E. Branquart et al., MACROARTHROPOD-HABITAT RELATIONSHIPS IN OAK FORESTS IN SOUTH BELGIUM .1. ENVIRONMENTS AND COMMUNITIES, Pedobiologia, 39(3), 1995, pp. 243-263
Woodlouse and millipede assemblages were studied in nine deciduous oak
-forest stands located in the three geomorphologically distinct region
s of the Viroin-Hermeton Natural Park, South Belgium (Ardenne, Calesti
enne and Fagne-Famenne). Principal component analysis revealed marked
regional structure of the edaphic conditions linked to humus type and
soil texture. During the present study and additional surveys, 70% of
the saprophagous macroarthropod species known in Belgium were found in
the park, which suggests a very high biodiversity in this area. Numer
ical size of populations was estimated using two sampling methods, i.e
. extraction from soil samples (abundances) and pitfall trapping (acti
vities). Although a quite good relationship was registered between abu
ndances and activities estimated in spring and autumn, pitfall efficie
ncy greatly depended on the taxa concerned. Multiple multivariate regr
ession analysis and canonical correspondence analysis were used to stu
dy spatial community structure. The most significant variables influen
cing the distribution of species are: (1) available water in the Ah la
yer correlated with C/N ratio of the litter layer (related to both the
litter structure and humus type); (2) the textural soil conditions (s
ilt content); and (3) the local biogeographical structure. Mull specie
s are essentially macrosaprophagous taxa belonging to ''bulldozer'' an
d ''roller'' ecomorphological types or small hypogeic species able to
resist summer drought whereas microsaprophagous epigeic taxa with high
water requirement are linked to moder soils. Finally, the results are
discussed in keeping with regard to the patchiness concept and the lo
cal edaphic and floristic conditions.