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1 Horizontal and vertical heterogeneity of resource availability, coupled with the specialized use of resources by tree species, results in complex patterns of tree species distributions in tropical rain forests. We studied the horizontal and vertical distributions of 4014 individuals in 11 species of early successional Macaranga (Euphorbiaceae) in tropical rain forest in Sarawak, Malaysia. 2 The horizontal distribution of individual trees was assessed with respect to crown light levels, establishment microsites, and broader scale variation in soil textural properties. Vertical distribution was assessed using an allometric approach to estimate maximum tree height (Hmax) and the slope of the sapling height-diameter relationship. 3 Average light levels intercepted and the proportion of individuals in each of five crown illumination classes varied significantly among the 11 species. Species ranged from extremely high-light demanding, to quite shade tolerant. Average light levels intercepted by trees generally increased through ontogeny, but the ranking of species did not change significantly. 4 Fewer individuals of the more shade-tolerant species established on disturbed microsites, irrespective of light levels. Among the more high-light demanding species, the proportion of trees on different types of disturbed sites varied. 5 Trees of seven species were significantly more common on clay-rich soils, two preferred sand-rich soils, and two were not strongly affected by soil texture. 6 Hmaxranged from 5.5 to 31.3 m and was negatively correlated with shade tolerance among species, although among the more high-light demanding species there was a wide range of tree sizes. Among species, Hmaxwas negatively correlated with both the slope and y-intercept of the sapling height-diameter relationship, indicating that small-statured species (also more shade tolerant) had more slender saplings than larger statured species. 7 Heterogeneity of resource availability leads to differences in horizontal and vertical tree distribution, which are important for the coexistence of 11 Macaranga species.

Interspecific differences in tree performance due to variation in resource availability are expected to influence the structure and dynamics of tropical forest communities. Patterns of mortality and growth over 32 mo in 11 species of Macaranga were analyzed to investigate factors influencing tree spatial distributions and the dynamics of early successional communities. Tree performance was assessed in relation to variation in light levels, soil texture, and tree ontogeny. Rates of mortality and growth varied by over an order of magnitude among species. Species common in high-light microsites had higher mortality and growth rates. Higher low-light mortality for these species reflected lower shade tolerances, supporting the view that shade tolerance involves a trade-off between high-light growth and low-light mortality. Logistic and multiple regressions were used to test for independent effects of tree size and microenvironment on performance in the 11 species. Mortality and growth were significantly related to tree size in nine and eight species, respectively. Higher mortality and lower growth rates for juvenile trees were common. Despite positive correlations between light availability and tree size, mortality rates increased in three species, and growth rates decreased in four species at larger tree sizes. This pattern was particularly strong in smaller statured shade-intolerant species and may reflect changes in biomass allocation following reproductive onset. Declines in growth at larger tree sizes for only some species resulted in changes in species' performance rankings through succession. Low-light mortality rates were strongly correlated with species' distributions in the forest with respect to light levels, whereas biases in distributions with respect to soil texture were not supported by differential mortality. For all trees pooled and in several species, growth showed a threshold response to light levels, being light-limited in low light but not in high light. Across all light levels, soil texture significantly influenced growth in six species. Five species and all trees pooled had significantly lower growth on the more nutrient-poor and potentially drought-prone sandy soils. The dynamics of Macaranga-dominated early successional communities are strongly influenced by soil resource and light availability, coupled with species-specific ontogenetic trajectories of performance.

Early successional (pioneer) tropical tree species are characterized by a suite of ecophysiological and life history traits; however, little is known of the relationships between these groups of traits, and their consequences for species' distribution patterns in diverse tropical forests. This study investigated leaf-level ecophysiological variation in seedlings of nine sympatric, pioneer tree species of Macaranga (Euphorbiaceae) from Borneo, grown at three light levels (high: ∼ 19 mol/d; medium: ∼ 7 mol/d; low: ∼ 3.6 mol/d). A multivariate analysis of traits associated with species' successional status was used to rank species according to life history variation, and then to investigate patterns of covariation in seedling ecophysiological and life history traits. Ecophysiological traits varied significantly among the nine species. On a leaf area basis, dark respiration (Rd-area) in high-light seedlings ranged from 0.51 to 0.90 μ mol CO2· m-2· s-1,, and light saturated net photosynthesis (Amax-area) ranged from 7 to 13 μ mol CO2· m-2· s-1. Amax-mass and Rd-mass were strongly negatively correlated with leaf mass per unit area (LMA). Among species, Amax-mass and Rd-mass were strongly positively correlated for high-light grown seedlings, reflecting a trade-off between high assimilation rates and respiratory costs. Within species, Amax-area, Rd-area, gs, LMA, and photosynthetic light compensation point were significantly greater in high-light grown plants for all species. Due to the high plasticity of LMA, Amax-mass and Rd-mass were only weakly influenced by light growth conditions, suggesting that resource allocation patterns that maximize photosynthetic ability are critical to survival and growth in low light for these species. Principal components analysis (PCA) of ecophysiological traits for the nine species revealed a continuum of variation from species with relatively low Amax, low gs, and high LMA to species with the opposite traits. The primary axis of the PCA of life history traits was strongly related to variation in shade tolerance and seed mass. The second life history axis distinguished among the more shade-intolerant species. The PCAs of ecophysiological and life history traits were not completely concordant due to variation in life history traits among high Amax species. Amax-mass and LMA, were correlated with a successional ranking of the species. The study shows how a suite of inter-related ecophysiological and life history traits can result in a diversity of pioneer tree ecologies.

A comparative approach was used to investigate life-history variation and evolution in tropical pioneer trees of the genus Macaranga (Euphorbiaceae). Ecological studies, conducted from 1991-1994 in Lambir Hills National Park, Sarawak, Malaysia, were used to investigate the relationships among life-history traits in eleven sympatric species. Growth and mortality rates, tree allometry, reproductive phenology, and fecundity were measured and related to individual micro-environment. The pioneer species varied in many life-history characteristics, and no single life-history trait characterizes the group. Demographic traits, for example growth rates, were shown to be strongly dependent on ontogeny and micro-environment. The degree of shade-tolerance, maximum tree size and reproductive phenology were important axes of life-history variation among the species, and numerous functionally inter-dependent traits were correlated with these axes. Two experimental studies investigated the relationships between phenotypic responses of seedlings to manipulated resource availability and tree life-history variation. (1) Seedlings of nine species were grown in three light levels. Ecophysiological traits varied widely among species, and were generally strongly correlated with life-history traits such as growth, mortality and shade-tolerance, but not with tree size, phenology or fecundity. (2) Responses of seedlings of eight species to variation in soil nutrients demonstrated that all species were extremely sensitive to nutrient availability, particularly phosphorus. Fast growing species responded more to a pulse of nutrients. A morphological phylogenetic study of Macaranga, including the 11 species, suggests that convergent evolution of life-history traits is common in Macaranga, for example, shade-tolerance evolved convergently twice in the 11 species, and myrmecophytism evolved at least twice in the genus. Phylogenetic history and contemporary ecological processes are inseparable components of biological diversity, and a comparative approach provides a method to assess the relative contribution of these factors in structuring the distribution and abundance of organisms.

Keith Hackett has strongly supported Phil Dowd and Chris Foy, the two referees criticised by Premiership managers at the weekend, safeguarding their position on the top-flight list. Hackett's stance also makes it unlikely that Blackburn and Tottenham will succeed in their appeals today over the dismissals of Tugay Kerimoglu and Hossam Ghaly, who were given red cards by Dowd during Sunday's ill- tempered draw at Ewood Park. Hackett yesterday had a lengthy telephone conversation with Aidy Boothroyd after the Watford manager verbally attacked Foy for his display at Fratton Park on Saturday. Boothroyd was deeply unhappy with Foy's decision to award Portsmouth a late penalty, although Hackett believes the official acted correctly - as TV replays subsequently illustrated. Boothroyd, like [Mark Hughes], had expressed his desire to speak to Hackett, head of the Professional Game Match Officials Board, so that he could air his grievances.

The recent emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the underlying cause of Coronavirus Disease 2019 (COVID-19), has led to a worldwide pandemic causing substantial morbidity, mortality, and economic devastation. In response, many laboratories have redirected attention to SARS-CoV-2, meaning there is an urgent need for tools that can be used in laboratories unaccustomed to working with coronaviruses. Here we report a range of tools for SARS-CoV-2 research. First, we describe a facile single plasmid SARS-CoV-2 reverse genetics system that is simple to genetically manipulate and can be used to rescue infectious virus through transient transfection (without in vitro transcription or additional expression plasmids). The rescue system is accompanied by our panel of SARS-CoV-2 antibodies (against nearly every viral protein), SARS-CoV-2 clinical isolates, and SARS-CoV-2 permissive cell lines, which are all openly available to the scientific community. Using these tools, we demonstrate here that the controversial ORF10 protein is expressed in infected cells. Furthermore, we show that the promising repurposed antiviral activity of apilimod is dependent on TMPRSS2 expression. Altogether, our SARS-CoV-2 toolkit, which can be directly accessed via our website at https://mrcppu-covid.bio/ , constitutes a resource with considerable potential to advance COVID-19 vaccine design, drug testing, and discovery science.