Dung Beetle Species Richness Research Articles

Impacts of Exotic Pasture Establishment on Dung Beetle Assemblages (Coleoptera: Scarabaeidae: Scarabaeinae) in the Brazilian Cerrado.

The Brazilian Cerrado is the second largest Neotropical biome and an important hotspot of biodiversity. However, land use change in this ecosystem is producing landscapes with modified natural environments and anthropogenic environments, such as exotic pastures. In this study, we evaluated how conversion of native Cerrado vegetation to exotic pastures affects the dung beetle assemblages (Coleoptera: Scarabaeidae: Scarabaeinae). We sampled dung beetles in four areas of Cerrado (sensu stricto) and in four areas of exotic pastures (Urochloa spp.) in Aquidauana, Mato Grosso do Sul, Brazil. In all, 7,544 individuals from 43 species of dung beetles were collected, and 19 species were found in both the Cerrado and exotic pastures. The abundance and species richness of dung beetles were higher in Cerrado remnants. Species composition differed between Cerrado and exotic pastures, where 11 species were classified as specialists of Cerrado, 10 species were considered specialists of exotic pastures, and 6 species were habitat generalists. Roller beetles were most negatively affected by exotic pasture establishment. We demonstrated that exotic pasture establishment has a negative impact on dung beetle assemblages in Brazilian Cerrado. The decline in abundance and richness of roller beetles has important implications for the understanding of ecosystem functioning because it can reduce the ecological functions performed by dung beetle assemblages in exotic pastures. Finally, the high number of dung beetle species shared between Cerrado and exotic pastures suggests that the Cerrado remnants is a fundamental requirement for the conservation of biodiversity of dung beetles in exotic pastures in the Brazilian Cerrado.

The Attraction of Amazonian Dung Beetles (Coleoptera: Scarabaeidae: Scarabaeinae) to the Feces of Omnivorous Mammals Is Dependent on Their Diet: Implications for Ecological Monitoring.

The immense sampling effort used in ecological research on dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) has required large amounts of human feces to conduct experiments in the field. Thus, the amount of human feces available can be an important limiting factor for research. Therefore, dung from large omnivorous mammals, such as pig, has been used to reduce this limitation. Here, we evaluated how the type of diet can influence the attractiveness of omnivorous-mammal feces to Amazonian dung beetles. We sampled dung beetles in 10 fragments of Amazon rainforest in July 2018 (dry season) and March 2019 (rainy season), using pitfall traps baited with swill pig dung (household waste-based diet), grain pig dung (maize+soybean-based diet), and human feces (control) in Juína, Mato Grosso, Brazil. In all, 2,080 individuals from 51 species of dung beetles were collected. Between the pig dung evaluated, higher total abundance and species richness was captured with grain pig dung. However, the species composition and community structure were similar between pig dung types. Additionally, grain pig dung captured total species richness, species composition, and structure similar to that for human feces. Thus, although grain pig dung did not sample total abundance similar to human feces, this type of dung can be efficient for an accurate survey of the total species richness, species composition, and structure of dung beetles in the Amazon rainforest.

Patterns of alimentary resource use by dung beetles in introduced Brazilian pastures: Cattle versus sheep dung

AbstractDung beetles (Coleoptera: Scarabaeidae) perform essential ecological functions in pastures, such as dung removal, nutrient recycling and parasite control. However, the patterns of alimentary use by dung beetles in introduced Brazilian pastures are poorly known. Here, we compared dung beetle species richness, abundance and species composition in cattle and sheep dung, and identified the dung beetle species preference by each dung type. In January 2019, dung beetles were sampled with pitfall traps baited with cattle and sheep dung in 12 introduced pastures (Urochloa spp.), in Aquidauana, Mato Grosso do Sul, Brazil. A total of 592 individuals belonging to 14 species of dung beetles were collected. Of the 14 species sampled, nine were recorded in both dung types, five were found exclusively in sheep dung and no species was exclusive to cattle dung. Species richness and abundance were higher in sheep dung. Species composition was different between the dung types. Dichotomius bos (Blanchard), Genieridium bidens (Balthasar), Onthophagus aeneus Blanchard and Trichillum externepunctatum Preudhomme de Borre were associated with sheep dung. Our results provide evidence that sheep dung is more attractive to dung beetles with a distinct community species between the two dung types, although the studied pastures have never been used before for sheep breeding. Thus, our data shows that the introduction of a new alimentary resource (e.g. sheep dung) can be an important strategy to help to obtain a more diverse dung beetle assemblage in introduced Brazilian pastures.

Habitat patch size and isolation drive the near-complete collapse of Amazonian dung beetle assemblages in a 30-year-old forest archipelago

The creation of mega-hydropower dams inundates vast lowland areas, causing widespread environmental impacts in tropical forest regions. Few studies, however, have taken advantage of these newly fragmented landscapes to examine the effects of habitat insularization on arthropod faunas. Here, we assess how dung beetle assemblages respond to 30 years of post-isolation history in forest islands within a major hydroelectric reservoir in Central Amazonia. We sampled 30 of the 3546 islands created by this reservoir, and three neighbouring forest sites. We collected a total of 865 individuals representing 34 dung beetle species and 15 genera. Remarkably, one third of all islands had been entirely defaunated of dung beetles in terms of overall occupancy. Isolation was the single best predictor of dung beetle species richness, followed by the interaction between isolation and island area, and these variables were key determinants of the relict species composition. Isolation was the most important predictor of dung beetle abundance, but area alone was the main predictor of abundance when the dominant species was excluded. We predicted species richness across all 3546 islands, indicating that 61.5% of all islands likely retain only a single ‘super-tramp’ species (Onthophagus osculatii). These community disassembly patterns were likely aggravated by the marked hostility of the open-water matrix combined with the poor flight dispersal capacity of dung beetles over wide gaps between insular forests. As such, the overwhelming number of small, isolated islands created by major dams has profound effects on regional forest biodiversity, including wholesale local extinctions in detritivore assemblages and their ecosystem functions.

Successional trajectory of dung beetle communities in a tropical grassy ecosystem after livestock grazing removal

Grazing by large herbivorous mammals is still a structuring force in tropical grassy ecosystems, and cattle grazing is one of the main economic activities carried out in these ecosystems in modern times. Therefore, understanding the impacts of cattle grazing removal on biodiversity may be a key step for conservation of this ecosystem. Here, we studied the successional trajectory of dung beetle communities in a tropical grassy ecosystem after cattle removal. For this, we assessed the patterns of dung beetle taxonomic and functional diversity of 14 natural grasslands with distinct cattle grazing removal ages (from 3 months to 22 years) along a chronosequence, applying the space-for-time substitution method. Our results show a strong decrease in dung beetle abundance (93 times) and species richness (6 times) in the first ten years of cattle removal. However, after ten years there is an increase in dung beetle abundance (73 times) and species richness (5 times). Taxonomic composition was also influenced by cattle removal time demonstrating the importance of cattle in the structuring of dung beetle communities in natural grasslands. In contrast, functional composition and diversity were not affected by cattle grazing removal, indicating these metrics are less sensitive to cattle absence than taxonomic diversity and composition. Our results provide evidence that cattle grazing removal, at least in the short term (10 years), may be an inefficient management tool for restoration and conservation of tropical grassy ecosystems. However, we highlight the need to investigate the reintroduction of cattle grazing after different removal times to provide complimentary information to livestock management able to integrate human use and conservation of tropical grassy ecosystems.

Forest habitat parameters influence abundance and diversity of cadaver-visiting dung beetles in Central Europe.

Dung beetles provide crucial ecosystem services and serve as model organisms for various behavioural, ecological and evolutionary studies. However, dung beetles have received little attention as consumers of large cadavers. In this study, we trapped copronecrophagous dung beetles on above-ground exposed piglet cadavers in 61 forest plots distributed over three geographically distinct regions in Germany, Central Europe. We examined the effects of land use intensity, forest stand, soil characteristics, vascular plant diversity and climatic conditions on dung beetle abundance, species richness and diversity. In all three regions, dung beetles, represented mainly by the geotrupid species Anoplotrupes stercorosus and Trypocopris vernalis, were attracted to the cadavers. High beetle abundance was associated with higher mean ambient temperature. Furthermore, A. stercorosus and T. vernalis were more abundant in areas where soil contained higher proportions of fine sand. Additionally, an increased proportion of forest understorey vegetation and vascular plant diversity positively affected the species richness and diversity of dung beetles. Thus, even in warm dry monocultured forest stands exploited for timber, we found thriving dung beetle populations when a diverse understorey was present. Therefore, forestry practices that preserve the understorey can sustain stable dung beetle populations and ensure their important contribution to nutrient cycles.

El Niño impacts on human‐modified tropical forests: Consequences for dung beetle diversity and associated ecological processes

AbstractOur knowledge of how tropical forest biodiversity and functioning respond to anthropogenic and climate‐associated stressors is limited. Research exploring El Niño impacts are scarce or based on single post‐disturbance assessments, and few studies assess forests previously affected by anthropogenic disturbance. Focusing on dung beetles and associated ecological functions, we assessed (a) the ecological effects of a strong El Niño, (b) if post‐El Niño beetle responses were influenced by previous forest disturbance, and (c) how these responses compare between forests impacted only by drought and those affected by both drought and fires. We sampled 30 Amazonian forest plots distributed across a gradient of human disturbance in 2010, 2016, and 2017—approximately 5 years before, and 3–6 and 15–18 months after the 2015–16 El Niño. We found 14,451 beetles from 98 species and quantified the beetle‐mediated dispersal of >8,600 seed mimics and the removal of c. 30 kg of dung. All dung beetle responses (species richness, abundance, biomass, compositional similarity to pre‐El Niño condition, and rates of dung removal and seed dispersal) declined after the 2015–16 El Niño, but the greatest immediate losses (i.e., in 2016) were observed within fire‐affected forests. Previous forest disturbance also influenced post‐El Niño dung beetle species richness, abundance, and species composition. We demonstrate that dung beetles and their ecological functions are negatively affected by climate‐associated disturbances in human‐modified Amazonian forests and suggest that the interaction between local anthropogenic and climate‐related stressors merits further investigation.Abstract in Portuguese is available with online material.

Spatial and temporal changes in the dung beetle diversity of a protected, but fragmented, landscape of the northernmost Neotropical rainforest

Abstract Studies addressing the temporal changes of ecological communities within fragmented forests transformed into natural protected areas are urgently needed. The creation of the Los Tuxtlas Biosphere Reserve (LTBR) in 1998 stopped the deforestation process of the northernmost tropical rainforest of the Neotropical region, allowing the analysis of the long-term effects on native communities after the halting of habitat fragmentation. We compared the diversity of dung beetles in 11 forest fragments and eight pastures in the LTBR between two periods: 1999–2000, the early years after the creation of the LTBR; and 2016–2017, i.e., 17 years later. Species richness and abundance of dung beetles were similar in both periods, being higher in forest fragments than in pastures; however, the dominant species were different in each period in both forest fragments and pastures. The number of habitat indicator species increased in 2016–2017 compared to 1999–2000, with a high species diversity of forest indicators relative to pasture indicators at both periods. Alpha and gamma diversities were lower in 1999–2000 than in 2016–2017. Beta-diversity at the spatial level was strongly driven by species turnover, which was higher in pastures than in forest fragments. All functional groups (dwellers, rollers, and tunnellers) showed higher abundances in forest fragments than in pastures in both 1999–2000 and 2016–2017 periods. Our results suggest that stopping the fragmentation process in the LTBR has allowed the survival of native dung beetle assemblages, which are undergoing a recovery process of their populations and ecological functions over the years.

Altitudinal gradient in species richness and composition of dung beetles (Coleoptera: Scarabaeidae) in an eastern Euro-Mediterranean locality: Functional, seasonal and habitat influences

The altitudinal gradient in diversity of dung beetles (Scarabaeidae) was studied in a Mediterranean mountain chain located in Central Anatolia to (i) determine if there are altitudinal differences between the main taxonomic groups, (ii) describe the seasonal variations in these assemblages and (iii) assess whether closed habitats influence dung beetle diversity differentially at different altitudes. Beetles were collected throughout a year at 14 localities between 469 and 1810 m above sea level in three different types of habitats. Dung beetle assemblages at 400 to 1200 m did not vary greatly in species richness, abundance and biomass. However, they varied in composition, with the assemblages dominated by species of Scarabaeinae up to 900 m, whereas in the mid-mountain assemblages (from 900 m to 1600 m) the numbers of species of Aphodiinae was higher. The decline with increase in altitude in richness, abundance and biomass of both small and large species of Scarabaeinae up to 1500 m, together with the constancy of these parameters in the case of Aphodiinae, accounts for the changes in the composition from the lowland to mid-mountain localities. Unlike at other Mediterranean localities, the open/closed structure of the habitat only slightly influences these assemblages independently of altitude or season. The general seasonal pattern follows the classical Mediterranean bimodal pattern associated with summer drought, but the patterns are more complex when the seasonal responses of the different groups and at different localities are analysed separately. We propose that the interplay between local climatic conditions (mainly temperature) and evolutionary conserved species preferences accounts for both the current seasonal and altitudinal gradients and the changes in species composition in terms of Aphodiinae and Scarabaeinae.

Climate rather than dung resources predict dung beetle abundance and diversity along elevational and land use gradients on Mt. Kilimanjaro

AbstractAimWhile elevational gradients in species richness constitute some of the best depicted patterns in ecology, there is a large uncertainty concerning the role of food resource availability for the establishment of diversity gradients in insects. Here, we analysed the importance of climate, area, land use and food resources for determining diversity gradients of dung beetles along extensive elevation and land use gradients on Mt. Kilimanjaro, Tanzania.LocationMt. Kilimanjaro, Tanzania.TaxonScarabaeidae (Coleoptera).MethodsDung beetles were recorded with baited pitfall traps at 66 study plots along a 3.6 km elevational gradient. In order to quantify food resources for the dung beetle community in form of mammal defecation rates, we assessed mammalian diversity and biomass with camera traps. Using a multi‐model inference framework and path analysis, we tested the direct and indirect links between climate, area, land use and mammal defecation rates on the species richness and abundance of dung beetles.ResultsWe found that the species richness of dung beetles declined exponentially with increasing elevation. Human land use diminished the species richness of functional groups exhibiting complex behaviour but did not have a significant influence on total species richness. Path analysis suggested that climate, in particular temperature and to a lesser degree precipitation, were the most important predictors of dung beetle species richness while mammal defecation rate was not supported as a predictor variable.Main conclusionsAlong broad climatic gradients, dung beetle diversity is mainly limited by climatic factors rather than by food resources. Our study points to a predominant role of temperature‐driven processes for the maintenance and origination of species diversity of ectothermic organisms, which will consequently be subject to ongoing climatic changes.

Local management actions override farming systems in determining dung beetle species richness, abundance and biomass and associated ecosystem services

Organic farming systems have been proposed to support higher biodiversity than conventional ones, and higher diversity might make ecosystems more resilient against environmental change. We investigated how dung beetle communities and associated ecological functions (dung removal) vary at two hierarchical levels among Swedish dairy farms: between farming systems (organic vs. conventional) and among farms within farming systems. At the level of farming systems, we detected no differences in dung beetle species richness, abundance or diversity. The total biomass of beetles was slightly higher on conventional farms than on organic ones, but this difference did not correspond to a difference in dung-system functioning. However, at the farm level, we found significant differences in species richness, abundance and total biomass, reflected in significantly different provisioning of ecological functions among farms. Our results identify the importance of farm-specific variation in dung beetle assemblages for ecosystem functioning. Local decisions made by farmers may thereby override general differences among farming systems. Thus, policies aimed at promoting fine-scale management actions are an important supplement to general rules for certification under different farming systems. The current results are likely context-dependent, as based on efficient uptake and substantial environmental awareness among Swedish dairy farmers.

Morphological traits reflect dung beetle response to land use changes in tropical karst ecosystems of Vietnam

Abstract Dung beetles (Coleoptera, Scarabaeidae) are known to respond sensitive to habitat changes, but difficulties in the delineation of species together with their high local diversity have hindered the generalization of results. Morphological traits instead may better reflect species’ adaptations to habitat changes. We investigated changes in morphological traits of 41 tunnelling dung beetle species in a sequence of land use change from primary forests, to secondary forests and meadows in a tropical karst mountain ecosystem in Vietnam (South East Asia). Tunnellers were by far the dominant functional group of dung beetles in these ecosystems. In addition, we measured dung removal rate as a key ecosystem service of these beetles. By combining RLQ and fourth-corner methods to characterize shifts in morphological species traits, we identified three distinct morphological trait clusters of dung beetles, reflecting distinct community adaptations to land use changes. Meadows, despite harbouring highest dung beetle abundance and species richness were severely impoverished in large-bodied dung beetles. The large-bodied dung beetles however, turned out to play crucial roles for dung removal. These data indicate that land use change led to significant changes of species traits in dung beetle communities which in turn fed back on critical ecosystem services. Our data demonstrate that trait-based approaches are well suited to describe the functional implications of environmental changes on species-rich arthropod communities and may better allow generalizations of adaptive responses between ecosystems.

Forest complexity drives dung beetle assemblages along an edge‐interior gradient in the southwest Amazon rainforest

1. The habitat heterogeneity hypothesis predicts that heterogeneous habitats may provide more niches and diverse ways of exploiting environmental resources, thereby allowing more species to coexist, persist and diversify.2. We aimed to investigate how an edge‐interior gradient related to forest complexity influences species composition, abundance and richness of dung beetles in the western Amazon rainforest. We expected dung beetle abundance and richness to increase along the forest edge‐interior gradient, in accordance with the habitat heterogeneity hypothesis. We also expected strong changes in species composition driven by species turnover in the forest interior and nestedness along the forest edges. We sampled dung beetles using baited pitfall traps across an edge‐interior gradient. We also assessed the variation in forest features along the edge‐interior gradient to identify changes in forest complexity.3. Both species richness and abundance of dung beetles increased along the forest edge‐interior, following the gradient of forest complexity. The Sorensen dissimilarity of dung beetle assemblages was higher among sampling units placed near the forest edge, although neither turnover, nor nestedness was different between the extremes of the forest edge‐interior gradient. There was a clear compositional change along the edge‐interior gradient mostly driven by species turnover. Individual indicator value analysis revealed that species were strongly associated with the forest interior conditions.4. The simplification of the Amazon rainforest near clearings causes compositional changes in dung beetle assemblages. These changes are characterised by species‐poor and low‐abundance assemblages and may impair dung beetle ecological functions and therefore forest recovery.

Co‐declining mammal–dung beetle faunas throughout the Atlantic Forest biome of South America

The millennial–scale evolutionary relationships between mammals and dung beetles have been eroded due to several drivers of contemporary biodiversity loss. Although some evidence of co‐decline has been shown for mammals and dung beetles at some Neotropical sites, a biome‐scale analysis for the entire Atlantic Forest of South America would strengthen our understanding of how relictual sets of mammal species can affect dung beetle co‐occurrences and co‐declines. We therefore collated hundreds of assemblages of both dung beetles and medium‐ to large‐bodied mammals throughout the world's longest tropical forest latitudinal gradient to examine to what extent mammal assemblages may exert a positive influence on dung beetle species composition and functional assembly, and whether this relationship is scale dependent. We also collated several climatic and other environmental variables to examine the degree to which they shape mammal–dung beetle relationships. The relationships between local mammal and dung beetle faunas were examined using regression models, variation partitioning, dissimilarity indices and ecological networks. We found a clear positive relationship between mammal and dung beetle species richness across this forest biome, indicating an ongoing process of mammal–dung beetle niche‐mediated co‐decline. We found a strong relationship between the species composition of both taxa, in which dung beetle species dissimilarity apparently track changes in mammalian dissimilarity, typically in 80% of all cases. Co‐variables such as phytomass and climatic variables also influenced mammal–dung beetle patterns of co‐decline along the Atlantic Forest. We conclude that dung beetle diversity and community assembly are shaped by the remaining co‐occurring mammal assemblages and their functional traits, and both groups were governed by environmental features. We emphasize that ecosystem‐wide effects of mammal population declines remain poorly understood both quantitatively and qualitatively, and curbing large vertebrate defaunation will ensure the persistence of co‐dependent species.

Dung beetle-mammal associations: methods, research trends and future directions.

Dung beetles are increasingly used as a study taxon—both as bioindicators of environmental change, and as a model system for exploring ecosystem functioning. The advantages of this focal taxon approach are many; dung beetles are abundant in a wide range of terrestrial ecosystems, speciose, straightforward to sample, respond to environmental gradients and can be easily manipulated to explore species-functioning relationships. However, there remain large gaps in our understanding of the relationship between dung beetles and the mammals they rely on for dung. Here we review the literature, showing that despite an increase in the study of dung beetles linked to ecosystem functioning and to habitat and land use change, there has been little research into their associations with mammals. We summarize the methods and findings from dung beetle–mammal association studies to date, revealing that although empirical field studies of dung beetles rarely include mammal data, those that do, indicate mammal species presence and composition has a large impact on dung beetle species richness and abundance. We then review the methods used to carry out diet preference and ecosystem functioning studies, finding that despite the assumption that dung beetles are generalist feeders, there are few quantitative studies that directly address this. Together this suggests that conclusions about the effects of habitat change on dung beetles are based on incomplete knowledge. We provide recommendations for future work to identify the importance of considering mammal data for dung beetle distributions, composition and their contributions to ecosystem functioning; a critical step if dung beetles are to be used as a reliable bioindicator taxon.

The role of habitat and daily activity patterns in explaining the diversity of mountain Neotropical dung beetle assemblages

AbstractThe interaction between land use and climate change is expected to strongly affect species distributions along high elevation landscapes. We aimed to test the effect of climatic variables on community metrics among five types of land use in a high elevation landscape. We described dung beetle spatial and temporal taxonomic and functional diversity patterns, and partitioned β‐diversity into turnover and nestedness components. The interaction between land use and daily period of activity mostly drives abundance, functional richness and functional diversity, but not dung beetle species richness. Unlike Neotropical lowlands, species richness and abundance in open environments are similar to those existing in forests. Temperature is an important predictor of abundance and functional divergence. There is a higher spatial component of the taxonomic β‐diversity, which is highly driven by species turnover. The temporal component of the taxonomic β‐diversity was strongly driven by nestedness, where night assemblages are sub‐sets, although not entirely, of diurnal assemblages. For functional diversity, the temporal β‐diversity was much higher than the spatial β‐diversity, but both were similarly represented by functional group turnover and nestedness. The composition of nocturnal and diurnal assemblages is clearly different, even more than the differences observed between habitats. However, taxonomic turnover is the dominant force between sampling sites while nestedness dominates the daily pattern. This means that forest habitats are unlikely to act as shelters for grassland species under a scenario of rising temperature.

Elevational and Possible Bushmeat Exploitation Effects on Dung Beetle (Scarabaeidae: Scarabaeinae) Communities on Mount Cameroon, West Central Africa.

Dung beetle species richness and abundance on Mt Cameroon were investigated to evaluate the effects of elevation. Surveys were done at five different elevations on the southwest facing slope from 216 to 2,102 m above sea level near the tree line at intervals of ~500 m. In total, 27 species and 1,886 specimens were collected during the study. No linear relationship between either species richness or beetle abundance and elevation was found with an expected highest diversity and abundance at low elevation and the lowest diversity and abundance at high elevation. Instead, both the highest diversity and abundance were discovered at the middle elevation (914-1,012 m) with 22 species and 48% of the total catch. The highest diversity indices (Shannon and Simpson) were found at the second lowest elevation (522-625 m). The lowest diversity found at the highest elevation (1,974-2,101 m) included only two species and represented only 4% of the beetles sampled. Unexpected low diversity and abundance at the lowest elevation are hypothesized to be due at least in part to the effects of bushmeat hunting in the more accessible lower elevations and the concomitant effects on dung beetles that mainly utilize mammal dung. The most similar faunas based on Morisita-Horn paired comparisons were those at the two highest and the two lowest elevations while the most dissimilar were the middle compared with the highest elevation. Faunas appear to be divided into high and low elevation communities with a boundary or division at c.1,500-1,750 m elevation.

How Guilds Build Success; Aspects of Temporal Resource Partitioning in a Warm, Temperate Climate Assemblage of Dung Beetles (Coleoptera: Scarabaeidae).

Succession in local dung beetle assemblages influences their delivery of ecological functions in natural and modified environments globally. Short-term changes in dung beetle (Coleoptera: Scarabaeidae) species richness, abundance, and biomass were investigated in standardized dung pads in northern, coastal Turkey. For mean tunneling guild abundance, dung deposition time, dung exposure period, and their interaction were significant, and for mean dung dwelling guild abundance, dung exposure period was significant, as was the interaction with dung deposition time, which collectively evidenced temporal resource partitioning, based principally on differences in diel activity. Succession was highly compressed, with maximum abundance at 12 h and maximum species richness at 24 h. A large ball roller and small- to medium-sized tunnelers dominated different periods in the first 24 h but were superseded by dwellers. Regression analysis demonstrated a significant, positive relationship between species richness and the evenness of abundance for both dung deposition times. Correlation analysis generally showed strong, positive correlations between tunneling species, low correlations between tunneling and dwelling species, and low correlations between dwelling species. Niche partitioning based on size difference appears to have acted on the environmental filtering of tunneling species along the temporal gradient of declining moisture, thereby limiting the number of abundant, concurrent species. The aggregation of tunneling species provided opportunities for the less competitive dwelling species to occupy less densely populated zones termed probability refuges. The network of strong, positive habitat' correlations between tunneling species may indicate that their collective functionality is vulnerable to loss of efficiency if species are lost.

The role of livestock intensification and landscape structure in maintaining tropical biodiversity

Abstract As tropical cattle ranching continues to expand, successful conservation will require an improved understanding of the relative impacts of different livestock systems and landscape structure on biodiversity. Here, we provide the first empirical and multi‐scale assessment of the relative effects of livestock intensification and landscape structure on biodiversity in the threatened tropical dry forests of Mesoamerica. We used a dataset of dung beetles (169,372 individuals from 33 species) collected from 20 1‐km2 landscapes, ranging from zero‐yielding forest sites to high‐yield cattle ranches and maize farms, to investigate the relative effect of livestock intensification (net cattle production; macrocyclic lactone use; annual dung production) and landscape structure (landscape composition and configuration) at multiple spatial scales on different attributes of dung beetle communities using a multi‐model averaging approach. Dung beetle species richness, biomass and composition were more strongly related to landscape structure than to livestock intensification. Forest cover was the best predictor of dung beetle assemblages, being positively related to species diversity and biomass across multiple spatial scales. The use of macrocyclic lactones was strong and negatively related to dung beetle communities at the local scale. Synthesis and applications: Maximising forest protection through a “land sparing” strategy is likely to be the best strategy for reducing negative impacts of cattle farming on Neotropical dung beetle communities. However, increasing or maintaining yields while reducing agrochemical inputs will be important for conserving on‐farm biodiversity and the ecosystem services that dung beetles provide in livestock‐dominated landscapes.

Attractiveness of Scarabaeinae (Coleoptera: Scarabaeidae) to different baits in the Brazilian Amazon region

Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) are considered essential for enhancing the physicochemical characteristics of soils, principally by changing organic materials (e.g. dead animals, faeces, fruits e leaf litter). This study compared the species richness and abundance of dung beetles captured using various types of baits, to demonstrate attractiveness differences in variable habitats of the Brazilian Amazon. Samplings were carried out with pitfall traps baited with human faeces, rotten banana, rotten meat and a non-baited trap, in February, March, June, September and October 2015. Habitats included native forests, agriculture areas, pastures and disturbed forests in different regeneration stages. A total of 13 736 Scarabaeinae beetles were captured, distributed over 98 species. Most individuals were captured using traps baited with faeces (76.7 % of individuals), followed by rotten meat baited traps (17.8 % of individuals), fermented banana baited traps (3.9 % of individuals) and finally by non-baited traps (1.6 % of individuals). A significant difference in attractiveness of the different baits used and habitats types was observed. Most of the captured assemblages were composed by coprophagous (42 %), generalist species (32 %), necrophagous (15 %) and none was classified as saprophagous. Approximately 54 % of the specimens were tunnelers, 25 % were rollers and 12 % were dwellers. The species of Scarabaeinae sampled in the region revealed qualitative and quantitative differences among their assemblages and the phytophysiognomies. The forest environments housed the greatest species richness observed, and a fraction of these is exclusive of those areas. We concluded that some species of Scarabaeinae have an important potential as disturbance indicators in the Amazonian ecosystem.