Understanding the relationship between species richness and productivity is fundamental to management preservation of biodiversity. Yet despite years study intense theoretical interest, this remains controversial. Here, we present results a literature survey in which examined 171 published studies. We extracted raw data from tables graphs subjected these standardized analysis, using ordinary least-squares (OLS) regression generalized linear-model (GLIM) test for significant positive,...

A growing body of research on plant–microbe interactions in soil is contributing to the development a new, microbially based perspective plant community ecology. Soil-dwelling microorganisms are diverse, and with plants vary respect specificity, environmental heterogeneity, fitness impact. Two microbial processes that may exert key influences structure dynamics mediation niche differentiation resource use feedback between community. The hypothesis observations nutrients occur different...

• We investigated the effects of arbuscular mycorrhizal fungal (AMF) species richness and composition on plant community productivity diversity, whether AMF mediate coexistence by promoting niche differentiation in phosphorus use. Our experiment manipulated identity across a range P conditions tallgrass prairie mesocosms. showed that increasing promoted diversity productivity, but this effect was small relative to individual species. found little support for AMF-facilitated complementarity...

• Arbuscular mycorrhizal fungi (AMF) are known to promote plant growth when phosphorus is limiting, but the role of AMF in under nitrogen (N) limiting conditions unclear. Here, we manipulated N (control vs inorganic and organic forms) species four species) for five old-field perennials grown individually a glasshouse N-limiting conditions. We found that were at best neutral some depressed (significant plant–fungus interaction). Native was strongly by all one species; exotic less sensitive...

Abstract Question Plant–soil feedback ( PSF ) has emerged as a ubiquitous phenomenon and potentially important predictor of plant community structure dynamics. However, the predictive power in field contexts is mixed, ecologists do not yet understand its relative importance compared to other factors that communities. Further progress requires more nuanced understanding how interacts with biotic abiotic factors. Environmental (e.g. natural enemies, moisture, light, nutrients) are known affect...

Fertilization via agricultural inputs and nutrient deposition is one of the major threats to global terrestrial plant richness, yet we still do not fully understand mechanisms by which fertilization decreases richness. Tall clonal species have recently been proposed cause declines in richness increasing abundance response competing strongly with other species. We tested this hypothesis a experiment low productivity grassland using novel experimental manipulation presence vs. absence...

Backward course design is a compelling strategy for achieving results-based, student-centered learning. The backward course-design approach first to identify student-learning outcomes, then the means of assessing and lastly classroom activities that would support learning outcomes. With demonstrated success at improving teaching K–12 levels, this receiving increasing attention college level. Yet faculty, who receive comparatively little instruction in design, may find it challenging enact...

The diversity and composition of a community are determined by combination local regional processes. We conducted field experiment to examine the impact resource manipulations seed addition on invasibility low-productivity grassland. manipulated levels both disturbance treatment that reduced adult plant cover in spring first year fertilizer every year. Seeds 46 native species, resident nonresident community, were added determine effects recruitment limitation from (seed limitation)...

Summary Coexistence theory predicts that greater heterogeneity of resources or other fitness‐constraining environmental factors will promote species diversity, yet this classic mechanism coexistence has rarely been tested in manipulative field experiments. Here we present results from the fourth year a long‐term experiment designed to test heterogeneity‐diversity hypothesis low productivity grassland where directly manipulated spatial soil nutrients. In addition unfertilized controls,...

Spatial heterogeneity in soil resources is widely thought to promote plant species coexistence, and this mechanism figures prominently resource-ratio models of competition. However, most experimental studies have found that nutrient enhancements depress diversity regardless whether nutrients are uniformly or heterogeneously applied. This mismatch between theory empirical pattern potentially due an interaction size the scale resource heterogeneity. Clonal plants spread vegetatively via...

Summary Most studies of soil heterogeneity have focused on underlying abiotic factors such as nutrients. However, increasing recognition plant–soil feedback ( PSF ) effects plant growth, combined with the observation that s operate at small spatial scales, suggests due to could affect population and community dynamics. The consequences ‐generated for coexistence depend heterogeneity's vital rates how those influence population‐level recruitment We measured dynamics three congeneric pairs...

Summary A critical challenge in the science and practice of restoration ecology is to understand drivers variation outcomes. Soil microbial communities may have a role explaining this due both site‐to‐site composition soil that can arise plant‐soil feedbacks. We tested relative importance between‐site community feedbacks shaping plant ecosystem function. used standard two‐phase feedback design. inoculum was collected from four tallgrass prairie sites. Then, soils were conditioned separately...

The range of nitrogen ions in nickel was measured for energies from 8 to 29 Mev. rate energy loss is nearly constant over this and has a value 3.7 Mev/(mg ${\mathrm{cm}}^{\ensuremath{-}2}$). average charge determined as function velocity. At velocity 1.93\ifmmode\times\else\texttimes\fi{}${10}^{9}$ cm/sec (27.3 Mev), the 6.2.

Understanding the relationship between species richness and productivity is fundamental to management preservation of biodiversity. Yet despite years study intense theoretical interest, this remains controversial. Here, we present results a literature survey in which examined 171 published studies. We extracted raw data from tables graphs subjected these standardized analysis, using ordinary least-squares (OLS) regression generalized linear-model (GLIM) test for significant positive,...

Environmental perturbations (e.g., disturbance, fertilization) commonly shift communities to a new mean state, but much less is known about their effects on the variability (dispersion) of around mean, particularly when are combined. Community dispersion may increase or decrease (representing divergence convergence among communities) if changing environmental conditions alter species interactions magnify small initial differences that develop during community assembly. We used data from an...

Net pairwise plant-soil feedbacks (PSF) may be an important factor structuring plant communities, yet the influence of abiotic context on PSF is not understood. Abiotic factors such as light availability can alter interactions, potentially resulting in strong dependence PSF. Here, we present experiment which measured whole-soil net amongst six common forest understory species across a gradient availability. Light treatments were imposed throughout both phases (the conditioning phase and...

Excitation functions for the reactions (1) ${\mathrm{N}}^{14}$(${\mathrm{N}}^{14}$, ${\mathrm{N}}^{13}$)${\mathrm{N}}^{15}$ and (2) ${\mathrm{O}}^{15}$)${\mathrm{C}}^{13}$ were determined from thick-target yields obtained with 26-Mev nitrogen ions on AgCN. The cross section both at 25 Mev is about 5 millibarns. As energy decreases, reaction decreases more rapidly than (2). Neither ${\mathrm{N}}^{13}$ nor ${\mathrm{O}}^{15}$ was observed proton bombardment of ${\mathrm{Al}}^{27}$ energies...

Abstract Experimental tests of community assembly mechanisms for host‐associated microbiomes in nature are lacking. Asymptomatic foliar fungal endophytes a major component the plant microbiome and increasingly recognized their impacts on performance, including pathogen defense, hormonal manipulation, drought tolerance. However, it remains unclear whether preferentially colonize certain host ecotypes or genotypes, reflecting some degree biotic adaptation symbioses, colonization is simply...