Water is usually referred to as the ‘Molecule of Life’. It constitutes the most abundant molecule in living (micro)organisms and is also essential for critical biochemical reactions, both for the global functioning and maintenance of Ecosystems (e.g., Photosynthesis) and individual (microbial) cells (e.g., ATP hydrolysis). However, most of Earth’s terrestrial environments present deficiencies in bioavailable water. Arid environments cover around a third of the land’s surface, are found on the six continents and, with the anthropogenic desertification phenomenon, will increase. Commonly defined by having a ratio of precipitation to potential evapotranspiration (P/PET) below 1, arid environments, being either hot or cold, are characterized by scant and erratic plant growth and low densities in macro-fauna. Consequently, these ecosystems are microbially mediated with microbial communities particularly driving the essential Na and C biogeochemical cycles. Due to the relatively simple trophic structure of these biomes, arid terrestrial environments have subsequently been used as ideal ecosystems to capture and model interactions in edaphic microbial communities. To date, we have been able to demonstrate that edaphic microorganisms (i.e., Fungi, Bacteria, Archaea, and Viruses) in arid environments are abundant, highly diverse, different from those of other terrestrial systems (both in terms of diversity and function), and are important for the stability and productivity of these ecosystems. Moreover, arid terrestrial systems are generally considered Mars-like environments. Thus, they have been the favored destination for astro(micro)biologists aiming to better understand life’s potential distribution and adaptation strategies in the Universe and develop terraforming approaches. Altogether, these points demonstrate the importance of significantly improving our knowledge in the microbial community composition (particularly for Fungi, Archaea and Viruses), assembly processes and functional potentials of arid terrestrial systems, as well as their adaptation mechanisms to aridity (and generally to various other environmental stresses). This Research Topic was proposed to provide further insights on the microbial ecology of hot and cold arid edaphic systems. We provide a detailed review and nine research articles, spanning hot and cold deserts, edaphic, rhizospheric, BSC and endolithic environments as well as culture-dependent and -independant approaches.

Water is usually referred to as the 'Molecule of Life'. It constitutes the most abundant molecule in living (micro)organisms and is also essential for critical biochemical reactions, both for the global functioning and maintenance of Ecosystems (e.g., Photosynthesis) and individual (microbial) cells (e.g., ATP hydrolysis). However, most of Earth's terrestrial environments present deficiencies in bioavailable water. Arid environments cover around a third of the land's surface, are found on the six continents and, with the anthropogenic desertification phenomenon, will increase. Commonly defined by having a ratio of precipitation to potential evapotranspiration (P/PET) below 1, arid environments, being either hot or cold, are characterized by scant and erratic plant growth and low densities in macro-fauna. Consequently, these ecosystems are microbially mediated with microbial communities particularly driving the essential Na and C biogeochemical cycles. Due to the relatively simple trophic structure of these biomes, arid terrestrial environments have subsequently been used as ideal ecosystems to capture and model interactions in edaphic microbial communities. To date, we have been able to demonstrate that edaphic microorganisms (i.e., Fungi, Bacteria, Archaea, and Viruses) in arid environments are abundant, highly diverse, different from those of other terrestrial systems (both in terms of diversity and function), and are important for the stability and productivity of these ecosystems. Moreover, arid terrestrial systems are generally considered Mars-like environments. Thus, they have been the favored destination for astro(micro)biologists aiming to better understand life's potential distribution and adaptation strategies in the Universe and develop terraforming approaches. Altogether, these points demonstrate the importance of significantly improving our knowledge in the microbial community composition (particularly for Fungi, Archaea and Viruses), assembly processes and functional potentials of arid terrestrial systems, as well as their adaptation mechanisms to aridity (and generally to various other environmental stresses). This Research Topic was proposed to provide further insights on the microbial ecology of hot and cold arid edaphic systems. We provide a detailed review and nine research articles, spanning hot and cold deserts, edaphic, rhizospheric, BSC and endolithic environments as well as culture-dependent and -independant approaches.

In arid lands, where vegetation is sparse or absent, the open ground is not bare but generally covered by a community of small, highly specialized organisms. Cyanobacteria, algae, microfungi, lichens, and bryophytes aggregate soil particles to form a coherent skin - the biological soil crust. It stabilizes and protects the soil surface from erosion by wind and water, influences water runoff and infiltration, and contributes nitrogen and carbon to desert soils. Soil surface disturbance, such as heavy livestock grazing, human trampling or off-road vehicles, breaks up the fragile soil crust, thus compromising its stability, structure, and productivity. This book is the first synthesis of the biology of soil crusts and their importance as an ecosystem component. Composition and functioning of different soil-crust types are discussed, and case studies are used to show the impact of crusts on landscape hydrology, soil stability, nutrient cycles, and land management.

Owing to man-made intervention, the shrub-steppe now represents a rapidly disappearing landscape in the arid regions of North America. This book represents a systems-level study of ecological variables affecting water balance, and responses to perturbation. The study focused on a very large, protected, landscape unit, comprising a natural ``watershed'' area located in the semi-arid western United States. Long-term and concurrent data sets were established with a view towards establishing system-level responses to manipulative interventions, and natural perturbations like wildfire. These data sets were established for micrometeorology, climatology, mineral cycling in soils, nutrient and mineral pathways in springs and streams, vegetational dynamics, and population changes on the site. In synthesizing nearly twenty years of data, the more interesting ecosystem level responses concerned vegetational recovery and water balance. For instance, the synthesis uniquely demonstrates the interaction of biotic and non-biotic factors and their integrated effect on regional water balance. However, special attention was also paid to species diversity and the genetic resource pool represented at this site.This book will be of primary interest as a reference resource to land managers and wildlife specialists, and as a research study for scientists interested in systems-level ecology. Conservation-minded citizens who take more than a cursory interest in ecology will also find it interesting.

This book brings together many of the world’s leading experts in the fields of Antarctic terrestrial soil ecology, providing a comprehensive and completely up-to-date analysis of the status of Antarctic soil microbiology. Antarctic terrestrial soils represent one of the most extreme environments on Earth. Once thought to be largely sterile, it is now known that these diverse and often specialized extreme habitats harbor a very wide range of different microorganisms. Antarctic soil communities are relatively simple, but not unsophisticated. Recent phylogenetic and microscopic studies have demonstrated that these communities have well established trophic structuring and play a significant role in nutrient cycling in these cold and often dry desert ecosystems. They are surprisingly responsive to change and potentially sensitive to climatic perturbation. Antarctic terrestrial soils also harbor specialized ‘refuge’habitats, where microbial communities develop under (and within) translucent rocks. These cryptic habitats offer unique models for understanding the physical and biological ‘drivers’ of community development, function and evolution.

Volume 20 of this series deals with a variety of plant and animal ecology topics.**Despite much recent work on herbivory, little attention has been given to insect herbivores active below ground. Brown and Gange describe the ecological adaptations of insects to this abundant but poor quality food resource, and the responses of plants to this potentially very damaging grazing pressure.**Plants living at high altitude must be able to cope with extreme climatic conditions, low carbon dioxide levels, and high radiation doses. Friend and Woodward describe these adaptations and discuss the degree to which they are genetically determined or merely the product of physiological plasticity.**Thomas presents a modular concept of ecology in which modules contain a resource and its associated consumers, and goes on to examine the general principles which may reflect the various mutualisms between organisms in some example fresh water modular systems.**Finally, West examines the microphytic soil crusts of arid and semi-arid soils. Although information on them is currently limited, they are likely to be important in some ecosystems.

Soils have been called the most complex microbial ecosystems on Earth. A single gram of soil can harbor millions of microbial cells and thousands of species. However, certain soil environments, such as those experiencing dramatic change exposing new initial soils or that are limited in precipitation, limit the number of species able to survive in these systems. In this respect, these environments offer unparalleled opportunities to uncover the factors that control the development and maintenance of complex microbial ecosystems. This book collects chapters that discuss the abiotic factors that structure arid and initial soil communities as well as the diversity and structure of the biological communities in these soils from viruses to plants.

Dr. Timothy Schowalter has succeeded in creating a unique, updated treatment of insect ecology. This revised and expanded text looks at how insects adapt to environmental conditions while maintaining the ability to substantially alter their environment. It covers a range of topics- from individual insects that respond to local changes in the environment and affect resource distribution, to entire insect communities that have the capacity to modify ecosystem conditions.Insect Ecology, Second Edition, synthesizes the latest research in the field and has been produced in full color throughout. It is ideal for students in both entomology and ecology-focused programs.NEW TO THIS EDITION:* New topics such as elemental defense by plants, chaotic models, molecular methods to measure disperson, food web relationships, and more* Expanded sections on plant defenses, insect learning, evolutionary tradeoffs, conservation biology and more* Includes more than 350 new references* More than 40 new full-color figures