Dung beetle species interactions and multifunctionality are affected by an experimentally warmed climate

Abstract

While substantial eff ort has been invested in modelling changes in species distribution with climate change, less attention has been given to how climate warming will aff ect interactions among co-occurring species, and the cascading functional consequences. In this study, realistic dung beetle communities were subjected to an experimental warming treatment and the net eff ect on the functions of dung decomposition (in terms of dung mass) and plant productivity (in terms of biomass production of ryegrass grown on soil from underneath the dung pats) were examined. A priori, we hypothesized that the largest tunneling species would be functionally dominant, and be diff erently aff ected by experimental warming compared to pat-dwelling, smaller species. In terms of dung decomposition, the largest beetles did prove to be the functionally most important, with the qualitative pattern unaff ected by experimental warming. In contrast, for plant productivity all species appeared equally important under ambient conditions. However, the eff ects of single species on plant productivity were reduced as temperature increased: In a warmed climate, a combination of both tunneling and pat-dwelling species came the closest to returning ecosystem functioning to levels found in the ambient treatment. Th ese results suggest diff erent roles for diff erent species, and highlight the importance of maintaining multiple species within an ecosystem -particularly when systems are perturbed.

The importance of species identity and interactions for multifunctionality depends on how ecosystem functions are valued

“…We also expected different species to modify the functional effect of each other (Lähteenmäki et al. ), and the functional efficiency of species to change with a change in the environment (Slade and Roslin ). Tunneling species ( G. stercorarius and A. erraticus ) are expected to contribute strongly to bioturbation of dung and soil, facilitating decomposition of dung, recycling of nutrients between dung and plants, and microbial activity (Slade et al.…”

“…Tunneling species ( G. stercorarius and A. erraticus ) are expected to contribute strongly to bioturbation of dung and soil, facilitating decomposition of dung, recycling of nutrients between dung and plants, and microbial activity (Slade et al. , Slade and Roslin ). Small‐bodied species living within dung pats ( A. pedellus and A. fossor ) are expected to contribute to the aeration of the pats, thus lowering fluxes of the greenhouse gas methane, which are greatest under anaerobic conditions (Penttilä et al.…”

“…) are expected to result in contrasting species contributions to individual functions (Slade et al. , Slade and Roslin ). Within the dung pat, species will exploit slightly different parts of the dung (Holter ) using different breeding strategies, and will have preferences for dung of varying ages (Gittings and Giller , ).…”

“…Thus, we expect the activity of different species to positively affect or complement each other, and complementarity in resource use to generate an overall positive correlation between species richness and functioning (Slade et al. , Slade and Roslin ) (Fig. ).…”

Increased temperature delays the late-season phenology of multivoltine insect

“…In ectotherms, increased ambient temperature has direct consequences for metabolic rates, activity patterns, and developmental rates111213141516. Multi-generation (i.e.…”