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This study aims to assess the vulnerability and tolerance levels of macroinvertebrate functional feeding groups (FFGs) in forested streams draining urban areas in the Niger Delta. It contributes to our understanding of how human activities affect freshwater ecosystems. Between 2008 and 2012, we conducted monthly measurements of physicochemical variables and collected macroinvertebrates. We categorised sampling sites into three groups based on disturbance levels: least impacted sites (LIS), moderately impacted sites (MIS), and heavily impacted sites (HIS). Multivariate (RLQ) analysis was used to visualise associations among physicochemical variables across the sampled sites, revealing distinct relationships between certain FFGs and different sites. The RLQ model we constructed showed that grazers and collector-filterers were predominantly observed in LIS, suggesting their vulnerability to environmental stressors. Conversely, predators and shredders were more prevalent in impacted sites (MIS and HIS), indicating their tolerance to disturbances such as elevated nitrate levels and higher water temperatures. The fourth corner graph highlighted differing responses of FFGs to physicochemical variables, with predators showing positive correlations with several factors but no significant association with phosphate levels. Overall, these findings showed the importance of considering the responses of different FFGs to environmental variables in assessing the health and integrity of aquatic ecosystems. [ABSTRACT FROM AUTHOR]

The expansion of urban areas has led to land-use changes that affect aquatic biodiversity and ecosystem processes through several ways, such as increased runoff, water pollution, habitat homogenization, and disturbance of the natural flow. It is well known that urbanization induces profound changes in freshwater macroinvertebrate communities, but relatively few studies have approached this topic using trait-based methods. This severely limits our ability to monitor and predict potential alterations of ecosystem processes. We here provide empirical evidence about the effects of urbanization-related changes on the trait composition and functional diversity of freshwater macroinvertebrates from Patagonia (Argentina). Macroinvertebrate sampling and environmental characterization were carried out in 13 study sites distributed across three water courses in the Futaleufú river basin. We found changes in environmental conditions over the urban impact gradient, in turn accompanied by variation in functional diversity and trait composition of aquatic macroinvertebrates. Specifically, we detected lower functional diversity in urban and post-urban reaches, mainly attributed to shifts in the distribution of taxa within the functional space, rather to the extirpation of functionally distinct taxa located at the edges of it (i.e., functional evenness and dispersion decreased, but functional richness remained constant). We also found signs of functional homogenization at the most impaired sites, where gatherers and tegument-breathing taxa dominated. These changes were mainly explained by conductivity, biological oxygen demand, and oxygen levels in the water column. [ABSTRACT FROM AUTHOR]

Globally, there is growing concern on the occurrence of multiple non‐native species within invaded habitats. Proliferation of multiple non‐native species together with anthropogenic‐driven habitat modifications raise questions on the mechanisms facilitating the co‐occurrence of these species and their potential impact within the recipient systems. Using the Great Fish River system (South Africa) which is anthropogenically‐modified by inter‐basin water transfer (IBWT), as a case study, this research employed trait‐based approaches to explore patterns associated with the co‐occurrence of multiple non‐native fish species. This was achieved by investigating the role of functional diversity of non‐native and native fishes in relation to their composition, distribution and environmental relationships. Nineteen functional traits that defined two broad ecological attributes (habitat use and feeding) were determined for 13 fish species that comprised eight native and five non‐native fishes. We used these data to, firstly, evaluate functional diversity patterns and to compare functional traits of native and non‐native fishes in the Great Fish River system. Secondly, we employed multivariate ordination analyses (factor analysis, RLQ and fourth‐corner analyses) to investigate interspecific trait variations and potential species‐trait‐environmental relationships. From a functional diversity perspective, there were no significant differences in most functional diversity indices between native and non‐native species. Despite interspecific variation in body morphology‐related traits, we also found no clear separation between native and non‐native species based on the ordination analysis of the functional traits. Furthermore, while RLQ ordination showed broad spatial patterns, the fourth‐corner analyses revealed no significant relationships among species distribution, functional traits and environmental variables. The weak species‐trait‐environment relationship observed in this study suggests that environmental filtering was likely a poor determinant of functional trait structure within the Great Fish River. Modification of the natural flow regime may have weakened the relationship between species traits and the environment as has been shown in other systems. [ABSTRACT FROM AUTHOR]

This study aimed to determine the impact of various pressures on the functional composition of OCH (Odonata, Coleoptera, and Heteroptera) in streams within the northwest Rif region of Morocco. We examined how OCH traits respond to human-induced pressures in selected stream sites in Morocco’s northwestern Rif region. OCH specimens were collected from 36 sites using a Surber sampler with dimension of 20 × 20 cm and mesh size of 500 µm over the course of two years, from 2021 to 2023. We measured physico-chemical and hydraulic parameters such as temperature, pH, DO, and NO-3. Sixty-seven trait attributes from 11 trait classes were assigned to the collected OCH taxa at the family level. Following the delineation of sites along the gradient of impacts in the study area, we categorized 7 sites as slightly impacted sites (SISs), 19 sites as moderately impacted sites (MISs), and 10 sites as heavily impacted sites (HISs). We successfully identified and categorized the traits as either vulnerable or tolerant based on RLQ models. Traits such as reproductive cycles per year and tegument respiration, which were positively correlated with SISs in the RLQ model and also positively correlated with depth and chlorine, were identified as vulnerable traits. Crawling locomotion and full water swimming were identified as tolerant traits. The distribution patterns of the OCH taxa revealed a robust correlation between the taxa and the sampling sites. Notably, taxa such as Nepidae, Naucoridae, and Corixidae exhibited widespread distribution and a strong association with the SISs. On the other hand, traits related to living macroinvertebrate food sources and reproduction in vegetation, specifically clutches, exhibited a negative correlation with total dissolved solids. Incorporating OCH functional traits into biomonitoring programs allows for a more comprehensive assessment of river ecosystems. This approach provides a nuanced understanding of how different stressors impact the community composition and overall ecological health.

Herbivorous fish can mediate spatial competition between algae and corals, which is crucial for coral ecosystems. However, in areas with limited coral coverage like the Mexican tropical Pacific (MTP), this dynamic is not fully understood. This study, using a functional trait approach and ordination analysis, explores whether herbivorous reef fish assemblage influences the benthic habitat components or if physicochemical factors define the habitat variability in the MTP's Cleofas and Marietas insular systems. We analyzed if this relationship persisted across systems and over time, and identified species traits tied to habitat variability. Island comparison analyses between Cleofas and Marietas reveal that both herbivorous reef fish and physicochemical variables shape the habitat. Cleofas had larger mobile herbivorous fish that formed groups related mostly to macroalgae cover. In contrast, temporal analysis of Marietas shows that the habitat is primarily shaped by physicochemical variables with herbivorous fish being mainly small farmer species related to branching corals. Notably, these closely situated insular systems present varied ecosystem mediators, influenced by diverse drivers including fish traits and environmental factors. This study underscores the potential of employing a framework of ecological species traits combined with ordination methods to unravel the distinct site dynamics that contribute to the persistence of coral ecosystems within the MTP. [ABSTRACT FROM AUTHOR]

This study aimed to determine the impact of various pressures on the functional composition of OCH (Odonata, Coleoptera, and Heteroptera) in streams within the northwest Rif region of Morocco. We examined how OCH traits respond to human-induced pressures in selected stream sites in Morocco's northwestern Rif region. OCH specimens were collected from 36 sites using a Surber sampler with dimension of 20 × 20 cm and mesh size of 500 µm over the course of two years, from 2021 to 2023. We measured physico-chemical and hydraulic parameters such as temperature, pH, DO, and NO-3. Sixty-seven trait attributes from 11 trait classes were assigned to the collected OCH taxa at the family level. Following the delineation of sites along the gradient of impacts in the study area, we categorized 7 sites as slightly impacted sites (SISs), 19 sites as moderately impacted sites (MISs), and 10 sites as heavily impacted sites (HISs). We successfully identified and categorized the traits as either vulnerable or tolerant based on RLQ models. Traits such as reproductive cycles per year and tegument respiration, which were positively correlated with SISs in the RLQ model and also positively correlated with depth and chlorine, were identified as vulnerable traits. Crawling locomotion and full water swimming were identified as tolerant traits. The distribution patterns of the OCH taxa revealed a robust correlation between the taxa and the sampling sites. Notably, taxa such as Nepidae, Naucoridae, and Corixidae exhibited widespread distribution and a strong association with the SISs. On the other hand, traits related to living macroinvertebrate food sources and reproduction in vegetation, specifically clutches, exhibited a negative correlation with total dissolved solids. Incorporating OCH functional traits into biomonitoring programs allows for a more comprehensive assessment of river ecosystems. This approach provides a nuanced understanding of how different stressors impact the community composition and overall ecological health. [ABSTRACT FROM AUTHOR]

The analysis of plant trait composition has raised significant interest among freshwater ecologists as a complementary approach for assessing the effects of environmental change on ecosystem functions. In this study, we investigated patterns of functional traits of the aquatic macrophyte assemblages of 74 lotic ecosystems of Greece, and we identified associations between species traits and environmental variables (hydromorphological and physicochemical parameters) through testing the hypothesis that the environmental features determine the spatial structure of traits. We allocated 12 traits to a total of 39 hydrophyte species, and we conducted RLQ and fourth corner analysis to explore relationships between species, trait composition, and environmental gradients. Based on the results of the RLQ, a hierarchical cluster analysis was conducted to identify groups of plants that share common trait characteristics. Plants were discriminated into five discrete groups based mostly on their life form (e.g., free-floating, rooted submerged etc.) and their ecological preference for nitrogen levels. Hydromorphological parameters had a higher contribution than physicochemical variables in explaining the total variance of the trait data, with water abstraction, channel substrate, and hydrologic alteration being the most important. Our analysis did not reveal significant bivariate relationships between single traits and environmental parameters, although the five groups of macrophyte assemblages appeared to associate with certain environmental gradients. Free-floating and emergent plants were related to higher concentrations of nutrients, whereas rooted submerged plants were related to higher oxygen concentration and increased pH. In addition, free-floating plants were highly associated with metrics of hydromorphological change. Our findings showed clear discrimination of macrophytes based on their functional composition and association of traits with environmental gradients. Thus, further research could explore whether macrophyte functional groups can serve as indicators of environmental change and the overall ecosystem health. [ABSTRACT FROM AUTHOR]

In the Arctic, climate-driven alterations to the quality and quantity of organic matter reaching the seafloor will likely affect benthic food web function. We used biomass-weighted diversity measures based on trophic traits (those related to feeding behaviours, e.g., mobility, size, food source), stable isotope ratios (δ15N and δ13C), and taxonomy to assess linkages between benthic food web structure and indicators of food supply in the shelf and slope ecosystems of the Canadian Beaufort Sea and Amundsen Gulf (down to 500 m). Benthic communities across both regions used a similar diversity of sedimentary organic matter sources according to stable isotopes, despite known differences between regions in organic matter input and benthic–pelagic coupling. Shelf-edge and upper-slope communities exhibited relatively high trophic trait diversity, which likely reflected the exploitation of pulsed food inputs associated with dynamic processes at the shelf break that affect the production and advection of organic matter to the benthos. Pairwise relationships between trophic traits and sedimentary proxies of benthic food supply were not significant at the regional scale. However, cluster analyses supported the notion that trophic trait composition was influenced by proximity to the shelf edge, where food supply is influenced by episodic events that may not be reflected by in situ sedimentary proxies. Our findings add to growing evidence that evaluating trophic traits composition may provide more information regarding functional responses to changes in benthic food supply than either isotopic or taxonomic diversity indices alone.

Anthropogenic pollution from urban and agricultural activities continually affects freshwater ecosystems in Africa, adversely affecting water quality and biodiversity. In this study, we explored the responses of macroinvertebrate functional feeding groups (FFGs) to an urban-agricultural disturbance in the Niger Delta Region, aiming to examine their utility for long-term monitoring of urban-agricultural disturbance in the region. We sampled 17 sites in 11 rivers between 2008 and 2012. We classified the sites into urban, agricultural, and reference (control) sites based on the watershed land-uses and reach-scale anthropogenic disturbance. Permutational multivariate analysis of variance showed that physical and chemical variables differed significantly between the site groups (P < 0.05) across the land-use types in the study area. Multivariate analysis of similarity (ANOSIM) indicated that urban land-use had more effect on FFGs than agricultural activities, differing significantly from the forested sites (P < 0.05). Macroinvertebrate FFGs such as collectors-filter, collector-gatherers, and scrapers/grazers were identified as sensitive FFGs of urban-agricultural pollution. These FFGs showed strong negative associations with physical and chemical indicators increasing urban-agricultural pollution (e.g. conductivity, nutrients, and turbidity) and favoured by DO at the reference sites. Conversely, shredders and predators were tolerant, indicating significant positive associations with increasing urban-agricultural pollution. They were associated with variables such as temperature, BOD and nitrates. Overall, this study revealed that urban and agricultural pollution differentially affected macroinvertebrate functional feeding groups, and indicator FFGs were identified. This provided further insights on urban-agricultural land-use effects on Afrotropical riverine systems and using FFGs as reliable indicators of ecosystem integrity. [ABSTRACT FROM AUTHOR]

Seabirds are top predators in coastal and pelagic ecosystems that forage at sea but return to land regularly during the breeding season (i.e., central place foragers). This unique life history strategy is directly related to their biological traits and helps define their role as top predators in marine systems. We analysed the effects of physiographic characteristics of nesting islands (area, elevation, and distance from the continent, as predicted by the General Dynamic Model of Oceanic Island Biogeography) and oceanographic variables from waters surrounding nesting islands that tend to be characterised by steep gradients (temperature, salinity, and primary productivity) on the trait diversity of nesting seabird assemblages on islands of the south-eastern Pacific Ocean. Four biological traits related to species’ life history and feeding strategy were used to calculate two indices, the Functional Richness and Rao’s Quadratic entropy. We used fourth-corner and RLQ analysis to determine the relationship between biological traits and environmental variables. Island physiography and primary productivity in the waters surrounding nesting islands significantly affected seabird trait diversity, which gradually decreased from Chilean coastal islands to the distant Polynesian Islands. The traits for body mass and clutch size showed a significant positive relationship with primary productivity. We identified three assemblages of seabirds that had contrasting trait structures. These were defined as the Galapagos, Coastal Chile, and south-eastern Oceanic islands assemblages, and reflected the adaptations of three different species pools to specific oceanographic conditions. Our results suggest that food-related constraints might be one of the most critical environmental filters that shaped the current trait structure of nesting seabird assemblages on the islands in the eastern South Pacific Ocean.

Heterogeneity in riverine habitats acts as a template for species evolution that influences river communities at different spatio‐temporal scales. Although birds are conspicuous elements of these communities, the roles of phylogeny, functional traits, and habitat character in their niche use or species' assembly have seldom been investigated. We explored these themes by surveying multiple headwaters over 3000 m of elevation in the Himalayan Mountains of India where the specialist birds of montane rivers reach their greatest diversity on Earth. After ordinating community composition, species traits, and habitat character, we investigated whether river bird traits varied with elevation in ways that were constrained or independent of phylogeny, hypothesizing that trait patterns reflect environmental filtering. Community composition and trait representation varied strongly with increasing elevation and river naturalness as species that foraged in the river/riparian ecotone gave way to small insectivores with direct trophic dependence on the river or its immediate channel. These trends were influenced strongly by phylogeny as communities became more clustered by functional traits at a higher elevation. Phylogenetic signals varied among traits, however, and were reflected in body mass, bill size, and tarsus length more than in body size, tail length, and breeding strategy. These variations imply that community assembly in high‐altitude river birds reflects a blend of phylogenetic constraint and habitat filtering coupled with some proximate niche‐based moulding of trait character. We suggest that the regional co‐existence of river birds in the Himalaya is facilitated by this same array of factors that together reflect the highly heterogeneous template of river habitats provided by these mountain headwaters. [ABSTRACT FROM AUTHOR]

The present study investigates the influence of seasonal dynamics on macrobenthic assemblages in four seasons of 2017–2018 from the central sector of Indian Sundarbans which is under the constant threat of climate change. Besides taxonomic analysis, a trait-based approach has also been applied to assess the change in their ecosystem functioning. The maximum species density (11675 ± 11883.31 ind. m−2) was observed during the spring season which declines considerably in the monsoon season (5875 ± 6224.08 ind. m−2). A total of 95 macrobenthic taxa were recorded from Sundarbans and they were dominated by families like Capitellidae, Donacidae, Magelonidae, Nereididae, Paraonidae and Spionidae. Overall, polychaetes have shown higher taxonomic and functional variation than other groups. Opportunistic polychaete species have shown a prominent compositional shift during post-monsoon seasons. Both the univariate and multivariate analyses have shown a significant relation between macrobenthic composition and environmental parameters. SIMPER has depicted that environmental parameters made the station 4 unique for several types of molluscs like Acteocina estriata, Stenothyra deltae and Meretrix meretrix during spring. Trait percentages also showed a seasonal succession pattern and among the trait categories, burrowers and deposit feeders dominated the estuary. A gradual increase in suspension feeders in spring has been noticed. RLQ approach with fourth-corner analysis was used to unravel the relationship between traits and environmental parameters. Hence, the present study provided a comprehensive idea about the species composition along with their trait categories from such a dynamic habitat. That could be the first stepping stone for a long term monitoring of macrobenthic assemblages from this largest delta on earth.

Aim: Species introductions have reshaped island faunas for the last 200 years, often threatening native biodiversity. Approximately equal numbers of native and alien species currently co‐occur in the New Zealand avifauna, but they show distinct habitat use. Antagonistic interactions, habitat affinities and legacies of introduction history may concur to explain their segregation along habitat gradients. To investigate these processes, we explored how habitat, ecological traits and introduction history relate with the current composition of bird assemblages. Location: New Zealand Taxon: Birds Methods: We analysed 917 bird point counts spread along habitat and elevation gradients in the Canterbury region, South Island and related 10 ecological traits to landscape composition using a three‐table ordination method known as "RLQ analysis", accounting for spatial autocorrelation and phylogeny. We tested whether alien species' positions in the RLQ were related to proxies of introduction history. Results: Eighteen endemic, 11 native and 19 alien species were distributed along a gradient from forest to open‐habitat assemblages, in relation to foraging mode, nesting site and body size. A second gradient segregated species between native and exotic forests according to territoriality, sedentarity and diet. Traits accounted for the separation of native and alien bird species in forests, but not in open habitats. Phylogenetic signals emerged from the separation of native and alien species by forest type, and spatial structures suggested a landscape‐level, rather than regional or local determinism. These correlations were independent of introduction history, although open‐habitat assemblages tended to host alien species introduced later in time. Main conclusions: Habitat type and resource availability explain the spatial partitioning of New Zealand bird assemblages between native and alien species more consistently than competitive exclusion. We conclude that trait‐mediated ecological differences among species have likely played a predominant role in species' segregation among landscapes, while maintaining endemic bird assemblages in native forests. [ABSTRACT FROM AUTHOR]

Headwater streams in Afromontane ecoregions harbour locally adapted aquatic communities. However, across many regions in Africa, these ecosystems and their unique aquatic biodiversity have been severely impacted by unsustainable land use practices. We tested the hypothesis that land use disturbances were the primary drivers of community dynamics by comparing spatial and temporal dynamics together with trait-environment relationships of macroinvertebrate communities in three headwater streams influenced by different land use practices. The three headwater streams were distinguished based on high conductivity, total dissolved solids and alkaline pH in the agriculture-disturbed stream, and low temperature in a stream whose riparian zone was invaded by non-native vegetation compared to a near-natural stream. Macroinvertebrate taxonomic diversity was, nevertheless, comparable among these three streams. Constrained canonical ordination revealed that seasonality was a major driver of macroinvertebrate dynamics that was reflected mostly by the abundances of six macroinvertebrate taxa (Baetis, Dicentroptelum, Afronurus, Tricorythus, Simulium and Cheumatopsyche), whereas land use contributed a small but significant difference. Trait-environment relationships reflected seasonal changes that included the importance of benthic substratum in winter, the occurrence of collector-gatherer invertebrates in spring and aerial breathing traits in summer. Land use-related traits were, nevertheless, reflected by gill respiration and grazer feeding traits represented by Afronurus in the near-natural stream, predator traits represented by Aeshna and Lestes in the invaded stream, and aerial respiration represented by Enithares, Orectogyrus and Rhagovelia in the agriculture-disturbed stream. Our results suggest that environmental variability associated with seasonality probably played a deterministic role within which land use disturbances operated. Overall, our study suggest that importance of using multiple metrics to unpack the patterns associated with land use disturbances in headwater streams.

Andean forests are home to a strikingly high diversity of plants, making it difficult to understand the main drivers of species assembly. Trait-based approaches, however, help overcome some challenges associated with high taxonomic complexity, providing insights into the main drivers of species coexistence. Here, we evaluated the roles of climate, soil fertility, and symbiotic root associations on shaping the assembly of six plant functional traits (leaf area, specific leaf area, dry leaf matter content, leaf thickness, leaf toughness, and wood density) along an elevational gradient in the species-rich northwestern Andean forests of Colombia. The two main axes of the correspondence RLQ analysis explained 95.75% of the variability. The first axis was associated with the leaf economic spectrum, while the second axis with the tradeoff between growth and survival. Furthermore, the fourth corner method showed that both regional (climatic variables) and local factors (soil fertility, symbiotic root associations, and light distribution) played a key role in determining plant trait assembly. In summary, our study emphasizes the importance of considering both individual size and local factors to better understand drivers of plant trait assembly along environmental gradients. [ABSTRACT FROM AUTHOR]

Understanding the neutral, biological, and environmental processes driving species distributions is valuable in informing conservation efforts because it will help us predict how species will respond to changes in environmental conditions. Environmental processes affect species differently according to their biological traits, which determine how they interact with their environment. Therefore, functional, trait-based modeling approaches are considered important for predicting distributions and species responses to change but even for data-rich primate communities our understanding of the relationships between traits and environmental conditions is limited. Here we use a large-scale, high-resolution data set of African diurnal primate distributions, biological traits, and environmental conditions to investigate the role of biological traits and environmental trait filtering in primate distributions. We collected data from published sources for 354 sites and 14 genera with 57 species across sub-Saharan Africa. We then combined a three-table ordination method, RLQ, with the fourth-corner approach to test relationships between environmental variables and biological traits and used a mapping approach to visually assess patterning in primate genus and species' distributions. We found no significant relationships between any groups of environmental variables and biological traits, despite a clear role of environmental filtering in driving genus and species' distributions. The most important environmental driver of species distributions was temperature seasonality, followed by rainfall. We conclude that the relative flexibility of many primate genera means that not any one particular set of traits drives their species–environment associations, despite the clear role of such associations in their distribution patterns. [ABSTRACT FROM AUTHOR]

Aims: Tidal marsh vegetation along estuaries is exposed to strong environmental gradients that determine which species — enabled through specific traits — can establish and persist. With these ecosystems under anthropogenic pressure, in-depth knowledge on the conservation of remaining tidal wetlands and restoration potentials is needed. In this study we elaborate the habitat conditions in the natural vegetation of the Elbe estuary and analyze: (a) which abiotic factors drive species composition; and (b) which species traits are key to the plants’ strategies in this specific ecotone. Location: Three sites in the Elbe estuary (river kilometer 671–703). Methods: We collected data on soil nutrients, inundation period and wave height and sampled traits of the 17 most abundant plant species, which we analyzed by RLQ (three-table analysis, including environment variables [R], species abundance [L] and a species traits table [Q]). Results: We detected a strong ˈwave–disturbance–inundation gradientˈ, which separated sparsely vegetated low-lying plots receiving high wave impact and exposed to long inundation periods, from high-lying plots showing dense vegetation and aerated soils. Close to the shore, plants showed low organ density and high investment into rhizomes, with a correlation of 0.72 between mass fraction of rhizome and phosphorus content of rhizome tissue. On higher elevations, plants strongly expressed traits relating to competition, like high allocation to stem biomass. Further, we found species with high leaf chlorophyll content showing low specific leaf area values and a negative correlation with the nutrient gradient. Conclusion: The results of our study are particularly relevant for restoration measures in order to re-establish healthy marsh vegetation. However, changes in the environmental conditions, for instance stronger wave energies by a higher shipping frequency in the river channel and sea level rise may trigger changes in species composition through plant trait adaptations, for example by demanding a stem flexibility beyond what would be structurally feasible. [ABSTRACT FROM AUTHOR]

Disturbances often act as ecological filters through which only certain combinations of biological traits may pass. Here, we aimed to determine if an unprescribed human-started wildfire can act as a filter for stream-dwelling macroinvertebrates. To do this, we sampled three burnt and two reference streams in Los Alerces National Park (Patagonia, Argentine side). Sampling began shortly after the fire was extinguished and comprised four visits during the following seven months. We explored how functional richness, evenness, and dispersion at the community level responded to post-fire environmental changes using generalized linear mixed models. We also used RLQ and fourth-corner analysis to identify which trait modalities were specifically affected, either positively or negatively, by the fire. We found that functional richness and dispersion decreased with increasing disturbance intensity, which in this case, was best represented by increased suspended solids. In addition, all three functional metrics were significantly lower in fire-affected sites. Burnt streams were characterized by bi-multivoltine taxa and collector-gatherers, among others. Overall, our study showed how a wildfire can directly constrain the functional composition of macroinvertebrate communities, and highlighted the importance of incorporating trait-based approaches into the study of large-scale disturbances. [ABSTRACT FROM AUTHOR]

To understand impacts of post-disturbance assembly mechanisms on the functional diversity (FD) of plant communities, it is necessary to determine how the environment drives their functional trait composition. In the boreal forest, post-fire abiotic filters may control community assembly by selecting plants with specific traits. Ericaceous heaths are characterized by low FD and are thought to be subject to such filters. We hypothesized that soil parameters select for a specific suite of traits and act as a secondary abiotic filter in post-fire ericaceous heath and contribute to the observed reduction of FD. We measured six soil parameters, five functional traits, and plant species abundances in eight post-fire heath and four regenerating forest sites in Eastern Canada. We conducted a combined analysis of RLQ (R-table Linked to Q-table) and fourth-corner methods to examine the links between plant traits and plot-level soil parameters, mediated by species abundances. Only below ground traits were significantly linked to soil variables. Specific root length and ericoid mycorrhizal associations were negatively linked to total soil nitrogen, available ammonium, and pH. Post-fire heath soils favour a specific suite of species traits. Only a portion of the regional species pool possesses the above-mentioned traits, and when they are favoured by habitat conditions, they assemble into a community with low FD. The novelty of our study is here we show how the relationship between traits and soil chemistry can act as a secondary filter and exert community-level trait changes responsible for the low functional diversity observed in heaths. [ABSTRACT FROM AUTHOR]

Andean forests are home to a strikingly high diversity of plants, making it difficult to understand the main drivers of species assembly. Trait-based approaches, however, help overcome some challenges associated with high taxonomic complexity, providing insights into the main drivers of species coexistence. Here, we evaluated the roles of climate, soil fertility, and symbiotic root associations on shaping the assembly of six plant functional traits (leaf area, specific leaf area, dry leaf matter content, leaf thickness, leaf toughness, and wood density) along an elevational gradient in the species-rich northwestern Andean forests of Colombia. The two main axes of the correspondence RLQ analysis explained 95.75% of the variability. The first axis was associated with the leaf economic spectrum, while the second axis with the tradeoff between growth and survival. Furthermore, the fourth corner method showed that both regional (climatic variables) and local factors (soil fertility, symbiotic root associations, and light distribution) played a key role in determining plant trait assembly. In summary, our study emphasizes the importance of considering both individual size and local factors to better understand drivers of plant trait assembly along environmental gradients.

The degree of trophic specialization determines the ability of predators to cope with changing foraging conditions, but in predators that prey on hundreds of species it is challenging to assess, especially when prey identity varies among predator individuals and across space and time.Here, we test the hypothesis that a bat species foraging on flying insects like moths will show ample flexibility in trophic niche, and this irrespective of phylogenetic relationships among moths, so as to cope with a high diversity of prey types that vary across seasons. We predict that individual bats will show functional dietary differences consistent with energetic requirements and hunting skills.We used DNA metabarcoding to determine the diet of 126 Mediterranean horseshoe bats (Rhinolophus euryale) from two different sites during three seasons. Simultaneously, we measured moth availability and characterized the traits of 290 moth taxa. Next, we explored the relationship between phylogeny and traits of all consumed and available moth taxa. Finally, we assessed the relationship between individual traits of bats and traits related to prey profitability, for which we used the RLQ and fourth‐corner statistical techniques.Seasonality was the main factor explaining the functional dietary variation in adult bats, with moths consumed irrespective of their phylogenetic relationships. While adults consumed moths with a broad range in wing loading, body mass and echolocation detection ability, juveniles consumed slower, smaller and lighter moths, which suggests that young individuals may undergo some fitness gain and/or psychomotor learning process during which they would acquire more effective foraging skills.Our approach revealed a degree of functional flexibility in the trophic niche previously unknown for an insectivorous bat. Rhinolophus euryale consumed a wide variety of moth taxa differing in profitability throughout seasons and between ontogenetic stages. We showed the validity of trait‐based approaches to gain new insights in the trophic specialization of predators consuming hundreds of species of prey. [ABSTRACT FROM AUTHOR]

• Harvesting of forest products negatively affects bird functional diversity. • Harvest effects on bird communities are mediated by species' functional traits. • Different harvest activities variably affect bird functional community structure. • Local harvest disturbances contribute to regional-scale bird community structure. • Unregulated harvesting negatively affects ecosystem function in the Eastern Cape. The ecological impact of forest product harvesting is poorly understood despite the reliance of millions of impoverished households on forest resources. As birds are indicators of environmental change and essential for the function and regeneration of forest ecosystems, this study aimed to assess the response of bird species richness and functional diversity to unregulated forest product harvesting, to illuminate the impact of harvest disturbances on forest biodiversity. Five forest ecotypes in the Eastern Cape Province, South Africa were sampled by means of circular plots in which bird communities, habitat structure and harvest intensities of sub-canopy trees harvested for poles, canopy trees harvested for timber, and bark harvested for medicinal use, were recorded. Generalized linear models (GLMs) were used to assess the response of bird diversity to harvesting activities measured on a continuous scale, and forest ecotype. Correlations between feeding traits and environmental variables relating to habitat structure and harvest disturbances were investigated using RLQ and fourth-corner analysis to better understand which traits were sensitive to harvest disturbances. Results indicated that forest ecotype was an important driver of variation in species richness and functional diversity. Additionally, harvesting disturbances negatively affected two measures of functional diversity, while species richness and functional richness were unaffected by harvesting. Specifically, functional evenness was negatively affected by timber harvesting, while functional dispersion declined in response to pole and bark harvesting. Bird traits relating to feeding ecology (i.e. primary diet and foraging strategy) were associated with habitat structure and harvest disturbances, indicating that harvest activities affected community structure. Specifically, frugivores and granivores were negatively affected by pole and bark harvesting respectively, while omnivorous species were positively affected by these harvest activities. Conversely, timber harvesting negatively affected omnivores, and positively affected nectarivores. Bark and timber harvesting, which resulted in canopy gaps, negatively affected species which forage in the understory or on the forest floor, while pole harvesting, which reduced tree abundance but not canopy cover, negatively affected canopy-foraging species. These results suggest that current unregulated forest product harvesting in the Eastern Cape may negatively affect forest productivity and ecosystem functioning. Specifically, this is the first study to measure the effects of harvesting of poles and medicinal bark on the functional diversity of avian forest communities. [ABSTRACT FROM AUTHOR]

Wildfires are increasing in incidence and severity across coniferous forests of the western United States, leading to changes in forest structure and wildlife habitats. Knowledge of how species respond to fire‐driven habitat changes in these landscapes is limited and generally disconnected from our understanding of adaptations that underpin responses to fire.We aimed to investigate drivers of occupancy of a diverse bat community in a fire‐altered landscape, while identifying functional traits that underpinned these relationships.We recorded bats acoustically at 83 sites (n = 249 recording nights) across the Plumas National Forest in the northern Sierra Nevada over 3 summers (2015–2017). We investigated relationships between fire regime, physiographic variables, forest structure and probability of bat occupancy for nine frequently detected species. We used fourth‐corner regression and RLQ analysis to identify ecomorphological traits driving species–environment relationships across 17 bat species. Traits included body mass; call frequency, bandwidth, and duration; and foraging strategy based on vegetation structure (open, edge, or clutter).Relationships between bat traits and fire regime were underpinned by adaptations to diverse forest structure. Bats with traits adapting them to foraging in open habitats, including emitting longer duration and narrow bandwidth calls, were associated with higher severity and more frequent fires, whereas bats with traits consistent with clutter tolerance were negatively associated with fire frequency and burn severity. Relationships between edge‐adapted bat species and fire were variable and may be influenced by prey preference or habitat configuration at a landscape scale.Predicted increases in fire frequency and severity in western US coniferous forests are likely to shift dominance in the bat community to open‐adapted species and those able to exploit postfire resource pulses (aquatic insects, beetles, and snags). Managing for pyrodiversity within the western United States is likely important for maintaining bat community diversity, as well as diversity of other biotic communities. [ABSTRACT FROM AUTHOR]

Plant functional traits and plant functional groups are increasingly used to assess the effect of the change in land use on plant species or plant communities, in nature conservation projects, to detect patterns in the expansion some invasive species or to asses the processes of succession or competition in plant communities. In this study, the main objective was to identify the main plant functional groups (based on plant traits) which co-exist in different plant communities of the dry grasslands (Festucetalia valesiacae) from North-Eastern Romania using the RLQ analysis (considering the plant traits, environment characteristics and vegetation). As RLQ analysis mainly revealed a soil moisture-soil nutrients gradient along the first axis, a transition from species with traits specific to more dry conditions and less available nutrients to moister and higher nutrients availability sites was observed (from perennial species with short flowering range and traits oriented to resources retention in storage organs to annual species with long flowering range and traits oriented to resource acquisition). Plant functional groups were identified using species scores along the first two RLQ axes via k-means clustering which generated six groups displayed along the above mentioned gradients. The floristic composition of the identified functional groups suggested that, in the context of Festucetalia valesiacae vegetation type from North-Eastern Romania, plant communities developed in areas with lower values for soil moisture and nutrients could possibly be richer in autochore and barochore geophyte and hemicryptophyte species with short flowering range and mixed reproduction type. As soil moisture and nutrients increase, in the floristic composition could possibly occur more anthropochore and zoochore therophyte species with long flowering range, mainly reproducing by seeds and, also, some taller endozoochore shrubs species.

Innovative approaches are needed to help understanding how species diversity is related to the latitudinal gradient at large or small scales. We have applied a novel approach, by combining morphological and biological traits, to assess the relative importance of the large scale latitudinal gradient and regional morphodynamic drivers in shaping the functional diversity of polychaete assemblages in shallow water habitats, from exposed to estuarine sandy beaches. We used literature data on polychaetes from beaches along the southern and southeastern Brazilian coast together with data on beach types, slope, grain size, temperature, salinity, and chlorophyll a concentration. Generalized linear models on the FDis index for functional diversity calculated for each site and a combined RLQ and fourth-corner analysis were used to investigate relationships between functional traits and environmental variables. Functional diversity was not related to the latitudinal gradient but negatively correlated with grain size and beach slope. Functional diversity was highest in flat beaches with small grain size, little wave exposure and enhanced primary production, indicating that small scale morphodynamic conditions are the primary drivers of polychaete functional diversity. [ABSTRACT FROM AUTHOR]

Traditionally, species richness and composition of freshwater communities are expected to change according to the structural variation from headwaters to river mouth. In the present study, we hypothesised that fish functional traits will respond to this gradient, leading to functional dissimilarities between fish assemblages of headwaters and those of rivers. We addressed the following questions: (1) which functional traits are present in fish assemblages of each habitat type; (2) which environmental factors determine the occurrence of fish functional traits; and (3) how functional traits are related to each environmental variable? Our findings showed dissimilarities between fish assemblages of headwaters and those of rivers, mainly driven by channel depth, channel width, water temperature, water turbidity and concentration of dissolved oxygen, whereas altitude, water temperature and pH were mainly correlated with variation within each habitat type. These results suggested that not only do the physical variables proposed in classical theory of the river-continuum concept follow the upstream-downstream gradient in structuring the functional organisation of fish assemblages, but that also physicochemical variables, such as turbidity and concentration of dissolved oxygen, display this trend in tropical river systems. Moreover, our results have given a first perspective on what kind of fish species and fish functional traits to expect in each habitat type and, consequently, along the headwater-river mouth gradient. [ABSTRACT FROM AUTHOR]

Abstract: Cumulative impacts of multiple stressors on freshwater biodiversity and ecosystem function likely increase with elevation, thereby possibly placing alpine communities at greatest risk. Here, consideration of species traits enables stressor effects on taxonomic composition to be translated into potential functional impacts. We analyzed data for 47 taxa across 137 mountain lakes and ponds spanning large latitudinal (491 km) and elevational (1,399 m) gradients in western Canada, to assess regional and local factors of the taxonomic composition and functional structure of zooplankton communities. Multivariate community analyses revealed that small body size, clonal reproduction via parthenogenesis, and lack of pigmentation were species traits associated with both introduced non‐native sportfish and also environmental conditions reflecting a warmer and drier climate—namely higher water temperatures, shallower water depths, and more chemically concentrated water. Thus, historical introductions of sportfish appear to have potentially induced greater tolerance in zooplankton communities of future climatic warming, especially in previously fishless alpine lakes. Although alpine lake communities occupied a relatively small functional space (i.e., low functional diversity), they were contained within the broader regional functional structure. Therefore, our findings point to the importance of dispersal by lower montane species to the future functional stability of alpine communities. [ABSTRACT FROM AUTHOR]

Coral reefs around the globe have been subjected to a wide range of stressors. In the present study, fish species were recorded across a pronounced in-to-offshore gradient in the Jakarta Bay-Pulau Seribu reef system. In addition to this, fish species traits were obtained from FishBase. RLQ analysis revealed a significant association between fish species traits and environmental variables. Fish species associated with perturbed, inshore waters were resilient to disturbance, had higher mortality rates, higher growth rates and mainly consumed animals. In contrast, fish species associated with less perturbed, mid- and offshore waters had greater life expectancy, higher age at maturity, greater life span, greater generation time and mainly fed on plants or plants and animals. Eutrophication, pollution and physical destruction of coral substrate in inshore waters has thus selected for a low biomass and depauperate fish community characterised by fast growing and short lived species. [ABSTRACT FROM AUTHOR]

Question How does a management change from sheep grazing by traditional pastoral herding plus occasional mowing to free-ranging grazing in temporarily fenced areas affect vegetation in dry and wet semi-natural grassland communities? Location Kösterbeck Nature Reserve, NE Germany. Methods We analysed the change in floristic and functional diversity and composition based on a resurvey of a 23-yr-old phytosociological data set. At 10 yrs after the original survey, the grazing regime had changed as described above. Since the exact locations of plots of the original survey could not be reconstructed, we placed the resurvey plots stratified randomly within the respective community types. Functional composition in relation to the environment was analysed with the RLQ approach using community means of Ellenberg species indicator values as proxies for environmental conditions. Results Although the grazing regime changed in the same direction in the whole area, the wet and dry grasslands responded differently: when the changes are analysed for the whole data set, they are hidden behind the differences between vegetation types, and neither plant species α- and γ-diversity, nor species composition changes are apparent. However, when analysed separately, diversity changes were negligible for the wet meadow communities, whereas both α- and γ-diversity increased in the drier sites, leaving β-diversity unchanged. Despite the minor changes in species diversity in the wet grassland, functional composition changed considerably towards graminoid species. In the dry communities, an increase in species richness was accompanied by an increase in functional richness, and a trend towards competitive strategist species. Conclusion Even minor changes in grazing regime can significantly affect grassland communities, while the effects may vary strongly between vegetation types and incoherently across different measures of change. This suggests that thorough analysis of vegetation developments after management changes should be carried out on different levels of data set integration and should include several measures of change. [ABSTRACT FROM AUTHOR]

Globally, as trends of urbanisation continue to intensify, there has been increasing concern over the impacts of urban expansion on biodiversity and greater attention towards addressing these impacts. Ecological infrastructure such as urban rivers and their catchments may enhance biodiversity, ecological functioning and ecosystem service delivery within cities. Birds are good indicators of urban habitat quality because their ecology is well-studied and they are habitat selective. This study assesses the ecological value of a small urban river catchment in Cape Town, South Africa, in terms of its effect on the taxonomic and functional diversity of birds. 178 bird counts were carried out at 89 sites and 95 species were recorded. The nine functional groups considered were present in equal proportions in the catchment and in the whole of southern Africa, making the catchment a microcosm of the region’s avifauna in terms of functional composition. Using RLQ and fourth-corner analyses, we showed that the river was responsible for the occurrence of certain species and functional groups that would not otherwise occur in the suburbs. Nutrient movers, insectivores, scavengers and seed dispersers responded strongly to a gradient of distance from the river and the position on the river. Contrary to the homogenised assemblage that might be expected of an urban area, the catchment contains a taxonomically and functionally diverse bird assemblage. The combination of a river, a heterogeneous urban matrix and an adjacent national park makes this catchment an exemplar of the value of ecological infrastructure for urban biodiversity. [ABSTRACT FROM AUTHOR]

We were interested in which biological attributes and environmental variables enhance the colonisation of vascular plant species on coarse woody debris (CWD) within and among forest communities along lower and upper montane forest belts. The study was carried out in the Sudeten Mts (south-western Poland). A total of 364 decaying logs were studied in terms of their characteristics and the cover of vascular plants colonising them. The three-table ordination analysis (RLQ) revealed that 9 plant traits and 11 environmental variables demonstrated significant associations. Decaying logs were colonised by 46 species, which can be classified into six clusters. The clusters differed in distribution and abundance along the lower-upper montane forest gradient. Annual and autochorous plants as well as herb perennials tended to colonise CWD in the lower montane belt, mainly in beech forests whereas tree seedlings, dwarf shrubs and graminoids prevailed on logs in the upper montane belt – in spruce forests. The localisation and site conditions of logs seemed to be a more important factor than the characteristics of CWD itself. There is a relatively low number of species that are frequently involved in the process of colonisation; however, it can be inferred that they differ in their response to the characteristics of dead wood especially the decomposition stage and the size of a log. Nevertheless, compositional and abundance changes in the vegetation that occurred along the altitudinal gradient played the most crucial role. [ABSTRACT FROM AUTHOR]

Concern regarding global change has increased the need to understand the relationship between fire regime characteristics and the environment. Pyrogeographical theory suggests that fire regimes are constrained by climate, vegetation and fire ignition processes, but it is not obvious how fire regime characteristics are related to those factors. We used a three-matrix approach with a multivariate statistical methodology that combined an ordination method and fourth-corner analysis for hypothesis testing to investigate the relationship between fire regime characteristics and environmental gradients across Spain. Our results suggest that fire regime characteristics (i.e., density and seasonality of fire activity) are constrained primarily by direct gradients based on climate, population, and resource gradients based on forest potential productivity. Our results can be used to establish a predictive model for how fire regimes emerge in order to support fire management, particularly as global environmental changes impact fire regime characteristics. [ABSTRACT FROM AUTHOR]

Assembly rules are ecological processes imposed on a regional species bank to establish the structure of communities and define diversity patterns regarding space and time. Here, we investigated the trait distribution of periphytic algae in floodplain lakes that are naturally under contrasting environmental pressures with and without flood pulse action (low and high water phases) and the relationship between functional traits and environmental variables at regional and local scales. We hypothesized that functional clustering will be related to the low water phase in local scale, based on environment filters, and functional overdispersion to the high water phase in regional scale. With respect to traits, we can expect that the flood pulse would favored the prevalence of nanoperiphyton, filamentous forms and loosely attached. For this, we conducted a two-year assessment of the structure and dynamic of periphytic algae communities regarding their functional traits in lakes belonging to two sub-basins in a subtropical floodplain (upper Paraná River floodplain). The samplings occurred during the high water phase in 2010 and 2011 and the low water phase in 2011. The functional diversity values of the communities were quantified and compared with the mean value of communities randomly generated using null models. The relationships between functional traits and environmental variables were examined using RLQ analysis. We have shown that the traits respond to abiotic factors, and they indicated overdispersion in high water phase, and higher functional diversity in most preserved environments with absence of the pulse. The flood pulse favored the prevalence of colonial life form, stalked, entangled and heterotrichous species. This study showed spatial and temporal differences in the limnological characteristics between the lakes caused by hydrological phase and local forces in different sub-basins and the importance mainly of assimilable nutrients in the evaluation of trait–environment relationships. The overdispersion result can be assigned to flood pulse, which promotes a higher probability of dispersion and colonization of new areas for rare species, disturbance and more heterogeneous habitats, allowing opportunities for resource partitioning and regeneration of different species strategies. Moreover, the higher periphytic algae functional diversity in preserved sites emphasizes the importance of understanding ecological patterns linked to environmental degradation, as well as of conservation initiatives, because variation in periphytic algal communities implies in changes in the trophic structure, dynamics and in the functioning of environments. [ABSTRACT FROM AUTHOR]

Meadows of Posidonia oceanica harbor rich biodiversity and ecosystem functions, yet Biological Traits Analysis on the resident benthic communities are lacking. This study aims to provide insight on the functional diversity of polychaetes communities, a dominant benthic group, between the different habitat types of P. oceanica (plain meadow, strips/patches and dead matte), as well as pilot indicators of habitat modification. The results showed how specific traits relate to the different habitat types. Plain meadow was different to strips/patches and dead matte in functional composition, diversity and thus, the ecosystem functions involved. However, an overlap was observed in functional composition between dead matte and living P. oceanica , due to the remaining matte structure. This highlights the importance of the former on ecosystem functioning and the serious consequences of its current exclusion from conservational legislation. In addition, the classification of species to ecosystem engineering types showed interesting potential as an indicator. • Different Posidonia oceanica habitats were analyzed using Biological Traits Analysis. • Specific trait modalities were found to relate to different layers of P. oceanica structure and habitat types. • Plain meadow differed to Strips/Patches and Dead Matte in functional composition, diversity and possibly ecosystem functions. • Dead Mattes highly contribute to ecosystem functioning but are threatened by lack of a conservational framework. • Types of ecosystem engineering showed potential as an indicator of habitat structure modification. [ABSTRACT FROM AUTHOR]

Question What is the effect of past land use and environmental gradients on plant functional traits within coastal marsh plant communities? Location Mediterranean microtidal marshes in the Llobregat Delta, NE Spain. Methods We used a data set collected previously comprising 45 vegetation plots with associated soil parameters, water table conditions and past land use. For each species we obtained the values or states for a set of plant functional traits: plant height, leaf dry matter content, specific leaf area, seed production, seed weight, life form and lateral expansion. To account for the effect of phylogeny, we evaluated trait diversity skewness by means of an ultrametric phylogenetic tree specifically constructed for the species studied. The association between both environmental gradients and past disturbance, and plant functional traits was tested by means of RLQ analysis. Results Of all the traits, only seed weight showed a phylogenetic signal; consequently, phylogeny was not included in the RLQ analysis. Conductivity was negatively correlated with seed weight, whereas water table conditions and soil ionic balance were negatively correlated with specific leaf area. Past disturbance was negatively correlated with leaf dry matter content and with lateral expansion. Conclusions Plant traits of Llobregat Delta coastal marsh communities are conditioned by environmental gradients and by past land use. Soil ionic balance and water table conditions determine key plant functional traits such as specific leaf area. This finding also corroborates the importance of soil ionic balance as a plant life driver in microtidal Mediterranean marshes. The effect of past land use on species traits might, however, be partially indirect and mediated by associated environmental changes. [ABSTRACT FROM AUTHOR]

Plant functional traits and plant functional groups are increasingly used to assess the effect of the change in land use on plant species or plant communities, in nature conservation projects, to detect patterns in the expansion some invasive species or to asses the processes of succession or competition in plant communities. In this study, the main objective was to identify the main plant functional groups (based on plant traits) which co-exist in different plant communities of the dry grasslands (Festucetalia valesiacae) from North-Eastern Romania using the RLQ analysis (considering the plant traits, environment characteristics and vegetation). As RLQ analysis mainly revealed a soil moisturesoil nutrients gradient along the first axis, a transition from species with traits specific to more dry conditions and less available nutrients to moister and higher nutrients availability sites was observed (from perennial species with short flowering range and traits oriented to resources retention in storage organs to annual species with long flowering range and traits oriented to resource acquisition). Plant functional groups were identified using species scores along the first two RLQ axes via k-means clustering which generated six groups displayed along the above mentioned gradients. The floristic composition of the identified functional groups suggested that, in the context of Festucetalia valesiacae vegetation type from North-Eastern Romania, plant communities developed in areas with lower values for soil moisture and nutrients could possibly be richer in autochore and barochore geophyte and hemicryptophyte species with short flowering range and mixed reproduction type. As soil moisture and nutrients increase, in the floristic composition could possibly occur more anthropochore and zoochore therophyte species with long flowering range, mainly reproducing by seeds and, also, some taller endozoochore shrubs species. [ABSTRACT FROM AUTHOR]

Highlights: [•] Traditional agro-forest systems (TLUS) have a high conservation value. [•] Abandonment and intensification of TLUS decrease their biodiversity. [•] Both types of land-use change decrease provision of ecosystem services of TLUS. [ABSTRACT FROM AUTHOR]

Question Quantification of the effect of species traits on the assembly of communities is challenging from a statistical point of view. A key question is how species occurrence and abundance can be explained by the trait values of the species and the environmental values at the sites. Methods Using a sites × species abundance table, a site × environment data table and a species × trait data table, we address the above question using a novel generalized linear mixed model ( GLMM) approach. The GLMM overcomes problems of pseudo-replication and heteroscedastic variance by including sites and species as random factors. The method is equally applicable to presence-absence data as to count and multinomial data. We present a tiered forward selection approach for obtaining a parsimonious model and compare the results with alternative methods (the fourth corner method and RLQ ordination). Results We illustrate the approach on a presence-absence version on two data sets. In the Dune Meadow data, species presence is parsimoniously explained by moisture and manure on the meadows in combination with seed mass and specific leaf area ( SLA). In the Grazed Grassland data, species presence is parsimoniously explained by the grazing intensity and soil phosphorus in combination with the C: N ratio and flowering mode. Conclusions Our GLMM approach can be used to identify which species traits and environmental variables best explain the species distribution, and which traits are significantly correlated with environmental variables. We argue that the method is better suited for providing an interpretable and predictive model than the fourth corner method and RLQ. [ABSTRACT FROM AUTHOR]

Highlights: [•] Weed communities in fields of different age since conversion to no-till were studied. [•] Eleven out the 13 weed traits tested responded to this age gradient. [•] Perennial and monocotyledon weed species were favored. [•] Favored species invested heavily in the development of their root system. [Copyright &y& Elsevier]

Abstract: Habitat templet theory predicts that habitat provides the templet on which evolution shapes species’ multiple traits and thus their characteristic life-history strategies. By analysing entire trait communities (multiple species and traits) in this framework we can enhance our understanding of how species composition changes as environmental constraints vary across the landscape. Here, we study multiple traits of floodplain Orthoptera communities under the influence of two different sources of disturbance, land use and seasonal flooding. The application of two recently developed statistical techniques – qualitative RLQ analysis and subsequent fourth-corner permutation tests – revealed two different life history strategies in Orthoptera as a response to ecological disturbances, resulting from land use management and seasonal flooding. Orthoptera species seem to have developed two complementary strategies: (i) the high active dispersal-low reproduction strategy in intensive land use situations and (ii) the high passive dispersal-high reproduction strategy in areas with high flood disturbance. Disturbance gradients act as trait filters allowing only particular trait combinations i.e. species with particular preadaptations to survive, whereas others go regionally extinct. Reproduction and dispersal capacity seem to be inversely associated with the disturbance gradients. Ovariole number, taken as the measure for reproduction, showed significant phylogenetic signal, which could potentially confound this relationship. Nonetheless, RLQ analyses coupled with fourth-corner permutation tests proved a powerful tool to reveal and disentangle different evolutionary strategies. [Copyright &y& Elsevier]

Plant functional traits have been proposed as a linkage between the environmental control of vegetation and ecosystem function. Identification of traits that mediate the response of plant species to the environment is well established, but the identification of effect traits and the linkage between the two sets is less developed. This was attempted for a study of eight contrasting land uses in a marginal agricultural landscape where data on vegetation, management controls of the disturbance regime, and soil characteristics, including nitrogen release, were measured simultaneously with measures of ecosystem function such as litter decomposition rates and primary productivity on 30 sites. Trait data were assembled from databases, and an iterative multivariate approach using the three table (species, trait, environment) method RLQ was employed to identify a parsimonious set of traits that predict plant species responses to the environment and a parsimonious set of traits that link vegetation to ecosystem function. The lists of response and effect traits were similar, and where differences were observed, traits were usually highly correlated with at least one trait in the other list. This approach identified a small number of traits (canopy height, leaf dry matter content, leaf size, and specific leaf area) that provide a means of linking vegetation responses to environmental change with changes in ecosystem function. Other response traits included vegetative spread strategy, start of flowering, and seed terminal velocity, but within the system studied these traits were all significantly correlated to the traits shared between the response and effect lists. [ABSTRACT FROM AUTHOR]

Abstract: The concept of functional trait-environment relationship posits that species in a local community should possess similar traits that match the selective environment. The present study examines species trait-habitat (using Fourth-corner and RLQ analyses) and habitat occupancy patterns (logistic regression models) of bird assemblages in boreal forest stands following disturbances by forest fire and salvage logging. The stands differed in the amount and composition of residual tree retention, salvage- and aquatic-edges, degree of burn severity (all measured at 100 and 500m buffers), as well as landscape-level variables such as distance to previously burned forests. Tests of trait-habitat relationships showed that canopy-nesters and bark- and foliage- insectivores required high levels of residual trees of low burn severity, with the feeding guilds showing affinity for different stand composition. In contrast, ground-nesters and omnivores thrived in salvaged areas and associated edges. In addition, cavity-nesting and ground-foragers were associated with severely burned stands. The species’ habitat occupancy patterns were commensurate with trait requirements, which also appeared to be scale-dependent. For example, some fire-associated species had high occupancy probability in severely burned stands at small-scale (100m buffer), which was consistent with their cavity-nesting trait. This pattern, however, was not evident at large-scale, where their feeding requirement (bark-insectivores) for low-severity burns dominated. Our study suggests that trait-habitat relationships can provide critical information to the complex ways species’ relate to key habitat factors following natural and anthropogenic disturbances. [Copyright &y& Elsevier]

The trait-based approach aims to detect functional patterns in vegetation beyond specific sites or taxa. In most cases, plant traits are assumed to be linearly related to environmental gradients such as grazing intensity. To generalize results beyond specific sites, it is important to know to which extent environment-trait relationships are non-linear. Non-linearity can be a source of inconsistency among different studies according to length and studied portion of a gradient. In this study, we test if and to what extent traits relate non-linearly to a grazing gradient using data from a grassland-matorral interface in the Mediterranean rangeland of “La Crau” (SE France). Because quantification of grazing by itinerant sheep flocks is difficult, we use a marker plant, Phillyrea angustifolia, and several independent pasture indicators to estimate grazing intensity. First, we related traits to grazing using a multivariate three-table ordination method (RLQ), which assumes linear reactions of traits. To evaluate the importance of non-linearity, we applied generalized additive models (GAMs) to our data. This revealed that a third of traits studied here showed non-linear relationships to grazing. These non-linear responses cover a large spectrum including seed mass, life form, phenology dispersal- and leaf traits. The high part of non-linear relations compromises a general assumption of linear trait-environment relationships. Future works should therefore more often consider non-linear relationships using methods with no constraints on shape of response, e.g., GAM in the analysis of functional trait studies. In this way, non-linear relationships can reveal new aspects of species and community response to global change and deepen our understanding of trait-environment relations. [ABSTRACT FROM AUTHOR]

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