•Studied species turnover, intraspecific trait variability and covariation in Collembola body size along an elevation gradient.•Variations in community weighted mean body size of total, epedaphic and ...hemiedaphic species were similar and more pronounced than in euedaphic Collembola.•Body size variation driven by intraspecific trait variability and species turnover, higher in total, epedaphic and euedaphic but not in hemiedaphic Collembola.•Body size differences explained more by local soil factors than by temperature, with varying importance among Collembola ecological groups.
Investigating functional facets of biodiversity across elevation gradients provides the perspective to deepen understanding of the response of communities to global changes. Functional ecology approaches typically assume that filtering of traits across broad environmental gradients is largely due to species turnover rather than intraspecific trait variability. However, few studies quantified the relative importance of species turnover versus intraspecific variability for the composition of soil animal communities across environmental gradients. Here, for the first time, we investigated the relative contribution of species turnover, intraspecific trait variability and their covariation to changes in Collembola body size based on measurements at the individual level along a temperate-boreal elevation gradient in northeastern China. The results indicated that community weighted mean (CWM) body size of Collembola varied significantly with elevation as well as with life form, with the variations in CWM body size in total, epedaphic and hemiedaphic species being similar and more pronounced than in euedaphic Collembola. These variations in body size were driven to a similar extent by intraspecific trait variability and species turnover, with the former being somewhat higher in total, epedaphic and euedaphic but not in hemiedaphic Collembola. Further, variations in body size were better explained by local habitat-related soil factors than by temperature, but the relative importance of these factors differed among ecological groups of Collembola. Overall, these findings show that intraspecific variations in traits may be of similar importance than the turnover of species and needs closer consideration when using trait approaches to understand biodiversity – ecosystem functioning relationships in face of global change.
•The archive of PE-curve parameters for 139 marine submerged plants was collected.•Clustering of macroalgae by photosynthetic traits in a narrow temperature range was proposed.•Dependences of ...PE-curve parameters on morphological traits are formulated as regressions.•Intraspecific variability can exceed the interspecific variability within a functional-form group.
The PE-curve describes dependence of the macroalgae and seagrasses photosynthesis rate on the irradiance. To determine the main parameters of the PE-curve (photosynthetic parameters) at various temperatures and light intensities, an archive of laboratory experiments data was collected from the available published sources, and systematized (a total of 125 species of macroalgae and 14 species of seagrasses). The available data on the ratio of plant surface area to volume (SA:V) were added to the database. All macroalgae species were assigned to functional-form groups according to Littler 15, and an additional group “seagrasses” was determined.
The data on photosynthetic parameters of macrophytobenthos were clusterized using the Ward's minimum variance criterion, which made it possible to identify clusters that differ greatly in the rate of photosynthesis. The composition of each cluster was determined within the framework of the classification by functional-form groups. The variability of functional parameters was studied by calculating the coefficients of variation within a functional-form group, cluster, and taxonomic division in a narrow temperature range.
Graphs of the oxygen daily production by plants were plotted for different water temperatures to determine the temperature dependence of the photosynthesis rate. Using the method of constructing a neural network, the regression equations for the photosynthetic parameters were found in the form of polynomial dependencies on the morphological characteristics of algae: the SA:V ratio and the Littler group. With limited prognostic value, they illustrate well the qualitative changes in photosynthetic parameters during the transition from thin sheet-like and filamentous structures of thalli to coarser and more resistant ones.
Floral traits represent a valuable yet underutilized resource for functional ecology. We aimed to examine the variability of six quantitative floral traits (carbon C and nitrogen N contents, C:N ...ratio, flower length and width, and dry biomass) among a randomly selected group of 79 temperate woody species at both interspecific and intraspecimen levels. We hypothesized that (1) flower traits are closely related to the evolutionary history of the species, resulting in a strong phylogenetic signal, and (2) flowers collected from the most and the least exposed to sunlight parts of the crown would not differ in trait values. We detected statistically significant phylogenetic signals for all six floral traits under study. We found significant differences between samples from the two light variants only for flower N content and C:N ratio. Given the substantial interspecific and the negligible intra-specimen variability observed, we are convinced that the incorporation of these studied traits, especially those related to flower size (i.e., dry biomass, length, and width), into research on flowering biology and ecology can significantly enrich our comprehension of the plant reproductive processes.
•Floral traits represent an underutilized resource for functional ecology.•We examined the variability of six floral traits among 79 woody species.•We found phylogenetic signals for all six floral traits under study.•We found significant intraspecimen differences only for N content and C:N ratio.•Integrating these traits can enhance our comprehension of plant reproduction.
•Specific leaf area (SLA) is a prominent functional trait in ecological modelling.•Protocols of SLA collection regard mainly sunny side of the crown.•We quantified SLA differences between sun and ...shade leaves among 179 taxa.•On average, shade leaves had 43.3% higher SLA than sun leaves.•We quantified SLA underestimation in trait databases.
Specific leaf area (SLA, leaf area to dry mass ratio) is a widely used functional trait in functional ecology. In most studies, SLA is collected by compiling large databases. However, standardized protocols of data collection include only measurements from the sunny side of the crown. We investigated interspecific SLA variability among 179 woody species in common garden conditions of Kórnik Arboretum (W Poland). Then, we quantified the differences in SLA measurements between sunny and shaded parts of the crowns of those species. On average, shade leaves had 43.3% higher SLA than sun leaves. Including differentiation between sun and shade measurements explained an additional 12.2% of SLA variability (in total 95.2% explained by species, family and canopy position). In conclusion, intra-canopy SLA variation can result in providing lower SLA values in databases while following the standardized data collection protocols. Here, we contribute to improved understanding of the importance of SLA variability in the context of its wide use in mechanistic and physiological modelling of ecosystem functioning.
Quantifying intraspecific and interspecific trait variability is critical to our understanding of biogeography, ecology and conservation. But quantifying such variability and understanding the ...importance of intraspecific and interspecific variability remain challenging. This is especially true of large geographic scales as this is where the differences between intraspecific and interspecific variability are likely to be greatest.
Our goal is to address this research gap using broad‐scale citizen science data to quantify intraspecific variability and compare it with interspecific variability, using the example of bird responses to urbanization across the continental United States.
Using more than 100 million observations, we quantified urban tolerance for 338 species within randomly sampled spatial regions and then calculated the standard deviation of each species' urban tolerance.
We found that species' spatial variability in urban tolerance (i.e. standard deviation) was largely explained by the variability of urban cover throughout a species' range (R2 = 0.70). Variability in urban tolerance was greater in species that were more tolerant of urban cover (i.e. the average urban tolerance throughout their range), suggesting that generalist life histories are better suited to adapt to novel anthropogenic environments. Overall, species differences explained most of the variability in urban tolerance across spatial regions.
Together, our results indicate that (1) intraspecific variability is largely predicted by local environmental variability in urban cover at a large spatial scale and (2) interspecific variability is greater than intraspecific variability, supporting the common use of mean values (i.e. collapsing observations across a species' range) when assessing species–environment relationships. Further studies, across different taxa, traits and species–environment relationships are needed to test the role of intraspecific variability, but nevertheless, we recommend that when possible, ecologists should avoid using discrete categories to classify species in how they respond to the environment.
Understanding species‐specific responses to urbanization is of great importance. Quantifying how these change over large geographic areas has significant implications for ecology and conservation.
Plant functional traits reflect the capacity of plants to adapt to their environment and the underlying optimization mechanisms. However, few studies have investigated trade-off strategies for ...functional traits in desert-wetland ecosystems, the mechanisms by which surface water disturbance and groundwater depth drive functional trait variation at the community scale, and the roles of intraspecific and interspecific variation. Therefore, this study analyzed specific differences in community-weighted mean traits among habitat types and obtained the relative contribution of intraspecific and interspecific variation by decomposing community-weighted mean traits, focusing on the Daliyabuyi Oasis in the hinterland of the Taklamakan Desert. We also explored the mechanisms by which surface water and groundwater influence different sources of variability specifically. The results showed that plant height, relative chlorophyll content, leaf thickness, leaf nitrogen content, and nitrogen-phosphorus ratio were the key traits reflecting habitat differences. As the groundwater depth becomes shallower and surface water disturbance intensifies, plant communities tend to have higher leaf nitrogen content, nitrogen-phosphorus ratio, and relative chlorophyll content and lower height. Surface water, groundwater, soil water content, and total soil nitrogen can influence interspecific and intraspecific variation in these traits through direct and indirect effects. As arid to wet habitats change, plant trade-off strategies for resources will shift from conservative to acquisitive. The study concluded that community functional traits are mainly contributed by interspecific variation, but consideration of intraspecific variation and the covariation effects that exist between it and interspecific variation can help to further enhance the understanding of the response of community traits in desert-wetland ecosystems to environmental change. Surface water disturbance has a non-negligible contribution to this adaptation process and plays a higher role than groundwater depth.
Twenty-six species of the cosmopolitan genus Pseudo-nitzschia can produce domoic acid (DA), a neurotoxin responsible for amnesic shellfish poisoning (ASP). To improve knowledge on this issue, we ...studied the physiological conditions favorable to DA production and accumulation by three Pseudo-nitzschia species from French coastal waters: P. australis, P. pungens, and P. fraudulenta. They were grown in batch cultures under silicate limitation to characterize their physiological traits and calculate their DA production rates. Three strains were studied per species to consider intraspecific diversity and better characterize interspecific differences. DA production was not influenced by growth or silicate limitation in any of the three species. In contrast, silicate limitation in the stationary phase led to DA accumulation by inhibiting cell division, while DA production was still active. The maximum cellular DA (cDA) production rate was 2.95 pg cell−1 d−1 for P. australis, 0.07 pg cell−1 d−1 for P. pungens, and 0.03 pg cell−1 d−1 for P. fraudulenta. The physiological conditions favorable to cDA production and accumulation by P. australis and P. pungens differed. The three species presented similar growth rates, but P. australis had higher photosynthetic capacities that could partly explain its higher DA production potential. The cDA production and the net dissolved DA (dDA) production in the culture medium were favored by different growth conditions. The cDA production to net dDA production ratio was species specific, with P. pungens excreting proportionally more of its produced DA. These laboratory results on cultures imply that cDA production and net dDA production can occur during all phases of P. australis, P. pungens, and P. fraudulenta blooms. The interactions between the species composition of the bloom, the species-specific capacity for DA production, and the effect of silicate limitation – among other factors – on DA cell quotas drive the toxigenicity of Pseudo-nitzschia blooms.
•Favorable physiological conditions for DA production by Pseudo-nitzschia species.•DA production is not favored by silicate limitation as opposed to DA accumulation.•P. australis higher photosynthetic capacities may explain higher DA production.
Dans les régions arides et semi-arides, la productivité des sols salinisés ne cesse de diminuer causant d’importants dommages socio-économiques et environnementaux. L’utilisation du genre Salix dont ...plusieurs espèces ont montré une aptitude à se développer sous des conditions de stress salin pourrait constituer une solution viable pour la restauration des potentialités des sols dégradés. Cinq espèces de Salix (S. purpurea, S. alba, S. vitellina, S. babylonica et S. viminalis) originaires de la zone méditerranéenne sud ont été évaluées en conditions hydroponiques, quant à leur degré de tolérance à la salinité. Des boutures ligneuses ont été soumises à un traitement salin (100 mmol·L
−1
NaCl) et un traitement témoin (0 mmol·L
−1
NaCl) pendant 30 jours. Au cours du traitement, une forte variabilité interspécifique a été mise en évidence en termes de changement dans la densité et la taille des stomates, de croissance, de perturbation de photosynthèse et de fuites d’électrolytes. L’indice de tolérance a permis de classer les cinq espèces de Salix selon un ordre décroissant de tolérance à la salinité : S. purpurea > S. alba > S. vitellina > S. babylonica ≥ S. viminalis. Ces résultats laissent présager la possibilité de l’utilisation de certaines espèces de Salix tolérantes à la salinité comme modèle agroforestier dédié à la restauration et à la mise en valeur des sols affectés par la salinisation.
Conditioning under low-oxygen modified atmosphere in sealed enclosures, containers or bags is widely used for the disinfestation of grain from insect pest species. The effect of hermetic vacuum ...storage on the survival of primary insect pests of cereals still lacks relevant documentation. To enhance knowledge on this topic, a pilot scale experiment was undertaken. Prior to the study, batches of wheat seeds were infested by some of the most harmful insects of stored cereals, Sitophilus oryzae, S. granarius, and Rhyzopertha dominica, in order to obtain infested seed samples by all development stages. Then, 5-kg sound wheat seed lots were placed inside multilayer aluminium-plastic flexible bags and 200 g of previously infested seeds were included before vacuum packing the bags at depression levels: 30, 50 or 70 kPa. In addition to storage at an average temperature of 25.8 °C, survival rate and progeny production of insects were checked at regular time intervals after opening a series of bags. After adult recovery by sieving, the 200 g-samples were incubated for 42 d at 25.8 °C for hidden stages recovery. The exposure time for 99% reduction of survival rate and progeny production (LT99) by S. oryzae and S. granarius, at 70 kPa depression level, was observed after 37.5 and 31 d exposure, respectively. For R. dominica, LT99 was assessed at 63.5, 75.6 and 88.5 d at 70, 50 and 30 kPa depression level, respectively. Rhyzopertha dominica was observed much more tolerant than the two weevil species, especially when depression level was more than 50 kPa. This species was able to produce progeny under vacuum. The origin of the differences in susceptibility between the weevils and the lesser grain borer in relation to storage under vacuum inside flexible high-barrier multilayer aluminium-plastic bags are discussed.
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•Vacuum packing of seeds in highly hermetic flexible bags can control insects.•Sitophilus species are more susceptible to vacuum than Rhyzopertha dominica.•Survival time and reproduction capacity may be related to physiological traits.•Vacuum packing in airtight flexible enclosures may be used for disinfestation.
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