Ecological Development And Functioning Of Biological Soil Crusts After Natural And Human Disturbances

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.

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.

Sand dune dynamics play a key role in many arid deserts. This volume provides a thorough analysis of a specific sand dune ecosystem, the Nizzana site in the Middle East’s Negev Desert. Describing its climate, as well as its geophysical/geochemical soil properties and ecology, this brilliant work draws out the relationships between the site’s ecological and geomorphological processes, based on long-term monitoring, in situ experiments and satellite imagery.

Soil fauna plays a significant role at all trophic levels of the soil food web and regulates processes that are crucial for soil functioning, such as nutrient cycling, immobilization and/or degradation of toxic compounds, formation of soil structure, greenhouse gas emissions and C turnover. Although soil fauna is not thought to contribute significantly to soil respiration during litter or soil organic matter (SOM) decomposition, the diversity of soil fauna has been found to strongly influence SOM distribution and dynamics. Yet, the functional contribution of soil fauna to many soil processes is not well understood due to methodological limitations and the high complexity of interactions at various spatiotemporal scales. In general, soil fauna has received far less scientific attention than bacteria and fungi (and lately archaea) in soil studies and has been regularly ignored in global biogeochemical models, with maybe exceptions for some earthworms. However, recent studies are raising the awareness of the influence of soil fauna on ecosystems dynamics. For instance, earthworms have been found to be major players in N2O emissions from soils. They exert a strong influence on C stabilization, and they promote the degradation of polycyclic aromatic hydrocarbons (PAHs). Less studied, ants and termites have been found to increase crop productivity in drylands, and different lifeforms of Collembola have been shown to impact microorganisms in various ways over time, thereby potentially affecting C and N cycles within farming systems. The influence of soil fauna indeed manifests over a broad ranges of spatiotemporal scales. For example, some effect such as aggregate formation may cumulate over time and finally contribute to the formation of whole soil profiles, which serve as a framework for other soil processes such as water movement, decomposition, etc. Meanwhile, soil biodiversity is impacted by an increasing human pressure through deforestation, agriculture intensification, habitat fragmentation or climate change (increasing temperatures, extreme weather events), which leads to soil biodiversity loss, in particular of soil fauna, with associated consequences on soil functioning and resilience.

Ecological restoration is a rapidly evolving discipline that is engaged with developing both methodologies and strategies for repairing damaged and polluted ecosystems and environments. During the last decade the rapid pace of climate change coupled with continuing habitat destruction and the spread of non-native species to new habitats has forced restoration ecologists to re-evaluate their goals and the methods they use. This comprehensive handbook brings together an internationally respected group of established and rising experts in the field. The book begins with a description of current practices and the state of knowledge in particular areas of restoration, and then identifies new directions that will help the field achieve increasing levels of future success. Part I provides basic background about ecological and environmental restoration. Part II systematically reviews restoration in key ecosystem types located throughout the world. In Part III, management and policy issues are examined in detail, offering the first comprehensive treatment of policy relevance in the field, while Part IV looks to the future. Ultimately, good ecological restoration depends upon a combination of good science, policy, planning and outreach – all issues that are addressed in this unrivalled volume.

This open access book synthesizes leading-edge science and management information about forest and rangeland soils of the United States. It offers ways to better understand changing conditions and their impacts on soils, and explores directions that positively affect the future of forest and rangeland soil health. This book outlines soil processes and identifies the research needed to manage forest and rangeland soils in the United States. Chapters give an overview of the state of forest and rangeland soils research in the Nation, including multi-decadal programs (chapter 1), then summarizes various human-caused and natural impacts and their effects on soil carbon, hydrology, biogeochemistry, and biological diversity (chapters 2–5). Other chapters look at the effects of changing conditions on forest soils in wetland and urban settings (chapters 6–7). Impacts include: climate change, severe wildfires, invasive species, pests and diseases, pollution, and land use change. Chapter 8 considers approaches to maintaining or regaining forest and rangeland soil health in the face of these varied impacts. Mapping, monitoring, and data sharing are discussed in chapter 9 as ways to leverage scientific and human resources to address soil health at scales from the landscape to the individual parcel (monitoring networks, data sharing Web sites, and educational soils-centered programs are tabulated in appendix B). Chapter 10 highlights opportunities for deepening our understanding of soils and for sustaining long-term ecosystem health and appendix C summarizes research needs. Nine regional summaries (appendix A) offer a more detailed look at forest and rangeland soils in the United States and its Affiliates.

This innovative book integrates practical information from restoration projects around the world with the latest developments in successional theory. It recognizes the critical roles of disturbance ecology, landscape ecology, ecological assembly, invasion biology, ecosystem health, and historical ecology in habitat restoration. It argues that restoration within a successional context will best utilize the lessons from each of these disciplines.