G. Franceschini et al., A GEOSTATISTICAL ANALYSIS OF THE SPATIAL-DISTRIBUTION OF ABAX-PARALLELEPIPEDUS (COLEOPTERA, CARABIDAE) IN A WOODLOT, European journal of soil biology, 33(3), 1997, pp. 117-122
In order to examine the small-scale distribution and population densit
y of Abax parallelepipedus and to assess the carrying capacity of wood
lots, we ran a capture/recapture study in a small woodlot (0.45 ha) at
Saint Marcan, Brittany, in the French 'bocage' (hedgerow network land
scape). We used a grid of 160 pitfall traps between June 23(rd) and Se
ptember 1(st), 1996, which was checked every 2 days. Each Abax paralle
lepipedus caught was individually marked with a micro-drill and releas
ed. The whole capture-recapture history was used to estimate the popul
ation density using the Jolly-Seber method. The density was of 0.1 ind
/m(2). Frequency distributions are approximately lognormal. Geostatist
ical analysis was used to display the spatial pattern of activity amon
g the traps. The variogram suggests that 75% of the sample variance wa
s related to spatial autocorrelation over a range of 50 m. Moreover, w
e used a block kriging to obtain a complete map of activity within the
study area. This activity appeared patterned at this scale, with two
fundamental well-defined patches. A one way ANOVA did not reveal any s
tatistical significance between the total catches and the structure of
the litter and the presence of rotten tree stumps. We propose that cl
uster or interaction groups of individuals could be used as basic unit
s to model populations in woodlots, at an intermediate ecological leve
l between individual and population. (C) Elsevier, Paris.