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.

Soil fungi, microbes, microfauna, nitrogen fixation, hydrology, erosion, global change

This volume summarizes our current understanding of biological soil crusts (biocrusts), which are omnipresent in dryland regions. Since they cover the soil surface, they influence, or even control, all surface exchange processes. Being one of the oldest terrestrial communities, biocrusts comprise a high diversity of cyanobacteria, algae, lichens and bryophytes together with uncounted bacteria, and fungi. The authors show that biocrusts are an integral part of dryland ecosystems, stabilizing soils, influencing plant germination and growth, and playing a key role in carbon, nitrogen and water cycling. Initial attempts have been made to use biocrusts as models in ecological theory. On the other hand, biocrusts are endangered by local disruptions and global change, highlighting the need for enhanced recovery methods. This book offers a comprehensive overview of the fascinating field of biocrust research, making it indispensable not only for scientists in this area, but also for land managers, policy makers, and anyone interested in the environment.

During recent decades, large-scale effects of pollution on marine estuaries and even entire enclosed coastal seas have become apparent. One of the first regions where this was observed is the Baltic Sea, whereby the appearance of anoxic deep basins, extensive algal blooms and elimination of top predators like eagles and seals indicated effects of both increased nutrient inputs and toxic substances. This book describes the physical, biochemical and ecological processes that govern inputs, distribution and ecological effects of nutrients and toxic substances in the Baltic Sea. Extensive reviews are supplemented by budgets and dynamic simulation models. This book is highly interdisciplinary and uses a systems approach for analyzing and describing a marine ecosystem. It gives an overview of the Baltic Sea, but is useful for any marine scientist studying large marine ecosystems.

The Fungal Community: Its Organization and Role in the Ecosystem, Third Edition addresses many of the questions related to the observations, characterizations, and functional attributes of fungal assemblages and their interaction with the environment and other organisms. This edition promotes awareness of the functional methods of classification over taxonomic methods, and approaches the concept of fungal communities from an ecological perspective, rather than from a fungicentric view. It has expanded to examine issues of global and local biodiversity, the problems associated with exotic species, and the debate concerning diversity and function. The third edition also focuses on current ecological discussions - diversity and function, scaling issues, disturbance, and invasive species - from a fungal perspective. In order to address these concepts, the book examines the appropriate techniques to identify fungi, calculate their abundance, determine their associations among themselves and other organisms, and measure their individual and community function. This book explains attempts to scale these measures from the microscopic cell level through local, landscape, and ecosystem levels. The totality of the ideas, methods, and results presented by the contributing authors points to the future direction of mycology.

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.