Among nectarivorous birds, the highest niche partitioning occurs between hummingbirds and plants. Although hummingbirds tend to visit morphologically well-matched resources, as ornithophilous species, they can also visit flowers with other traits. Here, we investigated whether the niche partitioning in hummingbird-plant interactions is also observed with ornithophilous species only. We also explored if hummingbird traits predicted resources use. We recorded a plant-ornithophilous species network in a semi-deciduous forest in Brazil. We quantified interaction partitioning through network connectance, complementary specialisation, and modularity. The influence of hummingbirds’ traits into their visits was investigated through methods of functional ecology and ecological networks. We recorded 948 interactions between nine hummingbirds and seven ornithophilous plants. We detected similar patterns of niche partitioning between hummingbirds and ornithophilous plants in comparison to networks considering the entire plant community. However, hummingbird species with the most specialised interactions are different from those when the whole system is evaluated. Therefore, we cannot downscale the patterns from one scale to the other. The pattern of interaction with ornithophilous plants was not related to hummingbirds’ traits. Therefore, the coexistence of species with shared traits might be occurring through facilitative and competitive processes, leading to trait mismatching and maintaining niche partitioning among ornithophilous plants.

Phenotypic plasticity and rapid evolution are two important strategies by which invasive species adapt to a wide range of environments and consequently are closely associated with plant invasion. To test their importance in invasion success of Crofton weed, we examined the phenotypic response and genetic variation of the weed by conducting a field investigation, common garden experiments, and intersimple sequence repeat (ISSR) marker analysis on 16 populations in China. Molecular markers revealed low genetic variation among and within the sampled populations. There were significant differences in leaf area (LA), specific leaf area (SLA), and seed number (SN) among field populations, and plasticity index (PIv) for LA, SLA, and SN were 0.62, 0.46 and 0.85, respectively. Regression analyses revealed a significant quadratic effect of latitude of population origin on LA, SLA, and SN based on field data but not on traits in the common garden experiments (greenhouse and open air). Plants from different populations showed similar reaction norms across the two common gardens for functional traits. LA, SLA, aboveground biomass, plant height at harvest, first flowering day, and life span were higher in the greenhouse than in the open-air garden, whereas SN was lower. Growth conditions (greenhouse vs. open air) and the interactions between growth condition and population origin significantly affect plant traits. The combined evidence suggests high phenotypic plasticity but low genetically based variation for functional traits of Crofton weed in the invaded range. Therefore, we suggest that phenotypic plasticity is the primary strategy for Crofton weed as an aggressive invader that can adapt to diverse environments in China.

Wood density and wood chemical traits are strong predictors of tree performance, carbon stock, and wood decomposition, which play important roles in ecosystem processes and carbon and nutrient cycling in forests. However, it remains unknown how root wood traits are related to stem wood traits. We examined the relationships of wood density and wood chemical traits (lignin and nitrogen concentrations, carbon-to-nitrogen ratio) between the stems and coarse roots of 90 individuals representing 53 tropical tree species in Malaysian Borneo. We developed regression equations of each wood trait using the standardized major axis method. Each root wood trait was highly correlated with the corresponding stem wood trait, and most regression equations fitted well (R2 > 0.5). The lignin concentration of roots was significantly greater than that of stems. We conclude that root wood traits can be estimated from the corresponding stem wood traits in South-East Asian tropical trees. Further analysis of coarse root decomposability will provide more accurate estimates of carbon and nutrient fluxes in tropical forest ecosystems.

In this study, we tested the hypothesis that functional traits associated with nutrient impoverishment contribute to enhancing shade-tolerance (survival at low light) for the juveniles of canopy tree species in Bornean rain forests. To test the hypothesis, survival and functional traits (biomass allocation, leaf dynamics and foliar nutrient concentration) were investigated as a function of light conditions for saplings of 13 species in three forests with different levels of nutrient availability. As predicted by the hypothesis, the species in the severely nutrient-poor site (a tropical heath forest on nutrient-poor soils) showed greater shade-tolerance (>91% survival for 8 mo at 5% global site factor) than in the other two sites (mixed dipterocarp forests) (54–87% survival). Across the species, greater shade-tolerance was associated with a higher biomass allocation to roots, a slower leaf production and a higher foliar C concentration, which are considered as C-conservation traits under nutrient impoverishment. These results suggest that the juveniles of the canopy species occurring on nutrient-poor soils can enhance shade-tolerance by the same mechanisms as the adaptation to nutrient impoverishments. Tree species in nutrient-poor environments may be selected for surviving also in shaded conditions.

Genetic parameters for test-day milk flow (TDMF) of 2175 first lactations of Holstein cows were estimated using multiple-trait and repeatability models. The models included the direct additive genetic effect as a random effect and contemporary group (defined as the year and month of test) and age of cow at calving (linear and quadratic effect) as fixed effects. For the repeatability model, in addition to the effects cited, the permanent environmental effect of the animal was also included as a random effect. Variance components were estimated using the restricted maximum likelihood method in single- and multiple-trait and repeatability analyses. The heritability estimates for TDMF ranged from 0.23 (TDMF 6) to 0.32 (TDMF 2 and TDMF 4) in single-trait analysis and from 0.28 (TDMF 7 and TDMF 10) to 0.37 (TDMF 4) in multiple-trait analysis. In general, higher heritabilities were observed at the beginning of lactation until the fourth month. Heritability estimated with the repeatability model was 0.27 and the coefficient of repeatability for first lactation TDMF was 0.66. The genetic correlations were positive and ranged from 0.72 (TDMF 1 and 10) to 0.97 (TDMF 4 and 5). The results indicate that milk flow should respond satisfactorily to selection, promoting rapid genetic gains because the estimated heritabilities were moderate to high. Higher genetic gains might be obtained if selection was performed in the TDMF 4. Both the repeatability model and the multiple-trait model are adequate for the genetic evaluation of animals in terms of milk flow, but the latter provides more accurate estimates of breeding values.