Increasing Intensity Of Competition Research Articles

Red Claw Crayfish Cherax quadricarinatus Cultivation Influences the Dynamics and Assembly of Benthic Bacterial Communities in Paddy Fields

Red claw crayfish Cherax quadricarinatus has emerged as a highly significant and suitable species to be raised in integrated rice–aquatic animal farming systems. To optimize an integrated aquaculture and agriculture (IAA) system and ensure sustainable utilization and development of land resources, an IAA system combining rice cultivation with red claw crayfish culture was implemented to assess the impacts of rice–red claw crayfish co-culturing on the dynamics and assembly of bacterial communities in paddy soils. We established two experimental groups, each with eight replicates. We utilized 16S rRNA Illumina high-throughput sequencing to access the bacterial community composition and assembly in paddy soils. Red claw crayfish C. quadricarinatus cultivation did not significantly affect the alpha diversity of the bacterial community in the paddy field, but it obviously increased the relative abundances of the phyla Acidobacteriota and Pseudomonadota involved in organic matter degradation and nitrogen, phosphorus, and carbon cycling. Red claw crayfish cultivation could lead to more complex bacterial communities, increased bacterial resistance to disturbances, the promotion of niche differentiation, and increased competition intensity between bacterial communities during the mid-cultivation period. Nitrogen emerged as a critical factor influencing the bacterial community composition in paddy soil during the culture period, and the red claw crayfish cultivation affected the bacterial community by altering the ammonia concentration in the paddy soil. As the culture progressed, the assembly of the bacterial community in the paddy soil was predominantly driven by stochastic processes, and red claw crayfish cultivation accelerated the evolution of the bacterial community assembly towards a stochastic process. Our study offers valuable insights into the dynamic changes occurring in the composition and assembly of bacterial communities in paddy soils in response to red claw crayfish cultivation.

Coexistence mechanism of alien species and local ecosystem based on network dimensionality reduction method

The interaction caused by nonnative species upset the balance of the existing ecosystem, the focus of previous studies is mainly on the survivability of alien species and their impact on the local ecosystem. However, the current research for the coexistence mechanism of alien species and resident species under different types of interactions are not very sufficient. Here, we apply an analysis framework that uses the weighted average neighbor activities to describe the state of local ecosystems, to map the multi-dimensional dynamic model to a one-dimensional equation, and simplify the structure and dynamics of the interaction between alien species and local ecosystems. Our work can help reveal the basic mechanism of species survival under the interaction of mutualism and competition. Remarkably, our results show that the species with fewer mutualistic interactions are prone to jump from high abundance to low abundance abruptly rather than continuous changes when encountering increased competition intensity. In addition, the local ecosystem with low species diversity is less tolerant to invasive alien species than the ecosystem with high species diversity.

Managing sustainable adoption of digital terrestrial television: demand-side and supply-side approaches

PurposeDigitization of terrestrial television enables government to reallocate a portion of spectrum to satisfy the 5G low-band spectrum demand. To accelerate the digitization process, the Indonesian Government has distributed digital terrestrial television (DTT) decoders for households in several DTT trial areas so that the recipients are able to experience DTT broadcasts on their analogue television. To ensure that the DTT is adopted sustainably, this study aims to provide evidence-based policy recommendations by first understanding underlying factors of the intention to purchase a new DTT receiver, either a new DTT decoder or an integrated digital television (DTV).Design/methodology/approachThis study uses 2018 survey data collected by Badan Aksesibilitas Telekomunikasi dan Informasi. The samples consist of 433 DTT decoder recipients in nine DTT trial locations in Indonesia. Two logistic models are used, one model for the DTT decoder and the other for integrated DTV. The two models have identical predictors, including respondents' demographics, television media use, technology cluster and DTT-related factors as innovation attributes.FindingsThe results indicate that the two models share some relevant variables but varying in sign and magnitude, namely, respondents' geographical location and the DTT picture and sound quality. The results also show that pay-television subscription, TV viewing and the difficulty of using the DTT decoder are other factors significantly associated with the intention to purchase a new DTT decoder.Research limitations/implicationsThis study has several limitations. First, the coefficients of determination are low, indicating that more independent variables should be included in the estimation models to obtain better insight about DTT adoption so that a better policy can be stipulated accordingly. Second, even though most of the predictors and proposed recommendations can be applied in general, all respondents of this study were DTT decoder recipients. Thus, future research can be more inclusive. Third, this study is designed based on the correlational model. This might cause the inability of the results to provide a conclusive direction of the relationship.Practical implicationsDemand-side and supply-side approaches are proposed to drive sustainable adoption of DTT, including the provision of subsidy or free DTT decoder for low-income households, increasing competition intensity among DTT devices manufacturers and distributors by allowing more players enter the Indonesian market, driving nationwide DTT infrastructure deployment and stipulating a national standard of the DTT devices.Originality/valueThis study enriches the understanding of the DTT adoption by incorporating geographical location variables for the proxy of infrastructure availability into the diffusion of innovation model, which has never been addressed by previous studies in the context of DTV adoption. In addition, this study focuses on a specific context in which all samples are free decoder recipients so that they have the same chance to experience DTT broadcasts.

Financing decisions of low-carbon supply Chain under Chain-to-Chain competition

Fierce market competition and consumers’ environmental awareness prompt manufacturers to gain competitive advantages through low-carbon production. However, many firms stay away from low carbon because of financial constraints. Considering chain-to-chain competition, this paper constructs three financing strategic models. The impacts of market competition intensity and consumers’ low-carbon preference on equilibrium decisions and corporate profits are analyzed. Then, comparative analysis is conducted to find the optimal financing strategy. Finally, numerical simulation is used for further analysis and robustness tests. It is indicated that under chain-to-chain competition, low-carbon production cannot improve the negative impact of increased competition intensity on corporate profits. Intense competition weakens the manufacturer’s emission reduction efforts. Moreover, the manufacturer does not always benefit more from internal financing though the low-carbon level is high. When the probability of obtaining a bank loan exceeds the threshold, bank financing is superior to internal financing. An increased low-carbon investment cost coefficient will lower the threshold, which is counterintuitive. Since the preference interval for the downstream retailer to provide prepayments is larger than the interval for the low-carbon manufacturer to choose internal financing, both parties have the incentive to negotiate prepayments. Under internal financing, the wholesale price discount does not affect corporate profits.

Different biomass production and soil water patterns between natural and artificial vegetation along an environmental gradient on the Loess Plateau

Loess Plateau (LP) is a vulnerable and climate-sensitive ecoregion. With the implementation of “Grain for Green” project (GGP), the vegetation cover has largely improved, while the contradiction between overconsumption of soil water and sustainability of restored vegetation is increasingly prominent, and further threatening the ecosystem sustainability and socioeconomic development. Understanding the different responses of relations of biomass production and soil water regimes between natural and artificial vegetation along environmental gradient will be crucial for sustainability of restored vegetation on the LP. Here, aboveground biomass (AGB) and soil water content (SWC) of natural and artificial vegetation were measured in steppe, forest-steppe and forest zone from 2008 to 2017 on the Yanhe River catchment. The results showed that artificial vegetation consumed more soil water than natural vegetation in steppe and forest-steppe zone, while it did not over consume soil water in forest zone. The AGB of natural vegetation in forest zone was significantly higher than that in steppe and forest-steppe zone. Steppe zone had serious overload of artificial vegetation (overload ratio: 5.35), while no overload occurred in forest zone. So, we suggest a cessation of artificial vegetation expansion in steppe zone. In steppe zone, planting artificial vegetation increased competition intensity between AGB and SWC, and the relative benefit tended to be AGB, their competition intensity was the highest. In forest zone, the trade-off relationship between AGB and SWC had no significant difference between natural and artificial vegetation, and the competition intensity between the AGB and SWC was the weakest. Optimal vegetation restoration approach would maintain the balance between vegetation restoration and soil water. To obtain social and ecological sustainability on the LP, vegetation suitability and suitable management along different environmental gradients should be considered and identified in the future revegetation project.

Stereoscopic Planting in Ridge and Furrow Increases Grain Yield of Maize (Zea mays L.) by Reducing the Plant’s Competition for Water and Light Resources

Increasing planting density is an important ways to increase maize yield. A hot topic of conversation in the current research is how to improve crop light efficiency and yield potential by optimizing the cultivation mode under high density planting is a hot topic in current research. Thus, in this study, a field experiment was conducted to explore the effects of stereo-planting patterns on water and the utilization light resource and maize yields. Planting patterns included the conventional flat planting pattern (as the control, CK) and the stereo-planting in ridge and furrow (T). Each planting pattern had three planting densities, i.e., 60,000 plants ha−1 (D1), 75,000 plants ha−1 (D2) and 90,000 plants ha−1 (D3). The results showed that stereo-planting affected the physiological characteristics of plants by changing the spatial distribution of soil moisture. At the silking stage (R1), photosynthetic rate (Pn) of plants on the ridge was similar to CK, and transpiration rate (Tr) was significantly lower than that of CK. Pn of maize in the furrow was significantly higher than that of CK, and Tr was similar to CK. Stereoscopic planting had different effects on intraspecific competition intensity in maize population in different growing stages. In the six-leaf stage (V6), stereo-planting increased competition intensity of maize on the ridge, but lowered that of maize in the furrow by affecting the spatial distribution of soil moisture. During the R1 stage, stereo-planting increased the light transmittance rate within the canopy and eased the plant’s competition for light by reducing plant height and leaf area of maize under three density conditions. Stereo-planting had no effect on grain yield and dry matter accumulation of ridge-planted maize in the later growing stage, but it did increased the dry matter accumulation and grain yield of furrow-planted maize due to the improvement of the light environment and photosynthetic characteristics of the population. In two test years, stereo-planting increased 5.0–11.0% average yield of maize compared to CK under three density conditions. These results indicate that stereo-planting can reduce the plant’s competition for light and water resources and improve its physiological traits of plant by optimizing its spatial distribution of soil moisture and canopy structure, thus further increasing grain yield of maize under high-density planting conditions.

THE EFFECTS OF COMPETITIVE INTENSITY AND TECHNOLOGY MANAGEMENT ON THE RELATIONSHIP OF ACCOUNTING INFORMATION SYSTEM AND FIRM PERFORMANCE

In today's conditions, where the intensity of the competition is high, the achievement of the desired performance outputs of the companies is closely related to the better understanding of the performance leaders. The aim of this study is to examine the effect of competitive intensity and technology management on firm performance through the accounting information system. The study covers data obtained from 256 SME managers in the West Marmara region. The data obtained were analyzed with the help of exploratory factor and multiple regression analysis. According to the exploratory factor analysis results, the variables were divided into sub-factors and the regression analysis was performed between the sub-components. As a result, the tendency of companies to preventive technology management and the increase in the use of internal and external accounting information systems increase the financial performance of companies in a meaningful and positive way. On the other hand, the increase in the intensity of competition, the use of company protective technology management and internal accounting information systems increases the market performance of the company in a meaningful and positive way. Again, the intensity of competition and the increase in collaborative technology management increase the use of external accounting information systems. Collaborative technology management increases the use of internal accounting information system. Finally, increased competition intensity increases collaborative technology management.

Is plant reproductive efficiency expressed on a continuum of facilitation and competition?

AbstractQuestionsCompetition and facilitation form a continuum of interactions between plants from intensely negative to intensely positive. Competition has long been understood to be a major selective force driving the expression of adaptive strategies in plants. However, we remain uncertain if facilitation plays a similar role. In previous studies, the relative allocation to reproduction across plant species increases with increasing competition intensity, and this observation is generally consistent with life history theory (rather than traditional plant strategy theory). However, is facilitation also an important force in shaping adaptive strategies in plants?MethodsWe surveyed the literature for plant facilitation studies that included measures of plant performance (e.g. vegetative biomass, height) and reproduction (e.g. reproductive biomass, seed number). We tested for a relationship between relative reproductive efficiency (the allocation to reproduction in the presence of neighbours relative to the allocation of reproduction in the absence of neighbours), and facilitation interaction intensity (i.e. the increase in plant performance due to the presence of neighbours). We also compared this relationship to the previously published relationship between reproductive efficiency and competition intensity to test for a continuum of strategies on an axis of plant–plant interactions from intensely positive (facilitation) to intensely negative (competition).ResultsThe overall relationship between facilitation intensity and the relative reproductive efficiency is a common negative relationship for both annual and perennial life histories. We found a highly significant negative relationship across the competition–facilitation continuum, with reproductive efficiency in the presence of neighbouring vegetation high under intense competition and low under intense facilitation.ConclusionPlant reproductive strategies are expressed on a continuum of interactions from facilitation to competition. This continuum of interactions will be important in understanding how interactions between plants drive the evolution of adaptive strategies and control coexistence and diversity in plant communities.

إعادة هندسة العملیات وتأثیرها على التعلیم الجامعی «دراسة تطبیقیة على الجامعة المصریة»

إعادة هندسة العملیات وتأثیرها على التعلیم الجامعی «دراسة تطبیقیة على الجامعة المصریة»

The impact of intraspecific competition on tree growth in planted Korean pine forest

The aim of this study was to explore the correlation of competition indices (CIs) on individual tree growth for Korean pine (Pinus koraiensis) plantation using partial correlation analysis and generalized linear models. The data were collected from 15 permanent plots in Mengjiagang forestry farm, Northeast China. The results showed that the distance dependent CIs have a higher predictive capacity for individual growth of pine trees. The control index of competitive trees number (CI1) combined with the selection fixed competitor trees (M2) was found to be the most well correlated competition measure with five - years diameter increment. Thus, the competition index (CI1- M2) was recommended for developing individual tree growth models. The subject tree diameter at breast height, crown width, height to crown base, tree volume and basal area all showed a significantly linear correlation with tree competition intensity (P < 0,05). Diameter at breast height, crown width, tree volume and basal area all decreased with increasing competition intensity, whereas the height to crown base increased. There was no significant relationship between competition intensity and tree height (P > 0,05). The optimal model of predicting individual growth with logarithm of diameter at breast height and CIs as the independent variables due to the best fitting performance. This results also showed considerable improvement in predicting individual tree periodic growth when including competition indices that the mean absolute error is reduced in the range of 22−25%.

The Rise of Merit-based Inequality Acceptance After Exposure to Competition: Experimental Evidence among Chinese University Students

This laboratory study examines an individual’s acceptance of distributional inequality after exposure to competition and the role of competitive intensity in this relationship among young adults in mainland China. We randomly assigned participants to tournaments with different levels of prize spread and winning selectivity, thereby engendering different levels of competitive intensity. Moreover, the lab experiment measured the participants’ preference for inequality in the distribution of tournament awards–what we call merit-based inequality acceptance. We obtained three main results. (1) Exposure to competition increases the level of inequality acceptance, and the effect of such increase tends to be great among strong performers in a tournament. (2) Exposure to competition with large prizes is positively associated with high level of inequality acceptance, whereas the relationship of winning selectivity to inequality acceptance has an inverted U shape. (3) The main source of inequality acceptance is the difference in the payoffs to strong and poor performers in a tournament. Results suggest that increasing competition intensity for economic rewards may have the unintended consequence of enhancing merit-based inequality acceptance among young Chinese university students.

PERAN PARTNERSHIP STRATEGY UNTUK MENINGKATKAN KINERJA PERUSAHAAN (Studi Pada Bank Perkreditan Rakyat di Provinsi Bali)

The background of this research is the phenomena of increasing competition intensity in the industry of Bank Perkreditan Rakyat (BPR) in Bali. These phenomana will decrease the performance achievement of BPR compared to other micro financial institutions like Lembaga Perkreditan Desa. It is expected to overcome the problem of performance achievement degradation by implementing partnership strategy. This research is aimed to analyze the relation between variables, so that this can be grouped as explanatory research. This research takes place in Bali Province with the populations target are Bank Perkreditan Rakyat (BPR). The population of this research are 143 BPR in Bali Province by using non proportionate random sampling. There are 105 BPR in Bali province are choosen as the samples based on Kracjie and Morgan Table. The respondents are Head Director of each BPR, who understand about the industry competitive environment, partnership strategy, and performance. The statistic analysis used to analyze the hypothesis is Structural Equation Model (SEM). The result of analysis shows that tight industry competition will decrease the corporate performance; meanwhile this negative influence can be diminished if the partnership strategy is applied by the corporate.

Biotic homogenization in an increasingly urbanized temperate grassland ecosystem

AbstractQuestionHow does urbanization and associated declines in fire frequency alter the floristic composition of native temperate grasslands? Does it lead to: (1) biotic homogenization, i.e. compositional similarity between remnants increases; (2) biotic differentiation, whereby similarity between remnants declines, or; (3) clustered differentiation, where similarity between remnants remains unchanged, but composition shifts from the historical state?LocationVictoria, Australia.MethodsUsing site‐level surveys, we examined changes in the floristic similarity of 29 urban grasslands from 1992 to 2013 and compared these changes to those of 63 rural grasslands from 1989 to 2014. Community‐level changes in the representation of key functional traits were also examined in urban grasslands, with traits advantaged following disturbance regime change and urban fragmentation predicted to increase in frequency.ResultsOur results supported the biotic homogenization hypothesis in urban grasslands. Compositional similarity between grasslands increased principally because of an increase in commonly shared non‐native species, with change in native composition comparatively minor. However, no evidence of biotic homogenization was found in rural grasslands, with no significant change in overall composition identified. The most urbanized sites had the highest number of non‐native species in both the current and historical data sets, yet non‐native composition over the past two decades changed the most in sites on the urban fringe, becoming more similar to sites closer to the urban core. As expected, following declines in fire frequency and increased urbanization, the overall composition of urban grasslands shifted to taller plant species, while native species capable of vegetative reproduction and exotic species with an annual life span increased in frequency.ConclusionUrbanization was an important driver of biodiversity change in the investigated system, with increasing competition intensity in response to disturbance regime change a likely cause of biotic homogenization. Our results demonstrate that non‐native species are a key driver of biotic homogenization, emphasizing the importance of managing non‐native immigration and maintaining historical disturbance processes once native ecosystems become urbanized.

PERAN PARTNERSHIP STRATEGY UNTUK MENINGKATKAN KINERJA PERUSAHAAN (Studi Pada Bank Perkreditan Rakyat di Provinsi Bali)

The background of this research is the phenomena of increasing competition intensity in the industry of Bank Perkreditan Rakyat (BPR) in Bali. These phenomana will decrease the performance achievement of BPR compared to other micro financial institutions like Lembaga Perkreditan Desa. It is expected to overcome the problem of performance achievement degradation by implementing partnership strategy. This research is aimed to analyze the relation between variables, so that this can be grouped as explanatory research. This research takes place in Bali Province with the populations target are Bank Perkreditan Rakyat (BPR). The population of this research are 143 BPR in Bali Province by using non proportionate random sampling. There are 105 BPR in Bali province are choosen as the samples based on Kracjie and Morgan Table. The respondents are Head Director of each BPR, who understand about the industry competitive environment, partnership strategy, and performance. The statistic analysis used to analyze the hypothesis is Structural Equation Model (SEM). The result of analysis shows that tight industry competition will decrease the corporate performance; meanwhile this negative influence can be diminished if the partnership strategy is applied by the corporate.

The role of market power in economic growth: an analysis of the differences between EU and US competition policy theory, practice and outcomes

The European Union has experienced weak economic performance over the past 15 years, compared to the United States. In order to restore investment, innovation, and therefore growth, the European Commission seeks to raise the level of static competition in all markets. The Commission’s economic policy is largely determined by its competition policy. This policy is derived from its doctrine on competition law, which regards the exercise of market power as a source of inefficiency and advocates that its effects should be banned. By contrast, the United States competition authorities, under the influence of the Chicago School, consider that market power is a necessary incentive to invest and a fair return on investment. Recent findings in economic growth theory, which state that increased competition intensity may harm endogenous innovation, provide a theoretical basis to support the United States approach and call for a review of European doctrine.

Carnivores and humans during the Early and Middle Pleistocene at Sierra de Atapuerca

It has been repeatedly proposed that the human presence in Europe during the late Early and the early Middle Pleistocene was conditioned, among other factors, by the available trophic resources and by the competition with carnivores for these resources. Competition for meat with other secondary consumers could delay the human dispersal through Europe. Moreover, some research suggests that human settlement was discontinuous in Europe during the late Early and the Middle Pleistocene and that this discontinuity might be related to the presence of other secondary consumers. The competition intensity among secondary consumer species in Europe has been previously analysed at both local and continental scales. At the local scale, two faunal assemblages from the Sierra de Atapuerca sites were analysed, demonstrating that competition intensity was higher in the early Middle Pleistocene than in the late Early Pleistocene. At a continental scale, 34 faunal assemblages were analysed and demonstrated an opposite pattern. In the present study, we extended the local analysis to include more faunal assemblages from the Sierra de Atapuerca sites to track the changes in the competition intensity during a longer time period. The results show that humans were able to successfully exploit the Atapuerca ecosystems at different levels of competition intensity, and that TD6-2 assemblage exhibits an exceptionally low degree of competition. It is proposed that the TD6-2 paleocommunity likely included a large felid species that is not recorded in the fossil assemblage. Lack of human presence in the TD8 assemblage may be related to increased competition intensity inside the guild of secondary consumers, while the technological development from Mode 2 to Mode 3 could be related to an increased degree of competition. There are similarities between the analyses at the continental and local scales from the point of view of the available biomass for secondary consumers, but the competition intensity shows little variation at the local scale, with the exception of the TD6-2 assemblage.

Interactive Effects of Nitrogen and Water Addition on Competitive Hierarchies Between Early- and Late- Successional Plant Species

Increased nitrogen (N) and water availability, resulting from global changes or ecosystem management, were predicted to promote plant productivity and change community composition through shifts in competition hierarchies. So far, however, it still remains unclear how competitive interactions respond to N and water additions, which will be important to understand how plant community composition changes. To test plant competition ability in different successional stages under N and water addition treatments, a pot experiment under field conditions was performed. Six dominant plant species, three early-successional species, Artemisia lavandulaefolia, Artemisia capillaris, and Pennisetum centrasiaticum versus three late-successional species, Stipa krylovii, Leymus chinensis, and Artemisia frigida, were grown in monocultures and in twospecies mixtures under factorial combinations of N and water addition treatments. We found that (1) there were interactive effects of N addition, water addition and interspecific competition on plant biomass; (2) For a given species, competitive abilities were correlated with biomass difference of neighboring species; (3) N and water additions interactively increased competition intensity and shifted species competitive hierarchies; (4) Late-successional species had stronger competitive abilities in the N addition treatment, whereas early-successional species had stronger competitive abilities after water addition or N water addition. Our results show that N and water additions increased the intensity and impact of interspecific competition on plant growth, which has great implications for community structures. Since interspecific differences in competitive abilities were not well explained by species biomass, species identity, such as plant functional traits, should be included to predict the impact of increased N and water availability on plant communities and ecosystem functions.

Influence of soil properties on silver fir (Abies alba Mill.) growth in the Dinaric Mountains

Tree growth can be influenced by a wide variety of complex interacting factors. The contribution of soil to site productivity is confounded by the interactions between other site factors and silviculture. The contribution of soil properties to the growth of silver fir (Abies alba Mill.) was studied in the Dinaric Mountains, which are characterised by abundant sinkholes and limestone outcrops, resulting in diverse micro topography and different soil development at small spatial scales. Basal area increment and height growth data were estimated based on stem analysis of dominant silver fir trees (n=65) on a 50m×50m sampling grid, and competition intensity was determined. The soil development around each tree was defined using morphological properties of the genetic horizons based on soil probing (n=65×12). In the study area, the chemical and physical soil characteristics (based on 21 soil profiles) were favourable for plant growth. Soil parameters e.g. soil depth, thickness of genetic soil horizons, share of soil types around each tree and soil associations were the factors controlling tree growth. Tree age and competition intensity were also influential factors in the case of height and radial tree growth respectively. Positive effects on height and radial growth were confirmed also for available water capacity of soil and location of tree in slope position (in the sinkhole, out of the sinkhole). The decrease in specific basal area increment with increasing competition intensity was most evident for trees growing on leached soils. The coefficient of determination and the statistical significance of the relationship between height growth and soil association over the last 100years emphasised the cumulative effect of the soil condition on tree height growth.

High reproductive efficiency as an adaptive strategy in competitive environments

Summary Reproductive efficiency (the efficiency of conversion of resources from vegetative tissue to reproductive output) is a central to our understanding of reproductive allocation and the evolution of reproductive strategies in plants. Plant strategy theory predicts that reproductive efficiency should decrease under competition. Short‐lived semelparous species are not predicted to evolve under competition and therefore should not express adaptive responses to the presence of competitors. Long‐lived iteroparous species are predicted to delay reproduction in favour of growth and resource acquisition in the presence of competitors. I use life‐history theory to advance a prediction that reproductive efficiency increases under competition in both short‐lived semelparous and potentially longer‐lived iteroparous species. Contrary to the predictions of plant strategy theory, short‐lived semelparous species are frequently observed to live in highly competitive environments. Further, iteroparous species under intense competition may die long before they reach competitive dominance or an optimal size for reproduction. I surveyed the literature for studies on plant species including measurements of vegetative and reproductive allocation in high and low (or no) competition treatments. Across species, relative reproductive efficiency (reproductive efficiency under high competition/reproductive efficiency under low competition) significantly increased with increasing competition intensity. Patterns of allocation to reproduction under competition support the existence of a competitive annual strategy and a reproductive perennial strategy. Under these strategies, short‐lived semelparous species and long‐lived iteroparous species express high reproductive efficiency under competition as an adaptation to high neighbour density. In addition, some species also expressed patterns of allocation to reproduction consistent with plant strategy theories. Under this interpretation, I predict that competitive strategies, where plants delay reproduction in competitive environments to gain competitive superiority, are favoured not under intense competition but under modest competition. Including a life‐history interpretation in reproductive efficiency under competition provides a much needed predictive framework for strategies of reproduction observed across species.

Crown architecture and its role in species interactions in mixed boreal forests

The species specific growth patterns make plastic crown architecture respond in different manner to different environments modifying their influence to neighbours. The main aims of this thesis were to separate the effect of neighbour species identity from the abundance, size and proximity of the neighbours in between-tree competition and to link crown architecture with hydraulic architecture by identifying the associated within-tree variation of crown traits. The empirical part of the work was based on digitising three-dimensional (3D) crown architecture and measuring xylem anatomy. Digitising allowed the development of crown architecture models for Betula pendula (Roth.) and Pinus sylvestris (L.). The models were further applied to simulate light transmission in mixed stands. Crown architecture of the studied species responded to increased competition intensity primarily by reducing branch number and size. Proportional biomass distribution to foliage and main branches over the stem increased in young B. pendula with increasing competition intensity, whereas Pinus sylvestris used the opposite strategy. In addition to competition intensity, crown architecture of the studied species showed plastic responses to the species identity of neighbouring trees. Lower overall growth but added height growth indicating stronger competition was found in mixtures of B. pendula and Pinus sylvestris when a tree was surrounded by interspecific neighbours compared to trees surrounded by intraspecific neighbours. Both species-specific effects on resource gradients and nonresource signals remain plausible explanations for this result: B. pendula transmitted more light than Pinus sylvestris at simulated dense stands. Hydraulic architecture was shown to be interlinked with crown architecture as the conduit diameter varied as a function of tree compartment, branching hierarchy, leaf area and distance from the apex. The results suggest that the use of detailed tree structure models and species-specific competition analysis is useful in predicting and understanding growth in mixed boreal stands.