A decrease in taxonomic and functional diversity of dung beetles impacts the ecosystem function of manure removal in altered subtropical habitats.

Landscape effects on taxonomic and functional diversity of dung beetle assemblages in a highly fragmented tropical forest

The loss of biodiversity caused by human activity is assumed to alter ecosystem functioning. However our understanding of the magnitude of the effect of these changes on functional diversity and their impact on the dynamics of ecological processes is still limited. We analyzed the functional diversity of copro-necrophagous beetles under different conditions of land use in three Mexican biosphere reserves. In Montes Azules pastures, forest fragments and continuous rainforest were analyzed, in Los Tuxtlas rainforest fragments of different sizes were analyzed and in Barranca de Metztitlán two types of xerophile scrub with different degrees of disturbance from grazing were analyzed. We assigned dung beetle species to functional groups based on food relocation, beetle size, daily activity period and food preferences, and as measures of functional diversity we used estimates based on multivariate methods. In Montes Azules functional richness was lower in the pastures than in continuous rainforest and rainforest fragments, but fragments and continuous forest include functionally redundant species. In small rainforest fragments (<5 ha) in Los Tuxtlas, dung beetle functional richness was lower than in large rainforest fragments (>20 ha). Functional evenness and functional dispersion did not vary among habitat types or fragment size in these reserves. In contrast, in Metztitlán, functional richness and functional dispersion were different among the vegetation types, but differences were not related to the degree of disturbance by grazing. More redundant species were found in submontane than in crassicaule scrub. For the first time, a decrease in the functional diversity in communities of copro-necrophagous beetles resulting from changes in land use is documented, the potential implications for ecosystem functioning are discussed and a series of variables that could improve the evaluation of functional diversity for this biological group is proposed.

The Brazilian Cerrado harbors great floristic and structural diversity composed of a mosaic of natural vegetation types and anthropogenic environments such as introduced pastures. Here, our goal was to evaluate the patterns of taxonomic and functional diversity of dung beetles in a human-modified landscape in Brazilian Cerrado. For this, we evaluated the species richness, species composition and abundance (non-weighted by abundance) and species diversity (Shannon index—weighted by abundance) and three functional indexes (functional richness, functional evenness and functional dispersion). We collected the insects in fragments of Cerrado (Cerrado stricto sensu), riparian forests under pressure of timber removal and livestock and exotic pastures (Urochloa spp.) in Anastacio and Aquidauana, Mato Grosso do Sul, Brazil. We used pitfall traps baited with human feces and fresh capybara dung, a large native rodent, as a representative of the mammal regional fauna. Dung beetle richness was higher in Cerrado fragments, while the abundance was higher in exotic pastures and riparian forests. Species composition differed among vegetation types. Finally, the species diversity and functional diversity did not differ among vegetation types. Thus, we demonstrated the information generated by conceptually similar indexes (e.g. functional richness, species richness and species diversity) may not provide similar information on dung beetles responses to disturbance due to differences in the weighting on species abundance. Finally, the use of taxonomic and functional metrics generate complementary information that can helps us to reach more efficient conclusions in terms of biodiversity conservation and ecosystem functionality in human-modified variegated landscape.

Replacing low-intensity cattle pasture with oil palm conserves dung beetle functional diversity when paired with forest protection

Assessing the effects of landscape structure on the relationship between species diversity and functional diversity

Urbanization is increasing globally and causing rapid taxonomic and functional changes in biological communities. Its effects through time in the same communities have not been addressed properly. Here, we evaluate the temporal changes in taxonomic and functional diversity of dung beetles between greenspace (Cerrado stricto sensu) and residential sites in an urban landscape in the Brazilian Cerrado. We sampled dung beetles across 3 years (2013–2015) during the rainy season in the same sites. We evaluated these temporal changes using Temporal Beta Index and beta diversity partitioning into its components of replacement and gain/loss. We expected that residential sites will be taxonomically and functionally poorer compared to greenspace sites over the years. We found a general loss of species and abundance-per species from 2013 to 2015, which was more pronounced in residential sites than greenspace sites, since greenspace sites showed some gain of species from 2014 to 2015. Functional richness, functional evenness, and functional divergence did not change over the years, but were always lower in residential sites than greenspace sites. Functional β-diversity did not change over the years, but was always higher in residential sites than greenspace sites, with similar contribution of functional replacement and nestedness-resultant components. We demonstrate that greenspace sites are taxonomically and functionally more stable, temporally, than residential sites. We advocate that public policies aimed at conservation and management of greenspace sites are important tools for maintaining dung beetle diversity and their ecosystem functions in urbanized landscapes in the Brazilian Cerrado.

The effects of biodiversity on ecosystem functioning comprise a central ecological theorem (BEF), because more diverse communities are expected to perform better, for example, in terms of resource use efficiency (RUE). Although biodiversity affects ecosystem functioning, it is seriously constrained by global environmental change. Epilithic algae are a crucial benthic functional group in aquatic food webs, but the effect of their biodiversity on ecosystem functioning is yet to be understood. Here, we compared the capacity of taxonomic versus functional richness and evenness to predict RUE in a dataset on epilithic algae from the Qinhuai River, Nanjing, China. We examined associations between environmental variables and taxonomic and functional diversity (response and ecological indication), and assessed whether taxonomic and functional diversity measures predicted RUE (quantified as total algal biomass standardised by total phosphorus (RUETP), and total nitrogen (RUETN)). Taxonomic and functional diversity varied more across seasons than space, peaking in spring and summer in association with pronounced environmental changes. Water temperature and nutrient concentrations positively and significantly predicted taxonomic and functional diversity measures. Taxonomic and functional richness positively associated with RUE, while functional evenness negatively associated. However, taxonomic evenness was not related to RUE. Structural equation modelling showed that taxonomic and functional diversity were positively associated with RUETP and RUETN. However, taxonomic diversity was more strongly predictive of RUE than functional diversity. Our results suggest that RUE is closely linked to species diversity, and functional diversity provides a complementary approach for better understanding of mechanisms underlying the BEF relationship for benthic algae in large rivers. We suggest using taxonomic and functional approaches in a complementary way to gain a deeper understanding of the interplay among environmental factors, community diversity and ecosystem functioning.

Windstorm effects on herbaceous vegetation in temperate forest ecosystems: Changes in plant functional diversity and species trait values along a disturbance severity gradient

Recovery of dung beetle assemblages in regenerating Caatinga dry forests following slash-and-burn agriculture

QuestionsTo what extent do changes in management (abandonment and fertilization) affect plant functional and taxonomic diversity in wet meadow communities? To what extent do the changes in functional and taxonomic diversity depend on site productivity?LocationŽelezné hory Mts., Czech Republic.MethodsExperimental plots were established on 21 wet meadows differing in productivity and species composition. In each meadow, in 2007, four 1 × 1 m plots were established, representing a full factorial design with abandonment and fertilization as the factors. In each plot, the number of species present was recorded in 100 subplots (0.1 × 0.1 m) in the years 2007, 2009 and 2011. Different indicators of functional diversity (functional richness, functional evenness, and Rao′s quadratic entropy) were calculated using five functional traits (SLA, LDMC, seed mass, plant height and clonality). Both abundance‐weighted and non‐weighted diversity indices were calculated. Randomization tests (conducted with PERMANOVA) were used to assess the effect of site productivity and management on both α‐ and β‐diversity components.ResultsMeadows along the productivity gradient differed in functional and taxonomic diversity. Both abandonment and fertilization decreased taxonomic diversity. Whereas fertilization decreased functional richness and Rao′s quadratic entropy, abandonment decreased functional evenness. The changes in both taxonomic and functional diversity caused by abandonment and fertilization occurred faster in more productive meadows.ConclusionsThe increased dominance of tall species with abandonment and fertilization, followed by the loss of species and the decrease in various indicators of functional diversity, suggest that increased competition for light resulted in increased trait convergence among co‐existing species. In addition, many processes occurring after abandonment and fertilization depend on meadow productivity. Results suggest that abundance‐ and non‐abundance‐weighted diversity indices give complementary insights on community structure. These results imply that changes are needed in current meadow management and conservation.

Mountains provide an interesting context in which to study the many facets of biodiversity in response to macroclimate, since environmental conditions change rapidly due to elevation. Although the decrease in biodiversity with increasing elevation is generally accepted, our understanding of the variation of functional diversity along altitudinal gradients is still poorly known. The partitioning of diversity into spatial components can help to understand the processes that influence the distribution of species, and these studies are urgently needed in face of the increasing threats to mountain environments throughout the world. We describe the distribution of dung beetle diversity along an altitudinal gradient on a tropical mountain in southeastern Brazil, including the spatial partitioning of taxonomic and functional diversities. The altitudinal gradient ranged from 800 up to 1400 m a.s.l. and we collected dung beetles at every 100 m of altitude. We used the Rao Index to calculate γ, α and β diversity for taxonomic and functional diversity of dung beetles. Climatic, soil and vegetation variables were used to explain variation in community attributes along the altitudinal gradient. Dung beetle richness declined with altitude and was related to climatic and vegetation variables, but functional diversity did not follow the same pattern. Over 50% of γ taxonomic diversity was caused by among altitudes diversity (β), while almost 100% of functional diversity was due to the α component. Contrasting β taxonomic with β functional diversity, we suggest that there is ecological redundancy among communities and that the environment is filtering species in terms of the Grinnellian niche, rather than the Eltonian niche. β taxonomic diversity is caused mainly by the turnover component, reinforcing the hypothesis of environmental filtering. Global warming may have strong effects on mountain communities due to upslope range shifts and extinctions, and these events will lead to an even larger than previously expected loss of diversity as dung beetles γ taxonomic diversity is caused mainly by the β component.

Long-term functional structure and functional diversity changes in Scottish grasslands

IntroductionEcuador harbors an astounding number of ecosystems and species. However, anthropogenic land-use changes are the primary drivers of biodiversity loss in major taxonomic groups, especially insects. Among them, the Scarabaeinae subfamily containing dung beetles, is an excellent taxon for studying taxonomic and functional diversity, as they are relatively stable taxonomically and have a wide variety of ecological services. Their distribution is mainly influenced by biogeography and climate as their main ecological and environmental factors will allow us to quantify what aspects of diversity are being impacted under different circumstances and at different scales.MethodsTo understand the main of dung beetle distribution drivers, we analyzed a museum database from the National Institute of Biodiversity, Ecuador (INABIO) of over 5000 dung beetle specimens with 122 species collected throughout the country, we addressed the following questions: i) How does tribe distribution vary across climatic and elevational gradients? and ii) How does functional and taxonomic beta diversity vary across spatial scales? To address them, we focused on three main tribes: Canthonini, Coprini, and Phanaeini. We constructed GLM’s and niche-based models to estimate Ecuador’s distributions based on climate variables to explore potential predictor variables, using tree classification models, along with taxonomic and functional beta diversity across scales.ResultsThe main variables influencing dung beetle distribution were elevation, and precipitation. The Phanaeini niche model is significantly better at predicting dung beetle presence throughout Ecuador than Canthonini and Coprini. We found high turnover in functional groups at larger scales, suggesting that dung beetles show high levels of habitat specialization, which associates to our findings where taxonomic beta diversity was higher in the Amazon basin compared to the coastal region. This may be due to the higher rate of dung production in Amazonia. Our findings also suggest that dung beetles are not found in areas above 2000m, mainly because dung beetles are well adapted to warmer and moist climatic regions. Precipitation and elevation are consistently essential variables for predicting Canthonini and Coprini presence, while temperature explains Phanaeini presence. Low levels of species turnover at the regional scale may be because the total species richness in Ecuador is different, where divergence in taxonomic beta diversity between the two regions is an artifact of such differences in richness in Amazonia versus the coast, the distinction is also due to nonrandomly low taxonomic beta diversity levels in the coastal region.ConclusionsOur results provide an essential framework for evaluating potential dung beetle habitat and diversity at different scales; therefore, by identifying dung beetles’ diversity, combined with considerations of habitat fragmentation, human land-use alteration, and climate change, will be an important next step to inform better and prioritize dung beetle conservation efforts in other countries.

Frameworks exclusively considering functional diversity are gaining popularity, as they complement and extend the information provided by taxonomic diversity metrics, particularly in response to disturbance. Taxonomic diversity should be included in functional diversity frameworks to uncover the functional mechanisms causing species loss following disturbance events. We present and test a predictive framework that considers temporal functional and taxonomic diversity responses along disturbance gradients. Our proposed framework allows us to test different multidimensional metrics of taxonomic diversity that can be directly compared to calculated multidimensional functional diversity metrics. It builds on existing functional diversity-disturbance frameworks both by using a gradient approach and by jointly considering taxonomic and functional diversity. We used previously unpublished stream insect community data collected prior to, and for the two years following, an extreme flood event that occurred in 2013. Using 14 northern Colorado mountain streams, we tested our framework and determined that taxonomic diversity metrics calculated using multidimensional methods resulted in concordance between taxonomic and functional diversity responses. By considering functional and taxonomic diversity together and using a gradient approach, we were able to identify some of the mechanisms driving species losses following this extreme disturbance event.

AimSuccessional changes in functional diversity provide insights into community assembly by indicating how species are filtered into local communities based on their traits. Here, we assess successional changes in taxonomic and functional richness, evenness and redundancy along gradients of climate, soil pH and forest cover.LocationNeotropics.Time periodLast 0–100 years.Major taxa studiedTrees.MethodsWe used 22 forest chronosequence studies and 676 plots across the Neotropics to analyse successional changes in Hill's taxonomic and functional diversity of trees, and how these successional changes vary with continental‐scale gradients in precipitation, soil pH and surrounding forest cover.ResultsTaxonomic and functional richness and functional redundancy increased, while taxonomic and functional evenness decreased over time. Functional richness and evenness changed strongly when not accounting for taxonomic richness, but changed more weakly after statistically accounting for taxonomic richness, indicating that changes in functional diversity are largely driven by taxonomic richness. Nevertheless, the successional increases in functional richness when correcting for taxonomic richness may indicate that environmental heterogeneity and limiting similarity increase during succession. The taxonomically‐independent successional decreases in functional evenness may indicate that stronger filtering and competition select for dominant species with similar trait values, while many rare species and traits are added to the community. Such filtering and competition may also lead to increased functional redundancy. The changes in taxonomically‐independent functional diversity varied with resource availability and were stronger in harsh, resource‐poor environments, but weak in benign, productive environments. Hence, in resource‐poor environments, environmental filtering and facilitation are important, whereas in productive environments, weaker abiotic filtering allows for high initial functional diversity and weak successional changes.Main conclusionWe found that taxonomic and functional richness and functional redundancy increased and taxonomic and functional evenness decreased during succession, mainly caused by the increasing number of rare species and traits due to the arrival of new species and due to changing (a)biotic filters.