Effects of varying retention tree patterns on ground beetle (Coleoptera: Carabidae) taxonomic and functional diversity

Abstract

Managing forests intensively for timber production can homogenize forest structure and, in turn, alter species richness and functional composition of native species communities. Retention forestry, the practice of retaining structural elements during timber harvest, can increase species diversity in recently harvested forests, but its effect on functional trait diversity is less understood. We used a broadscale, replicated experiment to evaluate the effect of five tree retention patterns on species and functional trait diversity of ground beetles (Family: Carabidae) within early-seral production forests in the Pacific Northwest, USA. We found no evidence for differences in carabid species or functional trait richness among treatments when considering species present in retention patches and adjacent clear-cuts. However, we found evidence for lower taxonomic and functional trait variation between carabid communities present in retention patches and those present in clear-cut areas of stands when retention was allocated to several small patches. Lower levels of functional trait variation in stands with several small patches were due to specialized predators found less often in small retention patches than in aggregated or riparian retention patches. Our findings indicate that relative to single large or riparian-associated patches, small retention patches functioned similarly to clear-cuts within harvested forests and several small patches did not increase species or functional trait richness. At current levels of retention in the region, allocation of trees to a single upland patch or split between riparian and upland patches can increase variation in ground beetle taxonomic and functional composition within harvested forests.

A novel method for monitoring ground-dwelling arthropods on hard substrates: characterizing arthropod biodiversity among survey methods

“…In addition to trap structure affecting captures, trapping efficiency of pitfalls can be impacted by habitat around the trap, with more open habitat structure significantly increasing species richness and composition observed [54]. Pitfalls used in the present study were a 100 ml transparent plastic specimen container, 7.5 cm in height with a 4.5 cm diameter opening, filled with soapy water (Dawn Original Liquid Dish Soap) (using similar methodology to Cates et al, 2021; Sultaire et al, 2021; Wills et al, 2019). An orange marking flag was placed next to sampling stations so that traps could be located within the vegetation (Figure 1b).…”

“…Pitfall traps consisted of a 100 ml transparent plastic specimen container, 7.5 cm in height with a 4.5 cm diameter opening, filled with soapy water (Dawn Original Liquid Dish Soap, Procter & Gamble, Cincinnati, OH, USA) (using similar methodology to Cates et al, 2021; Sultaire et al, 2021; Wills et al, 2019) (Figure 1a). Yellow ramp traps (ChemTica Internacional S.A., Santo Domingo, Costa Rica) were square yellow plastic containers (14 × 14 × 13 cm) with a roof and detachable ramps (30% slope) on four sides, placed on the ground’s surface and filled with soapy water (Figure 1b).…”

Coleoptera associated with intermittent streams and their riparian zones in south coastal British Columbia

“…Some beetle species are able to colonise streambeds after drying, whereas others may specialise in riparian habitats (Ramey and Richardson 2017). Previous studies in British Columbia and the Pacific Northwest region of the United States of America have compared beetle abundance and diversity in riparian areas to those in upland areas (Rykken et al 2007(Rykken et al , 2011Sultaire et al 2021); however, we are unaware of any published research that addresses how beetles use stream-edge and dry-streambed habitat in British Columbia. Here, we asked how beetle abundance and taxonomic richness compare across stream types (perennial versus intermittent), flow phases (flowing versus nonflowing), and riparian versus streambed habitats.…”