Perspectives on Plant Competition is mainly about addressing the many different perspectives in plant competition and finding a common ground among them. Its aim is that through this common ground, new theories can be created. Encompassing 20 chapters, this book is divided into three parts. Part I, Perspectives on the Determinants of Competitive Success, consists of eight chapters. This section deals mainly on the question of determination of competitive success. Different writers put forward various definitions of competition and competitive success to shed light on the question at hand. In the second part of this book, an opposing set of views regarding the consequences of competitive interactions for the plant community structure is provided. This section emphasizes the idea that competition is not the sole force in natural communities. Each chapter in this part focuses on a certain aspect of competition as seen in different communities – across and within habitats – and systems. Part III, which comprises of four chapters, focuses on the competition within the context of interaction of plants with organisms on the other trophic levels. The chapters set forth the idea that competition depends on the impacts of herbivores, parasites, and symbionts. The concluding part of the book greatly emphasizes the need to integrate the mechanisms of competition into the framework of the entire food web.

Competitiveness describes a key ability important for plants to grow and survive abiotic and biotic stresses. Under optimal, but particularly under non-optimal conditions, plants compete for resources including nutrients, light, water, space, pollinators and other. Competition occurs above- and belowground. In resource-poor habitats, competition is generally considered to be more pronounced than in resource-rich habitats. Although competition occurs between different players within an ecosystem such as between plants and soil microorganisms, our topic focusses on plant-plant interactions and includes inter-specific competition between different species of similar and different life forms and intra-specific competition. Strategies for securing resources via spatial or temporal separation and different resource needs generally reduce competition. Increasingly important is the effect of invasive plants and subsequent decline in biodiversity and ecosystem function. Current knowledge and future climate predictions suggest that in some situations competition will be intensified with occurrence of increased abiotic (e.g. water and nutrient limitations) and biotic stresses (e.g. mass outbreak of insects), but competition might also decrease in situations where plant productivity and survival declines (e.g. habitats with degraded soils). Changing interactions, climate change and biological invasions place new challenges on ecosystems. Understanding processes and mechanisms that underlie the interactions between plants and environmental factors will aid predictions and intervention. There is much need to develop strategies to secure ecosystem services via primary productivity and to prevent the continued loss of biodiversity. This Research Topic provides an up-to-date account of knowledge on plant-plant interactions with a focus on identifying the mechanisms underpinning competitive ability. The Research Topic aims to showcase knowledge that links ecological relevance with physiological processes to better understanding plant and ecosystem function.

For the past 20 years, the first edition of this text has been widely cited as authoritative academic reference. The latest edition continues the tradition set by the original book, and covers weed science research that has been published since 1980. This book aims to reduce the instance of research duplication—saving scientists and supporting institutions time and money. Not only does the second edition of Weed Crop Competition review, summarize, and combine current research; it critiques the research as well. This text has the potential to accelerate advancements in weed crop competition, which remains an important factor that affects crop yields. Scientists in foreign countries where access to literature is often limited or nonexistent, will find the information in this text invaluable. Weed scientists, crop scientists, plant ecologists, sustainable agriculturists, and organic agriculturists will be well-pleased with this long overdue and much needed new editionWeed Crop Competition provides a unique reference that reviews, summarises and synthesizes the literature published concerning research on this topic. The first edition has been one of the most frequently cited sources in weed science for the past 20 years. The second edition covers the significant body of literature that has been published since 1980. Originally intended to survey existing research, the intent of the book is to reduce the instance of research duplication, thus saving scientists and their institutions time and money, and expediting advancements in weed crop competition, an important factor affecting crop yields. Scientists in foreign countries where access to the literature is often limited or non-existent, find the information an invaluable resource. This long overdue and much needed new edition rejuvenates the tradition set by the original book.

The question "Why are there so many species?" has puzzled ecologist for a long time. Initially, an academic question, it has gained practical interest by the recent awareness of global biodiversity loss. Species diversity in local ecosystems has always been discussed in relation to the problem of competi tive exclusion and the apparent contradiction between the competitive exclu sion principle and the overwhelming richness of species found in nature. Competition as a mechanism structuring ecological communities has never been uncontroversial. Not only its importance but even its existence have been debated. On the one extreme, some ecologists have taken competi tion for granted and have used it as an explanation by default if the distribu tion of a species was more restricted than could be explained by physiology and dispersal history. For decades, competition has been a core mechanism behind popular concepts like ecological niche, succession, limiting similarity, and character displacement, among others. For some, competition has almost become synonymous with the Darwinian "struggle for existence", although simple plausibility should tell us that organisms have to struggle against much more than competitors, e.g. predators, parasites, pathogens, and envi ronmental harshness.

Over the past decade, the international political system has come to be characterized as a Great Power Competition in which multiple would-be hegemons compete for power and influence. Instead of a global climate of unchallenged United States dominance, revisionist powers, notably China and Russia alongside other regional powers, are vying for dominance through political, military, and economic means. A critical battleground in the Great Power Competition is the Middle East, the Horn of Africa, and the Central Asia South Asia (CASA), also known as the Central Region. With the planned withdrawal of U.S. military forces from Afghanistan, the U.S. has stated its intention of shifting attention away from the CASA Region in favor of a more isolationist foreign policy approach. This book provides an in-depth understanding of the implications for this shift related to regional diplomacy & politics, economic opportunities & rivalries, security considerations & interests, and the information environment. Amplifying the vital importance of success in the Central Region to U.S. prosperity and security, this volume advances dialogue in identifying key issues for stakeholders within and beyond the Central Region to gain a holistic perspective that better informs decision-making at various levels. This collection of work comes from scholars, strategic thinkers, and subject matter experts who participated in the Great Power Competition Conference hosted by the University of South Florida, in partnership with the National Defense University Near East South Asia Center for Strategic Strategies in January 2020.