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opencc-zeroDec 2011View details →

Data from: Nest predation risk and growth strategies of passerine species: grow fast or develop traits to escape risk?

Different body components are thought to trade off in their growth and development rates, but the causes for relative prioritization of any trait remains a critical question. Offspring of species at higher risk of predation might prioritize development of locomotor traits that facilitate escaping risky environments over growth of mass. We tested this possibility in 12 altricial passerine species that differed in their risk of nest predation. We found that rates of growth and development of mass, wings, and endothermy increased with nest predation risk across species. In particular, species with higher nest predation risk exhibited relatively faster growth of wings than of mass, fledged with relatively larger wing sizes and smaller mass, and developed endothermy earlier at relatively smaller mass. This differential development can facilitate both escape from predators and survival outside of the nest environment. Tarsus growth was not differentially prioritized with respect to nest predation risk, and instead all species achieved adult tarsus size by age of fledging. We also tested whether different foraging modes (aerial, arboreal, and ground foragers) might explain the variation of differential growth of locomotor modules, but we found that little residual variation was explained. Our results suggest that differences in nest predation risk among species are associated with relative prioritization of body components to facilitate escape from the risky nest environment.

Data from: Bird and bat species' global vulnerability to collision mortality at wind farms revealed through a trait-based assessment

Mitigation of anthropogenic climate change involves deployments of renewable energy worldwide, including wind farms, which can pose a significant collision risk to volant animals. Most studies into the collision risk between species and wind turbines, however, have taken place in industrialized countries. Potential effects for many locations and species therefore remain unclear. To redress this gap, we conducted a systematic literature review of recorded collisions between birds and bats and wind turbines within developed countries. We related collision rate to species-level traits and turbine characteristics to quantify the potential vulnerability of 9538 bird and 888 bat species globally. Avian collision rate was affected by migratory strategy, dispersal distance and habitat associations, and bat collision rates were influenced by dispersal distance. For birds and bats, larger turbine capacity (megawatts) increased collision rates; however, deploying a smaller number of large turbines with greater energy output reduced total collision risk per unit energy output, although bat mortality increased again with the largest turbines. Areas with high concentrations of vulnerable species were also identified, including migration corridors. Our results can therefore guide wind farm design and location to reduce the risk of large-scale animal mortality. This is the first quantitative global assessment of the relative collision vulnerability of species groups with wind turbines, providing valuable guidance for minimizing potentially serious negative impacts on biodiversity.

Data from: A phylogenetic comparative method for evaluating trait coevolution across two phylogenies for sets of interacting species

Evaluating trait correlations across species within a lineage via phylogenetic regression is fundamental to comparative evolutionary biology, but when traits of interest are derived from two sets of lineages that co-evolve with one another, methods for evaluating such patterns in a dual-phylogenetic context remain underdeveloped. Here we extend multivariate permutation-based phylogenetic regression to evaluate trait correlations in two sets of interacting species while accounting for their respective phylogenies. This extension is appropriate for both univariate and multivariate response data, and may utilize one or more independent variables, including environmental covariates. Imperfect correspondence between species in the interacting lineages can also be accommodated, such as when species in one lineage associate with multiple species in the other, or when there are unmatched taxa in one or both lineages. For both univariate and multivariate data, the method displays appropriate type I error, and statistical power increases with the strength of the trait covariation and the number of species in the phylogeny. These properties are retained even when there is not a 1:1 correspondence between lineages. Finally, we demonstrate the approach by evaluating the evolutionary correlation between traits in fig species and traits in their agaonid wasp pollinators. R computer code is provided.

opencc-zeroJul 2019View details →

Data from: Leaf trait variability between and within subalpine grassland species differs depending on site conditions and herbivory

Plant traits are commonly used to predict ecosystem-level processes, but the validity of such predictions is dependent on the assumption that trait variability between species is greater than trait variability within a speciesthe robustness assumption. Here, we compare leaf trait intraspecific and interspecific variability depending on: geographical differences between sites, and five years of experimental herbivore exclusion in two vegetation types of subalpine grasslands in Switzerland. Four-leaf traits were measured from eight herbaceous species common to all 18 sites. Intraspecific trait variability differed significantly depending on site and herbivory. However, the amount and structure of variability depended on the trait measured and whether considering leaf traits separately or multiple leaf traits simultaneously. Leaf phosphorus (P) concentration showed the highest intraspecific variability, while specific leaf area (SLA) showed the highest interspecific variability and displayed intraspecific variability only in response to herbivore exclusion. Species identity based on multiple traits was not predictable. We find intraspecific variability is an essential consideration when using plant functional traits as a common currency not just species mean traits. This is particularly true for leaf nutrient concentrations, which showed high intraspecific variability in response to site differences and herbivore exclusion; a finding which suggests that the robustness assumption does not always hold.

opencc-zeroDec 2018View details →

Data from: Variation in plant functional traits is best explained by the species identity: stability of trait based species ranking across meadow management regimes

1. It is commonly assumed in trait-based studies that plant functional traits are species-specific, being more variable among species than among different environmental conditions. If the environment affects traits it is assumed that species react in a similar direction and conserve the functional distances. The rank of species based on the trait values is then unchanged, which justifies the use of species trait averages from database values. Such assumptions of species specificity are, however, increasingly disputed by studies showing overall high intraspecific trait variability. 2. To test the species specificity and ranking stability of functional traits we sampled plant individuals of almost all species (66 in total) within each plot of a long term (19 years) land use management experiment, which comprised a factorial combination of fertilization, mowing and removal of the dominant species Molinia caerulea in an oligotrophic wet meadow in the Czech Republic. Plant individuals were measured for eight commonly used traits: height, leaf dry matter content (LDMC), specific leaf area (SLA), leaf δ13C content, leaf carbon content, leaf δ15N content, and leaf nitrogen content. Height, LDMC, and SLA were also extracted from the LEDA trait database for comparison. 3. Species identity consistently explained the largest portion of trait variability (40%-68%). Land use managements had a considerably lower effect (0.4%-9% of explained trait variability for individual traits). The species trait averages computed for each land use management regime separately were mutually correlated, showing the stable trait-based species ranking. Ranking stability of species trait averages was observed despite land use management changing absolute trait values and despite the tremendous intraspecific trait variability (causing substantial overlap of trait values for different species). For all treatments our measured species averages for LDMC and SLA were also stably ranked with species averages from the LEDA database. 4. Synthesis. Our results showed that species conserve the functional distances in different environmental conditions from where they were measured. Species trait averages can describe general trends in functional composition, although averaging reduces the ecologically interesting information of the intraspecific trait variability.

Data from: Intraspecific variability and reaction norms of forest understory plant species traits

1.Trait-based models of ecological communities typically assume intraspecific variation in functional traits is not important, though such variation can change species trait rankings along gradients in resources and environmental conditions, and thus influence community structure and function. 2. We examined the degree of intraspecific relative to interspecific variation, and reaction norms of 11 functional traits for 57 forest understory plant species, including: intrinsic water-use efficiency (iWUE), Δ15N, 5 leaf traits, 2 stem traits and 2 root traits along gradients in light, nitrogen, moisture and understory cover. 3. Our results indicate that interspecific trait variation exceeded intraspecific variation by at least 50% for most, but not all traits. Intraspecific variation in Δ15N, iWUE, leaf nitrogen content and root traits was high (47-70%) compared with most leaf traits and stem traits (13-38%). 4. Δ15N varied primarily along gradients in abiotic conditions, while light and understory cover were relatively less important. iWUE was related primarily to light transmission, reflecting increases in photosynthesis relative to stomatal conductance. Leaf traits varied mainly as a function of light availability, with some reaction norms depending on understory cover. Plant height increased with understory cover, while stem specific density was related primarily to light. Resources, environmental conditions and understory cover did not contribute strongly to the observed variation in root traits. 5. Gradients in resources, environmental conditions and competition all appear to control intraspecific variability in most traits to some extent. However, our results suggest that species cross-over (i.e., trait rank reversals) along the gradients measured here are generally not a concern. 6. Intraspecific variability in understory plant species traits can be considerable. However, trait data collected under a narrow range of environmental conditions appears sufficient to establish species rankings and scale between community and ecosystem levels using trait-based models. Investigators may therefore focus on obtaining a sufficient sample size within a single set of conditions rather than characterizing trait variation across entire gradients in order to optimize sampling efforts.

opencc-zeroDec 2013View details →

Data from: Species' traits explain differences in Red list status and long-term population trends in longhorn beetles

Some species are more likely to go extinct than others and this is partially due to species' traits. Therefore, it is important to establish links between traits and extinction risks. Different aspects of a species' biology also relates to different sources of threat, such as fragmented populations or low population growth rate. In a comparative study of Swedish longhorn beetles (Coleoptera: Cerambycidae), we related species' traits to two aspects of extinction risk – population decline and small/fragmented populations – measured by long-term population trends and IUCN Red list classifications. Trait relationships were analysed with generalized linear models and multi-model inference. We found that extinction risk generally increased with longer generation times, corresponding to slower life histories. Adult activity period was also related to both metrics of extinction risk, but in different ways. We also found that extinction risk increased with larval host plant specialization, but only for Red list classification. Large body size was related to increased Red list classification in species overwintering as adults, and overwintering stage also structured the effects of several other traits. Our results show that both intrinsic demographic traits and ecological traits affect extinction risks, and also suggest that risks are shaped by multiple mechanisms. Therefore, researchers should carefully choose their metric of extinction risk for comparative studies, as the Red list classification may best capture current risk, whereas population trends can be used more proactively but may reflect historical relationships between traits and extinction risk.

opencc-zeroDec 2015View details →

Data from: Introducing resprouters to enhance Mediterranean forest resilience: importance of functional traits to select species according to a gradient of pine density

Resprouter species are important for Mediterranean ecosystem resilience, but they are scarce in landscapes dominated by pioneer pines. Sound knowledge of resprouter seedling functional responses and establishment success across different pine habitats would help guide forest restoration efforts. Four broadleaved resprouter species, that is two shrubs – Arbutus unedo and Pistacia terebinthus – and two trees – Fraxinus ornus and Sorbus domestica – were planted under an experimentally created gradient of pine cover from totally open conditions to dense pine cover. Seedling survival and growth were monitored for 5 years. Phenological, physiological and morphological traits were measured to gain insight into the mechanisms of pine–seedling interaction. Interaction outcomes varied according to species identity, pine cover treatment and time. Light-to-moderate pine cover induced greater height growth and little or no effects on diameter and survival of the two trees. Competition was always detected for shrubs, whereas competition and facilitation were noted for trees. Within pine stands, negative interactions increased with tree cover, making dense stands the most limiting. Interactions were only detectable after 2–3 years, but increased in intensity with time. Functional responses to increasing pine cover indicated a seedling strategy of carbon gain optimization in the shade (increased specific leaf area and leaf area, decreased leaf dry matter content), particularly in tree species seedlings. Increasing pine cover induced higher water stress, but lower photochemical stress. The deciduous species had a longer vegetation season under pine canopies, whereas the evergreen shrub Arbutus unedo showed a lower polycyclism rate and flower production. Synthesis and applications. Moderate pine cover facilitates the establishment of deciduous trees at the expense of shrubs. This pattern can be attributed to a higher shade tolerance of the trees than the shrubs combined with a low tolerance of trees to photoinhibition. We therefore recommend using evergreen shrubs for the restoration of open land and high-specific-leaf-area deciduous trees for pine stand diversification. However, in dense forests, thinning is needed to increase light availability prior to seedling introduction.

opencc-zeroDec 2017View details →

Data from: Multi-dimensional patterns of variation in root traits among coexisting herbaceous species in temperate steppes

1. Characterizing patterns of variation in plant traits across species and environmental gradients is critical for understanding performance of species in ecosystems. One-dimensional pattern of variation has been demonstrated in leaf traits, which is known as the leaf economic spectrum. However, it is unclear whether such a spectrum exists for root traits. 2. For roots of 15 species from temperate grasslands, we determined respiration rate, relative growth rate, lifespan as well as 10 morphological, chemical and anatomical root traits. We further evaluated pairwise and multiple-trait relationships by the Pearson's correlation and principle component analysis including phylogenetic contrasts. 3. We found that root functions were related to three clusters of variation. Root respiration rate and relative growth rate were positively correlated with average root diameter, but they were negatively correlated with specific root length. In contrast, root lifespan was not correlated with average root diameter, but it was positively correlated with specific root length. These results are inconsistent with the presumption of the root economic spectrum. 4. The principle components analysis revealed a multi-dimensional pattern of variation in root traits among the 15 coexisting herbaceous species. Moreover, species within the same phylogenetic clades tended to have similar root trait syndromes. Most of the root traits exhibited a significant phylogenetic signal. 5. Synthesis. Our results do not support a one-dimensional root economic spectrum in the coexisting herbaceous species of temperate grasslands. In contrast, the pattern of variation in root traits was multi-dimensional. We further demonstrated that species in different phylogenetic clades possess diverse root trait syndromes for efficient resource acquisition. Our findings provide a next step in understanding root functions and plant strategies in temperate grasslands.

opencc-zeroJun 2021View details →

Genetics of quantitative traits with dominance under stabilizing and directional selection in partially selfing species

<p>Recurrent self-fertilization is thought to lead to reduced adaptive potential by decreasing the genetic diversity of populations, thus leading selfing lineages down an evolutionary 'blind alley'. Though well supported theoretically, empirical support for reduced adaptability in selfing species is limited. One limitation of classical theoretical models is that they assume pure additivity of the fitness-related traits that are under stabilizing selection, despite ample evidence that quantitative traits are subject to dominance. Here we relax this assumption and explore the effect of dominance on a fitness-related trait under stabilizing selection for populations that differ in selfing rates. By decomposing the genetic variance into additional components specific to inbred populations, we show that dominance components can explain a substantial part of the genetic variance of inbred populations. We also show that ignoring these components leads to an upward bias in the predicted response to selection. Finally, we show that when considering the effect of dominance, the short-term evolutionary potential of populations remains comparable across the entire gradient in outcrossing rates, and genetic associations can even make selfing populations more evolvable on the longer term, reconciling theoretical and empirical results.</p>

opencc-zeroAug 2019View details →

Data from: Divergence in drought-response traits between sympatric species of Mimulus

Differential adaptation to local environmental conditions is thought to be an important driver of speciation. Plants, whose sedentary lifestyle necessitates fine-tuned adaptation to edaphic conditions such as water availability, are often distributed based on these conditions. Populations occupying water-limited habitats may employ a variety of strategies, involving numerous phenotypes, to prevent and withstand desiccation. In sympatry, two closely related Mimulus species – M. guttatus and M. nasutus – occupy distinct microhabitats that differ in seasonal water availability. In a common garden experiment, we characterized natural variation within and between sympatric M. guttatus and M. nasutus in the ability to successfully set seed under well-watered and drought conditions. We also measured key phenotypes for drought adaptation, including developmental timing, plant size, flower size, and stomatal density. Consistent with their microhabitat associations in nature, M. nasutus set seed much more successfully than M. guttatus under water-limited conditions. This divergence in reproductive output under drought was due to differences in mortality after the onset of flowering, with M. nasutus surviving at a much higher rate than M. guttatus. Higher seed set in M. nasutus was mediated, at least in part, by a plastic increase in the rate of late-stage development (i.e., fruit maturation), consistent with the ability of this species to inhabit more ephemeral habitats in the field. Our results suggest adaptation to water availability may be an important factor in species maintenance of these Mimulus taxa in sympatry.

opencc-zeroDec 2015View details →

Data from: Patterns and thresholds of grazing-induced changes in community structure and ecosystem functioning: species-level responses and the critical role of species traits

Overgrazing has resulted in widespread decline in biodiversity and ecosystem functioning in grasslands worldwide in recent decades. However, few studies have examined the patterns and thresholds of grazing-induced changes in community structure and ecosystem functioning along a grazing gradient and based on species-level responses and plant functional traits. To identify the thresholds of grazing intensity at both species and community levels, we conducted a grazing manipulation experiment with seven levels of grazing intensity (0–9 sheep ha-1) and two topographies (flat versus slope) in a typical steppe. Four plant functional traits were measured, including specific leaf area (SLA), plant height, leaf nitrogen content (LNC) and stem: leaf ratio (SLR). The threshold of grazing intensity that significantly altered community composition was at 3.75 sheep ha-1 for the flat system and 3.0 sheep ha-1 for the slope system. For both flat and slope systems, the threshold grazing intensity for changes in primary productivity was at 3.0 sheep ha-1, beyond which the productivity decreased substantially. At species level, the abundances of common species, most of which are perennial grasses, declined at moderate grazing intensities (3.0–4.5 sheep ha-1). The abundances of most rare species, which are perennial forbs, declined at low grazing intensities (1.5–3.0 sheep ha-1). Specific leaf area and leaf nitrogen content are good predictors of species-level responses to grazing. Low SLA and high LNC species are negatively affected by high grazing intensity, while high SLA and low LNC species are little affected by grazing. The negative effect of grazing intensity on species abundance was greater in the slope system than in the flat system. Synthesis and applications. Our results indicate that the structural and functioning thresholds of grazing intensity depend on plant traits and species composition, which is mediated by topographic location. These findings, integrating plant functional traits and threshold approaches, have important implications for determining sustainable grazing intensity in grassland management and biodiversity conservation in semi-arid regions.

Data from: Oviposition traits generate extrinsic postzygotic isolation between two pine sawfly species

Background: Although empirical data indicate that ecological speciation is prevalent in nature, the relative importance of different forms of reproductive isolation and the traits generating reproductive isolation remain unclear. To address these questions, we examined a pair of ecologically divergent pine-sawfly species: while Neodiprion pinetum specializes on a thin-needled pine (Pinus strobus), N. lecontei utilizes thicker-needled pines. We hypothesized that extrinsic postzygotic isolation is generated by oviposition traits. To test this hypothesis, we assayed ovipositor morphology, oviposition behavior, and host-dependent oviposition success in both species and in F1 and backcross females. Results: Compared to N. lecontei, N. pinetum females preferred P. strobus more strongly, had smaller ovipositors, and laid fewer eggs per needle. Additionally, we observed host- and trait-dependent reductions in oviposition success in F1 and backcross females. Hybrid females that had pinetum-like host preference (P. strobus) and lecontei-like oviposition traits (morphology and egg pattern) fared especially poorly. Conclusions: Together, these data indicate that maladaptive combinations of oviposition traits in hybrids contribute to extrinsic postzygotic isolation between N. lecontei and N. pinetum, suggesting that oviposition traits may be an important driver of divergence in phytophagous insects.

opencc-zeroMay 2019View details →

Data from: Detrital traits affect substitutability of a range-expanding foundation species across latitude

Climate-driven range shifts of foundation species could alter ecosystem processes and community composition by providing different resources than resident foundation species. Along the US Atlantic coast, the northward expanding foundation species, black mangrove, Avicennia germinans, is replacing the dominant salt marsh foundation species, marsh cordgrass, Spartina alterniflora. These species have distinct detrital attributes that ostensibly provide different resources to epifauna. We experimentally examined how detritus of these species affects decomposition and community composition in different habitat contexts at regional and local scales. First, we manipulated detritus identity (Avicennia, Spartina) at 13 sites across a 5° latitudinal gradient spanning mangrove, mixed marsh-mangrove, and salt marsh habitats. Across latitude, we found that Avicennia detritus decomposed 2-4 times faster than Spartina detritus, suggesting that detrital turnover will increase with mangrove expansion. Epifaunal abundance and richness increased 2-7 times from south to north (mangrove to salt marsh) and were equivalent between Avicennia and Spartina detritus except for crabs, a dominant taxonomic group that preferred Spartina detritus. Second, to examine the whether changing habitat context affected regional patterns, we manipulated detritus identity and surrounding habitat type (mangrove, salt marsh) at a single mixed site, also including inert mimics to separate structural and nutritional roles of detritus. Epifaunal richness was similar between the two detrital types, but crabs were 2-7 times more abundant in Spartina detritus, due to its structural attributes. Surrounding habitat type did not influence decomposition rate or community patterns, which suggests that latitudinal influences, not surrounding habitat, drove the regional community patterns in the first experiment. Overall, mangrove expansion could alter epifaunal communities due to the lower structural value and faster turnover of mangrove detritus. As species shift with changing climate, understanding foundation species substitutability is critical to predict community change, but we must account for concomitant environmental changes that also modify communities.

FIGURE 6. Sabellaria jeramae n in Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

FIGURE 6. Sabellaria jeramae n. sp., scanning electron micrographs. A—operculum, B—middle (below) and inner (center to upper) paleae, C—close-up of outer paleae, D—E—distal end of outer paleae, F—nuchal spines, G—abdominal uncini. Scales on images. Scale: 0.2mm in A, 0.1mm in B, D, 0.05mm in C, E, 0.02mm in F, 0.01mm in G.

FIGURE 5. Sabellaria jeramae n in Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

FIGURE 5. Sabellaria jeramae n. sp., outline drawings of paleae, chaetae, hooks and uncini. A—outer paleae, B, C—middle paleae, D—inner paleae, E–H—distal end of outer paleae, I—nuchal hook (spine), J—parathoracic chaetae, K—thoracic chaetae, L—abdominal uncini. E–L are drawn from SEM figures. Scale: 100 µm in A—I, 20 µm in J and K, 10 µm in L.

FIGURE 2. Sabellaria jeramae n in Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

FIGURE 2. Sabellaria jeramae n. sp., outline drawings of the holotype. A—anterior end, lateral view, B—same, ventral view, C—same, dorsal view, D—anterior view of opercular disc showing the rows of paleae. Scales 1mm (upper in A-C, lower in D).

FIGURE 4. Sabellaria jeramae n in Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

FIGURE 4. Sabellaria jeramae n. sp., compound microscope images. A–C—outer paleae, D—middle paleae, E—inner paleae, F—nuchal spines. Scale: 0.2mm in A, B, D, E, 0.05mm in C, 0.025mm in F.

FIGURE 8. Sabellaria jeramae n in Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

FIGURE 8. Sabellaria jeramae n. sp., light and compound microscope images of abdominal and caudal features. A—first two abdominal chaetigers abdominal notopodia and neuropodia, B—posterior abdominal chaetigers and cauda, dorsal view, Csame, lateral view, D—same ventral view, E—abdominal neurochaetae, F—uncini anterior abdominal chaetigers, G—same, mid-abdominal chaetigers, H, I—same, posterior abdominal chaetigers. Scale: 0.5mm in A-D, 0.02mm in E-I.

FIGURE 1 in Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

FIGURE 1. Map of the Malay Archipelago and Jeram Beach. A—Malay Peninsula, B—Jeram Beach (with an arrow) and adjacent area: detail of arrowed site in A near Kuala Lumpur, C—view of Sabellaria jeramae n. sp. reef, D and E – detail of small clumps of Sabellaria jeramae n. sp.