Autor(es):
Benhadi Marin, Jacinto 
; Pereira, J.A. ; Barrientos, José-Antonio ; Bento, Albino ; Santos, Sónia A.P.
Data: 2013
Identificador Persistente: http://hdl.handle.net/10198/8801
Origem: Biblioteca Digital do IPB
Assunto(s): Araneidae; Philodromidae; Thomisidae; Castanea sativa; Diversity; Guilds
Descrição
Chestnut (Castanea sativa Mill.) is one of the economically more important trees in the north of Portugal. Spiders, as generalist
predators, are potential controlling agents of pests, yet the composition of the community of spiders associated with this crop
is only poorly known. The objective of this study was to determine the spider communities in the canopies of chestnut trees subject
to three different soil management practices in northeastern Portugal. Three chestnut groves each subject to a different agricultural
practice (grazed, tilled or untilled) were studied in 2008 and 2009. The Araneae communities were sampled by beating the branches
and the individuals collected were identified to family and species when possible. To investigate the structure of the spider community
in each grove the abundance and family richness of spiders were calculated and compared between managements. In total, 4172
spiders were collected and, in both years, the three most abundant families were Araneidae, Philodromidae and Linyphiidae. In
2008, there was a greater abundance of spiders in the grazed, followed by the tilled and untilled groves, but no significant differences
among groves. However, in 2009 there was a greater abundance of spiders in the tilled grove, followed by grazed and untilled groves
and the differences between the untilled and the other two groves were significant. Araniella, Oxyopes and Anyphaena were the most
abundant genera in the three groves. This study showed that soil management may influence the diversity of spiders, but the effects
were weak and not consistent between years. The reduction or absence of a suitable habitat for spiders under the trees in the tilled
treatment might have resulted in the spiders migrating up into the canopy. However, based on the weak effects on spider abundance
recorded and its potentially adverse effects on soils, tillage is not recommended for managing the incidence of pests in chestnut
groves.
