Quantifying immediate and delayed effects of anthelmintic exposure on ecosystem functioning supported by a common dung beetle species

Abstract

Dung beetles (Coleoptera: Scarabaeoidea) support numerous ecosystem functions in livestock-grazed pastures. Exposure to veterinary anthelmintic residues in livestock dung can have lethal and sublethal effects on dung beetles, and can reduce rates of dung removal, but the immediate and longer-term consequences for other dung beetle mediated functions have rarely been studied. We investigated the consequences of anthelmintic exposure on survival of the dung beetle Aphodius fossor and its delivery of four ecosystems functions that underpin pasture production: dung removal, soil fauna feeding activity, primary productivity, and reduction of soil compaction. We tested whether anthelmintic exposure had immediate or delayed effects on these functions individually and simultaneously (i.e., ecosystem multifunctionality). We found no evidence that ivermectin residues had a lethal effect on adult beetles. For dung removal, we found a significant interaction between the timing of exposure and functioning: while dung removal was impaired by concurrent exposure to high levels of ivermectin, functioning was unaffected when beetles that had been exposed previously to the same concentration of anthelmintic later interacted with untreated dung. Other ecosystem functions were not affected significantly by anthelmintic exposure, and there was no evidence to suggest any persistent impact of anthelmintic exposure on ecosystem multifunctionality. While anthelmintic residues remain a significant threat to dung beetle populations, for adult beetles, we found no evidence that residues have detrimental consequences for ecosystem functioning beyond the immediate point of exposure.

Reproductive sublethal effects of macrocyclic lactones and synthetic pyrethroids on the dung beetle Onthophagus similis

“…Over a period of 36 weeks, mixed species assemblages of Aphodius and Onthophagus dung beetles were shown to achieve the highest cattle dung decomposition rates in comparison to monoculture treatments, when the biomass of beetles was standardised (Beynon et al, 2012). A similar conclusion was reached in a study by Manning et al (2017) where the dung-removing capacity of Aphodius ater (De Geer), Aphodius fossor (L.) and…”

A niche for ecosystem multifunctionality in global change research

“…Thus, metrics of multifunctionality often qualitatively reflected the positive or negative responses of some single functions, while other single functions showed an opposite response or no response (Alsterberg et al, ; Antiqueira et al, ; Bradford et al, ; Ramus et al, ). The inverse was also observed, whereby global change drivers affected some single functions but not others, producing no discernible overall effects on EMF (Alsterberg, Sundback, & Gamfeldt, ; Manning et al, ). In contrast, others found that nearly all single functions responded in the same manner, which was inevitably reproduced in the multifunctionality metric (Chandregowda, Murthy, & Bagchi, ; Luo et al, ; Quero et al, ).…”

“…Abiotic and biotic components interact with each other, for example, through the impact of soil compaction on plant roots and nutrient uptake global change on EMF (Liu et al, 2017;Robroek, Jassey, & Hefting, 2017;Zhang, Eldridge, & Delgado-Baquerizo, 2016). Importantly, other studies considered it vital to understand (or just summarize) the complex trade-offs and interactions that occur among global change drivers and multiple functions, for example, when functions are not correlated with each other (Birkhofer et al, 2018;Luo et al, 2018;Manning, Beynon, & Lewis, 2017;Vandandorj, Eldridge, Travers, & Delgado-Baquerizo, 2017;Zhang et al, 2016).…”

“…| 767 facets (here we refer to "essential biodiversity variables" as defined by Pereira, Ferrier, & Walters, 2013), including reporting the impact of global change on community composition, species and phylogenetic diversity, and trait distributions (Figure 1a). Populations of single species were also considered, such as increased cover of an invasive seaweed that provided habitat structure (Ramus, Silliman, Thomsen, & Long, 2017) or the survival of dung beetles after exposure to veterinary drugs (Manning et al, 2017). Nearly all of the reviewed studies formally tested the mediation of global change effects on EMF by shifts in some aspect of biodiversity (Supporting information affecting the foraging activity of organisms (Mattos & Orrock, 2010).…”

Ivermectin residues in cattle dung impair insect‐mediated dung removal but not organic matter decomposition

“…()) dung removal is not always positively linked to other ecosystem functions. For instance, while dung removal by the dung beetle Aphodius fossor was negatively affected by 0.5 mg kg −1 exposure to ivermectin, exposure had no significant effect on three other relevant ecosystem functions (Manning et al ., ). While our results suggest that flies have a limited importance for dung removal compared with beetles, their importance may be much more significant when considering other pasture‐relevant ecosystem functions.…”