Dung Beetle Assemblages Research Articles

Livestock areas with canopy cover sustain dung beetle diversity in the humid subtropical Chaco forest

Abstract We assessed differences in the alpha and beta diversity of dung beetles in native forest and two livestock systems (with and without canopy cover) typical of the Argentine Chaco region and related the dung beetle assemblages to environmental conditions. Dung beetles were sampled in native forest and two livestock systems in the spring (2015–2016), in two areas of the humid Chaco region in northern Argentina. In each area, five sampling sites were selected for each habitat type, and ten pitfall traps were baited with human faeces and carrion and placed at each site. The livestock systems with canopy cover preserved the environmental conditions from the native forest (temperature and vegetation structure) and the richness and composition of the native forest dung beetle community in the two areas studied, whereas the open pastures exhibited higher ground temperature, simplified vegetation structure and lower dung beetle richness and similarity in species composition in relation to the native forest. In livestock systems of the humid Chaco, the canopy cover is the main determinant of dung beetle communities through the maintenance of temperature and humidity. In the light of these results, livestock production in silvopastoral systems preserving canopy cover can be an alternative compatible with conservation of the dung beetle diversity of native forests. Considering the central role of dung beetles in maintaining soil structure and fertility (through the relocation of cow dung), silvopastoral systems will probably maintain the productivity compared to open pastures.

A comparison of dung beetle assemblages (Coleoptera, Scarabaeoidea) collected 34 years apart in an Iberian mountain locality

Knowing how recent environmental changes may have affected species diversity is a major objective to estimate the consequences of habitat alteration and climate change. In this study two dung beetle inventories made in the same locality of the Sierra de Guadarrama (Madrid, Spain) 34 years apart (1983–2017) are compared. Changes in diversity, species richness, abundances and composition were analysed and species replacements described considering the three main functional dung beetle groups: large paracoprids, small paracoprids and small endocoprids. In addition, changes in vegetation cover and climate between the two periods were also analysed to examine their association with the detected faunistic changes. Both the vegetation and climatic data show that the surveyed locality would have experienced an increase in the area covered by bushes and forest and an increase in temperature and warm conditions during the 34 years. These changes are associated with a probable increase in species richness and species dominance, a decrease in diversity and an important change in composition that would have positively affected small paracoprids but negatively affected large paracoprids.

Estacionalidad del ensamblaje de escarabajos coprófagos (Coleoptera: Scarabaeinae) del jardín botánico de Cartagena “Guillermo Piñeres” Bolívar-Colombia

En Colombia el Bosque Seco Tropical (bs-T) ha sufrido una drástica reducción debido al incremento de la frontera agrícola y ganadera que ha fragmentado este ecosistema. Los escarabajos coprófagos (Coleoptera: Scarabaeinae) se consideran un excelente grupo para evaluar los efectos de las perturbaciones antrópicas debido a su carácter bioindicador, sin embargo, el conocimiento sobre la estacionalidad y diversidad de este grupo en los bs-T del departamento de Bolívar es escaso. Para llenar este vacío, se realizó un inventario y análisis de la dinámica estacional del ensamblaje de escarabajos en el bs-T del jardín botánico de Cartagena. Se realizaron cuatro muestreos (noviembre 2015, enero, mayo y septiembre 2016) cubriendo las variaciones estacionales y tomando datos de precipitación y temperatura. Las capturas se realizaron con trampas de caída cebadas con excremento y carroña. Se capturaron 3550 individuos agrupados en 18 especies y diez géneros. La mayor abundancia y menor riqueza se registró en enero (época seca). Los grupos funcionales de los pequeños telecópridos y paracópridos fueron los más abundantes en todos los muestreos. Se registraron diferencias significativas entre la abundancia y la riqueza entre estaciones. Se encontró una regresión negativa entre la precipitación y la riqueza (r = -0,370) y la abundancia (r = -0,381). Se propone que la estacionalidad del bs-T tiene un potencial efecto en la abundancia, riqueza y estructura del ensamblaje de escarabajos coprófagos.

Consequences of habitat change in euromediterranean landscapes on the composition and diversity of dung beetle assemblages (Coleoptera, Scarabaeoidea)

In southern Europe, an intensive agricultural abandonment occurs for more than a century. This change in land use concerns both farming and breeding and induces a large-scale expansion of forest habitats. In the Mediterranean region, which is a centre of endemism and species richness for many groups, a large amount of biodiversity is related to ancient agricultural practices. This current abandonment could consequently induce a drastic flora and fauna impoverishment. This study attempts to identify the consequences of the widespread Mediterranean forest expansion on dung beetle assemblages. Dung beetle assemblages were monitored monthly with dung-baited pitfall trapping in four Mediterranean sites from 250 to 2030 m in elevation. At each site, different grazed habitats (grassland, forest and shrubland or wooded grassland) were sampled during the most seasonally active period. In total, 61,645 specimens consisting of 70 species, namely 65 Scarabaeidae (42 Aphodiinae, 23 Scarabaeinae) and 5 Geotrupidae. Sixty-four out of the 70 sampled species (91.43%) were widely distributed in the Palaearctic region. A drastic loss in species richness consecutive to the replacement of grassland by forest was observed all along the elevation gradient: 63 species recorded in grassland habitat versus 60 and 45 species in shrubland and forest, respectively. There was often a loss in species richness according to elevation: 45 versus 30 species in low and high elevation, respectively. For Aphodiinae, the extension of forest also induced a shift in distribution across elevation. This important biodiversity loss that is mainly concerned with lowland thermophilous species was accompanied by crucial changes in the structure of assemblages. The measurement of alpha and beta-diversity in different habitats as well as between habitats across an elevation gradient is essential to our understanding of which habitats are required to best conserve biodiversity. Alpha diversity decreased from grassland to shrubland to forest. Intra-habitat alpha and beta-diversity decreased with elevation. Whereas, inter-habitat beta-diversity (spatial turnover) increased from grassland to shrubland and then to forest regardless of elevation. The contrarily, intra-site beta-diversity increased with elevation. Thus, at the regional scale, the spatial turnover decreased with elevation and increased with the vegetation cover. So, the composition and structure of dung beetle assemblages were affected by vegetation cover, which causes a decreasing abundance and species richness and could result in a drastic loss of dung beetles biodiversity in southern Europe.

Exploring the predictive performance of several temperature measurements on Neotropical dung beetle assemblages: Methodological implications

AbstractBasic characteristics of species assemblages are frequently related to temperature variables recorded at a coarse‐grained scale. In this study, 15 min instant‐measurements of environmental and soil temperatures were recorded during 1 year in six Atlantic Forest sites of southern Brazil, ranging from 250 to 1,630 m a.s.l. These measurements were used to examine the comparative explanatory capacity of several temperature variables in predicting species richness and total or specific variations of dung beetle abundance. The results suggest that temperature measurements obtained during the survey period have the highest explanatory capacity. Furthermore, average temperature values seem to have a relatively higher explanatory capacity than absolute minimum or maximum values reflecting extreme conditions. In general, there is no rule in selecting a temperature variable when the objective involves explaining the variation in species abundances. Both soil and air variables can have similar explanatory capacities. The present results should be considered when designing future ecological studies in Neotropical conditions.

Functionally richer communities improve ecosystem functioning: Dung removal and secondary seed dispersal by dung beetles in the Western Palaearctic

AbstractAimIn several ecosystems, the diversity of functional species traits has been shown to have a stronger effect on ecosystem functioning than taxonomic diversity alone. However, few studies have explored this idea at a large geographical scale. In a multisite experiment, we unravelled the relationship between ecosystem function and functional completeness of species assemblages using dung beetles as a model group, focusing on dung removal and secondary seed dispersal.LocationSeventeen grassland locations across the Western Palaearctic.MethodsWe used a randomized block design with different exclosure types to control the dung and seed removing activities of individual functional groups of the local dung beetle assemblage. We classified dung beetle species according to resource specialization and into functional groups based on dung processing behaviour (dwellers, tunnellers, rollers) and body size (small, large). Additionally, we assessed the role of other soil macro‐invertebrates. By sampling the dung beetle community and measuring the remaining dung and seeds after the experiment, the impact of each functional group was estimated.ResultsDung beetle assemblages differed along a north–south and east–west gradient. Dwellers dominated northernmost sites, whereas at lower latitudes we observed more tunnellers and rollers indicating a functional shift. Resource specialists were more abundant in southern and eastern areas. Overall, functional group diversity enhanced dung removal. More dung (+46.9%) and seeds (+32.1%) were removed in the southern sites and tunnellers and rollers were more effective. At the northernmost sites, where tunnellers were scarce or absent, other soil macro‐invertebrates removed the majority of dung.Main conclusionsThe conservation of functionally complete dung beetle assemblages is crucial to maintain the ecosystem functions provided by dung beetles. Given the latitudinal variation in functional group diversity, it is reasonable to expect compositional changes due to climate change. These changes could lead to increased dung removal and a higher secondary seed dispersal rate in northern regions.

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.

Tree retention in cattle ranching systems partially preserves dung beetle diversity and functional groups in the semideciduous Atlantic forest: The role of microclimate and soil conditions

The disturbance of natural environments affects, among others, the diversity of dung beetle assemblages, which could have serious consequences for the ecological processes regulated by these insects. The objective of this study was to evaluate and compare species diversity and functional groups of dung beetle assemblages both in the native forest and in three livestock systems that differed in their structure and composition of vegetation: a livestock system with native trees, a livestock system with exotic trees (Pinus taeda), and traditional open pastures, in the semideciduous Atlantic forest of Argentina, in an area previously covered by continuous forest and currently with a heterogeneous landscape of native forest and different land uses. Pitfall traps baited with cow dung were used in the natural forests and the livestock systems studied. A total of 2461 beetles belonging to 38 species were captured. Treed livestock systems showed the highest species richness (0D) and diversity (1D and 2D). Twelve functional groups were identified. The native forest showed the highest functional group richness, while open pastures had the lowest. In general, livestock systems showed a low proportional abundance of telecoprid, diurnal and large beetles. Microclimate (average temperature and humidity) and soil conditions (soil composition: sandy or clayey) were closely associated with the species and functional group composition. Results confirm that cattle ranching with tree retention preserves dung beetle diversity, and suggest that cattle systems without canopy cover have higher impact (negative effects) than silvopastoral systems on both species and functional groups.

Spatial and temporal variations of aridity shape dung beetle assemblages towards the Sahara desert.

BackgroundAssemblage responses to environmental gradients are key to understand the general principles behind the assembly and functioning of communities. The spatially and temporally uneven distribution of water availability in drylands creates strong aridity gradients. While the effects of spatial variations of aridity are relatively well known, the influence of the highly-unpredictable seasonal and inter-annual precipitations on dryland communities has been seldom addressed.AimsHere, we study the seasonal and inter-annual responses of dung beetle (Coleoptera, Scarabaeidae) communities to the variations of water availability along a semiarid region of the Mediterranean.MethodsWe surveyed a 400 km linear transect along a strong aridity gradient from the Mediterranean coast to the Sahara (Eastern Morocco), during four sampling campaigns: two in the wet season and two in the dry season. We measured species richness, abundance and evenness. Variations in community composition between sites, seasons and years were assessed through beta diversity partitioning of dissimiliarity metrics based on species occurrences and abundances. The effects of climate, soil, vegetation and dung availability were evaluated using Spearman-rank correlations, general linear regressions and partial least-squares generalized linear regressions for community structure, and non-metric multi-dimensional scaling, Permutational Analysis of Variance (PERMANOVA) and distance-based RDA variation partitioning for compositional variations.ResultsDung beetle abundance and species richness showed large seasonal variations, but remained relatively similar between years. Indeed, aridity and its interaction with season and year were the strongest correlates of variations in species richness and composition. Increasing aridity resulted in decreasing species richness and an ordered replacement of species, namely the substitution of the Mediterranean fauna by desert assemblages dominated by saprophagous and generalist species both in space towards the Sahara and in the dry season.DiscussionOur study shows that aridity determines composition in dung beetle communities, filtering species both in space and time. Besides the expected decrease in species richness, such environmental filtering promotes a shift towards generalist and saprophagous species in arid conditions, probably related to changes in resource quality along the transect and through the year. Our results highlight the importance of considering the effects of the highly-unpredictable seasonal and inter-annual variations in precipitation when studying dryland communities.

Grazing abandonment and dung beetle assemblage composition: Reproductive behaviour has something to say

Grazed pastures are important habitats that support high biodiversity. However, in recent decades pasture management practices have experienced drastic changes. To identify better management practices that permit the coupling of productivity and biodiversity conservation, attention must be given to the intensity of grazing management. By using a recognized bio-indicator group such as dung beetles, we analysed the impact of grazing intensity on assemblage composition in a gradient from abandoned grazing to low and moderate grazing levels. Moreover, we studied whether or not assemblage composition shifts are related to species-specific responses or to more generalized effects by categorizing dung beetles into functional groups. We found differential effects on dung beetle communities depending on their feeding and reproductive behaviour; “no-nest building” species were the functional group most affected because of their inability to relocate food. Moreover, the decreased level of herbivory in abandoned areas led to shrub and tree encroachments. We demonstrated that dung beetles from abandoned areas were sensitive to this incipient habitat change due to the presence of indicator species associated with shrub and woodland habitats. Therefore, community composition varies depending on both species-specific and generalized responses due to the sensitivity of “no-nest building” species. From a management standpoint, we suggest maintaining a low to moderate level of grazing intensity to conserve a well-structured functional assemblage of dung beetles.

Prescribed Fire Effects on Rangeland Dung Beetles (Coleoptera: Scarabaeinae, Aphodiinae) in the Southern Great Plains

Rangeland dung beetles represent an important assemblage of insects for the Great Plains. In this study, we examine the effects of a postfire rangeland environment on a dung beetle assemblage in north-central Texas. We deployed baited pitfall traps to examine spring prescribed fire treatment, differences in vegetation visual obstruction, and dung density influence on dung beetle abundance and community composition. Using model-based multivariate methods, we did not find an influence of prescribed burning on the dung beetle assemblage. We report a negative influence of vegetation visual obstruction and no significant influence of dung density on dung beetle assemblages. These results suggest that prescribed fire may not negatively affect dung beetle species within the North American Great Plains; however, vegetation structure correlated to postfire rangeland environments may influence local beetle abundance.

Altitudinal Turnover of Species in a Neotropical Peripheral Mountain System: A Case Study With Dung Beetles (Coleoptera: Aphodiinae and Scarabaeinae).

The study of diversity gradients is a frequent approach to understand evolutionary processes that structure communities. Altitudinal gradients allow the analysis of community spatial responses to environmental fluctuations. One interesting place to study altitudinal gradients is the Andes system because of the coexistence of isolated and continuous mountain ranges. We investigated the altitudinal turnover of species in peripheral mountainous systems by analyzing the structure of dung beetle assemblages along a complete gradient in the Sierra Nevada de Santa Marta, Colombia. Seven sites ranging from 480 to 2,890 m were evaluated, using linear transects of pitfall traps. A total of 2,992 individuals and 46 species were collected. Abundance, richness, and diversity diminished with altitude, revealing significant differences among sites. Some genera appeared at certain altitudes and most species appeared at unique sites, indicating a marked altitudinal turnover. A similarity analysis demonstrated the existence of separate lowland and high mountain groups with a turnover at 1,200-1,600 m asl. We registered for the first time a species replacement between Scarabaeinae (low-lands) and Aphodiinae (high-lands) in the Neotropical region. Our results largely agree with the species pattern described for Mesoamerica, although, in this case the altitudinal turnover is more evident, unveiling a transition zone between lowland and high mountain fauna elements. This result suggests an equilibrium between a weak horizontal colonization and a strong vertical turnover, that appears to be higher in isolated mountains. Future investigations with other insect groups are necessary to corroborate this altitudinal pattern in isolated mountains.

Climatic variables drive temporal patterns of α and β diversities of dung beetles.

Understanding the mechanisms underpinning spatiotemporal diversity patterns of biological communities is a major goal of ecology. We aimed to test two ecological hypotheses: (i) temporal patterns of β-diversity will mostly be driven by nestedness, with a loss of species from summer to winter, and (ii) nestedness values will correlate with climatic variables instead of turnover values, indicating either a loss of species during winter or a gain of species during summer. We sampled dung beetles using standardized sampling protocols along a year in four Atlantic forest sites: two at the northwest and two at the central region of Rio Grande do Sul state, southern Brazil. We partitioned temporal patterns of β-diversity into turnover and nestedness in order to investigate if community changes are driven by species substitution or gain/loss across time. Our results highlighted five main findings: (i) dung beetle composition varied more with sites than site geographic position; (ii) there was almost one and a half 'true' dung beetle assemblages regarding the spatial distribution of species weighed by abundance; (iii) we found a positive influence of mean temperature and a negative influence of relative humidity on both species richness and abundance; (iv) both spatial and temporal dissimilarity among sites were dominated by species replacement, while the relative importance of nestedness was higher in temporal than spatial patterns; (v) there was an effect of precipitation and relative humidity on temporal patterns of β-diversity components, but these effects were site-dependent. Contrary to our expectations, the β-diversity component of turnover dominated both spatial and temporal patterns in dung beetle dissimilarity among sites and months. Distinct climatic variables affected differently the α-diversity and β-diversity components of dung beetle assemblages. Partitioning β-diversity into temporal components is a promising approach to unveil patterns of the community dynamics and to produce insights on mechanisms underlying such patterns.

Dung beetle assemblages, dung removal and secondary seed dispersal: data from a large-scale, multi-site experiment in the Western Palaearctic

By manipulating faeces during feeding and breeding, dung beetles (Coleoptera: Scarabaeidae) fulfil important ecosystem functions in terrestrial ecosystems throughout the world. In a pan-European multi-site experiment (MSE), we estimated the ecosystem functions of dung removal and secondary seed dispersal by differing combinations of dung beetle functional groups. Therefore, we classified dung beetles into five functional groups according to their body size and dung manipulation method: dwellers, large and small tunnelers, and large and small rollers. Furthermore, we set up a dung beetle sampling database containing all sampled dung beetles during the project. By identifying dung beetle specimens to the species level, we obtained a detailed insight into the dung beetle communities at each study location.By establishing experimental plots allowing and inhibiting specific combinations of functional groups in the local dung beetle assemblage from removing dung and seeds, we estimated the role of each group in dung removal and secondary seed dispersal during a 4-week period. We performed all experiments in grazed (semi-)natural grasslands, and used different dung types (cattle, horse, sheep, goat or red deer) to match the herbivore species grazing in close vicinity of each of the study areas. Simultaneously, we sampled dung beetle assemblages by using pitfalls baited with the same dung types as used in the experiments.This data paper documents two datasets collected in the framework of this MSE project. All the experiments took place between 2013 and 2016 at 17 study sites in 10 countries and 11 biogeographic zones. The entire dung beetle sampling dataset was published as a sampling event dataset at GBIF. The dataset includes the sampling results of all 17 study sites, which contain 1,050 sampling events and 4,362 occurrence records of 94 species. The second dataset contains the results of the dung removal and secondary seed dispersal experiments in which we used 11 experimental treatments and the five dung types mentioned above. This experimental results dataset holds all experimental results of the MSE project (11,537 records), and was published in the online data repository Zenodo.

Dung beetle assemblages, dung removal and secondary seed dispersal: data from a large-scale, multi-site experiment in the Western Palaearctic

Dung beetle assemblages, dung removal and secondary seed dispersal: data from a large-scale, multi-site experiment in the Western Palaearctic

Early-stage ecological influences of population recovery of large mammals on dung beetle assemblages in heavy snow areas

Past conservation initiatives and rapidly decreasing human populations in modern Japan have contributed to population recoveries of Sika deer (Cervus nippon), wild boar (Sus scrofa), and Japanese macaque (Macaca fuscata) throughout the country. Ironically, however, these recoveries have not always received a favorable reception, because these mammals can also be agricultural pests. To open public debate on the recoveries, based on a thorough understanding of their multifaceted roles in sustaining the local ecosystem, we evaluated the initial stage ripple effects caused by the mammalian population recovery on the community assembly of dung beetles, which are keystone decomposer organisms in terrestrial ecosystems. For the evaluation, we conducted manipulative snapshot experiments, using camera and pitfall traps, for mammal and dung beetle assemblages, respectively, in four different mountain ranges within the heavy snow areas of northern Japan, where the recovery of three mammal populations was at an early stage. The current findings implied that, although the feces of every recovering mammal species could provide valuable resources for most beetles, the ripple effects from the mammal population recoveries were subject to hysteresis of the local ecosystem, i.e., catastrophic shifts in ecosystems originating from the historical background of regional mammal defaunation. In particular, the abundance of tunnelers that could benefit from positive ripple effects decreased with an increase in past disturbances, which resulted in emptier forests, i.e., an ecosystem with fewer large mammals. The findings suggested that recovering populations of large mammals do not always contribute to the restoration of the original dung beetle communities, at least initially.

Escarabajos coprófagos de la cuenca alta y media del río Bita, Vichada, Colombia

The dung beetle assemblage of the upper and middle basin of the Bita River was characterized in the interinstitutional framework alliance of “Rio Bita, protegido (protected Bita River)”. The beetles were collected with pitfall traps in 4 locations in the department of Vichada, Colombia between January and June 2016. The dataset contains 1904 records from the 6253 specimens inspected and deposited at the Research Institute of Biological Resources Alexander von Humboldt (IAvH). Seventeen genera and 34 species are reported for the Bita River; 15 species with complete scientific names and 19 species with single morphospecies code identifier (12 codes previously established in the reference collection of IAvH (CRECC) and 7 new codifications, based on the study of morphological characters including male genitalia). To date, there was no information on the dung beetles richness in the Bita River basin; these results are the first records of this taxonomic group in the northeastern part of the national territory, and thus contribute to the construction of the baseline for the declaration of the Bita River as the first protected river of Colombia.

Disentangling the correlates of species and site contributions to beta diversity in dung beetle assemblages

AbstractAimWe aimed to test whether contributions of individual species (SCBD) and contributions of single sites (LCBD) to overall beta diversity can be predicted by species metrics and species characteristics and also by community metrics and ecological variables, respectively.LocationA mainland‐island landscape in the southern Brazilian Atlantic Forest domain.MethodsDung beetles were sampled along 100 sampling units within four large forest fragments. We partitioned beta diversity into SCBD and LCBD aiming to explore their relationships to species and site characteristics, respectively. We then used a combination of multivariate methods and beta regression analyses to examine patterns in SCBD and LCBD. The occupancy, total abundance, niche position, niche breadth and biological traits of species were used as predictor variables for SCBD values. Community metrics, environmental and spatial variables, and temporal patterns in the beta diversity components of turnover and nestedness were used as predictor variables for LCDB values.ResultsWe found that SCBD was strongly related to various species characteristics, such as occupancy, abundance and niche position, but was not related to biological traits of species and niche breadth. In particular, occupancy and its quadratic term showed a very strong unimodal relationship with SCBD, suggesting that intermediate species in terms of site occupancy contribute most to beta diversity. LCBD was mostly explained by variation in species richness, with a negative relationship being detected. Litter height and large‐scale spatial variables were also important in explaining variation in LCBD.Main conclusionsSCBD and LCBD were highly predictably related to species occupancy and species richness, respectively. Environmental conditions and large‐scale spatial variables also correlated with LCBD values. Understanding the determinants of SCBD and LCBD may thus hold a key to various general ecological, bioassessment and conservation issues. Protecting sites with high LCBD values may be a suitable approach to practical biodiversity conservation.

Down‐sizing of dung beetle assemblages over the last 53 000 years is consistent with a dominant effect of megafauna losses

The ongoing down‐sizing of the global mammal communities is assumed to have subsequent effects on mutualistic species communities. Dung beetles co‐evolved with large‐sized animals since millennia and depend on the megafauna feces of an appropriate size. Mammal community down‐sizing as a result of past and ongoing megafauna losses is therefore likely to result in a down‐sizing of dung beetle communities. However, empirical evidence for this co‐down‐sizing is lacking especially on larger spatial scales and over extended periods of time.Here, we show a significant down‐sizing of European dung beetle assemblages over the last ~53 000 years by relating Quaternary fossil records with trait information on body size of beetles. This significant down‐sizing of dung beetle communities was thereby not linear, but characterized by a weak decrease until the early Holocene but a strong acceleration in the recent pre‐history, from 6–7000 years BP onwards. This acceleration of down‐sizing coincides with the completion of the Quaternary megafauna extinction and the start of major shifts in human agricultural land‐use. In contrast, assemblage mean body size of non‐coprophagous scarabids as well as ground beetles – two groups of beetles with no or weak relations to megafauna – was observed to increase towards the present with an acceleration of body size increase coinciding with the onset of late‐glacial warming (14 200 years BP).In summary, the observed late‐Quaternary down‐sizing of European dung beetle communities is consistent with an effect of pre‐historic megafauna losses, and not with the coincident general warming. Ongoing down‐sizing of mammal communities is therefore likely to result in further down‐sizing of dung beetle assemblages, with potential effects on their important role for nutrient cycling and secondary seed dispersal in natural and extensive agro‐ecosystems. Future nature management initiatives could halt or even reverse this functional diversity loss via effective protection or restoration of megafauna communities.

Turnover and nestedness in subtropical dung beetle assemblages along an elevational gradient

AbstractAimWe investigated changes in dung beetle β‐diversity components along a subtropical elevational gradient, to test whether turnover or nestedness‐related processes drive the dissimilarity of assemblages at spatial and temporal scales.LocationAn elevational gradient (200–1,600 m a.s.l.) of the Atlantic Forest in southern Brazil.MethodsWe investigated the extent to which β‐diversity varied along the elevational gradient (six elevations) at both spatial (among sites at different elevations) and temporal (different months at the same site) scales. We compared both the turnover and nestedness‐related dissimilarity of species and genera using multiple‐site or multiple‐month measures and tested whether these measurements were different from random expectations.ResultsA mid‐elevation peak in species richness along the elevational gradient was observed, and the lowest richness occurred at the highest elevations. We found two different groups of species, lowland and highland species, with a mixing of groups at intermediate elevations. The turnover component of β‐diversity was significantly higher for both spatial (i.e. elevational) and temporal changes in species composition. However, when the data for genera by site were considered, the elevational turnover value decreased in relative importance. Nestedness‐related processes are more important for temporal dissimilarity patterns at higher elevation sites.Main conclusionsSpatial and temporal turnover of dung beetle species is the most important component of β‐diversity along the elevational gradient. High‐elevation assemblages are not subsets of assemblages that inhabit lower elevations, but this relationship ceases when β‐diversity is measured at the generic level. Environmental changes across elevations may be the cause of the differential establishment of distinctive species, but these species typically belong to the same higher taxonomic rank. Conservation strategies should consider elevational gradients in case‐specific scenarios as they may contain distinct species assemblages in lowlands vs. highlands.