Season determines the efficiency of a rapid sampling protocol for non‐acarine arachnids (Chelicerata: Arachnida) in Afrotemperate grassland biotopes

Abstract

AbstractThe Grassland Biome covers large parts of the inland plateau of South Africa, but many areas have historically been poorly sampled for arachnids. This study aimed to survey non‐acarine arachnids in western KwaZulu‐Natal and compare their biodiversity during winter (June and July 2015) and summer (December 2015 and January 2016). A standardised rapid sampling protocol was used to collect specimens from four biotopes (riparian bush, montane grasslands, lowland grasslands and Eucalyptus plantations). In total, 4623 non‐acarine arachnids were collected, representing five orders, of which 185 spp. were represented by adult specimens (n = 774). Although overall abundance (including immatures) was higher in winter, more adult individuals and species were collected in summer (n = 425, 139 spp.) than in winter (n = 349, 89 spp.). Day hand collecting yielded the highest abundance and species richness during both seasons, and largest number of unique species overall, while Berlese–Tullgren funnels were generally the least efficient method. Seasonal changes in assemblage composition are the result of considerable differences in phenology between the dominant families, resulting in only a small degree of overlap (23.2%) in the adult arachnid fauna between seasons. Several methods collected low adult species richness, but when combined, sample completion values were above 50% for both seasons and overall. This study has highlighted the importance of implementing rapid sampling protocols in multiple seasons to broaden knowledge of local species richness, to effectively address conservation and management objectives.