• Unit-2 Ecosystems Amit K. Singh Dr.Deepak Singh
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Grassland Ecosystems in British Columbia
Grassland Ecosystems in British Columbia © Grasslands Conservation Council of BC 1 The Grasslands Conservation Council of British Columbia’s mission is to: • Foster understanding and appreciation for the ecological, social, economic, and cultural importance of BC grasslands. • Promote stewardship and sustainable management practices to ensure the long-term health of BC grasslands. • Promote the conservation of representative grassland ecosystems, species at risk, and their habitats. &/OR Acknowledgements for original author and illustrator &/OR Another message that it makes sense to include. Maybe the mission in simple language. Grasslands Conservation Council of British Columbia. (Year). Grassland Ecosystems in British Columbia. Kamloops, BC: Author. © Grasslands Conservation Council of BC 2 Grassland Ecosystems Ecological systems (ecosystems) consist of all the living organisms in an area and their physical environment (soil, water, air). Ecosystems are influenced over time by the local climate, the parent material under the plants, variations in the local landscape, disturbances such as fire and floods, and by the organisms that live in them. Grassland ecosystems in British Columbia generally occur in areas where the climate is hot and dry in summer and cool to cold and dry in winter. The parent material is often composed of fine sediments, and grasslands are most often in valley or plateau landscapes. The organisms that live in them include plants and animals that have adapted to the dry climatic conditions in a variety of ways. Differences in elevation, climate, soils, aspect, and their position in relation to mountain ranges have resulted in many variations in the grassland ecosystems of British Columbia. The mosaics of ecosystems found in our grasslands, including wetlands, riparian areas, aspen stands and rocky cliffs, allow for a rich diversity of species. -
Terrestrial Decomposition
Terrestrial Decomposition • Objectives – Controls over decomposition • Litter breakdown • Soil organic matter formation and dynamics – Carbon balance of ecosystems • Soil carbon storage 1 Overview • In terrestrial ecosystems, soils (organic horizon + mineral soil) > C than in vegetation and atmosphere combined 2 Overview • Decomposition is: 1. Major pathway for C loss from ecosystems 2. Central to ecosystem C loss and storage 3 Overview 4 Incorporation 1 year later Overview • Predominant controls on litter decomposition are fairly well constrained 1. Temperature and moisture 2. Litter quality • N availability • Lignin concentration • Lignin:N • Mechanisms for soil organic matter stabilization: 1. Recalcitrance (refers to chemistry) 2. Physical protection • Within soil aggregates • Organo-mineral associations 3. Substrate supply regulation (energetic limitation) 5 Overview • Disturbance can override millenia in a matter of days or years: 1. Land use change 2. Invasive species 3. Climate change • Understanding the mechanistic drivers of decomposition, soil organic matter formation, and carbon stabilization help us make management decisions, take mitigation steps, and protect resources. 6 Overview Native Ōhiʻa - Koa forest Conversion to Reforestation in grass-dominated pasture (80 yr) Eucalyptus plantation (10 yr) Conventional sugar cane harvest. 20° C 18° C 16° C 14° C 7 Sustainable ratoon harvest. Decomposition • Decomposition is the biological, physical and chemical breakdown of organic material – Provides energy for microbial growth -
Plant Species Effects on Nutrient Cycling: Revisiting Litter Feedbacks
Review Plant species effects on nutrient cycling: revisiting litter feedbacks Sarah E. Hobbie Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA In a review published over two decades ago I asserted reinforce those gradients and patterns of NPP, focusing that, along soil fertility gradients, plant traits change in on feedbacks operating through plant litter decomposition. ways that reinforce patterns of soil fertility and net Specifically, I evaluate two key assumptions underlying primary productivity (NPP). I reevaluate this assertion the plant litter feedback idea: (i) plant litter traits vary in light of recent research, focusing on feedbacks to NPP predictably along fertility gradients, and (ii) such variation operating through litter decomposition. I conclude that reinforces soil fertility gradients through effects on decom- mechanisms emerging since my previous review might position and litter N release. Given the number of synthetic weaken these positive feedbacks, such as negative cross-site analyses of plant traits and their consequences effects of nitrogen on decomposition, while others for nutrient cycling over the past two decades, the time is might strengthen them, such as slower decomposition ripe for revisiting my original assertions. Indeed, I show of roots compared to leaf litter. I further conclude that that my original assertion is more nuanced and complex predictive understanding of plant species effects on than originally claimed. In particular, I discuss the need to nutrient cycling will require developing new frameworks consider leaf litter decomposition more carefully and move that are broadened beyond litter decomposition to con- beyond consideration of leaf litter feedbacks to a more sider the full litter–soil organic matter (SOM) continuum. -
Assessing Predicted Isolation Effects from the General Dynamic Model of Island Biogeography with an Eco‐Evolutionary Model for Plants
Received: 4 January 2017 | Revised: 27 March 2019 | Accepted: 6 April 2019 DOI: 10.1111/jbi.13603 RESEARCH PAPER Assessing predicted isolation effects from the general dynamic model of island biogeography with an eco‐evolutionary model for plants Juliano Sarmento Cabral1,2,3 | Robert J. Whittaker4,5 | Kerstin Wiegand6 | Holger Kreft2 1Ecosystem Modeling, Center of Computation and Theoretical Abstract Biology, University of Würzburg, Würzburg, Aims: The general dynamic model (GDM) of oceanic island biogeography predicts Germany how biogeographical rates, species richness and endemism vary with island age, area 2Biodiversity, Macroecology & Biogeography, University of Göttingen, and isolation. Here, we used a simulation model to assess whether the isolation‐re‐ Göttingen, Germany lated predictions of the GDM may arise from low‐level process at the level of indi‐ 3Synthesis Centre of the German Centre for Integrative Biodiversity Research (iDiv), viduals and populations. Leipzig, Germany Location: Hypothetical volcanic oceanic islands. 4 Conservation Biogeography and Methods: Our model considers (a) an idealized island ontogeny, (b) metabolic con‐ Macroecology Group, School of Geography and the Environment, University of Oxford, straints and (c) stochastic, spatially explicit and niche‐based processes at the level Oxford, UK of individuals and populations (plant demography, dispersal, competition, mutation 5Center for Macroecology, Evolution and speciation). Isolation scenarios involved varying the distance to mainland and the and Climate, Natural History Museum of Denmark, University of Copenhagen, dispersal ability of the species pool. Copenhagen Ø, Denmark Results: For all isolation scenarios, we obtained humped temporal trends for species 6Ecosystem Modelling, Büsgen‐Institute, University of Göttingen, Göttingen, richness, endemic richness, proportion of endemic species derived from within‐is‐ Germany land radiation, number of radiating lineages, number of species per radiating lineage Correspondence and biogeographical rates. -
Organic Matter Decomposition in Simulated Aquaculture Ponds Group Fish Culture and Fisheries Daily Supervisor(S) Dr
O rganic matter decomposition in simulated aquaculture ponds Beatriz Torres Beristain Promotor: Prof. Dr. J.A .J. V erreth H oogleraar in de V isteelt en V isserij W ageningen U niversiteit C o-promotor: Dr. M .C .J. V erdegem U niversitair docent bij the Leerstoelgroep V isteelt en V isserij W ageningen U niversiteit Samenstelling promotiecommissie: Prof. Dr. Y . A vnimelech Technion, Israel Institute of Technology Prof. Dr. Ir. H .J. Gijzen U N ESC O -IH E, Delf, N etherlands Prof. Dr. Ir. M . W .A . V erstegen W ageningen U niversiteit Prof. Dr. Ir. A .A . K oelmans W ageningen U niversiteit Dit onderzoek is uitgevoerd binnen de onderzoekschool W IA S O rganic matter decomposition in simulated aquaculture ponds Beatriz Torres Beristain Proefschrift Ter verkrijging van de graad van doctor O p gezag van de rector magnificus van W ageningen U niversiteit, Prof. Dr. Ir. L. Speelman, In het openbaar te verdedigen O p dinsdag 15 A pril 2005 des namiddags te half tw ee in de A ula Torres Beristain, B. O rganic matter decomposition in simulated aquaculture ponds PhD thesis, Fish C ulture and Fisheries Group, W ageningen Institute of A nimal Sciences. W ageningen U niversity, P.O . Box 338, 6700 A H W ageningen, The N etherlands. - W ith R ef. œW ith summary in Spanish, Dutch and English ISBN : 90-8504-170-8 A Domingo, Y olanda y A lejandro Table of contents C hapter 1 General introduction. 1 C hapter 2 R eview microbial ecology and role in aquaculture ponds. -
Ecosystems and Biodiversity
Unit 2: Ecosystem An organism is always in the state of perfect balance with the environment. The environment literally means the surroundings. The environment refers to the things and conditions around the organisms which directly or indirectly influence the life and development of the organisms and their populations. “Ecosystem is a complex in which habitat, plants and animals are considered as one interesting unit, the materials and energy of one passing in and out of the others” – Woodbury. Organisms and environment are two non-separable factors. Organisms interact with each other and also with the physical conditions that are present in their habitats. ―The organisms and the physical features of the habitat form an ecological complex or more briefly an ecosystem.‖ (Clarke, 1954). The concept of ecosystem was first put forth by A.G. Tansley (1935). Ecosystem is the major ecological unit. It has both structure and functions. The structure is related to species diversity. The more complex is the structure the greater is the diversity of the species in the ecosystem. The functions of ecosystem are related to the flow of energy and cycling of materials through structural components of the ecosystem. According to Woodbury (1954), ecosystem is a complex in which habitat, plants and animals are considered as one interesting unit, the materials and energy of one passing in and out of the others. According to E.P. Odum, the ecosystem is the basic functional unit of organisms and their environment interacting with each other and with their own components. An ecosystem may be conceived and studied in the habitats of various sizes, e.g., one square metre of grassland, a pool, a large lake, a large tract of forest, balanced aquarium, a certain area of river and ocean. -
Fermentation and Anaerobic Decomposition in a Hot Spring
Fermentation and anaerobic decomposition in a hot spring microbial mat by Karen Leigh Anderson A thesis submitted in partial fulfillment of requirements for the degree of Master of Science in Microbiology Montana State University © Copyright by Karen Leigh Anderson (1984) Abstract: Fermentation was investigated in a low sulfate hot spring microbial mat (Octopus Spring) according to current models on anaerobic decomposition. The mat was studied to determine what fermentation products accumulated, where in the mat they accumulated, and what factors affected their accumulation. Mat samples were incubated under dark anaerobic conditions to measure accumulation of fermentation products. Acetate and propionate (ca. 3:1) were the major products to accumulate in a 55°,C mat. Other products accumulated to a much lesser extent. Incubation of mat samples of varying thickness showed that fermentation occurred in the top 4mm of the mat. This has interesting implications for fermentative organisms in the mat due to the diurnal changes in mat oxygen concentrations. Fermentation measured in mat samples collected at various temperatures (50°,-70°C) showed acetate and propionate to be the major accumulation products. According to the interspecies hydrogen transfer model, the hydrogen concentration in a system affects the types of fermentation products produced. At a 65° C site, with natural high hydrogen levels, and at a 55°C site, with active methanogenesis, fermentation product accumulation was compared. There was a greater ratio of reduced fermentation products to acetate, with the exception of propionate, at 65°C. Ethanol accumulated at the 65°C site, as did lactate, though to a lesser extent. -
Ecology Intro
www.logannature.org 2969 East Highway 89 P.O. Box 4204 Logan, UT 84323 Phone: 435.755.3239 Introduction to Ecology Objectives Students will understand the difference between an individual, a population, a community, and an ecosystem. Method Students will use shapes to depict individuals. They will start the activity as individuals and progress towards becoming an ecosystem. Materials At least 8-10 different shapes (multiple pieces of each shape should be cut out of paper or other material), paper and pencils for each student, a ball of yarn. Background Ecology is the study of ecosystems. But first, we have to understand what an ecosystem is. An ecosystem is a community of living organisms interacting with their abiotic environment. To best explain this to students, it is important that they understand the components you must have to make an ecosystem. The first is the individual. An individual is a single member of a species; a population is many members of the same species living in a specific habitat; a community is a group of interdependent organisms of different species growing or living together in a specified habitat. This brings us to the ecosystem where the community of living organisms interacts with the non-living components of the environment. Procedure 1. Each student will receive a single shape. This shape represents an individual of a species. 2. Each student must find at least 9 more individuals of the same species (They can find these shapes in buckets around the room). This creates a population. 3. Each student should find two more students with different species and combine their shapes to create a community of organisms. -
Decomposition Responses to Climate Depend on Microbial Community Composition
Decomposition responses to climate depend on microbial community composition Sydney I. Glassmana,b,1, Claudia Weihea, Junhui Lic, Michaeline B. N. Albrighta,d, Caitlin I. Loobya,e, Adam C. Martinya,c, Kathleen K. Tresedera, Steven D. Allisona, and Jennifer B. H. Martinya aDepartment of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697; bDepartment of Microbiology and Plant Pathology, University of California, Riverside, CA 92521; cDepartment of Earth System Science, University of California, Irvine, CA 92697; dBioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545; and eDepartment of Biological Sciences, University of Denver, CO 80210 Edited by Mary K. Firestone, University of California, Berkeley, CA, and approved October 10, 2018 (received for review June 29, 2018) Bacteria and fungi drive decomposition, a fundamental process in soil moisture and extracellular enzyme production across a natural the carbon cycle, yet the importance of microbial community climate gradient (16). composition for decomposition remains elusive. Here, we used an Given that the factors regulating decomposition are often 18-month reciprocal transplant experiment along a climate gradient context dependent and can vary in their influence across a range in Southern California to disentangle the effects of the microbial of spatial and temporal scales (17, 18), we hypothesized that community versus the environment on decomposition. Specifically, decomposition responses to changing climatic conditions would we tested whether the decomposition response to climate change depend on microbial community composition. To test this hy- depends on the microbial community. We inoculated microbial pothesis, we conducted the largest microbial community trans- decomposers from each site onto a common, irradiated leaf litter plant experiment to date. -
Organic Matter Decomposition and Ecosystem Metabolism As Tools to Assess the Functional Integrity of Streams and Rivers–A Systematic Review
water Review Organic Matter Decomposition and Ecosystem Metabolism as Tools to Assess the Functional Integrity of Streams and Rivers–A Systematic Review Verónica Ferreira 1,* , Arturo Elosegi 2 , Scott D. Tiegs 3 , Daniel von Schiller 4 and Roger Young 5 1 Marine and Environmental Sciences Centre–MARE, Department of Life Sciences, University of Coimbra, 3000–456 Coimbra, Portugal 2 Faculty of Science and Technology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain; [email protected] 3 Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA; [email protected] 4 Department of Evolutionary Biology, Ecology and Environmental Sciences, Institut de Recerca de l’Aigua (IdRA), University of Barcelona, Diagonal 643, 08028 Barcelona, Spain; [email protected] 5 Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand; [email protected] * Correspondence: [email protected] Received: 4 November 2020; Accepted: 8 December 2020; Published: 15 December 2020 Abstract: Streams and rivers provide important services to humans, and therefore, their ecological integrity should be a societal goal. Although ecological integrity encompasses structural and functional integrity, stream bioassessment rarely considers ecosystem functioning. Organic matter decomposition and ecosystem metabolism are prime candidate indicators of stream functional integrity, and here we review each of these functions, the methods used for their determination, and their strengths and limitations for bioassessment. We also provide a systematic review of studies that have addressed organic matter decomposition (88 studies) and ecosystem metabolism (50 studies) for stream bioassessment since the year 2000. Most studies were conducted in temperate regions. Bioassessment based on organic matter decomposition mostly used leaf litter in coarse-mesh bags, but fine-mesh bags were also common, and cotton strips and wood were frequent in New Zealand. -
Inherent Factors Affecting Soil Organic Matter
Soil organic matter (SOM) is the organic component of soil, consisting of three primary parts including small (fresh) plant residues and small living soil organisms, decomposing (active) organic matter, and stable organic matter (humus). Soil organic matter serves as a reservoir of nutrients for crops, provides soil aggregation, increases nutrient exchange, retains moisture, reduces compaction, reduces surface crusting, and increases water infiltration into soil. Components vary in proportion and have many intermediate stages (Figure 1). Plant residues on the soil surface such as leaves, manure, or crop residue are not considered SOM and are usually removed from soil samples by sieving through a 2 mm wire mesh before analysis. Soil organic matter content can be estimated in the field and tested in a lab to provide estimates for Nitrogen, Phosphorus and Sulfur mineralized available for crop production and adjust fertilizer recommendations. Soil organic matter impacts the rate of surface applied herbicides along with soil pH necessary to effectively control weeds. Soil organic matter impacts the potential for herbicide carryover for future crops, and amount of lime necessary to raise pH. Figure 1. Major soil organic matter components (Source: The Soil Food Web, USDA-NRCS). Inherent Factors Affecting Soil Organic Matter Inherent factors affecting soil organic matter such warm and humid and slower in cool, dry climates. as climate and soil texture cannot be changed. Organic matter also decomposes faster when soil is Climatic conditions, such as rainfall, temperature, well aerated (higher oxygen levels) and much moisture, and soil aeration (oxygen levels) affect slower on saturated wet soils (refer to soil the rate of organic matter decomposition. -
Soil Food Web: Implications to Soil Health
Soil Food Web: Implications to Soil Health Dr. Sajeemas “Mint” Pasakdee, Soil Scientist/Agronomist Advisor, Student Operated Organic Farm CIT-Jordan College of Agri. Sci. & Tech., Fresno State 1 Outline • Soil organisms and their interactions • What do soil organisms do? • Where do soil organisms live? • Food web structure • When are soil organisms active? • How is the food web measured? • Living soils—Bacteria; Fungi; Earthworms • Soil Environment 2 Organisms & Their Interaction 3 4 What do soil organisms do? Soil organisms support plant health as • decompose organic matter, • cycle nutrients, • enhance soil structure, • control the populations of soil organisms including crop pests. 5 Organic Matter • Food sources for soil organisms • Agricultural top soil ~1-6% (In CA, ~1-3% SOM) 6 Where do soil organisms live? • Around roots(rhizosphere) • Plant litter (C sources) • Humus (stabilized organic matter) • Surface of soil aggregates 7 Typical Food Web Structure • bacterial-dominated food webs o Grassland & Agri Soils o Ratio of fungi to bacteria, ~1:1 for productive agri. soils • fungal-dominated food webs o Ratio of fungal to bacterial, ~5:1 to 10:1 in a deciduous forest and 100:1 to 1000:1 in a coniferous forest 8 9 When are soil organisms active? 10 How is the food web measured? • Counting. Organism groups (bacteria, protozoa, arthropods, etc.); or subgroups (bacterial-feeding, fungal-feeding, and predatory nematodes), are counted and through calculations, can be converted to biomass. • Measuring activity levels. The amount of by-products, i.e., respiration (CO2); nitrification and decomposition rates • Measuring cellular constituents. Biomass carbon, nitrogen, or phosphorus; Enzymes; Phospholipids and other lipids; DNA and RNA 11 12 Soil Bacteria • One-celled organisms – generally 4/100,000 of an inch wide (1 µm) • A teaspoon of productive soil generally contains between 100 million and 1 billion bacteria (~two cows per acre).