Riverine floodplains support diverse amphibian communities by providing essential habitats, with lateral hydrological connectivity (LHC or hydrology) determining local environmental conditions. Our study evaluated the direct and indirect effects of LHC on the two most abundant species in a riverine floodplain. We assessed the relative abundance of water frogs (Pelophylax spp.) and common toads (Bufo bufo) using eDNA surveys at 30 sites along an LHC gradient in the Danube River floodplain. We examined the habitat structure, vegetation cover, and the physical and chemical characteristics of waterbodies. Structural equation models (SEM) were used to explore LHC’s direct and indirect effects, mediated by these environmental factors. Results showed that LHC did not directly influence Pelophylax spp. and B. bufo abundance but affected them indirectly and species specifically through environmental drivers. Hydrology negatively and indirectly impacted Pelophylax spp. through vegetation cover and the physical and chemical properties of waterbodies. B. bufo was affected in a similar way but primarily through habitat structure. Our findings highlight the importance of understanding species-specific responses to lateral hydrological connectivity in dynamic environments, as river regulation altering LHC can differentially impact amphibian species in riverine floodplains.

Quantifying dissimilarity between ecological communities is fundamental to functional community ecology. In this study, we develop a conceptual and analytical framework that integrates species-based and trait-based dissimilarity measures. The core of the proposed approach involves two steps: the first computes the products of species abundances and trait values, while the second combines products into aggregated trait abundances (ATAs) for use in both species- and trait-based analyses. Building upon the additive decomposition of the Marczewski-Steinhaus and Bray-Curtis indices into difference and replacement components, we introduce a suite of novel methods that allow for the independent weighting of species abundances and trait values. We first detail the methodology and elucidate its conceptual foundations. Subsequently, we assess its performance using both illustrative toy examples and ecologically realistic simulated datasets. To demonstrate its practical utility, we apply the method to compare macroinvertebrate assemblages from natural and anthropogenically impacted stream sections. Our findings indicate that the proposed framework provides a continuum between traditional species-based and trait-based approaches. Finally, we offer practical guidance for ecologists on selecting the most appropriate dissimilarity measure based on specific research objectives and data characteristics.

The ternary diagram of functional diversity (TDFD) is a novel framework for biodiversity assessment that jointly and non-independently represents classical (indices combining species richness and abundance) and functional (indices based on species’ functional traits) dimensions of community diversity by partitioning them into three non-independent fractions: quadratic entropy (Q), functional redundancy (R), and Simpson dominance (D). We applied this approach in parallel with traditional methods to characterize community diversity of stream-dwelling macroinvertebrate assemblages and compare assemblages collected from natural and settlement-impacted stream sections. The TDFD indicated that these assemblages in general exhibit low functional redundancy and, consequently, high functional uniqueness, implying that stream macroinvertebrates deliver many unique functions rather than a few functions supported by high redundancy. We also found that the Simpson dominance fraction (D), which captures the classical diversity component, exhibited the widest range among the tree fractions, indicating that classical diversity explains most of the observed community variability. Settlements influenced the TDFD fractions overall, but effects were stream specific. Our results suggest that small settlements affect both classical and functional diversity dimensions of macroinvertebrate assemblages in a context-dependent manner. Overall, the TDFD provides insights into community diversity that is not detected by traditional approaches.

Urbanization contributes to an overall decline in the diversity of freshwater macroinvertebrate assemblages, while beta diversity in stream communities is primarily driven by local environmental conditions. Our study explored how anthropogenic stream modification influences taxonomic beta diversity and its components richness difference (D) and replacement (R) in low-order stream macroinvertebrate assemblages and how environmental variables shape these patterns. The two components (D and R) together with the Jaccard similarity (S) were used to generate the ternary diagrams (SDR simplexes) to evaluate the effects of urban land-use change and stream identity. We found that effect of urbanization on compositional heterogeneity varies across streams due to their unique characteristics. Furthermore, our results indicated that stream size drove community differences among natural and degree of urbanization between urban stream sections. The varying responses of streams beta diversity to anthropogenic modifications highlight the need for site-specific management in conservation strategies. To our knowledge, this is the first study to examine how local environmental parameters influence compositional heterogeneity among samples (beta diversity, replacement and richness difference component) in natural and urban sections of low-order streams, focusing on the entire macroinvertebrate assemblages.

Soil fauna is crucial for carbon cycling, controlling organic matter decomposition and contributing to ecosystem services[1][1]–[7][2]. Soil microarthropods are top-down regulators in the decomposer food web and serve as fundamental indicators of soil health. Yet, routine field-level monitoring remains restricted to resource-intensive research, leaving a critical gap in arable land management and policy. To address this, we developed Edapholog® extractor, a fully automated laboratory device that detects and identifies live soil microarthropods via real-time, AI-based image analysis, enabling taxonomic identification. Here, we demonstrate its accuracy across 319 arable fields spanning ten European countries. We show that computer vision can support ecological interpretation in arable systems and long-term studies on conservation tillage and cover cropping, offering a scalable tool for integrating soil biodiversity metrics into regenerative agriculture and carbon farming. We validated the system against classical taxonomy and found that across ∼35,000 microarthropod individuals, the device achieved an overall accuracy of 86%, sensitivity of 75%, and specificity of 99% compared to manual identifications. Community composition analyses revealed high similarities (83%), with minimal richness differences (7%) and low species replacement (13%) across countries, indicating that the AI does not introduce taxonomic bias. When applied in a long-term field experiment, the system detected significant taxon-specific responses to conservation tillage, with effect sizes ranging from 0.5 to 4. Total abundance, richness, and a soil biological health index were 39%, 47%, and 150% higher, respectively, under conservation tillage compared to conventional ploughing. These effects were statistically consistent between the automated and classical methods. However, while manual microscopy required several hours per sample, the AI-based system delivered immediate results without the need for taxonomic expertise. Edapholog® extractor offers exciting opportunities for rapid, scalable soil biodiversity monitoring for future sustainable land management. ### Competing Interest Statement The authors have declared no competing interest. Co-operative Doctoral Program, HU [C2269690], KDP-IKT-2023-900-I1-00000957/0000003 [1]: #ref-1 [2]: #ref-7

Lakes and their catchment area, which are of great interest for tourism, are now heavily modified and subject to urbanisation and other forms of shoreline development. All these processes can contribute to the appearance and spread of non-native species. Although Theodoxus fluviatilis (L., 1758) appeared in Lake Balaton (Hungary) in 2013, we have limited information on the spread of the species as well as on the ecological preference of the species in the lake. To address these shortcomings, we surveyed the spatial distribution of the species, examined how land-use pressures along with the geographical location of sampling sites influence the abundance of T. fluviatilis, and investigated the depth preference of the species along the shoreline of the lake. We found that the species has successfully conquered the artificial rocky shoreline of Lake Balaton eight years after its first appearance. Our results indicate that the geographic location of the sampling sites had a significant role since the abundance of T. fluviatilis decreased from southwest to northeast, corresponds to the nutrient gradient in Lake Balaton. This result suggests that, beyond local factors like artificial rip-rap habitats, lake-level factors also significantly influence the distribution of the species. We observed that T. fluviatilis favours 70-80 cm water depth, which might be due to the decreasing rate of wave-induced disturbances along the depth gradient and the available food for the species. We argue that the occurrence and the spread of the species in the lake can be explained by the existence of shoreline modification and by the water management practice that maintains high water levels. These assumptions are consistent with literature evidence stating that the high water level can influence key environmental variables such as wind-induced turbidity, sediment resuspension, and underwater light conditions, which may affect the distribution of aquatic organisms in the littoral zone.

The degradation of freshwater ecosystems due to land use changes is one of the major driver of global biodiversity loss and amphibian declines with these impacts varying across different spatial scales. Our study aimed to assess how natural and human-modified land affects smooth newt (Lissotriton vulgaris) abundance in the surrounding waterbodies of Lake Balaton, a highly urbanized area. We conducted aquatic trap surveys at 32 wetland sites during the breeding season and quantified land cover within 250, 500, and 1000-m radius buffer zones. We hypothesized that urban land use, cropland, and proximity to roads and railways would negatively correlate with newt abundance, while wetlands areas (marshes, swamps, periodically flooded grasslands) and natural terrestrial habitats (grasslands, forests and woodlands) would positively correlate, with effects varying across spatial scales. N-mixture models were used to analyse survey data, estimating abundance and examining relationships with covariates. Results revealed that wetland cover within a 500-m buffer zone increased newt abundance, probably due to supporting metapopulation connectivity. In contrast, cropland cover within 250 m and proximity to roads and railways negatively affected newt abundance. Conservation efforts should prioritize providing smooth newts with adequate breeding habitats and reducing disturbances from croplands, roads, and railways.

Natural wetlands have frequently been converted to fishponds, particularly in the Central and Eastern European lowlands. In this study, we compared environmental parameters and taxonomic and functional diversity of benthic chironomids of natural wetland habitats with converted successor fishponds and effluent-impacted stream sections. Fishponds had deeper water depth, no emergent macrophytes and higher concentration of chlorophyll-a compared to natural wetland pools. Pondside stream sections had lower current velocity, more deposited allochthonous organic matter, and higher concentrations of total phosphorous and chlorophyll-a than upstream stream sections. Stream habitats recovered only partially downstream. Mean number of chironomid taxa in the samples was similar, while total number of chironomid taxa and taxonomic and functional assemblage composition differed between natural and fish farming-impacted habitats. The increased phytoplankton production was particularly influential on the organization of chironomid assemblages, and trait-based analyses showed changes in the source and processing of organic matter. Environmental impacts of fish farming could be decreased through environmentally friendly management practices, by reconstructing the less effective fishponds to a natural state and constructing artificial and densely vegetated wetland pools to treat the effluent water. Because of the high biotic heterogeneity in the studied system, a regional perspective is needed in conservation planning.

Transitioning from perennial to non-perennial flow regimes causes ecological shifts in aquatic communities. Aquatic macroinvertebrates deploy resistance and resilience strategies to cope with flow intermittency, crucial in rivers with long-term seasonal dry episodes. Less is known, about how these strategies support community persistence in streams that only recently have experienced drying, and where local assemblages lack such adaptations. Our study conducted two four-season campaigns, separated by a one-year break, to assess macroinvertebrate responses in newly drying intermittent streams by comparing intermittent and perennial stream sections. We characterize communities from structural and functional perspectives, and then evaluate the response at the trait state level. We observed a decline in taxa richness and abundance, but not structural diversity, in response to flow intermittency. Resistance traits are more important than resilient traits in structuring macroinvertebrate communities in newly intermittent stream sections. Taxa in intermittent sections exhibit a smaller trait space, indicating lower functional redundancy. The macroinvertebrate response to intermittency lacks a predictable pattern, suggesting time-dependent and trait-state-specific colonization by adapted taxa and community assembly with resistance and resilience strategies. As river drought increases due to climate change, recognizing the temporal dimension becomes crucial for understanding ecological responses to intermittency.

Context Human-induced landscape modification, such as urbanization, creates new environments that can have adverse effects on flora and fauna, posing threats to biodiversity. Understanding how reptiles respond to urbanization is crucial, especially in light of their ongoing population declines. Objectives We examined the influence of landscape-scale and local-scale urbanization features on the abundance of an aquatic snake species. Our investigation focused on dice snakes (Natrix tessellata) inhabiting a lake with a heavily urbanized shoreline. Methods We conducted visual encounter surveys at 25 study sites during the activity period of dice snakes around Lake Balaton in Hungary. We measured both landscape-scale and local-scale variables, including urban land use cover, vegetation cover, road cover, distance of main roads and city size, emergent vegetation cover and the area of artificial rock and concrete shoreline protection structures. We analysed snake survey data using N-mixture models to estimate abundance and examine relationships with landscape-scale and local-scale variables. Results Urban land use cover, road cover, the proximity of main roads and the extent of artificial rock and concrete shoreline protection structures positively affected the abundance of snakes. These findings imply that urban habitats may offer new ecological opportunities for dice snakes. Conclusions The findings of this study indicate that both landscape-scale and local-scale human-induced landscape modifications may have a positive impact on the abundance of urban snakes. Taken together, our findings suggest that urbanization is a complex phenomenon, affecting species at different levels and with subtle effects.

Several theoretical models have been proposed as the underlying mechanisms behind occupancy frequency distribution (OFD) patterns. For instance, the metapopulation dynamic model predicts bimodal OFD pattern indicating the dominance of dispersal processes in structuring the assemblages, while the niche‐based model predicts unimodal right‐skewed OFD pattern, and thus assemblages are driven mostly by niche processes. However, it is well known that the observed OFD pattern reflects the interplay of several other factors (e.g. habitat heterogeneity, species specificity and sampling protocol parameters). It follows that the individual contribution of each factor to the OFD pattern is rather complicated to explore. Our main objective was to examine the role of the spatial extent of the sampling and the dispersal strategies of species in shaping OFD pattern. For this, we collected samples of stream insect assemblages inhabiting near‐natural streams in the Pannon Ecoregion. We formed groups of species representing contrasting dispersal strategies (referred to as dispersal groups). Applying a computer program algorithm, we produced samples with different spatial extent. We found that with increasing spatial extent, the OFD pattern changed from bimodal to unimodal for active dispersers. Insect groups with different dispersal strategies differed in the strength of support for OFD patterns within all spatial extent. Furthermore, the strength of support for OFD patterns varied across dispersal groups differently as the spatial extent increased. Our results reflected underlying changes in mechanisms structuring assemblages along an increasing spatial extent. We also assumed that the stream insect dispersal strategy influences the relative role of dispersal and niche processes particularly as spatial extent increases from stream reaches to the extent of adjacent valleys. We could define spatial extents and dispersal strategies within which unique metacommunity processes could underlie the organisation of assemblages.

The non-native invasive box-tree moth (Cydalima perspectalis) causes severe damage to ornamental box trees (Buxus spp.) and natural boxwood stands (Buxus sempervirens). Using two light traps, we recorded the seasonal flight activity and abundance of C. perspectalis in the suburbs of Basel (Switzerland) over a 15-year period (2009-2023) shortly after the moth's introduction to Europe in 2007. In each year, we also assessed the grazing damage and number of box-tree larvae in a nearby natural box-tree forest. We recorded two peaks in the number of C. perspectalis caught in the settlement area (2009-2010 and 2017-2018). Cross-correlation analysis showed that waves of C. perspectalis moths invaded the settlement area in the year after the peak years of forest damage. Moderate numbers of C. perspectalis were caught each year during off-peak periods. The outbreaks of C. perspectalis resulted in a complete defoliation of the box trees in the forest, after which the moth population collapsed. The slowly regenerating box-tree forest was recolonised by C. perspectalis, most probably from the settlement area. After the second outbreak, the box-tree forest did not appear to be able to fully recover, as moderate numbers of C. perspectalis larvae fed on the emerging new leaves. The annual mean temperature measured in Basel increased by 1.5 degrees C between 2009 and 2023. During this period, the first C. perspectalis moths were caught earlier each year and the last moths were caught later each year. Thus, the duration of flight activity of C. perspectalis (all three generations of a year combined) increased from 13 weeks in 2010 to 20 weeks in 2023, indicating the impact of climate warming. Our study shows that the dynamics of C. perspectalis in the settlement area are strongly influenced by the presence of box trees in the adjacent forest.

Abstract Exposure to synthetic chemicals, such as pesticides and pharmaceuticals, affects freshwater communities at broad spatial scales. This risk is commonly managed in a prospective environmental risk assessment (ERA). Relying on generic methods, a few standard test organisms, and safety factors to account for uncertainty, ERA determines concentrations that are assumed to pose low risks to ecosystems. Currently, this procedure neglects potential variation in assemblage sensitivity among ecosystem types and recommends a single low-risk concentration for each compound. Whether systematic differences in assemblage sensitivity among ecosystem types exist or their size, are currently unknown. Elucidating spatial patterns in sensitivity to chemicals could therefore enhance ERA precision and narrow a fundamental knowledge gap in ecology, the Hutchinsonian shortfall. We analyzed whether taxonomic turnover between field-sampled macroinvertebrate assemblages of different broad river types across Europe results in systematic differences in assemblage sensitivity to copper and imidacloprid. We used an extensive database of macroinvertebrate assemblage compositions throughout Europe and employed a hierarchical species sensitivity distribution model to predict the concentration that would be harmful to 5% of taxa (HC5) in each assemblage. Predicted $$H{C}_{5}$$ H C 5 values varied over several orders of magnitude. However, variation within the 95% highest density intervals remained within one order of magnitude. Differences between the river types were minor for imidacloprid and only slightly higher for copper. The largest difference between river-type-specific median $$H{C}_{5}$$ H C 5 values was a factor of 3.1. This level of variation is below the assessment factors recommended by the European Food Safety Authority and therefore would be captured in the current ERA for plant protection products. We conclude that the differences in taxonomic composition between broad river types translate into relatively small differences in macroinvertebrate assemblage sensitivity toward the evaluated chemicals at the European scale. However, systematic differences in bioavailability and multi-stressor context were not evaluated and might exacerbate the differences in the ecological effects of chemicals among broad river types in real-world ecosystems.

A ten-year-long examination of macroinvertebrate community recovery was conducted following a catastrophic spill of highly alkaline red sludge (pH >13) into lowland streams. Our primary objective was to compare recovery patterns after coarse- and fine-grain disturbances, focusing on two aspects: i) trend analysis to reveal long-term changes of six community parameters, and ii) variation analyses to assess parameter changes over time. We conducted statistical analysis on long-term data series of macroinvertebrates obtained from quantitative samples collected at four sections with varying degrees of disturbance along the impacted stream sections. We developed a comprehensive theoretical framework comprising a series of sequential phases: Ramp-up, Overshoot, and Oscillation Phases. i) A trend analysis revealed that disturbances show a gradual recovery pattern, while variance analyses showed an asymptotic convergence to an equilibrium. ii) Evaluating these trends across phases unveiled that the initial recovery phase exhibited a steep trajectory, lasting 4-9 months, irrespective of disturbance severity. Coarse-grain disturbances induced a remarkable Overshoot phenomenon across all community metrics. The more severe the disturbance, the greater the height and duration of the Overshoot. Our results suggest that the presence or absence of Overshoot can serve as an indicator for coarse-grain disturbances in the context of large and infrequent disturbances (LID). The entire recovery process lasts for 2.5-3 years irrespective of the severity of the LID. In conclusion, a minimum survey duration of two and half years is deemed imperative to capture the phases of recovery, and changes associated with LID are not expected to extend beyond the three-year threshold. The theoretical framework, including Overshoot parameters, may assist future studies in comparing recovery patterns of different LID types. Furthermore, our theoretical framework is likely to be applicable to other groups of organisms given a sufficiently long monitoring of recovery, influenced also by the length of reproductive cycles.

Studies examining the effect of populated areas on streams are mainly focusing on densely populated towns and cities, while that of small settlements is less understood. This study evaluated the influence of small rural settlements on the taxonomic and functional organisation of chironomid assemblages in low-order streams of the Lake Balaton region (Hungary). Environmental variables and chironomid assemblage attributes were compared between unaffected upstream, settlement, and downstream sections in eight streams. Both stream habitat properties and chironomid assemblages changed between upstream and settlement sections, and partially recovered downstream. Settlement sections showed an increased occurrence of regulated and artificial channel structures and a decreased proportion of arboraceous riparian vegetation. Sample level taxon richness was the same in the three sections, while section level total taxon richness increased downstream. The functional approach provided stronger explanatory power in the majority of analyses than the traditional taxonomic approach, and indicated ecosystem wide shifts in functioning within the settlements, especially in the source and processing of organic matter. The negative effect of settlements on the stream biota could be compensated by a more natural-like channel design and by a reforested riparian zone. The high environmental and biotic heterogeneity necessitates regional thinking in conservation planning.

The expansion of urban areas leads to a decrease in natural habitats, resulting some species to live in urban environments. Novel environmental factors might influence their size, body condition and development stability. The environmentally induced developmental instability can be indicated by fluctuating symmetry, which means random deviations from perfect symmetry in bilaterally symmetric creatures.Our research aimed to explore the impact of various urbanization factors on snake populations within urban habitats. To achieve this, we examined how dice snake (Natrix tessellata) populations differ in their asymmetry, body condition and size in a lake characterized by highly modified lakeside habitats, intensive urban land use, and severe human disturbance. The average size, body condition and two asymmetry indices were determined for 25 dice snake populations around Lake Balaton in Hungary. The impacts of the urban environment were characterized by land use and local variables, and the risk of road kill was also estimated.Populations living in areas with a more intensive road network or near a main road showed more asymmetric traits. It is conceivable that pollutants from vehicle traffic lead to developmental disorders that manifest themselves in more asymmetric individuals. In addition, the body condition of snakes was negatively correlated with the area of the harbours, possibly due to the intensive boat traffic and human disturbance. Finally, populations living in more urbanized areas had larger body sizes meaning that despite its negative effects through pollution, anthropized areas can provide a suitable habitat for dice snakes.While urban artificial surroundings can function as suitable habitats, our results confirm that urban environmental factors have negative effects on dice snakes. Our findings indicate that the density of road networks and the proximity of roads have adverse effects on the developmental stability of urban snakes. This underscores the need to implement conservation actions to mitigate the negative effects of roads on biodiversity.

Urbanization is one of the most serious threats to stream ecosystems worldwide. It is crucial to understand its effects on stream organisms as a prerequisite for the mitigation of urban degradation. Our aim was to investigate the general effects of urbanization in a moderately urbanized landscape and to assess the relationship between local environmental variables and biotic attributes of macroinvertebrate assemblages. Multiple sites at low-order streams flowing from natural forested areas to moderately urbanized landscapes were surveyed. We found that local habitat properties presented degraded conditions at urban sites. Urbanization had a negative effect on the richness and Shannon diversity of macroinvertebrate assemblages, and altered assemblage composition. Biotic assemblage parameters showed negative, neutral or positive relationships with local physical parameters. Concrete cover was one of the most important variables, which explained a decreasing richness and diversity of macroinvertebrates. In natural conditions, microhabitat-level environmental variables significantly impacted community variation, while in degraded conditions microhabitat and site-level environmental variables had a substantial impact together. Individual streams showed considerable variability under natural conditions, as well as in their response to urban effects. Subsequently, the mitigation of the effects of urbanization might also need considerable variability in the type of actions required.

Among the many diversity indices in the ecologist toolbox, measures that can be partitioned into additive terms are particularly useful as the different components can be related to different ecological processes shaping community structure. In this paper, an additive diversity decomposition is proposed to partition the diversity structure of a given community into three complementary fractions: functional diversity, functional redundancy and species dominance. These three components sum up to one. Therefore, they can be used to portray the community structure in a ternary diagram. Since the identification of community‐level patterns is an essential step to investigate the main drivers of species coexistence, the ternary diagram of functional diversity can be used to relate different facets of diversity to community assembly processes more exhaustively than looking only at one index at a time. The value of the proposed diversity decomposition is demonstrated by the analysis of actual abundance data on plant assemblages sampled in grazed and ungrazed grasslands in Tuscany (Central Italy).

Motivation: Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological studies and applied freshwater research is missing. We aim to fill this gap and present the Global EPTO Database, which includes worldwide geo-referenced aquatic insect occurrence records for four major taxa groups: Ephemeroptera, Plecoptera, Trichoptera and Odonata (EPTO).Main type of variables contained: A total of 8,368,467 occurrence records globally, of which 8,319,689 (99%) are publicly available. The records are attributed to the corresponding drainage basin and sub-catchment based on the Hydrography90m dataset and are accompanied by the elevation value, the freshwater ecoregion and the protection status of their location.Spatial location and grain: The database covers the global extent, with 86% of the observation records having coordinates with at least four decimal digits (11.1 m precision at the equator) in the World Geodetic System 1984 (WGS84) coordinate reference system.Time period and grain: Sampling years span from 1951 to 2021. Ninety-nine percent of the records have information on the year of the observation, 95% on the year and month, while 94% have a complete date. In the case of seven sub-datasets, exact dates can be retrieved upon communication with the data contributors.Major taxa and level of measurement: Ephemeroptera, Plecoptera, Trichoptera and Odonata, standardized at the genus taxonomic level. We provide species names for 7,727,980 (93%) records without further taxonomic verification.Software format: The entire tab-separated value (.csv) database can be downloaded and visualized at . Fifty individual datasets are also available at , while six datasets have restricted access. For the latter, we share metadata and the contact details of the authors.

Functional diversity is regarded as a key concept for understanding the link between ecosystem function and biodiversity. The different and ecologically well-defined aspects of the concept are reflected by the so-called functional components, for example, functional richness and divergence. Many authors proposed that components be distinguished according to the multivariate technique on which they rely, but more recent studies suggest that several multivariate techniques, providing different functional representations (such as dendrograms and ordinations) of the community can in fact express the same functional component. Here, we review the relevant literature and find that (1) general ecological acceptance of the field is hampered by ambiguous terminology and (2) our understanding of the role of multivariate techniques in defining components is unclear. To address these issues, we provide new definitions for the three basic functional diversity components namely functional richness, functional divergence and functional regularity. In addition, we present a classification of presence-/absence-based approaches suitable for quantifying these components. We focus exclusively on the binary case for its relative simplicity. We find illogical, as well as logical but unused combinations of components and representations; and reveal that components can be quantified almost independently from the functional representation of the community. Finally, theoretical and practical implications of the new classification are discussed.