Explore the vast range of titles available.

The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global data sets. However, theory suggests that native and invasive species occurring in low‐resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource‐use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five mediterranean‐climate regions, which are drought prone and increasingly threatened by human activities, including the introduction of exotic species. Traits differed strongly across the five regions. In regions with functional differences between native and invasive species groups, invasive species displayed traits consistent with high resource acquisition; however, these patterns were largely attributable to differences in life form. We found that species invading mediterranean‐climate regions were more likely to be annual than perennial: three of the five regions were dominated by native woody species and invasive annuals. These results suggest that trait differences between native and invasive species are context dependent and will vary across vegetation communities. Native and invasive species within annual and perennial groups had similar patterns of carbon assimilation and resource use, which contradicts the widespread idea that invasive species optimize resource acquisition rather than resource conservation.

Studies in disturbed, resource-rich environments often show that invasive plants are more productive than co-occurring natives, but with similar physiological tradeoffs. However, in resource-limited habitats, it is unclear whether native and invasive plants have similar metabolic constraints or if invasive plants are more productive per unit resource cost – that is, use resources more efficiently. Using a common garden to control for environment, we compared leaf physiological traits relating to resource investments, carbon returns, and resource-use efficiencies in 14 native and 18 nonnative invasive species of common genera found in Eastern North American (ENA) deciduous forest understories, where growth is constrained by light and nutrient limitation. Despite greater leaf construction and nitrogen costs, invaders exhibited greater instantaneous photosynthetic energy-use efficiency (PEUE) and marginally greater photosynthetic nitrogen-use efficiency (PNUE). When integrated over leaf lifespan (LL), these differences were magnified. Differences in efficiency were driven by greater productivity per unit leaf investment, as invaders exhibited both greater photosynthetic abilities and longer LL. Our results indicate that woody understory invaders in ENA forests are not constrained to the same degree by leaf-based metabolic tradeoffs as the native understory flora. These strategy differences could be attributable to pre-adaptation in the native range, although other explanations are possible

• The degree of plant iso/anisohydry is a popular framework for characterising species-specific drought responses. However, we know little about associations between below-ground and above-ground hydraulic traits as well as the broader ecological implications of this framework. • For 24 understory shrub species in seasonally dry subtropical coniferous plantations, we investigated contributions of the degree of isohydry to species’ resource economy strategies, abundance, and importance value, and quantified the hydraulic conductance (K h) of above-ground and below-ground organs, magnitude of deep water acquisition (WAdeep), shallow absorptive root traits (diameter, specific root length, tissue density), and resource-use efficiencies (A max, maximum photosynthesis rate; PNUE, photosynthetic nitrogen-use efficiency). • The extreme isohydric understory species had lower wood density (a proxy for higher growth rates) because their higher WAdeep and whole-plant K h allowed higher A max and PNUE, and thus did not necessarily show lower abundance and importance values. Although species’ K h was coordinated with their water foraging capacity in shallow soil, the more acquisitive deep roots were more crucial than shallow roots in shaping species’ extreme isohydric behaviour. • Our results provide new insights into the mechanisms through which below-ground hydraulic traits, especially those of deep roots, determine species’ degree of isohydry and economic strategies.

1. Plastic responses to spatiotemporal environmental variation strongly influence species distribution, with widespread species expected to have high phenotypic plasticity. Theoretically, high phenotypic plasticity has been linked to plant invasiveness because it facilitates colonization and rapid spreading over large and environmentally heterogeneous new areas. 2. To determine the importance of phenotypic plasticity for plant invasiveness, we compare well-known exotic invasive species with widespread native congeners. First, we characterized the phenotype of 20 invasive-native ecologically and phylogenetically related pairs from the Mediterranean region by measuring 20 different traits involved in resource acquisition, plant competition ability and stress tolerance. Second, we estimated their plasticity across nutrient and light gradients. 3. On average, invasive species had greater capacity for carbon gain and enhanced performance over a range of limiting to saturating resource availabilities than natives. However, both groups responded to environmental variations with high albeit similar levels of trait plasticity. Therefore, contrary to the theory, the extent of phenotypic plasticity was not significantly higher for invasive plants. 4. We argue that the combination of studying mean values of a trait with its plasticity can render insightful conclusions on functional comparisons of species such as those exploring the performance of species coexisting in heterogeneous and changing environments.

This article is a commentary on Onoda et al., 214: 1447–1463.

The global population is increasing rapidly, together with the demand for healthy fresh food. The greenhouse industry can play an important role, but encounters difficulties finding skilled staff to manage crop production. Artificial intelligence (AI) has reached breakthroughs in several areas, however, not yet in horticulture. An international competition on “autonomous greenhouses” aimed to combine horticultural expertise with AI to make breakthroughs in fresh food production with fewer resources. Five international teams, consisting of scientists, professionals, and students with different backgrounds in horticulture and AI, participated in a greenhouse growing experiment. Each team had a 96 m2 modern greenhouse compartment to grow a cucumber crop remotely during a 4-month-period. Each compartment was equipped with standard actuators (heating, ventilation, screening, lighting, fogging, CO2 supply, water and nutrient supply). Control setpoints were remotely determined by teams using their own AI algorithms. Actuators were operated by a process computer. Different sensors continuously collected measurements. Setpoints and measurements were exchanged via a digital interface. Achievements in AI-controlled compartments were compared with a manually operated reference. Detailed results on cucumber yield, resource use, and net profit obtained by teams are explained in this paper. We can conclude that in general AI performed well in controlling a greenhouse. One team outperformed the manually-grown reference.

. A number of investigators have interpreted the slope of a linear production‐resource relationship as a measure of efficiency of resource utilization. However, this is rarely true and may lead to incorrect conclusions. Here, by means of simple mathematical equations and conceptual definitions, we point out the theoretical differences between slope and efficiency. While a slope represents the change in the dependent variable per unit change in the independent variable, efficiency expresses the amount of output produced by a unit amount of input. Practical implications of using slopes as indicators of resource‐use efficiency are less important as the resource amount increases. Slopes may be used as indicators of the sensitivity of production to changes in input, which is by itself an interesting property of biological systems. Finally, production function intercepts determine whether the efficiency will decrease, increase, or remain constant as resources increase.

Agricultural intensification is required to feed the growing and increasingly demanding human population. Intensification is associated with increasing use of resources, applied as efficiently as possible, i.e. with a concurrent increase in both resource use and resource use efficiency. Resource use efficiency has agronomic, environmental, economic, social, trans-generational, and global dimensions. Current industrial agriculture privileges economic resource use efficiency over the other dimensions, claiming that that pathway is necessary to feed the world. Current agronomy and the concept of sustainable intensification are contested. Sustainable intensification needs to include clarity about principles and practices for priority setting, an all-inclusive and explicit cost-benefit analysis, and subsequent weighing of trade-offs, based on scientifically acceptable, shared norms, thus making agriculture “green” again. Here, we review different forms of intensification, different principles and concepts underlying them, as well as the norms and values that are needed to guide the search for effective forms of sustainable and ecological intensification. We also address innovations in research and education required to create the necessary knowledge base. We argue that sustainable intensification should be considered as a process of enquiry and analysis for navigating and sorting out the issues and concerns in agronomy. Sustainable intensification is about societal negotiation, institutional innovation, justice, and adaptive management. We also make a plea for at least two alternative framings of sustainable intensification: one referring to the need for “de-intensification” in high-input systems to become more sustainable and one referring to the need to increase inputs and thereby yields where there are currently large yield (and often also efficiency) gaps. Society needs an agriculture that demonstrates resilience under future change, an agronomy that can cope with the diversity of trade-offs across different stakeholders, and a sustainability that is perceived as a dynamic process based on agreed values and shared knowledge, insight, and wisdom.

Crop residues, the byproduct of crop production, are valuable natural resources that can be managed to maximize different input use efficiencies. Crop residue management is a well-known and widely accepted practice, and is a key component of conservation agriculture. The rapid shift from conventional agriculture to input-intensive modern agricultural practices often leads to an increase in the production of crop residues. Growing more food for an ever-increasing population brings the chance of fast residue generation. Ecosystem services from crop residues improve soil health status and supplement necessary elements in plants. However, this is just one side of the shield. Indecorous crop residue management, including in-situ residue burning, often causes serious environmental hazards. This happens to be one of the most serious environmental hazard issues witnessed by the agricultural sector. Moreover, improper management of these residues often restrains them from imparting their beneficial effects. In this paper, we have reviewed all recent findings to understand and summarize the different aspects of crop residue management, like the impact of the residues on crop and soil health, natural resource recycling, and strategies related to residue retention in farming systems, which are linked to the environment and ecology. This comprehensive review paper may be helpful for different stakeholders to formulate suitable residue management techniques that will fit well under existing farming system practices without compromising the systems’ productivity and environmental sustainability.

Aim We estimated how seasonality in conjunction with key climatic variables affects morphological and physiological plant functional traits (PFTs) and soil essential (micro and macro) nutrients in oak, pine, and mixed forests. Method The different PFTs were tested using several laboratory methods and using the portable photosynthesis system Li-COR 6400 XT, Lincoln NE, USA. Likewise, some chemical traits and soil nutrients were analyzed by using CHNS analyzer. Results In this study, physiological traits such as CO 2 assimilation rate, stomatal conductance and transpiration rate were significantly higher in the rainy season followed by summer and winter seasons. Among the different forest land uses, physiological traits and resource use efficiency have been significantly higher in oak forest (OF) compared to the mixed forest (MF) and pine forest (PF). Likewise, the concentration of macro–micro nutrients was also recorded higher during the rainy season. The concentration of macro–micro nutrients was higher in OF than in MF and PF in different forest land uses. Conclusion Changes in PFTs ultimately affect the ecosystem services imparted by the different forests. Such changes lead to the local adaptation of these forests through the interaction between PFTs and soil nutrients.