The impact of the introduced Digitonthophagus gazella on a native dung beetle community in Brazil during 26 years

Abstract

Following successful establishment in Australia and North America, the South African dung beetle (DB) Digitonthophagus gazella was introduced in Brazil in 1990. We investigated the impact of the exotic species on the native community of 42 native DB species using a unique weekly data set spanning 26 years, including 4 years of pre-invasion data. The invasion of D. gazella was very rapid with abundances increasing by 4 orders of magnitude during the first few years following establishment. We show that the DB diversity shrank to sixty percent of the preinvasion level. Results from multivariate analyses identified three distinct periods of changes in composition and abundance: before the invasion (BI); after invasion I (AI-I); and AI-II each one characterized by a particular dynamic of the native species. The impacts on the native species differed according to their nesting behavior. Species with the same behavior as D. gazella (tunneler) became less abundant and five species went locally extinct. Dweller species, in contrast, became more abundant. Although the analysis of all species combined showed an increase in abundance and a less oscillatory dynamic in AI-II compared to BI, this was the case only for the dweller species, as the tunnelers showed a tendency to continued decrease throughout the 26-year study. Our results show that a new community was originated as a consequence of the invasion, in which dweller species, particularly Labarrus pseudolividus, are the dominant species and all the tunnelers, including D. gazella, are decreasing in abundance. Keywords Scarabaeidae Á Biological invasion Á Invasive species Á Native community Á Dung beetles Á Pasture area Electronic supplementary material The online version of this article (

Global distribution patterns provide evidence of niche shift by the introduced African dung beetleDigitonthophagus gazella

“…Evaluation of potential negative interactions between D. gazella and other native dung beetles (i.e., competition, spatial displacements, or local extinctions) has been generally inconclusive, especially in saturated dung beetle assemblages (Noriega et al, 2017). Although reports from the USA, Mexico, the West Indies, and Brazil suggest that introduced D. gazella have caused a decline in native species (Howden & Scholtz, 1986; Montes de Oca & Halffter, 1995; Young, 2007; Ivie & Philips, 2008; Filho et al, 2017), this is disputed by other findings from the USA, Mexico, and Nicaragua (Lobo & Montes de Oca, 1994; Howden & Howden, 2001; Horgan, 2008; Tiberg & Floate, 2011). Nevertheless, studies from the USA and Brazil indicate clear changes in the abundance structure of assemblages (Fincher et al, 1986; Filho et al, 2017), and studies from the USA and Australia indicate changes in the dominance of D. gazella in terms of assemblage abundance (Edwards, 2003; Kaufman & Wood, 2012).…”

Dung beetle species introductions: when an ecosystem service provider transforms into an invasive species

“…Its invasion has reduced native dung beetle diversity by some 40% during a period of 26 years in areas of Brazil (Filho et al, 2018). However, they have used black-light flight-intercept traps to capture dung beetles weekly only from dusk to dawn (Filho et al, 2018). Six native dung beetle species are reported to be locally extinct, and other native dung beetle species have declined their abundance (Filho et al, 2018).…”

“…However, they have used black-light flight-intercept traps to capture dung beetles weekly only from dusk to dawn (Filho et al, 2018). Six native dung beetle species are reported to be locally extinct, and other native dung beetle species have declined their abundance (Filho et al, 2018). The invasion has changed native dung beetle communities as it outcompeted the native tunneller species-as their nesting behaviour and phenology overlap with D. gazella-resulting the appearance of new native dweller species (Filho et al, 2018).…”

“…Six native dung beetle species are reported to be locally extinct, and other native dung beetle species have declined their abundance (Filho et al, 2018). The invasion has changed native dung beetle communities as it outcompeted the native tunneller species-as their nesting behaviour and phenology overlap with D. gazella-resulting the appearance of new native dweller species (Filho et al, 2018). Tunnellers, such as D. gazella, dig tunnels beneath the dung pats and store the dung balls into the nest whilst, the dwellers just feed, make broods and reproduce just within the dung pats (Bornemissza, 1976).…”

“…Dung beetle species do not have any direct impacts through predation, parasitism, or by causing diseases to other taxa (Bornemissza, 1979;Dymock, 1993;Mackereth et al, 2013). Therefore, the impact of introduced dung beetle species is considered indirect usually because they compete with native or resident dung beetle species and can lead to change in their assemblage (Blanco et al, 2013;Filho et al, 2018;Tyndale-Biscoe, 1990). The objective assessment of the environmental and economic impacts of any invasive species needs a comprehensive method (Ricciardi et al, 2017;Simberloff et al, 2013;Simberloff & Stiling, 1996).…”