DOI: 10.4225/08/5aa706d95615e
title: Dynamic effects of ground-layer plant communities on beetles in a fragmented farming landscape

description: Seasonal differences in beetle assemblages and the vegetation community in woodland remnants compared with four adjoining farmland uses. Study area was a highly modified agricultural landscape in eleven sites in the Lachlan River Catchment, New South Wales, Australia. 

Seasonal differences in beetle assemblages and the vegetation community in woodland remnants compared with four adjoining farmland uses. Study area was a highly modified agricultural landscape in eleven sites in the Lachlan River Catchment, New South Wales, Australia. Our survey design consisted of four 400 m transects running from inside each patch out into the adjoining farmland. We sampled beetles and vegetation at three locations along each transect: 200 m inside the patch, 200 m inside the farmland, and 0 m at the patch-farmland boundary. 

We sampled from the same trap location during two distinct periods in terms of plant phenology and agronomic practices in farmland: spring when crops and spring-active species were at peak growth, and summer when crops have been harvested (stubble retained; fine woody debris treatment applied) and summer-active species at peak growth. Each sampling location comprised a pair of pitfall traps, consisting of plastic jars (6.5 cm diameter, 250 ml) dug into the ground with the rim level with the soil surface, filled with 100 ml of preservative (1:3 glycol – water mixture, and a drop of detergent to reduce surface tension). Individual traps from each pair were placed on either side of a drift fence (60 cm long x 10 cm high) to help direct arthropods into the trap. We opened a total of 132 pairs of traps (11 replicate sites x 4 transects x 3 trap pairs) for 14 days during spring (October–November 2014) and summer (January–February 2015).

During beetle sampling in spring and summer, the same observer (KN) recorded: (1) six vegetation structural variables (vegetation height and cover of litter, native forb, native grass, exotic perennial grasses, exotic annual forbs and grasses) within a 20 × 10 m plot centred around the sampling location (Table 1); and (2) the composition of all plant species from five 1 × 1 m quadrats placed randomly within each 20 × 10 m plot. Plant species composition data were pooled from these quadrats for each sampling location.

Our survey design consisted of four 400 m transects running from inside each patch out into the adjoining farmland. We sampled beetles and vegetation at three locations along each transect: 200 m inside the patch, 200 m inside the farmland, and 0 m at the patch-farmland boundary. Individual traps from each pair were placed on either side of a drift fence (60 cm long x 10 cm high) to help direct arthropods into the trap. Traps were plastic jars (6.5 cm diameter, 250 ml) dug into the ground with the rim level with the soil surface, filled with 100 ml of preservative (1:3 glycol – water mixture, and a drop of detergent to reduce surface tension). We sampled from the same pitfall trap locations during two distinct periods of the cropping cycle: spring when crops were at peak flowering, and summer after crop harvest (stubble retained).