Habitat structure: a fundamental concept and framework for urban soil ecology

Habitat structure is defined as the composition and arrangement of physical matter at a location. Although habitat structure is the physical template underlying ecological patterns and processes, the concept is relatively unappreciated and underdeveloped in ecology. However, it provides a fundamental concept for urban ecology because human activities in urban ecosystems are often targeted toward management of habitat structure. In addition, the concept emphasizes the fine-scale, on-the-ground perspective needed in the study of urban soil ecology. To illustrate this, urban soil ecology research is summarized from the perspective of habitat structure effects. Among the key conclusions emerging from the literature review are: (1) habitat structure provides a unifying theme for multivariate research about urban soil ecology; (2) heterogeneous urban habitat structures influence soil ecological variables in different ways; (3) more research is needed to understand relationships among sociological variables, habitat structure patterns and urban soil ecology. To stimulate urban soil ecology research, a conceptual framework is presented to show the direct and indirect relationships among habitat structure and ecological variables. Because habitat structure serves as a physical link between sociocultural and ecological systems, it can be used as a focus for interdisciplinary and applied research (e.g., pest management) about the multiple, interactive effects of urbanization on the ecology of soils

Scale Model of a Soil Aggregate and Associated Organisms: A Teaching Tool for Soil Ecology

Soil is a complex habitat for diverse biota. A significant challenge in teaching soil ecology is our inability to observe organisms as they live and interact in the soil. The objective of this article is to describe an interactive class project to help students visualize the sizes of different groups of soil organisms and to relate these to soil structural components. This project was carried out by students in an upper-level undergraduate soil ecology class. It involved the design and construction of a 4000× scale model of a soil aggregate and its associated organisms. The body of the model was made from inexpensive, lightweight materials and had a diameter of approximately 1 m to depict a 0.25-mm aggregate. Students identified and discussed appropriate size ranges and construction materials for the model’s bacteria, fungi, nematodes, mites, springtails, and other components. Instructor-guided questions addressed size and arrangement of sand, silt, and clay particles; pores; and organic matter in a typical soil aggregate. The model is a useful tool for conveying physical and ecological relationships among soil organisms and is adaptable for use at diverse educational levels

A Tale of Four Stories: Soil Ecology, Theory, Evolution and the Publication System

International audienceBACKGROUND: Soil ecology has produced a huge corpus of results on relations between soil organisms, ecosystem processes controlled by these organisms and links between belowground and aboveground processes. However, some soil scientists think that soil ecology is short of modelling and evolutionary approaches and has developed too independently from general ecology. We have tested quantitatively these hypotheses through a bibliographic study (about 23000 articles) comparing soil ecology journals, generalist ecology journals, evolutionary ecology journals and theoretical ecology journals. FINDINGS: We have shown that soil ecology is not well represented in generalist ecology journals and that soil ecologists poorly use modelling and evolutionary approaches. Moreover, the articles published by a typical soil ecology journal (Soil Biology and Biochemistry) are cited by and cite low percentages of articles published in generalist ecology journals, evolutionary ecology journals and theoretical ecology journals. CONCLUSION: This confirms our hypotheses and suggests that soil ecology would benefit from an effort towards modelling and evolutionary approaches. This effort should promote the building of a general conceptual framework for soil ecology and bridges between soil ecology and general ecology. We give some historical reasons for the parsimonious use of modelling and evolutionary approaches by soil ecologists. We finally suggest that a publication system that classifies journals according to their Impact Factors and their level of generality is probably inadequate to integrate "particularity" (empirical observations) and "generality" (general theories), which is the goal of all natural sciences. Such a system might also be particularly detrimental to the development of a science such as ecology that is intrinsically multidisciplinary

A Challenge and Chance for Soil Ecology

Soil ecology is concerned with interactions between organisms or between organisms and the soil environment. Soil ecology has its origins in soil biology and soil zoology, the study of organisms in the soil habitat. Soil ecology and soil science are related, yet different disciplines, with soil science focusing more on physical processes, the classification and genesis of soils, soil chemistry, and soil physics. Recent efforts in soil ecology have focused on developing a mechanistic understanding of how organisms and soils interact to yield patterns of soil biodiversity, nutrient cycling function within ecosystems, and feedbacks to global change mechanism

When “conservation” leads to land degradation: lessons from Ban Lak Sip, Laos

Land degradation / Soil erosion / Farming systems / Environmental policy / Political ecology / Households / Population growth / Laos / Ban Lak Sip

Litter layer influence on the thermal regime of a sandy soil under a pine forest in mediterranean Portugal

Decomposition of needle litter is a relevant process in applied ecology, namely in the nutrient dynamics of forested ecosystems. Soil temperature strongly influences soil microbian activity. Temperature profiles of a sandy soil (Haplic Podzol) under a pine forest were measured at several depths down to 16 cm, with and without litter layer. Daily cycles were analysed by means of Fourier series. Daily cycles were studied based on data from four days defined according to soil water content. The daily periodic variations of soil temperature follow closely the time-course of solar irradiance. Daily course of soil temperature is generally well described by the two first Fourier harmonics. The litter layer acts as a thermal insulator, reducing soil temperature gradients and amplitudes and increasing damping depth, particularly in dry soil

Conserving land, protecting water

Water resource management / Water productivity / Water conservation / Recycling / Land management / Soil conservation / Ecosystems / Ecology / Evapotranspiration / Food security / Poverty / River basins / Irrigated farming

Knowledge Enhancement Among Members of the Women Farmers Group (WFG) through Islamic Science-Based Soil Ecology Education

Farmers' knowledge about soil ecology, which is a key factor in increasing the productivity of agricultural products, needs to be evaluated considering that various counseling efforts to increase agricultural yields have not shown satisfactory results. Farmers still unequally manage farmland, providing excessive chemical fertilizers without regard to soil ecology. The purpose of this education is to evaluate the knowledge of the Women's Farmers Group (WFG) before and after conducting soil ecology education based on Islamic science. The subjects of this education were 15 members of WFG Bunga Padi, Jorong Kawai, Nagari Batu Bulek, Lintau Buo Utara, Tanah Datar, West Sumatra, Indonesia. The community-based research (CBR) approach is used in this educational activity. The stages of educational activities start from socialization, laying the basis of the research and the research design, providing pretests and materials, gathering information and analyzing data on biological factors, capillarity of groundwater, water holding capacity, soil aeration, soil fertility, and soil pH, and the evaluation (post-test). The results show an increase in knowledge and understanding among WFG Bunga Padi members after Islamic science-based soil ecology education. It is hoped that, over time, their mindset in managing farmland will be balanced, with less reliance on chemical fertilizers and more emphasis on soil ecology. As a result, Islamic science-based soil ecology education could have a role in improving farmland and laying the foundation for organic farming

The effects of arbuscular mycorrhizal fungi (AMF) and Rhizophagus irregularis on soil microorganisms assessed by metatranscriptomics and metaproteomics

Arbuscular mycorrhizal fungi (AMF) form symbioses with approximately 80% of plant species and potentially benefit their hosts (e.g. nutrient acquisition) and the soil environment (e.g. soil aggregation). AMF also affect soil microbiota and soil multifunctionality. We manipulated AMF presence (via inoculation of non-sterile soil with Rhizophagus irregularis and using a hyphal compartment design) and used RNA-seq and metaproteomics to assess AMF roles in soil. The results indicated that AMF drove an active soil microbial community expressing transcripts and proteins related to nine metabolic functions, including the metabolism of C and N. We suggest two possible mechanisms: 1) the AMF hyphae produce exudates that select a beneficial community, or, 2) the hyphae compete with other soil microbes for available nutrients and consequently induce the community to mineralize nutrients from soil organic matter. We also identified candidate proteins that are potentially related to soil aggregation, such as Lpt and HSP60. Our results bridge microbial ecology and ecosystem functioning. We show that the AMF hyphosphere contains an active community related to soil respiration and nutrient cycling, thus potentially improving nutrient mineralization from soil organic matter and nutrient supply to the plants

Soil Viruses: A New Hope.

As abundant members of microbial communities, viruses impact microbial mortality, carbon and nutrient cycling, and food web dynamics. Although most of our information about viral communities comes from marine systems, evidence is mounting to suggest that viruses are similarly important in soil. Here I outline soil viral metagenomic approaches and the current state of soil viral ecology as a field, and then I highlight existing knowledge gaps that we can begin to fill. We are poised to elucidate soil viral contributions to terrestrial ecosystem processes, considering: the full suite of potential hosts across trophic scales, the ecological impacts of different viral replication strategies, links to economically relevant outcomes like crop productivity, and measurable in situ virus-host population dynamics across spatiotemporal scales and environmental conditions. Soon, we will learn how soil viruses contribute to food webs linked to organic matter decomposition, carbon and nutrient cycling, greenhouse gas emissions, and agricultural productivity