Circumpolar terrestrial arthropod monitoring: A review of ongoing activities, opportunities and challenges, with a focus on spiders

Abstract

The terrestrial chapter of the Circumpolar Biodiversity Monitoring Programme (CBMP) has the potential to bring international multi-taxon, long-term monitoring together, but detailed fundamental species information for Arctic arthropods lags far behind that for vertebrates and plants. In this paper, we demonstrate this major challenge to the CBMP by focussing on spiders (Order: Araneae) as an example group. We collate available circumpolar data on the distribution of spiders and highlight the current monitoring opportunities and identify the key knowledge gaps to address before monitoring can become efficient. We found spider data to be more complete than data for other taxa, but still variable in quality and availability between Arctic regions, highlighting the need for greater international co-operation for baseline studies and data sharing. There is also a dearth of long-term datasets for spiders and other arthropod groups from which to assess status and trends of biodiversity. Therefore, baseline studies should be conducted at all monitoring stations and we make recommendations for the development of the CBMP in relation to terrestrial arthropods more generally.

Keywords: Bioindicators; Climate change drivers; Community composition; Surrogates for biodiversity.

Fig. 1

Circumpolar map indicating the locations of research stations with current or expected future arthropod monitoring activities. Details of the stations are in Table 1

Fig. 2

The diversity of the main spider families in the circumpolar region (those present in seven or more regions; the Other category consists of 10 families—see Table 2; note Franz Josef Land with only two Linyphiidae species is omitted for clarity). The size of the pie charts corresponds to the total richness of each area (see Table 2). Note that species richness for sub-Arctic regions consists only of alpine species, except for Canada, which includes both alpine and non-alpine species. The red dots indicate monitoring stations that target arthropods (Fig. 1, Table 1), but with those not using techniques to capture spiders removed

Fig. 3

Abundance of individuals per trap across the snow-free season and for all habitats combined, from 1996 to 2014 at Zackenberg Research Station, North-East Greenland, separated by key spider species. Abundances have been calculated to control for trapping effort by calculating abundance per trap-day for each trap, and then multiplying this value by the total number of trap days for the site (85). Solid lines are linear regression lines, significant at the p < 0.05 level. (Redrawn with permission from Bowden et al. 2018)