How Do Morphological Traits and Abundance Reflect the Effects of Land Use Change in a Seasonal Floodable Savannah? A Dung Beetle Case in the Brazilian Pantanal

ABSTRACTThe Pantanal is one of the largest Neotropical seasonal freshwater wetlands on Earth, with high biodiversity. Livestock farming has historically been the main economic activity in the Pantanal, in large areas of exotic pastures, and more recently, new areas for soybean croplands were implemented in this biome. However, the impacts of the new areas with soybean crops on biodiversity are still unknown. Here, we used dung beetles, a recognised bioindicator group, to assess the effect of the exotic pastures and soybean croplands on biodiversity in the Brazilian Pantanal. For this, we sampled dung beetles in January 2023 (rainy season) using standardised sampling protocols in the native grasslands, exotic pastures, and soybean croplands in Aquidauana municipality, Mato Grosso do Sul, Brazil. Our results show a consistent shift in dung beetle species composition and a reduction of abundant and dominant species from native grasslands to soybean croplands. These results indicate that the effects caused by soybean croplands are more severe on dung beetle biodiversity than exotic pastures, demonstrating that soybean croplands established in the Pantanal have severe negative consequences for biodiversity. Therefore, management of native grasslands and exotic pastures may be an alternative to avoid the loss of dung beetle biodiversity and to maintain livestock sustainable production in the Brazilian Pantanal. Finally, we highlight the importance of evaluating the effects of traditional and new agricultural systems on biodiversity for the development of more efficient, sustainable management and conservation strategies in the Brazilian Pantanal.

ABSTRACTAlthough many tropical savannas are highly influenced by humans, the patterns of biodiversity loss in these systems remain poorly understood. In particular, the biodiversity consequences of replacing native grasslands with exotic pastures have not been studied. Here we examine how the conversion of the native savanna grasslands affects dung beetle communities. Our study was conducted in 14 native (grassland:campo limpo), and 21 exotic (Urochloaspp. monoculture) pastures in Carrancas, Minas Gerais, Brazil. We collected 4996 dung beetle individuals from 66 species: 3139 individuals from 50 species in native pastures and 1857 individuals from 55 species in the exotic pastures. Exotic pastures had lower dung beetle richness, abundance and biomass than native pastures. Species composition between the two pasture types was significantly different and exotic pastures were dominated by few abundant species. Indicator species analysis detected 16 species indicators of native pastures and three of exotic pastures, according to relative abundance and frequency in each pasture system. Our results show that the conversion of native pastures to exotic pastures leads to a predictable loss of local species richness, increasing dominance and changes in species composition. These results highlight the importance of maintaining native pastures in the Cerrado agro‐pastoral landscape.Abstract in Portuguese is available athttp://www.blackwell‐synergy.com/loi/btp.

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

Dung beetles are efficient indicators to obtain responses regarding the effects of land use change on biodiversity. Although the biological consequences of Cerrado conversion into pasture have been observed at the assemblage scale, there are no cues regarding the effects of tropical savanna conversion into pasture on physiological condition of dung beetle individuals. In this study, we evaluated whether native and non-native habitats in Cerrado affect the physiological condition and body traits of males and females of Phanaeus palaeno. The individuals were collected from a Cerrado fragment (sensu stricto) and an exotic pasture (Urochloa spp.). Physiological condition was assessed through the estimation of individuals' dry body mass, fat mass, and muscle mass. Body traits were estimated through individual body size and males' horn length. We did not find differences between dung beetle morphological traits between Cerrado and pastures. However, individuals collected in exotic pastures had lower dry mass and fat mass, but higher muscle mass, than in conserved Cerrado. Understanding how the land use change affects individuals' body condition is essential to maintain abundant and healthy populations of dung beetles in human-modified landscapes. Although the estimation of physiological condition is logistically more complex than species body traits, future studies aiming to present complex and finer ecological responses of dung beetles should incorporate physiological data to their approaches.

The Pantanal is the largest seasonal freshwater wetland on Earth, characterized by the seasonal flooding and complex mosaic vegetation, which determines its biodiversity. Among this biodiversity, dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) are a group of insects that perform important ecological functions, such as: nutrient cycling, seed dispersion and parasite control. In order to mitigate the lack of information on dung beetle fauna of the Brazilian Pantanal, we conducted a bibliographic search of virtually all literature published until november-2020 on dung beetles sampled in the Pantanal. In addition, we had accessed to the records the largest collection of the dung beetle species from Brazilian Pantanal. We recorded 68 dung beetle species of 30 genera. The genera Canthon Holffmanseg 1847 is the most diverse with 13 species recorded. Although our knowledge about the dung beetle fauna in this ecosystem is still incipient, our results demonstrated a high richness of dung beetles in the Brazilian Pantanal. In addition, our study provides first list of dung beetle species and an illustrated dichotomy key to identify genera and some species occurring in the Brazilian Pantanal. Thus, the use of this guide for identification of dung beetle species and a list of species can be important tools to help researchers and provide incentive for new inventories on dung beetle fauna in the Brazilian Pantanal.

Dung beetles present a high specificity degree to certain habitat types and they are widely used as bioindicators of environmental changes. Pitfall traps usually baited with human feces are the main method for collecting these insects. However, despite dung beetles being good flyers and actively move in the environment, collections with flight intercept traps have been little used in inventories of these insects in the wild. The fact that the intercept trap usually does not use any attractants, randomly capturing individuals can minimize sampling artifacts related with bait, light or other attractive methods. Here, we use flight intercept traps to analyze the dung beetle assemblages in different habitats in the Amazon rainforest. Dung beetles were sampled weekly from March 2017 to February 2018 in an Amazon forest fragment under anthropic pressure, cupuacu orchard, and exotic pasture in Porto Velho, Rondonia, Brazil. A total of 1041 individuals belonging to 35 species of dung beetles were collected. The species accumulation curve showed no significant difference in the number of species among the three different habitats. The dung beetle species composition found in the forest fragment and cupuacu orchard was similar, but the community of these two habitats was different from the exotic pasture. Our study provides a list of dung beetle species sampled using a method that is still little used in ecological studies using dung beetles as a study model. Finally, the flight intercept trap is a useful tool for dung beetle inventories in different habitats in the Amazon rainforest.

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.

1. Dung beetles perform relevant ecological functions in pastures, such as dung removal and parasite control. Livestock farming is the main economic activity in the Brazilian Pantanal. However, the impact of cattle grazing on the Pantanal's native dung beetle community, and functions performed by them, is still unknown. 2. This study evaluated the effects of cattle activity on dung beetle community attributes (richness, abundance, biomass, composition, and functional group) as well as their ecological functions (dung removal and soil bioturbation) in the Pantanal. In January/February 2016, dung beetles were sampled and their ecological functions measured in 16 sites of native grasslands in Aquidauana, Mato Grosso do Sul, Brazil, 10 areas regularly grazed by cattle and six control ungrazed areas (> 20 years of abandonment). 3. In all, 1169 individuals from 30 species of dung beetles were collected. Although abundance, species richness, and biomass did not differ between grasslands with and without cattle activity, species composition and functional groups differed among systems. Large roller beetles were absent from non‐cattle grasslands, and the abundance, richness, and biomass of medium roller beetles was higher in those systems. 4. Despite causing changes in species/functional group composition, the results of this study show that a density compensation of functional groups in cattle‐grazed natural grasslands seems to have conserved the ecological functions (dung removal and soil bioturbation), with no significant differences between systems. 5. Therefore, these results provide evidence that cattle breeding in natural grasslands of the Brazilian Pantanal can integrate livestock production with the conservation of the dung beetle community and its ecological functions.

Conversion of Cerrado savannas into exotic pastures: The relative importance of vegetation and food resources for dung beetle assemblages

Abstract1. The replacement of natural systems with agricultural lands is the main factor resulting in land use change in tropical regions. Tropical savannas cover more than 20% of the global land surface, and one‐fifth of the world's population depends directly on these systems.2. Here, we aim to understand how the conversion of tropical savanna into exotic pastures affects the taxonomic and functional metrics of communities and dung removal, using dung beetles as a focal group in a biodiversity hotspot—the Brazilian Cerrado biome. We used species richness, abundance, total biomass, and species composition as assemblage metrics, and functional richness, equitability and dispersion indices, and functional composition as functional diversity metrics.3. The replacement of native savanna with exotic pastures negatively affected taxonomic and functional metrics, suggesting a simplified system where some disturbance‐tolerant species become dominant. However, the relationship between dung removal and functional richness was higher in pastures compared to savanna.4. Our results demonstrated that responses of dung beetle assemblages and dung removal to land use changes are decoupled, idiosyncratic and context‐dependent, presenting challenges for making predictions and generalisations about the effects of land use change on ecological processes mediated by animals.

In the tropics, human disturbance continuously challenges initiatives for habitat conservation. In these regions, as economical budgets for conservation shrink, conservation planning requires precise information on when and how different kinds of disturbance may affect natural populations, but also on adequate experimental designs to monitor them. Due to their high diversity, ecological role, stable taxonomy and facilities to sample, dung beetles are used in biodiversity surveys for conservation purposes worldwide. Here we studied the short-term effects of dung beetle communities to an important and widespread ecological disturbance due to road construction in the Amazon basin. We surveyed the dung-beetle community in a spatio-temporal context, i.e. in transects located at 10, 50 and 100-m from a newly constructed, 10-m wide, paved road. The sampling periods took place 1, 3 and 6 months after the construction. During the survey, we collected 4895 specimens that belong to 69 species in 19 dung beetles genera. Six dung beetles species (Canthon aequinoctialis, C. luteicolis, Dichotomius fortestriatus, Eurysternus caribaeus, E confusus and Onthophagus haematopus) accounted for 55% of all individuals collected. Both species diversity and abundance tended to decrease during the 6 months after the opening of the road, but not with distance from the road. Accordingly, an NMDS analysis revealed clear differences in dung beetle community composition and biomass among the three sampling periods, but not with respect to transect location. However, the number of rare species tended to increase toward the forest interior. A detailed analysis of dung beetle species among transects revealed that 5 species (Sylvicanthon bridarollii, Canthidium sp. 2, C. sp. 6, C. sp. 7 and Ontherus diabolicus) were more abundant when getting further from the road. On the contrary 6 species (Eurysternus hamaticollis, E. velutinus, E. confusus, E. caribaeus, Deltochilum oberbengeri and D. orbiculare) increased in abundance in the transect next to the road. Our study therefore confirmed that while overall community metrics did not respond to road construction, several rare dung beetle species did, within an incredibly rapid time frame. While pattern based descriptions of dung beetle responses to anthropogenic activities are common in the literature, our findings suggest that effect of roads is certainly under emphasized.

Dung beetles feed and nest in mammal feces, are influenced by habitat quality and have limited dispersal ability. We hypothesized that dung beetle community structure is affected by mammal composition, habitat structure, and spatial distance, and that these predictors vary among the functional groups in communities. Dung beetles and mammals were sampled using pitfall traps and camera traps, respectively, at 15 Atlantic Forest sites between 2005 and 2013. Habitat structure was described using the point-quadrant method. We utilized descriptive ecological values and used variation partitioning to identify predictors of dung beetle community composition both as a whole, and after organizing the community into functional groups. We recorded 43 dung beetle species and 28 mammal species. Mammal and dung beetle species richness were positively correlated. Mammals and habitat explained the majority of the variation among dung beetle communities, and explanatory values varied substantially when using the functional group approach. Our results indicate that mammals are, indeed, important drivers of dung beetle community structure. Individually, or in combination with habitat structure, mammal composition explained 40 % of the total variation in dung beetle data, i.e., the abundance and species composition of dung beetles and mammals covary. However, herbivorous mammals, medium-sized mammals and omnivorous mammals numerically contributed more than did other groups to the explanation of variation in dung beetle guilds. Habitat structure was an important determinant for dung beetle functional group abundance, and spatial distance influenced covariation between dung beetles and mammals. Thus, the integrity and maintenance of ecological processes in the Atlantic Forest may be dependent on these groups, and further fragmentation, habitat loss and defaunation may increase the sensitivity of this already reduced and threatened biome.

The conversion of Brazilian savanna into exotic pastures leads to the loss of dung beetles and a decrease in their contribution to ecological functions. We hypothesized that the dung beetle communities from exotic pastures would show greater significant differences between climatic zones, when contrasted to communities from Brazilian savanna in the same region, since dung beetle assemblages in pastures are more simplified. We assessed which variables (purpose of production, type of management, percentage the habitat per buffer, soil penetration resistance, pasture area and herd size) affect more the dung beetle community in exotic pastures. We carried out this study in 48 areas of native Brazilian savannas and exotic pastures distributed across four bioclimatic zones: BZ1, hot with three dry months; BZ2, hot with 4–5 dry months; BZ3, sub‐hot with 4–5 dry months and BZ4, meso‐thermal with 4–5 dry months of Minas Gerais State, Brazil. In each BZ, six areas of Brazilian savannas and six areas of exotic pasture were selected. In the Brazilian savanna areas, the species richness, abundance and biomass of dung beetles did not differ between the bioclimatic zones, unlike the exotic pastures. The composition of the dung beetle community was different between land use systems and between bioclimatic zones; the interaction between the two factors was also significant. Our results provide evidence that dung beetle communities active in exotic pastures are more susceptible to climatic environmental variations than communities from more complex and stable habitats, such as savannas. Finally, the best model suggested that all the six variables combined explained about 91% of the total variability in species composition observed between sampling sites.

Dung beetles (Coleoptera, Scarabaeinae) attracted to sheep dung in exotic pastures. In this study we provide data on the abundance and richness of dung beetles (Coleoptera, Scarabaeidae, Scarabaeinae) attracted to sheep dung in exotic pastures (Brachiaria spp.). In four areas of exotic pasture pitfall traps were installed and baited with fresh sheep dung for sampling of dung beetles. A total of 2,290 individuals were captured belonging to 16 species, 10 genera and five tribes of Scarabaeinae beetles. Trichillum externepunctatum Preudhomme de Borre, 1886 and Dichotomius bos (Blanchard, 1843) were dominant. The guild of dwellers was the most abundant in pastures. We demonstrate that dung beetles are attracted to sheep dung. Since the production of both cattle and sheep in the same area is common in tropical pasturelands, results obtained here highlight the need to investigate the actual role of dung sharing (cattle dung + sheep dung) by dung beetles. It is also suggested that experiments be performed for evaluation of the ecological functions performed by dung beetles using sheep dung.

An important service in many ecosystems is the turnover and degradation of dung deposited by cattle. Dung beetles are the primary group of insects responsible for dung turnover, and factors affecting their abundance and distribution thus impact dung degradation. Lands lost to grazing due to dung buildup and pasture contamination total millions of acres per year in US pastures.We evaluated the structural differences in dung beetle assemblages in natural grasslands versus a managed agroecosystem in subtropical southeastern Florida (USA). We measured the direct effect of dung longevity when dung beetle fauna normally inhabiting dung pats were excluded.Our results indicate dung beetle abundance, functional diversity, and species richness have a substantial impact on the rate of dung turnover in subtropical pastoral lands with ~70% of dung removed from the soil surface after three months. Functional diversity and evenness did not have a significant positive effect on dung removal in managed, versus natural grasslands demonstrating a strong relationship between dung beetle assemblage composition and delivery of a key ecological process, dung degradation.We suggest the importance of trees, which provide a thermal refuge for beetles, should be dispersed within matrixes of open pasture areas and within proximity to adjacent closed‐canopy hammocks to facilitate the exchange of dung beetles between habitats and therefore maintain the provisioning of dung degradation services by dung beetle assemblages.