TITLE:
Age of grassy strips influences biodiversity of ground beetles in organic agro-ecosystems
AUTHORS:
Mazhar Ranjha, Ulrich Irmler
KEYWORDS:
Organic Agriculture; Carabidae; Biodiversity; Grassy Strips
JOURNAL NAME:
Agricultural Sciences,
Vol.4 No.5,
May
28,
2013
ABSTRACT: The following
investigations were conducted to evaluate grassy strips of different age for organic
arable fields. From September 2009 to October 2010, adult ground beetles were
sampled by pitfall traps in three grassy strips (2, 4, and 9 years old), their
adjacent cropping areas, their field edges, and a control field (age 0) in
Schleswig-Holstein, northern Germany. Carabid assemblages were similar among
the fields, strips and edges. Grassy strips and edges had higher species
richness and lower activity density than the control field. Activity density increased
with increasing distance from the field edge in grassy strips and in the
adjacent fields. In cropping areas, species richness andShannon’s
H increased with increasing age of strips, whereas evenness and activity
density decreased with increasing distance from the field edges. Compared to
carnivorous and phytophagous carbides, omnivorous species were affected less by
age of strips and distance from field margins. In the strips, species richness
of the dominant species increased with age and decreased with distance, but the
effect of strip age on species richness was still found in more than150 mfrom the margin. A positive effect
of the age of grassy strips on species richness was found for cropping fields,
grassy strips and field edges. Old grassy strips also exerted greater influence
on the species richness and biodiversity of the adjacent arable fields than the
younger strips.