Functional diversity and seasonal activity of dung beetles (Coleoptera: Scarabaeoidea) on native grasslands in southern Alberta, Canada N. Kadiri, 1 J.-P. Lumaret, K.D. Floate Abstract—To characterise their functional diversity and seasonal activity, dung beetles (Coleoptera: Scarabaeoidea) were collected with baited pitfall traps at three sites for three years on a native grassland in southern Alberta, Canada. The total collection of 125 820 beetles comprised 12 species of which eight were of European origin. For each combination of site and year, assemblages were dominated by two or three core species of European origin that represented 70–95% of total beetles and more than 75% of total biomass, but only 10–30% of species richness. Core species consistently included Onthophagus nuchicornis (Linnaeus) and occasionally Chilothorax distinctus (Mu ¨ller) and Colobopterus erraticus (Linnaeus). Coexistence of these core species appears to be facilitated by differences in their size, seasonal activity, and life history traits. Re ´sume ´—Afin de caracte ´riser leur diversite ´ fonctionnelle et l’activite ´ saisonnie `re, des cole ´opte `res coprophages (Coleoptera: Scarabaeidae) ont e ´te ´ collecte ´s avec des pie `ges standards appa ˆte ´s sur trois sites pendant trois ans dans la prairie naturelle de Purple Springs dans le sud de l’Alberta, Canada. 125 820 cole ´opte `res ont e ´te ´ collecte ´s, re ´partis en 12 espe `ces, dont huit d’origine europe ´enne. Pour chaque combinaison de site et d’anne ´e, les assemblages d’espe `ces e ´taient domine ´s a ` chaque fois par seulement deux a ` trois espe `ces, toutes d’origine europe ´enne, formant un noyau fonctionnel rassemblant 70 a ` 95% du total des individus et plus de 75% de la biomasse totale, mais seulement 10 a ` 30% de la richesse spe ´cifique. Les noyaux fonctionnels incluaient syste ´matiquement Onthophagus nuchicornis (Linnaeus), avec parfois Chilothorax distinctus (Mu ¨ller) et Colobopterus erraticus (Linnaeus). La coexistence entre les espe `ces dominantes est facilite ´e par des diffe ´rences de taille, ou de phe ´nologie et de traits d’histoire de vie en cas de taille comparable. Introduction The degradation of organic materials on pas- tures is a complex process in which micro- organisms and edaphic fauna at and just below the soil surface play a key role. Dung beetles (Coleoptera: Geotrupidae and Scarabaeidae) are common participants in this process and promote pasture quality by accelerating the decomposition of cattle dung and its incorporation back into the soil. In California, United States of America (Anderson et al. 1984) and southern France (Lumaret and Kadiri 1995), dung deposited on pastures in May and July, respectively, fully degraded in 18 months in the presence of insects, but required up to four years when insects were excluded. In Great Britain, dung deposited on pastures in mid-June was largely degraded in 100 days, but showed few signs of degradation when insects were excluded (Wall and Strong 1987). In Alberta, Canada, dung deposited on native pastures in May was mostly degraded after 340 days, but showed no signs of degradation if first treated with an insecticide (Floate 1998). Dung beetle activity may also reduce popu- lations of pestiferous flies and gastrointestinal N. Kadiri, 1 De ´partement Biologie-Ecologie-Environnement, Laboratoire de Zooge ´ographie, UMR 5175 CEFE, Universite ´ Paul-Vale ´ry Montpellier 3, Route de Mende, 34199 Montpellier cedex 5, France; and Lethbridge Research Center, Agriculture and Agri-Food Canada, Lethbridge, Canada AB T1J 4B1 J.-P. Lumaret, De ´partement Biologie-Ecologie-Environnement, Laboratoire de Zooge ´ographie, UMR 5175 CEFE, Universite ´ Paul-Vale ´ry Montpellier 3, Route de Mende, 34199 Montpellier cedex 5, France K.D. Floate, Lethbridge Research Center, Agriculture and Agri-Food Canada, Lethbridge, Canada AB T1J 4B1 Corresponding author (e-mail: nassera.kadiri@univ-montp3.fr). Subject editor: Keith Summerville doi:10.4039/tce.2013.75 Received 28 May 2013. Accepted 28 July 2013. First published online 16 December 2013. Can. Entomol. 146: 291–305 (2014)  2013 Entomological Society of Canada 291