Dom Ers Notes

ENVIRONMENTAL RESOURCE MANAGEMENT

Systems Ecology 1 – An introduction to systems analysis What is Systems Analysis? It is a method that attempts to understand complex interactions between processes and components. It identifies the fundamental units of a system, how they interact, and how they function in response to changing conditions. An example of conventional versus systems analysis: We don’t look at the composing elements of photosynthesis, but rather the rate of photosynthesis and how it is controlled. We also look at how it interacts with transpiration, etc. We look at the role and affects of photosynthesis on a system rather than understanding its operation. Important words - see slides: Energy balance, whole, external, controlled, rate.

Systems analysis thus looks at the whole thing, rather than the function of a chloroplast in a leaf. It emphasizes factors controlling rates of photosynthesis (water stress; nutrient availability; shading within the canopy; climate; genetic potential of species; movement of energy/carbon, nutrients, and water). These principles equally apply to other processes. e.g.:

Organic matter decomposition, nutrient cycling (N, P,K, Ca, Mg), succession, climate control, water control, carbon control.

Ecosystems analysis

focuses on rates of organic matter decomposition and how this process interacts with plant uptake and nutrient cycling rather than focusing on how this is achieved biochemically.

The conventional approach is reductionism, whilst the system analysis is looking at the whole system. The idea here is that the sum of the parts does not make up the whole. Systems thinking is holism. Reductionism vs. Holism

Ecosystem analysis must be built on a substantial database of solid information. Therefore we must understand individual parts (reductionism) in order to understand the system (holism).

There exists three levels of Ecosystem Analysis. 1. Single component and its response to the environment 2. Interactions between the components 3. Integrated response(s) of the whole system to an external factor

Concepts pertaining to Single Components i.

ii.

iii.

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Systems state a. Describes the current condition of the systems. b. Analogy – a light switch is either on or off Ecosystem state a. The quantity and capacity of a component to carry out a function. b. Analogy: how much organic matter, nutrients, water; actively photosynthesizing and growing or senescent and dormant. Turnover Rate a. The fraction of material that enters or leaves the system in a specific time interval. Residence time a. The inverse of turnover rate (1/T)

The relationships between inputs to, outputs from, and storage within components. e.g.: A reservoir holds 10,000,000 liters of water from which 1 million litres are pumped out every month. What is the turnover rate? T=

1,000,000L leaving 10,000,000L capacity

Take home calculation example A prairie soil contains 200 t of organic matter, and plant death and senescence contributes 4 tons of new material each year.

1. What is the turnover rate of the prairie soil? 0.02 t/year 2. What is the residence timem of the organic matter? 50 years Concepts pertaining to Interaction i.

ii.

Resource use efficiency a. The quantity of water, energy, nutrients (i.e.: Resources) required for an ecosystem process (e.g.: Decomposition). b. E.g.: A deciduous forest takes up, cycles, and uses more N per unit area than a evergreen forest: The deciduous forest has a lower N-use efficiency because it needs more N. Feedback a. Negative feedback, e.g: as the temp falls the office switches on to release heat. When the thermostat rises past a set level, the thermostat switches off. Body heat control is also an example – cyclical.

b. Positive feedback, e.g.: The office is too hot. This leads to the destabilization and may ultimately lead to the destruction of the system; never turns off. The ice caps melting is also an example, the albedo decreasing and more head reflecting into the atmosphere. Concepts pertaining to the Whole Systems Resistance is little response to disturbance. It needs severe disturbance to change system state. Resilience is the opposite of resistance. The system is altered easily to find equilibrium. Once the disturbance stops, it returns rapidly to its old state. Ecosystems Research

The HBEF (Hubbard Brook Experimental Forest) was one of the first ecosystem research projects. Established in 1955 by the US Forest Service, it was a major centre for hydrologic research. It’s located in the White Mountain National Forest, Central New Hampshire. The area was chosen because it presented unbroken areas of northern hardwood, and spruce and fir at higher elevations. The area had not experienced logging in the past 80 years. The ecosystem (more than hydrology) study did not start until 1960. It was awarded LTER (long term ecological research site) until 1987. LTER mission: To understand northern hardwood ecosystem response to large-scale disturbance. Specific LTER Goals (for most projects)

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Evaluation of vegetation structure, composition, and productivity.

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Evaluation of dynamics of dead organic matter.

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Evaluation of silviculture and land-use disturbance. Evaluation of air pollution. Climatic disturbance and change.

Evaluation of atmospheric-terrestrial-aquatic linkages.

Undisturbed forests exhibit regularity and predictability in their input-output balances. The removal of trees raises soil and stream temperatures by 6 degrees Celsius, stream flow increases by 40%, and an increase in NO3- in soil solution and leached out of system (to streams). Up to 80% of the slash was decomposed in 14 years after the harvest. However, there is no appreciable increase in erosion and sedimentation, due to slash being left on soil.

Ecological Footprint Carrying Capacity The maximum population of a given species that can be supported indefinitely in a defined habitat without permanently impairing the productivity of that habitat. For our continued existence on Earth we need adequate land and resources for extraction. However, at present the human population and general consumption is increasing, but our resources (like productive land and resources) are fixed or in decline. Therefore our traditional definition of carrying capacity needs to be revised: humans eliminate competing species; import scarce resources; use technology to maximize resource extraction. Thus, the new definition is “An environment’s carrying capacity is its maximum supportable load.” (Catton, 1986). What is meant by load?

The maximum “load” that can be safely imposed on the environment by people. Load being a function of population and per capita consumption.

New technology has increased our need to extract resources. They require more but do not increase the carrying capacity. Because of this, the average energy consumption in the US went from 11,000kcal in 1970 to over 200,000 in 1980. Ecological Footprints The corresponding area of productive land and aquatic ecosystems required to produce the resources used, and to assimilate the wastes produced by a defined population of living, where ever on Earth they may be located. Or in professor Oeelbermann’s words: Ecological footprints are a measure of our use of resources and deposal of wastes. To calculate the ecological footprint is: EF = (C/P) x N C = average annual consumption (kg/capita) P = average annual productivity (kg/ha) N = Population size

The traditional concept of carrying capacity addresses what particular region a population can be supported. But now, it is “how large of an area of productive land is needed to sustain a defined population wherever on Earth that land is located?” in ecological confines. Ecological vs Geographical Locations High population densities, increase in per capita energy and material, consumption through technological innovation, universal dependence on trade are all ecological locations of human

settlements that no longer coincide with their geographic locations. Modern cities and Industrial regions We depend on a vast and increasing global hinterland of ecologically productive landscapes for survival growth. “Modern settlements have become the human equivalent of cattle feedlots” – W. Rees, 1996 Netherlands: A Global Example of an Ecological Footprint 33,920km2, but the people require land area 14-15 times greater than their country can support (energy, food, forests). In reality, they need 140,000km2 to support their life style. Thus, they get most of their products from developing nations.

Vancouver: A regional example of an Ecological Foot print 114km2, 472,000, according to the average Canadian life style, each Vancouverite needs 4.2 ha – total of 1.98 ha of land.

MISSED CLASS – SEPTEMBER 29 – – – – –

Water Characteristics Water Cycle Global Water Resources Who is using Water Water Scarcity

A word on reading scientific papers Focus On: The overall story of the paper and what they are trying to examine. And of course, the reasons for doing this investigation; what they have found. Forget:

Methods or to understand and memorizing complicated equations. Read these sections only if interested.

Water as a Major Resource What determines Water Quality?Rivers and lakes that appear healthy are not pure. They contain naturally occurring substances (impurities) – even in distilled water. These substances include bicarbonates, sulphates, sodium, chlorides, calcium, magnesium, potassium. They get there through soil and sediments in the catchment, surrounding vegetation and animals

(erosion). Precipitation and runoff are also factors that can cause the input of substances – biological, physical, and chemical processes in water as well; and finally, human activities (pollution). How does water clean itself?

Energy drives photosynthesis of aquatic plants that produce oxygen. The oxygen breaks down plant and animal wastes (a source of decomposition). The process of decomposition releases carbon dioxide, food for aquatic biota. Aquatic decomposition is a natural process. But if other substances are added, we get pollution in our water. We can get persistent and non-persistent substances. These toxins come from agricultural run-offs (pesticides, animal wastes, fertilizer), erosion from irrigation – non point source pollution; industrial wastes – point source pollution; and disposal by people.

Pollution affects: The aquatic ecosystems through harming plant and animal; reproduction, biodiversity, causes animal and plant death, and leads to cancerous growths on animals, e.g.: fish. It also affects human health by compromising our drinking water. For example, drinking water that contains a lot of hormones will not be very good for us. It also affects our recreational activities, like swimming. The irrigation water used in agriculture will also get polluted. And finally, it affects the aesthetic quality of lakes and rivers. How do we measure Water Quality? Water sample collections analysed in laboratories is a good way. Using specialized instruments and specific procedures is required. With these tools are can measure small quantities of toxins. Parts per trillion is measured, like a teaspoon of salt dissolved in an Olympic-sized swimming pool. What are persistent substances? They are very toxic and break down very slowly or not at all. Thus, they remain, or “persist” in our environment for a long time. They are also

bioaccumlator – they pass through the food chain. They have very complex molecular structures and as a result are very difficult to break down. Pesticides, landfill leachates, petroleum and petroleum products, PCBs, dioxins, radioactive (strontium, radium, cesium, uranium), and heavy metals (lead, cadmium, mercury) all need decades/centuries to repair damage from these substances. What are non-persistent substances? They are more readily degradable. They enter the aquatic ecosystems in large quantities: domestic sewage, agriculture fertilizers, and some industrial wastes. They lead to low oxygen levels, eutrophication, minimal input reverses problem. Water Quality and Ecosystems We know that pollution affects water quality, and affects biota and humans. Thinking at the systems level helps to regain aquatic ecosystem balance, and restore them as well.

FINAL EXAM FROM THIS POINT ON Agriculture and Soil Conservation – Part I The origins of agriculture began with a shift to cultivation form hunter gatherer (swidden). In about 10,000 BC, we saw the roots of agriculture begin. Because it was short term, it was not permanent or settled – we worried about getting food today and not next week. There was short cultivation followed by a long fallow – and area about 1 hectare is deforested and used for 4 to 5 years until the yield decreases, than is abandoned for 20 years. Usually this kind of agriculture took place on levelled ground with rich soil. The long fallow allowed the soil to recover, and there was minimal soil degradation. This still occurs in some areas today. But, with today’s population increases, there is a great need for agricultural land.

From 8,000 to 500 AD this nomadic nature began to decrease. However, it was still subsistence oriented. Slowly as time went on, domestication took place. Evidence of first settling is found in present day Iraq – we found a stone hand sickle that dates from 11,000 years ago. Settled agriculture leads to increased human population. The increase leads to a larger demand for food and thus more pressure on soil resources.

These days there is only a certain amount of land for agriculture. This amount of land and its fertile soils are declining. This has caused soil degradation (movement

of soil by water and wind), and a loss of soil nutrients (erosion and over exploitation). This leads to marginal lands. In Mesopotamia that had an increase of population. Because of that they began to run out of land, and had no choice but to start deforesting forests on steeper slopes. That with overgrazing and the cultivation of crops leads to soil degradation and the sedimentation of riverbeds. Also, because of the deforestation they changed their microclimate. They needed to start to irrigate their crops with lead to salinization problems and the eventual desertification and abandonment of land.

Soil Degradation in the Middle East After the collapse, they began to cultivate on slopes. They needed to do something about the soil loss and degradation, they developed terraces. Some of the ancient terraces are still functioning today. Soil Degradation in Africa

Africa has different kinds of soil. Overgrazing is one of the major problems in the grasslands, as is intense cultivation with no erosion control. They have lost the first metre of their topsoil. They are all the way down to the bedrock and have abandoned the land. The presence of laterites is found (self preservation method) – aluminum oxides react with rainfall forms hard lumps; these lumps protect the small amount of top soil left.

Soil Degradation in Europe

They often had severe erosion problems from deforestation. Particularly mountain areas like the alps used terraces. They developed cross-slope cultivation.

Soil Degradation in China

They had and still have a population problem. Cultivation on steep slopes was necessary. A long time ago they were already concerned with soil conservation, and terraces have been found from 956 BC.

Soil Degradation in Australia

They also have major problems. They have about 150 years of extremely exploitive agriculture. At one point in time they began to become concerned about soil resources. So, in the 1930s they developed and implemented soil conservation policies. A lot of barren or wastelands that exist today did n. ot look like that before – we created unproductive land.

Soil Degradation in the Americas In Latin America the Incas developed a terrace system. Macchu Picchu is the World’s most effective erosion structure and is still functional today. 1,000 – 2,000 years old today. They are very well known for their agricultural practices – like the diversification of crops and we still use them today (potatoes, corn, etc). Soil Degradation in Central Americas Mayans cultivated on steep slopes and used complex terracing structures. They also had water diversification structures to mitigate heavy rainfall. Soil Degradation in the USA

There was a philosophy of Unconcern – because of the abundance of land; this lead to -major- erosion problems. The Dustbowl in the 1930s – 12% of the cropland was ruined completely, 12% severely damaged, 20% had 50% of topsoil loss, 24% had measurable erosion loss, and 28% was unaffected. They implemented conservation measures – today they still have very good measures at work.

Soil Degradation in Canada

We had a similar philosophy of unconcern. It lead to soil degradation in all parts of Canada, and severe problems in southern Ontario. We thus established tree nurseries (late 1800s, early 1900s – North of Lake Erie). This resulted in the school of forestry at U Toronto (began in Guelph). He grew red pines because he figured they would grow well in the very nutrient poor soil. This saved the areas from complete degradation. In 1987 the Soil Conservation Council of Canada was formed.

Soil Organic Matter (SOM) It is the backbone of soil. Some of it is high, others is low. Humus is rich, sandy is low. It maintains soil moisture and is formed by the decomposition of leaves – as well as animal residue. Every year during harvests we return crop residue to the soil to compensate for the lack of leaves. It maintains not only the moisture, but fertility and structure (organization of soil minerals and organic matter) – decreases erosion. It is the glue of soil. It is derived from plant residues and is decomposed over time (climate, pH, and nutrient availability all play a role). There is fast decomposition of sugars, amino acids, and proteins. As decomposition slows, more SOM accumulates. To sequester carbon, more must be stored than is released by decomposition. Soil humus is

composed of two parts: lignin (a stable form of carbon hard to break down) and physical protection that binds to clay. Thus soil humus can be 1,000 of years old. Soil Organic Carbon (SOC) SOM = 58% soil organic carbon. The shortcut for soil is taking the % of SOM and divided by 1.742 to give us the % of carbon in the soil. By the same way, we multiply SOC by 1.742 to find the percentage of SOM. However, if were told 10,000kg/ha of biomass in a forest, we would multiply it by 50% to estimate the amount of carbon. This is important because the long-term storage of C in the soil is C sequestration. A Word on Soil Coverage Once bare soil is exposed by water and wind, we lose SOM (and SOC) and the soil loses its fertility. Covered soil reduces erosion and loss of soc + som.

MISSED CLASS: OCTOBER 16th ○

How we used to practice agriculture

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The green revolution (what we tried to achieve and what we achieved) High Tech agriculture Soil Formation Soil loss and loss of tolerance levels

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Agriculture and Soil Conservation – Part III How can Soil loss be predicted? We developed empirical models that incorporate actual data from field experiments. It is then calibrated and predicts outcomes. Good models are flexible and can accommodate change. Universal Soil Loss Equation (USLE) is an empirical and standard model. It was developed in 1954 at Perdue University. It is still used widely because of its flexibility. It is designed to predict erosion by water; a separate model exists for wind erosion. It predicts the average soil loss and compares these losses to tolerant levels. A = R * K * LS * C * P Soil Loss Equation A = Estimated average soil loss (t/a/y or t/ha/y) R = Rainfall and runoff factor (MJ mm/ha/h) K = Soil erodibility factor, the soil texture (t h /mj/mm) LS = Slope length and steepness factor (unitless) C = cover management factor (unitless) P = Support practice factor, the cultivation type (unitless)

Why conservation in Agriculture? The green revolution tried to lower the world poverty problem at the time, but the problem with it was its intense way of doing agriculture and thus promoted the intensification of agriculture leading to poor practices that degraded the soil. It was then realized that a sustainable approach to agriculture was needed. We then began integrated practices, like crop rotation, secondary (conservation) or no till, and soil cover (30% or more). These practices were promoted by the UN-FAO. They called it the next green revolution, and it has been adapted for grain crops, vegetables, and sugar cane. Conservation agriculture has thus been adapted to 58 million ha of land of land globally. US = 20 mill. Ha Brazil = 13.5 mill. Ha Argentina = 9.5 mill. Ha Canada = 4 mill. Ha Paraguay = 0.8 mill. Ha Why do we Till the Soil in the first place? Conventional tillage is done to prepare the soil for the seeding. It is also used as a method of weed control and helps the incorporation of plant residues. It is classified by the quantity of soil disturbance. Primary tillage is a major soil disturbance. It completely turns over the soil, inverts the top layer, and makes it at great risk for erosion. This works great in Europe because of their gentile rain, but in North America our heavier rain makes this practice awful. Secondary tillage disturbs the soil a lot less. They simply loosen up the soil, rather than turn it over. It leaves at least 30% of the residue on top of the soil to prevent erosion. This kind of tillage is also used for weed control and seedbed preparation. It`s much more gentle than primary tillage. The no till is the ultimate of tillage. The plants are seeded directly into the soil. It cuts into the soil and drops a seed without disturbing the soil. It requires specific equipment because the soil is much harder. However, it costs less in fuel and machinery. Conventional tillage requires you to pass over at least three times (pass over, smooth soil, plant). It also benefits wildlife, it provides food and wildlife. The only disadvantage to not ill is that it requires more herbicide because there is no way to remove herbs. Thus, it`s more pesticides verses more greenhouse gasses. Ultimately, studies say no till has a greater yield.

Good for sandy soil but not clay soil. It doesn`t matter what you do, there will always be harm done to the environment. It`s about balancing. Crop Rotations: What is it and why? Crops are changed in a yearly sequence. Rotation with legumes increases nitrogen input. It also increases organic matter input, because the biomass yield is higher. An increase in crop diversity influences soil biodiversity and it decreases pests and weeds (good for organic farmers). Organic Farming Focuses on balancing the soil: no pesticides or herbicides are input, no inorganic fertilizers. There is an input of organic fertilizers, crop rotation and conservation tillage. The balanced soil rids itself of weeds, pests, erosions, and maintains crop yield. Higher yield in corn and soybeans, 30% less energy, less water, no pesticides – study by David Pimental 22 years in the making.