Effects of Tillage on the Activity Density and Biological Diversity of Carabid Beetles in Spring and Winter Crops

Abstract

The effects of tillage regimen (conventional [CT] and no-tillage [NT]) on the activity density and diversity of carabid beetles (Coleoptera: Carabidae) was studied by pitfall trapping within a rain-fed cropping system in northwestern Idaho, 2000-2002. The cropping rotation consisted of a spring cereal (barley, Hordeum vulgare L., in 2000 and 2001; and wheat, Triticum aestivum L., in 2002), spring dry pea (Pisum sativum L.) 2000-2002, and wheat (T. aestivum), spring in 2000 and 2001, and winter in 2002. A total of 14,480 beetles comprised of 30 species was captured, with five numerically dominant species [Poecilus scitulus L., Poecilus lucublandus Say, Microlestes linearis L., Pterostichus melanarius Ill., and Calosoma cancellatum (Eschscholtz)], accounting for 98% of all captures. All species including the dominants responded idiosyncratically to tillage regimen. Adjusting for trapping biases did not significantly change seasonal activity density of Poecilus spp. or Pt. melanarius to tillage. More beetles were captured in CT than in NT crops because of the dominance of P. scitulus in CT, whereas species richness and biological diversity were generally higher in NT crops. Observed patterns suggest that direct effects of tillage affected some species, whereas indirect effects related to habitat characteristics affected others. CT may provide habitat preferable to xerophilic spring breeders. A relationship was found between beetle species size and tillage regimen in pea and to a lesser extent across all spring crops, with large species (>14 mm) conserved more commonly in NT, small species (<7 mm) in CT, and intermediate species (7-14 mm) conserved equally between tillage systems.

Factors that influence the level of weed seed predation: A review

“…In general, seed-feeding species tend to prefer undisturbed fields (Hatten et al 2007;Menalled et al 2007;Trichard et al 2013). Hence, some management guidelines, such as no-tillage or delaying primary tillage to allow predators time to consume recently dispersed seeds before they are protected through burial, appear to have strong theoretical and empirical validity (Fig.…”

Tillage affects the activity‐density, absolute density, and feeding damage of the pea leaf weevil in spring pea

“…CT pea plots were plowed in the spring of 2000 to a depth of approximately 18 cm, and subsequently chisel plowed to a depth of 22 cm in the fall of 2000 and 2001. To prepare the seedbed, CT plots were cultivated and harrowed each spring with two passes using a field cultivator (Hatten et al., 2007b). The NT plots were not disturbed prior to planting, and both CT and NT were seeded on the same days in each year.…”

“…To prepare the seedbed, CT plots were cultivated and harrowed each spring with two passes using a field cultivator (Hatten et al, 2007b). The NT plots were not disturbed prior to planting, and both CT and NT were seeded on the same days in each year.…”

“…However, during the 2003 mark-recapture studies, pesticides were directed away from the cages. No fertilizer was applied to pea during the experiments, but fertilizer was applied to the plots when they were planted to other crops during the rotation (see Hatten et al, 2007b). Additional information on management of the Kambitsch plots is presented by Hatten et al (2007b).…”

“…Pitfall trapping is commonly employed to sample soil‐ and litter‐dwelling invertebrates and has been used for prior studies of PLW and other soil arthropods in pea production systems in the Palouse (Hatten et al., 2007b; Hanavan et al., 2008). The method allows inexpensive and relatively easy estimation of population abundances or arthropod community metrics (Sunderland et al., 1995).…”