Capturing northern biodiversity: diversity of arctic, subarctic and north boreal beetles and spiders are affected by trap type and habitat

Abstract

Rapid environmental changes in arctic, subarctic and boreal biomes are fuelling the need for effective biodiversity monitoring programs in these regions. Terrestrial arthropods are ideal focal taxa for monitoring, but quantitative comparisons of the efficacy and outcomes of different sampling protocols are limited. Here, the influence of trap type (yellow pan trap or traditional pitfall) and habitat (wet or mesic) on the abundance and diversity of ground‐dwelling arthropods is determined for samples collected in the three northernmost ecoclimatic zones of Canada, using over 32 000 specimens of beetles and spiders. Trap and habitat both influence the abundance, richness, and assemblage composition of arthropods collected, but these effects differ between ecoclimatic zones and depend on taxonomic resolution. Sampling in different habitats yields greater diversity than sampling with different traps in the high arctic, while the inverse is true in the north boreal zone, and neither factor appears to have a significant effect on the diversity of arthropods collected in the subarctic. In all zones, the addition of recessed yellow pan traps to a traditional pitfall trap‐based sampling regime results in the capture of many additional unique species, suggesting that colour is an attractant for at least some ground‐dwelling taxa. These findings have significant implications for large‐scale terrestrial diversity monitoring programs being established or implemented in northern systems. It is recommended that sampling regimes be designed to maximize the diversity of arthropods collected, by including a minimum of two distinct habitats and by using yellow pitfall traps.

A DNA Barcoding Survey of an Arctic Arthropod Community: Implications for Future Monitoring

“…Pitfall traps are a standard method for sampling ground-dwelling arthropod species [37], but the diversity sampled with pitfall traps in this study was surprisingly low-155 BINs in total, of which only 12 were not captured by any other method. By contrast, soil and leaf litter sifting produced most of the unique BINs of Acari and Collembola (77 and 18 BINs, respectively), and the total number of unique BINs recorded with sifting was on par with Malaise traps (110 vs. 112 BINs; Figures 4 and 5).…”

Small to large-scale patterns of ground-dwelling spider (Araneae) diversity across northern Canada

“…In each ecoclimatic region, four sites were selected for sampling. At each site, we sampled grounddwelling arthropods in mesic and wet natural open habitat (i.e., no canopy cover by trees) to capture a greater diversity of arthropods (Ernst et al 2016). Mesic open sites were characterized by elevated topography and well-drained soils.…”

The Effect of Road Proximity on Arthropod Communities in Yukon, Canada + Supplementary Appendix 1 (See Article Tools)

“…We chose yellow pans because of their proven effectiveness at sampling arthropods, especially in the North (Blades and Marshall, 1994;Gollan et al, 2011;Ernst et al, 2016). Pan traps are known to attract certain taxa more than others (Ernst et al 2016): for example, they �r� mor� �ffici�n� �� c�p�uring flying ins�c�s �h�n m�ny ground-dwelling groups like spiders (Ernst et al, 2016), but this is likely not a major issue in our study since we are focusing on the patterns of change within groups and no� �h� �bso�u�� �bund�nc�s� W� ins�����d �h� p�ns flush wi�h �h� ground �nd fi���d �h�m wi�h �r�p �iquid �o � d�p�h of approximately 2 cm. The liquid consisted of equal parts w���r �nd �V p�umb�r's �n�ifr��z�, wi�h � sm��� �moun� of dish detergent (Thomas, 2008).…”