patterns are strongly defined by water availability. Even though
some taxa belong strictly to a given part of the vertical forest structure, a
great number of arthropods move across the different soil layers and even
across the epigeal and hypogeal environments. The litter marks the border
between the above- and belowground subsystems, and, here, the composition
of the fauna changes continuously according to a seasonal pattern. When
moisture conditions are advantageous, the litter is inhabited by arthropods
characteristic of the deeper soil layers. On the other hand, arthropods that
inhabit the aboveground parts of plants or temporary habitats (some
Hemiptera, larvae of Coleoptera or Diptera, and some Psocoptera species),
such as dung or decaying stumps, are mainly active on the ground surface
from July to September. Reproductive rhythms and food search define the
epigeal activity pattern.
Belowground, mycophages and detritivores account for most of the arthropods, and the humus layers are the focus from which colonization extends towards the upper and lower horizons. Here, the seasonal pattern is
strongly related to the organic matter decomposition rhythm and to the
evolution of the fungal colonies. For most of the mesofauna, the upper mineral soil is only an emergency shelter, to be occupied during summer
drought.
References
Andres P (1990) Descomposici6n de la materia organica en dos ecosistemas forestales del Macizo del Montseny (Barcelona): Papel de los acaros oribatidos (Acarina, Oribatei). PhD Thesis, Autonomous University of Barcelona, Bellaterra
Ascaso C (1986) Analisis cuantitativo de poblaciones a partir de muestreos indirectos: aplicaci6n a comunidades de artr6podos en dos bosques del Montseny. PhD Thesis, Autonomous
University of Barcelona, Bellaterra
Athias-Binche F (1987) Modalites de la cicatrisation des ecosystemes mediterraneens apres incendie: cas de certains arthropodes du sol. 3. Les acari ens Uropodides. Vie Milieu 37:39-52
Athias-Binche F, Briard J, Fons R, Sommer F (1987) Study of the ecological influence of fire on
fauna in Mediterranean ecosystems (soil and above-ground layer). Patterns of post-fire recovery. Ecol Mediterr 13:135-153