Land-use responses of dung beetle communities and their ecosystem services

During their feeding process, dung beetles perform a series of ecosystem functions that provide valuable ecosystem services, such as soil fertilization, improvement of soil properties, plant growth enhancement, and biological pest control. However, in the grasslands of the Central Asian dry steppe, the effects of dung beetles on dung removal remain almost unstudied. Here, we examined dung removal by different dung beetle species (Colobterus erraticus (Linnaeus, 1758), Onthophagus bivertex Heyden, 1887, Onthophagus gibbulus (Pallas, 1781), Gymnopleurus mopsus (Pallas, 1781), Cheironitis eumenes Motschulsky, 1859, and Geotrupes koltzei Reitter, 1892), and compared the impacts with control treatments (without beetles) under natural pasture conditions and in the laboratory. We examined the influence of different variables on dung removal rates, such as dung type and dung beetle traits (nesting strategies, abundance, body size, and biomass). We found higher dung removal rates during the initial 48 h in field and laboratory conditions. Among nesting strategies, tunnellers demonstrated significantly higher dung removal rates than dweller and roller species. The highest amount of dung removal was estimated for C. eumenes (6.5 g/day by seven individuals). We found no significant relationship between dung removal rates and dung beetle body size or biomass, but we observed a strong negative correlation between dung beetle abundance and dung removal rates. Our findings highlight the importance of dung type and age, nesting strategies and abundances of dung beetles, and experimental conditions, which are the main factors driving the process of dung removal.

Monitoring the ecosystem service provided by dung beetles offers benefits over commonly used biodiversity metrics and a traditional trapping method

Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest-dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm-dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.

Land use affects dung beetle communities and their ecosystem service in forests and grasslands

Herbivore dung quality (physical and chemical parameters) varies between animal species and animal diet which is influenced by seasonal fluctuations and farm management practices. Subsequently, this influences the reproductive success of dung beetles. In Australian pasture systems, how the introduced dung beetle assemblage interacts in the field with cattle dung derived from different resources is unknown. This study quantifies the colonization by dung beetles (abundance, species richness and evenness) and removal of cattle dung derived from three common temperate pasture systems (improved native, forage oat and rye/clover pasture, henceforth dung type) over 24 h for 12 months. From the three dung types, 13 species of dung beetle were captured. Abundance and species richness were influenced by month and transect, with weak evidence for differences between dung types influencing overall abundance: Onthophagus binodis (49.7%), Aphodius fimetarius (24.4%) and Labarrus lividus (17.1%) were the most abundant species. Dung removal (organic matter) was influenced by month and dung type, with more dung buried in improved native (23.9 g) and rye/clover (24.7 g) derived dung compared with forage oat (12.3 g) dung. Dung beetle abundance was positively correlated with removal of all dung types, with O. binodis biomass significantly influencing dung removal. This study showed that diet of bovine animals weakly influences the abundance of a local dung beetle assemblage, warranting further investigation on the influence of other dung types in different regions. Improvements to reporting of pasture species and growth stage is recommended for comparisons between dung derived sources.

We evaluated the effects of different land-use systems on the ability of dung beetles to control the population of detritus-feeding flies. We tested the hypotheses that intensification of land use will reduce dung beetles richness, abundance and biomass and, consequently, their dung burial ability, affecting the interaction between dung beetles and flies and reducing its effectiveness as a natural biological control. In the Brazilian Amazon we sampled dung beetles, fly larvae and adults; and recorded the rate of dung removal by dung beetles across a gradient of land-use intensity from primary forest, secondary forest, agroforestry, agriculture to pasture. Our results provide evidence that land-use intensification results in a reduction of the richness, abundance and biomass of dung beetles, and this in turn results in lower rates of dung removal in the most simplified systems. We found no significant differences in the abundance of fly larvae between the different systems of land use. However, the number of adult flies differed significantly between land-use systems, presenting higher abundance in those sites with greater intensity of use (pasture and agriculture) and a lower abundance of adult flies in forested systems (primary and secondary forests, and agroforestry). Information-theoretic model selection based on AICc revealed strong support for the influence of land-use systems, dung removal rates and dung beetle abundance, biomass and richness on adult dung-fly abundance. Our results also reveal that dung beetles are not solely responsible for fly control and that other factors linked to land use are influencing the populations of these detritus-feeding insects.

1. Changes in land use have been identified as one of the main drivers of global biodiversity loss, and also negatively affect ecosystem services. Dung beetles are capable of providing a variety of ecosystem services and can be used as bioindicators. 2. We assess whether the land use changes of the Cerrado areas for agricultural purposes (pasture and soybean crops) affects dung beetle community and the associated ecosystem services (dung removal and secondary seed dispersal) provided by dung beetles on their diversity in the Federal District, Brazil. 3. A total of 32 261 individuals (Scarabaeinae, Aphodiinae and Anaidinae) were collected. The abundance and biomass of dung beetles were significantly higher in soybean (n = 19 354; biomass = 1145.4 g) and pasture (n = 9865; biomass = 753.6 g) compared to cerrado (n = 3042; biomass = 311.6 g). Sixty‐one species were collected in the cerrado, 58 in soybean and 56 in pasture, most species were paracoprids (52–60%), but no significant differences were observed for the species richness and diversity indices among the different land use systems. The structure of the dung beetle community in areas of the cerrado was distinct from that in pasture and soybean areas, and the latter two were similar. The land use systems did not affect the ecosystem services provided by dung beetles. 4. Our results showed that the Cerrado dung beetle community was unique and specific, indicating an imperative need for its preservation, due to its intrinsic value and its importance for the functioning of the ecosystem.

Conversion of forest habitat to different land uses will change the environmental quality of the altered land. Since the relationship between anthropogenic disturbance and animal diversity and ecosystem services emerged, much scientific research has been conducted on this aspect. The present study focuses on comparing dung beetles, a known biological indicator, on examining five diverse environs (large forests, forest patches, Pinus plantations (Pinus caribaea), home gardens, and tea plantations) Coprophagous beetles of the subfamily Scarabaeinae (Coleoptera: Scarabaeidae). This study examined whether dung beetles' diversity, species richness, functional groups, and ecosystem services (dung removal) vary with the habitat types. We also assumed that the intensity of anthropogenic activities varies in these habitats. The experiment was conducted for 48 hours each in five habitat types with three selected replicates per each habitat type. The Shannon-Weiner Diversity Index shows that the highest dung beetle diversity is recorded in large forest areas (2.1719). The highest species abundance (186) and richness (22) were recorded in the large forest. The lowest species abundance was recorded in tea plantations (109). The lowest species richness was recorded in pinus plantations (10). Moreover, functional group diversity is high in habitats with fewer human activities. The dominant species in large forests is Onthophagus favrei (dominancy index-2.9%). In forest patches and pinus plantations, Onthophagus amphinasus (19%) and Paracopris signatus (36.30%) appeared consecutively. In home gardens and tea plantations, the most dominant species is Onthophagus unifasiatus (26.50% and 28.40%). Habitats with anthropogenic activities have less species richness and a high dominancy index. Furthermore, dung beetle resource relocation efficiency was skewed toward forest areas. The highest dung removal percentage was recorded in forest areas (large forest-9.58% and forest patches-7.33%). The dung removal in the anthropogenic activities related to land uses was decreased as a home garden (7.17%), Pinus plantation (6.58%), and tea plantation (5.42%). Moreover, large dung beetles (body mass≥0.5 g) were only recorded in large forests and forest patches. Low diversity in tea plantations could be attributed to pesticide and fertilizer usage, as beetles are highly sensitive to these chemicals. Pinus plantations showed low rates of dung removal because resource availability in those habitats is less due to the fewer mammals. These findings indicate that replacing forests and forest areas with simplified human residential areas and agricultural systems can result in shifts towards less specialized dung beetle communities with altered proportions to other animal groups. 
 Keywords: Scarabaeinae, Dung removal, Species richness, Species abundance, Dominance index

Dung beetles (Coleoptera: Scarabaeidae) feed on decomposing animal carcasses and mainly on dung that are also used for building their nests. This study aims to estimate the dung beetles ecosystems services in relation to dung removal and to secondary seed dispersal, as well as to characterize the beetles community based on richness, abundance, species composition and functional guilds, and verify how these ecological indicators are influenced by the habitat type and by the seasonal variation (dry and rainy season). The dung removal rate was only affected by the seasonal variation and was higher during the dry season. The seed dispersal presented a positive relation with the proportion of the dung removal. The richness and abundance of dung beetles were greater during the dry season; however, these indicators were not influenced by habitat types. The forest patch and pasture area only differed in relation to composition of species but the number of represented species of each functional guild did not vary significantly between the habitats. This study emphasizes the functional importance of dung beetles in ecosystems through their efficient development of primary (dung removal) and secondary (seed dispersal) ecosystem functions. Key-words: Richness, abundance, dung removal, seeds dispersal, seasonality.

Biodiversity drives ecological functioning, ultimately providing ecosystem services. Ecosystem processes are favored by greater functional diversity, particularly when groups of functionally different species interact synergistically. Many of such functions are performed by insects, among which dung beetles stand out for their important role in dung decomposition. However, anthropogenic disturbances are negatively affecting their ecological dynamics and ecosystem services. We conducted a manipulative field study to evaluate the effect of human disturbance on dung beetle diversity (abundance, species richness, and functional group richness) and dung removal rates, comparing perturbed and conserved forests in three regions of Colombia (Caribbean, Andes, and Amazon). We also assess the relationship between dung beetle diversity and dung removal rates. Dung beetle diversity was assessed using pitfall traps, and specimens were measured and assigned to functional groups according to body size and dung relocation strategy. We used exclusion control units and experimental units to assess dung degradation with and without dung beetle activity and evaluate differences in removal rates between two dung removal strategies: paracoprids and telecoprids. Dung removal rates, abundance, and functional group richness were lower in perturbed forests compared to conserved forests. Dung removal increased with abundance, species richness, and functional group richness. Moreover, dung removal performed by telecoprids increased with species richness of telecoprids and paracoprids. Our results evidence a negative effect of human perturbation on dung beetle richness, abundance, and dung removal rates, and also that dung beetle diversity and functional group richness enhance dung removal rates.Abstract in Portuguese is available with online material.

Spatio-temporal modelling suggests that some dung beetle species (Coleoptera: Geotrupidae) may respond to global warming by boosting dung removal

Dung removal by macrofauna such as dung beetles is an important process for nutrient cycling in pasturelands. Intensification of farming practices generally reduces species and functional diversity of terrestrial invertebrates, which may negatively affect ecosystem services. Here, we investigate the effects of cattle-grazing intensification on dung removal by dung beetles in field experiments replicated in 38 pastures around the world. Within each study site, we measured dung removal in pastures managed with low- and high-intensity regimes to assess between-regime differences in dung beetle diversity and dung removal, whilst also considering climate and regional variations. The impacts of intensification were heterogeneous, either diminishing or increasing dung beetle species richness, functional diversity, and dung removal rates. The effects of beetle diversity on dung removal were more variable across sites than within sites. Dung removal increased with species richness across sites, while functional diversity consistently enhanced dung removal within sites, independently of cattle grazing intensity or climate. Our findings indicate that, despite intensified cattle stocking rates, ecosystem services related to decomposition and nutrient cycling can be maintained when a functionally diverse dung beetle community inhabits the human-modified landscape.

Central European forest management strategies promoting structurally homogeneous closed‐canopy forests have led to landscape‐level declines in biodiversity and ecosystem multifunctionality. Conservation‐targeted management programs aim at reintroducing structural heterogeneity into production forests; however, it is not well‐understood if species diversity and ecosystem functions generally profit from management promoting heterogeneity in forest structure. By removing and processing mammalian dung remains, dung beetles play an integral role in ecosystem functions in forests. In one of the largest manipulative forest experiments in Central Europe to date, we analysed the effects of enhanced structural heterogeneity in production forests, climate, and mammalian defecation on dung beetle diversity and dung removal rates at the local and landscape level. We assessed dung beetle assemblages and dung removal rates on 234 study patches (50 × 50 m) in 11 paired forest landscapes across a climatic gradient in Germany. Forest landscapes were managed either to conserve a homogeneous closed canopy or to create a heterogeneous forest structure with forest patches varying in canopy coverage and dead wood availability. We did not find that more heterogeneously managed forests had a higher dung beetle species diversity and dung removal rates. Canopy openings did not increase species turnover but decreased species diversity. Along the climate gradient, dung beetle average biomass and dung removal decreased with increasing temperature. Canopy openings in combination with higher temperatures negatively impacted all abundant dung beetle species, but especially the large species Anoplotrupes stercorosus , comprising >90% of the total dung beetle biomass. Synthesis and applications . Our results suggest that dung beetles do not profit from management increasing the structural heterogeneity of production forests. Future warming and openings in forest structure might have negative effects on dung beetles, and consequently on the ecosystem services they provide in production forests. Forest management should aim at preserving closed‐canopy forest stands, which would buffer temperature extremes and protect temperate dung beetle communities and their ecosystem functions.

Dung beetles form an insect group that fulfils important functions in terrestrial ecosystems throughout the world. These include nutrient cycling through dung removal, soil bioturbation, plant growth, secondary seed dispersal and parasite control. We conducted field experiments at two sites in the northern hemisphere temperate region in which dung removal and secondary seed dispersal were assessed. Dung beetles were classified in three functional groups, depending on their size and dung manipulation method: dwellers, large and small tunnelers. Other soil inhabiting fauna were included as a fourth functional group. Dung removal and seed dispersal by each individual functional group and combinations thereof were estimated in exclusion experiments using different dung types. Dwellers were the most diverse and abundant group, but tunnelers were dominant in terms of biomass. All dung beetle functional groups had a clear preference for fresh dung. The ecosystem services in dung removal and secondary seed dispersal provided by dung beetles were significant and differed between functional groups. Although in absolute numbers more dwellers were found, large tunnelers were disproportionally important for dung burial and seed removal. In the absence of dung beetles, other soil inhabiting fauna, such as earthworms, partly took over the dung decomposing role of dung beetles while most dung was processed when all native functional groups were present. Our results, therefore, emphasize the need to conserve functionally complete dung ecosystems to maintain full ecosystem functioning.

Malnutrition and parasitism shape ecosystem services provided by dung beetles