Ecosystem functioning in relation to species identity, density, and biomass in two tunneller dung beetles

Abstract

1. Species abundance, biomass, and identity are the main factors that influence ecosystem functioning. Previous studies have shown that community attributes and species identity help to maintain natural ecosystem functioning. 2. This study examined how species identity, biomass, and abundance in dung pats (i.e. density) of dung beetles affect multiple ecological functions: dung removal, seed dispersal, and germination. Specifically, two species of tunnellers were targeted: Onthophagus illyricus (Scopoli, 1763) and Copris lunaris (Linnaeus, 1758). In accordance with their natural abundance, densities ranging from 10 to 80 individuals were considered for O. illyricus, and those from two to eight were considered for C. lunaris, spanning the total biomass per treatment from 0.22 to 1.76 g. 3. Results showed that, even at higher abundance, O. illyricus is not as efficient as C. lunaris. These results show that species identity, biomass, and density are crucial factors for maintaining ecosystem functioning. The combined effect of species identity and density/biomass facilitated dung removal and seed dispersal. Conversely, species identity is the only relevant factor for germination. Moreover, relationships among functions depend on the species investigated: C. lunaris showed a positive correlation between dung removal and seed dispersal, whereas O. illyricus showed a positive correlation between germination and dung removal. 4. In conclusion, optimal ecosystem functioning depends on multiple factors, such as density and species identity, and thus also on body size, nesting strategies and ecological functions investigated. Moreover, the loss of larger and efficient species cannot be compensated by higher abundances of small species.

Primary forest loss and degradation reduces biodiversity and ecosystem functioning: A global meta‐analysis using dung beetles as an indicator taxon

“…This functional group requires larger quantities of excrement for feeding and nesting that can only be generated by large mammals, which are the first to disappear with vegetation cover changes due to anthropogenic perturbation, potentially explaining the observed sensitivity to changes in tunnelling beetles (Raine & Slade, 2019). The disappearance of large species can exacerbate negative effects for ecosystem functioning since these are the species that make the greatest functional contribution (Piccini et al, 2019).…”

Wood Pastures: A Transitional Habitat between Forests and Pastures for Dung Beetle Assemblages

“…During this one-year sampling in three locations, nearly half of the species of Hungarian dung beetle fauna were recorded; this seems to be outstanding for the results of the mosaic-like structural complexity of the studied habitats. The conservation of dung beetles should focus on maintaining compositional diversity, as different species have different roles, and the loss of a species cannot be compensated by the presence of others [70]. Species-specific thermal tolerance is very important [71], as is poor flight capacity limiting dispersal that potentially leads to local extinctions if habitats are further degraded (e.g., Storck-Tonon et al [72]).…”

A trait‐based framework for dung beetle functional ecology

“…Protibia area is the only trait known to relate to burrow depth (Macagno et al, 2016 ). Several non‐morphological traits, such as thermal tolerance, yearly and daily activity period, dung colonization stage, and interactions between individuals and sex within species may also indirectly affect dung removal (Giller & Doube, 1989 ; Nervo et al, 2022 ; Piccini et al, 2020 ), reducing nitrogen loss from dung pats (Gillard, 1967 ), since nutrient content decreases with dung aging (Holter, 2016 ).…”