Sand Hill Arthropods in Canadian Grasslands

Sand hill environments in the Canadian grasslands can be classified as sandstone outcrops, upland dunes, sand features associated with water, non-human disturbances, anthropogenic disturbances, beach dunes, or sandbars. Insects and other arthropods use these environments for burrow construction, access to sand-associated host plants, open ground predation and scavenging, thermoregulation, and locomotion in a quiet substrate. The arthropod faunas of sand hills in the Canadian grasslands are diverse, include organisms that are specific to sand hills, and include a number of rare or endemic taxa. Dune stabilization is cause for conservation concern, whereas the threat of global warming may reverse the stabilizing trend and create larger areas of open drifting sand. Résumé. Les milieux dunaires des prairies canadiennes peuvent être divisés en plusieurs catégories : affleurements de grès, dunes des hautes terres, terrains sableux liés à la présence de l’eau ou aux perturbations liées ou non à l’homme, plages ou barres de sable. Les insectes et les autres arthropodes utilisent ces milieux pour creuser leurs terriers, accéder aux plantes hôtes adaptées à ces conditions, profiter du terrain découvert pour trouver leurs proies vivantes ou mortes, assurer leur thermorégulation et se déplacer sans bruit. La faune des arthropodes des dunes des prairies canadiennes est diversifiée et comprend des organismes spécialement adaptés à ce milieu, y compris un certain nombre de taxons rares ou endémiques. La stabilisation et la préservation des dunes suscitent des préoccupations, et le changement climatique risque de renverser la tendance à la stabilisation et de créer ainsi de vastes superficies de sables mouvants. Introduction to Sand Hill Environments Among the various subregions of the prairie grasslands in Canada, “sand hills” are associated with one of the most distinctive faunas of insects and other arthropods. Some, such as tiger beetles (Coleoptera: Carabidae, Cicindelinae) and sand wasps (Hymenoptera: Crabronidae, Bembicinae), are classic open sand organisms. However, the diversity of arthropods associated with sandy substrates also includes a variety of organisms with less obvious sand adaptations and sand-adapted members of groups generally not associated with sandy habitats. The terms ammophilous and psammophilous are used ambiguously for both sandadapted and sand-associated terrestrial arthropods (e.g., Hefetz et al. 1984; Sole et al. 2005), as well as for marine organisms in benthic sands under water or in the intertidal zone. For clarity, the terms “sand-adapted” and “sand-associated” will be used in the current chapter. Sand hill environments, as defined here, have been formed by the actions of wind and/or water on reworked sandstone bedrock. Indeed, much of the bedrock underlying the grassland region of Canada consists of poorly consolidated sandstone, most of it dating from the Cretaceous and Paleogene periods (Acorn 2007a). Erosion of this sort of bedrock results in ample volumes of loose sand, which may be reshaped to form dunes, sandbars, blowouts, and other types of sandy sites. Further disturbance of these topographic features, Acorn, J. H. 2011. Sand Hill Arthropods in Canadian Grasslands. In Arthropods of Canadian Grasslands (Volume 2): Inhabitants of a Changing Landscape. Edited by K. D. Floate. Biological Survey of Canada. pp. 25-43. © 2011 Biological Survey of Canada. ISBN 978-0-9689321-5-5 doi:10.3752/9780968932155.ch2