Exam 1 Geo4372

Renewable resources

Can naturally regenerate so long as their capacity for so doing is not irreversibly damaged, perhaps by natural catastrophe or human activity.

Once plastic enters the marine environment, many marine species - including birds, turtles, seals, whales and dolphins

face the risk of entanglement, ingestion and suffocation

How do human societies benefit from tropical deforestation?

food, timber and other raw materials, as well as jobs and income to numerous countries, many of them relatively poor

Technological developments are responsible

for much environmental degradation by increasing demand for natural resources. However, technology is not always environmentally damaging

International markets on the global scale in deforestation

for timber and the produce from agricultural plantations and ranches, must also be considered

Non-consumptive resource use for

for tourism is well developed in Viet Nam's Halong Bay, a spectacular seascape of some 1600 islands and islets in the Gulf of Tonkin and a UNESCO World Heritage Site since 1994

Examples of non-renewable resources

fossil fuels (coal, oil, natural gas) and nuclear energy); other minerals, some ground water

The forest landscape is in a state of dynamic equilibrium

gaps are continually formed in the forest canopy as older trees die, are struck by lightning or are blown over, while regrowth occurs continually in such gaps so that small areas are in a state of perpetual flux

Three types of drought are commonly recognized:

meteorological, agricultural and hydrological, the latter two of which are typically caused by meteorological drought

1. What are the three pillars of sustainable development?

The three pillars of sustainable development are economic development, social development, and environmental protection. (Middleton, 2018, p. 53). These three pillars acknowledge the environment's value in assessments within the economy, promoting green economy.

The socio-economic factors

that push people to the forest frontier include poverty, low agricultural productivity and an unequal distribution of land

A study in the Magdalena River basin in Colombia (Restrepo and Escobar, 2016), found

that the river's tributaries have experienced increasing trends in sediment load during the period 1980-2010 and that the increases are in close agreement with trends in land use change and deforestation

The open ocean, by contrast,

is relatively little affected

Salinization also leads to a

range of off-site hazards

Areas Affected by Desertification: 'Spreading Deserts

- Lamprey (1975) set out to measure the rate of desert advance in northern Sudan -The vegetational edge of the desert was mapped by reconnaissance in 1975 and then compared to the boundary drawn from another survey carried out in 1958 -The two boundaries indicated that the desert's southern margin had advanced by 90-100 km between the two dates, at an average rate of advance of 5.5 km per year over 17 years -However, two 'snapshot' surveys can only be of very limited use in determining significant changes in vegetation, particularly since the 1970s was a period of drought in the Sudan while the 1950s was a decade characterized by above-average rainfall

The US Great Plains

- Over a period of 50 years, drought-resistant grasslands were turned into fields of drought-sensitive wheat by a culture set on dominating and exploiting natural resources using ploughs and other machinery developed in western Europe (Worster, 1979) -When drought hit in the 1930s, as it periodically does, severe dust storms carried soil dust northwards as far as Canada and eastwards to New York and out over the Atlantic Ocean -Parton et al. (2007) identify two schools of thought: one group sees Great Plains farming as an ongoing ecological mistake, while another group recognises the benefits of technical and social innovations, ranging from zero-tillage management to crop insurance, which they believe have stabilized the agroecosystem on the Plains -However, soil erosion by wind has not ceased to be a problem and during drought in the 1970s was on a comparable scale to that in the 1930s (Lockeretz, 1978) -The irrigated area of crops on the Great Plains has expanded by about 6 million ha since the 1940s (Parton et al., 2007), causing groundwater depletion, another form of desertification -Groundwater quality has also fallen - salinity levels in the Ogallala have risen as highly mineralized groundwater from lower geological formations has welled up into the aquifer (Chaudhuri et al., 2014)

rates of deforestation

- We lack knowledge of the rates of deforestation in part because of lack of standard definitions of what a forest is and what deforestation means -Measurements of deforestation rates by the FAO define deforestation as the clearing of forestlands for all forms of agriculture and for other land uses such as settlements, other infrastructure and mining -In tropical forests, this entails clearing to reduce tree crown cover to <10%, thus does not cover some damaging activities such as logging (this would therefore be referred to as degradation, not deforestation) -Different countries and individuals often define the terms in different ways and the quality and availability of data vary between countries

Intergenerational Inequalities

-As wealthy, powerful groups exploit resources on global and national scales, the inheritance of future generations is compromised -Overusing a renewable resource leaves that resource degraded for future users; using a non-renewable resource means that less of that resource will be available -Various economic, political and social aspects of intergenerational inequalities are shown in Figure 2.9

Time and space scales

-Key factors influencing events in the human environment vary at different spatial and temporal scales -Decisions about environmental governance are taken at all levels, from the individual up to the global level -None of these decision-makers operates in a closed self-supporting system; all are a part of larger interacting systems -Environmental views and decisions are also taken with a wide range of time perspectives -Successful management of environmental issues relies on the successful identification of appropriate scales and their linkages in the human environment

Exploitation and Dependency on the Global Scale

-Many poorer countries are in debt to the countries and banks of the rich world - this is often called the 'debt trap' -Many less-developed countries rely on a limited number of exports, which are usually primary products (Figure 2.4) -Terms of trade and prices for primary exports ('unequal exchange') are set largely by the countries of the North -Overexploitation in poorer countries often occurs due to falling commodity prices and the need to service debts

Fisheries in the North Sea

-Overfishing encouraged by open access and a lack of governance characterised fisheries in the North Sea for much of the 20th century -Exploitation of North Sea herring is seen as a classic example of poor fisheries management and the boom and bust consequences of the industrialisation of fishing fleets which led to its virtual extinction as a commercial fishery in the 1970s (Dickey-Collas et al., 2010) -Fishing in the North Sea was open-access outside 12-mile national coastal zones and stocks were exploited until the start of 1977 when all countries around the North Sea extended their so-called Exclusive Economic Zones (EEZ) to 200 miles from national coastlines -A 5-year closure of all fishing between 1977 and 1981 was imposed and generally well respected -The economic consequences of the closure (bankruptcy for some ship-owners, loss of markets and changes in consumer behaviour) led to an awareness of the need for better management of the North Sea herring to ensure sustainable exploitation, realised via an agreement between the EU and Norway to limit catches so a core viable population of herring is maintained -This viable population is defined as the total weight of the fish in the stock that are old enough to spawn (the spawning stock biomass, or SSB) of more than 800,000 tonnes - a management strategy that is both dynamic and iterative (Dickey-Collas, 2016)

The Sahel

-Sahelian Africa, where catastrophe in the 1970s and 1980s sparked worldwide interest in desertification, continues to be a focus of global concern -Averaged over 30-year periods, annual rainfall in the region declined by between 20% and 30% between the decades (1930s to 1950s) leading upto political independence for Sahelian countries and the decades since (post-1960s)

Brazil's Amazon deforestation rates

-The annual deforestation rate in Brazil's Amazon peaked at 2.5 million ha in 2004, since when deforestation rates have fallen -This decline occurred in response to a combination of government policies, supply chain interventions and changes in market conditions -Some retailers and commodity traders have imposed new environmental criteria on their suppliers e.g. zero-deforestation agreements whereby TNCs have stopped buying produce from farms with recent records of forest clearing -However, although Amazon deforestation rates dropped by more than 80 per cent between 2004 and 2014, the Brazilian Amazon still has one of the world's highest absolute rates of deforestation: nearly 0.5 million ha in 2014

Fish stocks impact

-The share of fish stocks being overfished (i.e. at biologically unsustainable levels) rose from 10% in 1974 to just over 31% in 2013 (FAO, 2016) -Among other impacts are a decline in the biomass of certain predatory species, and the degradation of marine habitats, particularly of the seabed by trawling -Growth in global catches in the 1970s and 80s was targeted at pelagic (free-swimming) species that move in shoals because most demersal (bottom-dwelling) stocks were, and still are, fully fished

The poor and disadvantaged

-are frequently the victims and agents of environmental degradation -often only access environmentally sensitive areas - they may be forced to extract what they can from the sparse resources available -The mutually reinforcing links between poverty and environmental damage is often referred to as the 'poverty-environment nexus' -§Problems tend to arise when a poor society is subject to perturbation, causing them to try and survive or become 'environmental refugees' (Figure 2.8)

Culture

-may be thought of as the values, beliefs and norms shared by a group of people. -Establishing the environmental effects of culture is very difficult -factors may dictate the ways in which people perceive certain aspects of the environment, such as plants and animals -norms often incorporate taboos which play a role in the conservation of natural resources e.g. in the past, particular areas of habitat called sacred groves were set aside for religious or cultural purposes -The relationships between religious identification and environmental issues are complex and variable, and remain a subject for continuing research

Resources under common ownership may be prone to

-overuse and abuse - this has been called the 'tragedy of the commons'

The types of population dynamics shown in Table 6.1 should dictate suitable management policies.

-steady-state -low-variation/low-frequency -cyclic -irregular -high-variation/high frequency -spasmodic

Tropical Forest management

1.Assure the legality of forest products through international partnership agreements (e.g. the EU's Forest Law Enforcement, Governance and Trade plan, or FLEGT, and the 2008 Amendment to the Lacey Act in the USA) which will increase market prices and access for legally produced timber while simultaneously promoting more responsible forest management 2.Strengthen voluntary third-party certification programmes that promote responsible management by securing or even increasing market access and prices for forest products 3.Harness finance from climate change mitigation programmes such as REDD+ by recognising the substantial carbon benefits from improvements in tropical forest management 4.Devolve control over forests to indigenous and other rural communities, clarify their tenure and provide long-term business support for sustainable forest management

§Three main management failings are driving a fisheries crisis:

1.Free and open access, especially on the high seas, encourages overfishing, leading to a tragedy of the commons situation. Members of fisheries bodies are only weakly committed to cooperating on conserving stocks 2.Many nations heavily subsidize their fishing fleets, encouraging unprofitable and unsustainable fishing, making overfishing even worse. 3.Some attempts to conserve fisheries may unintentionally allow fishing fleets to grow too much. Owners continue to build and operate boats even if they have to be kept in port for part of the year

Attempts to manage physical change along coastlines can be divided into 2 fundamentally different approaches:

1.Hard Engineering: physical structures, usually rocks or concrete, protect the coast from natural processes 2.Soft Engineering: use natural systems such as beaches or mangroves to aid coastal defence -A combined approach may offer the best protection for any particular coastline deemed worthy of protection from physical change

Although people have hunted whales for thousands of years, modern commercial whaling for oil, and in time also for meat, is traced back to the

11th or 12th centuries when groups of Basque villagers began to hunt right whales from small rowing boats in the Bay of Biscay

The number of major spills over the period

1970-79 averaged about 25 a year, but this average fell below two a year in the second decade of the present century

The IWC declared a moratorium on all commercial whaling in

1986

Almost 3 million whales were killed in the

20th century alone, and several species could ultimately disappear altogether

Erosion of Britain's Humberside coastline between Bridlington and Spurn Head has removed a

3 km strip of coastal terrain, with the loss of 30 villages, since Roman times

In 2001, these planted mangrove forests made up nearly

80 per cent of the country's total mangrove forest area

In Pakistan, where irrigated land supplies more than

90% of agricultural production, salinity problems affect about a quarter of the irrigated area or about 11% of the country's land area (Middleton and van Lynden, 2000)

critically eutrophic following a surge in nutrient loads entering the sea over the last few decades of the 20th century

A major part of the Black Sea, one of the world's largest inland seas, became

What was the most important factor is responsible for forest clearance?

Agriculture expansion, both by smallholders and large-scale commercial agriculturalists.

Cornucopian (a.k.a. prometheanism, contrarianism, environmental scepticism)

Any environmental issues easily solved by human ingenuity, technological developments and the market economy, but no major problems perceived - the environmental crisis identified by other environmental groups is exaggerated

What is a natural resource?

Anything that is in the natural environment is a natural resource. Renewable resources are organic material that can regenerate itself if there no direct interfere with their regeneration process. Renewable resources are part of Earth and can be utilized continuously if they are used in a balanced manner. Renewable resources tend to be clean due to its natural way of being produced. Examples of renewable resources are resources such as solar energy, which is produced by the sun, long lasting source of energy, which can be captured to produce electricity. Another source of renewable resources would be wood which can regenerate itself to be used for many different purposes although if utilized faster than it regenerates it be depleted quickly.

Middleton claims that we do not have good data on the rate of deforestation. Why not?

At a very simple level, it is due to harvesting timber AND clearing land for other uses, especially agriculture, ranching, settlement, and (to a much lesser extent) mining. But a more nuanced explanation suggests many related factors such as road construction (which provides access), poverty/population pressure, global economic forces, and government policy. Slash and Burn agriculture is actually an efficient use of the forest resource—unless populations grow too rapidly.

Deep ecology

Based on nature as having intrinsic value, this philosophy calls for a profound shift in our attitudes and behaviour. It often advocates a strong commitment to direct personal action to protect nature and bring about fundamental societal change

Are resources useful or negative?

Both

Define sustainable development in the words of the Brundtland Commission

Brundtland Commission simplifies sustainable development as "development that meets the needs of the present without compromising future generations' ability to meet their own needs." While the Brundtland Commission's definition of sustainable development, the concept is far more complex. For understanding resources needed to sustain, there needs to be a clarification of who it is intended for, for instance, an entire community or an individual. Another factor is that the Brundtland Commission implies future generations will rely on the same resources used in the present, which is highly unlikely as things continuously change. The most challenging part of applying sustainable development is contributing to governments, businesses, and society. (Middleton, 2018, p. 52). While there is a generic definition for sustainable development, it requires an understanding and compliance in various departments to achieve genuine sustainability throughout ecological and economical.

Herding

Changing seasonal grazing migrations to take advantage of alternative forage when usual grazing is damaged by drought. Herders' adaptive strategies in East Africa have included accessing tree fodders, selling animals, and intensifying animal health care.

Agriculture (commercial)

Clearance for cropland, pasture and tree plantations, usually medium to large scale, for international and domestic markets

wood extraction

Commercial timber, fuelwood and charcoal (domestic and industrial)

Explain the difference between conservation and preservation.

Conservation protects the environment as it responds responsibly to natural resources, unlike preservation, that protects the environment from harmful human activities.

The earliest effort to control the whaling industry was the

Convention for the Regulation of Whaling, drawn up in 1931

Middleton cites reports that suggest nearly one billion hectares of land have been deforested since the development of agriculture several thousand years ago. Where did most deforestation happen in the past, and where is it happening now?

Deforestation was the consequence of agriculture's progression, as it allowed communities to take a break from hunting as they introduced gathering and herding. (Middleton, 2018). The practice of forest removal and deforestation began in the Mesolithic and Neolithic times throughout Europe's central and western regions. The movement led to the rapid expansion while European settlers moved in North America. (Middleton, 2018). Middleton references the UN Food and Agriculture Organization's statement that most deforestation has recently occurred in temperate latitudes throughout the northern hemisphere. The tropics continue to show an escalation of deforestation as human populations increase.

NON-CONSERVATIVE

Degradable wastes (including sewage, slurry, wastes from food processing, brewing, distilling, pulp and paper, and chemical industries, oil spillages) • Fertilizers (from agriculture) • Dissipating wastes (principally heat from power station and industrial cooling discharges, but also acids, alkalis and cyanide from industries, which can be important very locally)

Desertification

Degradation of land, especially in semiarid areas, primarily because of human actions like excessive crop planting, animal grazing, and tree cutting. -the extent of deserts is increasing, usually into desert-marginal lands -Most, though not all, authorities agree that desertification occurs in drylands, which can be defined using the boundaries of climatic classifications and make up about 41% of the world's land surface -The official definition adopted by UNCCD is 'land degradation in arid, semi-arid and dry subhumid areas resulting from various factors, including climatic variations and human activities'

How do different cultures view resources?

Differently; Resources vary in character (see Table 2.1) and include ecosystem services that are not directly consumed

Free market environmentalism

Emphasis on the free market as the best tool to preserve the environment and promote sustainability. Market-based instruments rather than government intervention can successfully internalize environmental externalities and tackle sources of market failure

Middleton notes that for a long time environmental determinism was the leading approach use/d in explaining the relationship between people and the environment. "What is environmental determinism?" why did the approach lost ground?

Environmental determinism is one of the earliest outlooks found supporting the dependent relationship between human society and the physical environment. The concept explained human behaviors influenced by culture, race, and intelligence and concluded that the natural environment is a prime contributor to influencing human development and activities. (Middleton, 2018 p. 46). Middleton (2018) explains that environmental determinism lost ground "...because of the way it was used by some as a justification for imperialism, colonial exploitation, and racist views." One may argue that while the environment can introduce an alternative view, it never determines a way of life as individuals are given various opportunities throughout a lifetime, explaining how those ends with drastically different lifestyles in similar environments. (p. 46).

a concern of governments and the general public in most countries of the world

Environmental issues -Worry over environmental issues is not a recent phenomenon e.g. atmospheric pollution prompted a royal decree in 1306 forbidding the burning of coal in London -An ethic of environmental conservation has been a prominent feature of many pre-industrial societies, and Buddhism is particularly recognized as cultivating a conservationist ethos -More recent interest in the natural environment has thrown up a wide range of different approaches to dealing with the issues (Table 2.5)

Cyclic

Ex Japanese anchovy, Atlantic mackerel, Pacific halibut Relatively low frequency cyclic patterns

Low-variation, low-frequency

Ex Pacific Ocean perch (Eastern Bering Sea) Very long-lived, slow-growing demersal species

Steady-state

Ex. Pacific cod, Pacific hake Typically longer-lived demersal species

Income diversification and migration

Farmers harvest natural products, adding value by manufacturing simple objects, labouring and otherwise exploiting multiple (though poorly rewarded) local work opportunities. Migration further afield for temporary, low paid employment is another option.

Spasmodic

ex California sardine, Japanese sardine, Peruvian anchoveta Typically small, pelagic species

What is humankind's largest source of wild or domestic animal protein?

Global marine fish production and is particularly important in the developing countries -In 2014, 82 million tonnes of fish were caught at sea (FAO, 2016) and many marine biologists suspect that this level is close to the global maximum sustainable catch -Ten species made up about 27% of landings in 2013, and many regional stocks show signs of biological degradation

Deforestation in the Amazon Basin

In Brazil, government policy was instrumental in initiating deforestation on a large scale in the mid-1970s with a concerted effort to develop the country's tropical frontier -The Brazilian government's view of the Amazon as an empty land rich in resources spurred programmes of resettlement -The 1990s was a period of rapid large-scale expansion of agribusiness - soybean plantations and other mechanized crops - into the Brazilian Amazon

Contradictory against Malthus?

In many cases the relationship between population numbers and environmental degradation is not straightforward, and is influenced by multiple political and economic forces (photo in slide CH2)

High-variation, high-frequency

ex Dungeness crab, South African pilchard, Pacific herring Possible cyclic patterns

Agriculture (subsistence)

Includes both permanent and shifting cultivation, usually by smallholders

Developing and implementing a strategy for the conservation and sustainable multiple use of coastlines is frequently referred to as

Integrated Coastal Zone Management, an approach that aims to balance social and economic demands on the coast with the protection of coastal environments that provide the ecosystem services on which society depends

Ecofeminism

Intellectual and practical movement viewing the domination and oppression of women and nature by men as linked historically, materially, culturally, and ideologically

Explain intergenerational inequalities in the context of resource use.

Intergenerational inequalities are one temporal level of disparities that have existed through groups from economic, political, and social processes from exploitation and dependency of misused resources.

In 1946, this convention was replaced by the

International Convention for the Regulation of Whaling (ICRW), which established the International Whaling Commission (IWC)

Iceland and Norway lodged official objections to the moratorium and have continued to hunt commercially, while

Japan and Iceland have continued to hunt whales for 'scientific purposes'

Mining

Large-scale industrial, small-scale and artisanal

Middleton identifies TWO ways in which livestock herders in less developed countries defend themselves against periodic drought. What are they?

Less developed countries depend on food production. With livestock herders being a standard job, periodic droughts often do severe damage to the economy. These countries have responded to periodic droughts by treating the impacts without directly responding to the economy's people and sectors. Another response from developing countries is drought assistance or relief to continue supporting land and water management practices.

Where is the Sahel, and why has it become such a problematic region?

Many herders are mobile and move their animals to better pasture; and they often keep several species of animals, which eat different types of vegetation and have differing tolerances to drought.

Middleton notes that "the term Anthropoceneis now widely used to reflect the fact that human action dominates many functions of the planetary system..." What other key features of the Anthropocene that Middleton outlines?

Middleton (2018) references Steffen et al. (2015) that "Other key features of the Anthropocene include a recognition that human influence is occurring at multiple spatial scales, ranging from local to global; that the magnitude and spatial scale of human-induced change may reach thresholds and regional or planetary boundaries that will result in major regime shifts in the Earth system when passed; and that there has been a pronounced surge in human influence and the pace of change since the mid-twentieth century, the so- called Great Acceleration."

What can be done to reduce deforestation?

Middleton provides multiple solutions to combat deforestation. The most directive form to decrease deforestation is by shifting the development to more sensible and equitable forest resources. Another solution is to slow population growth and improve employment opportunities in agriculture and urban areas. While the government does need to get involved by demanding a reduction or discontinuation of deforestation by targeting agriculture products to lessen the demand, legal protection is not always dependable. (Middleton, 2018). However, the most effective solution is to provide conservation that supports all ecological processes and all species to practice a sustainable approach, allowing humans to continue benefiting from forests' resources while avoiding destruction towards the whole forest.

satellite imagery

One tool increasingly used to avoid poor data and problems of definition

HCHs (hexachlorocyclohexane isomers)

Organochlorine insecticides used from the 1950s to the 1970s in many countries and as late as the 2000s in some countries

POPs that are widely distributed throughout marine ecosystem

PCBs (polychlorinated biphenyls) DDTs (dichlorodiphenyltrichloroethane and related chemicals) HCHs (hexachlorocyclohexane isomers)

CONSERVATIVE

Particulates (including mining wastes and inert plastics) • Persistent wastes (heavy metals such as mercury, lead, copper and zinc; halogenated hydrocarbons such as DDT and other chlorinated hydrocarbon pesticides, and polychlorinated biphenyls; radionuclides)

Causes: why do people engage in deforestation, to begin with?

People engage in deforestation for the motive of using the forests' resources. The forest can provide resources such as food, timber, and other raw materials. It creates economic value by forming jobs throughout many countries. (Middleton, 2018).

Political ecology

Priority given to interconnections between politics and the environment. Includes study of political struggles over natural resources or where outcomes of political struggles are defined by access to natural resources

What is the interactions between humankind and the physical environment?

Result from our attempts to satisfy real and perceived needs and wants.

Infrastructure

Roads, railways, pipelines, electricity transmission, hydroelectric dams

Urban expansion

Settlement growth

Cultivation

Shifting between crops, varieties, specializations, in response to rainfall. Sahelian farmers typically spread risks associated with rainfall timing (e.g. cultivate both long and short cycle millets). Different fields in different parts of village planted with different crops to spread risks associated with characteristic patchiness of rainfall.

Example of Continuous Resource

Solar energy, wind, tidal energy

Middleton calls out the U.S. Great Plains, which periodically endures drought, but which became a Dust Bowl in the 1930s, and experienced much soil erosion on the 1970s. What caused each of these tragedies? What issue is likely to lead to a future desertification tragedy in the region?

The Dust Bowl in the 1930s was caused by drought-resistant grasslands that changed the wheat fields through a culture set where natural resources were exploited for over 50 years. The soil eventually became exhausted, dealing with drought and wind erosion. The Dust Bowl motivated advances in soil conservation techniques. While long term consequences cannot be determined, issues theorized are Great Plains farming grain production is an ecological mistake and lead to another disaster worse than the 1930s Dust Bowl. Overgrazing (too many animals on land that has too little vegetation). In some cases, government policies promoting agricultural irrigation or sedentary (rather than nomadic) living have reduced grazing lands so that herders often try to make use of marginal grazing land. Middleton contends that recent research suggests that rainfall variability may be a more important factor than overgrazing.

According to the document World conservation strategy, what three priorities should be included in all development programs?

The World conservation strategy argues that the priorities: maintenance of ecological process, sustainable use of resources, and maintenance of genetic diversity should all be included in all development programs. (Middleton, 2018, p. 52).

How do governments contribute to deforestation?

The advance of soybean plantations stimulated further massive government investment in infrastructure such as waterways, railways, and highways

explain the five drivers of environmental degradation.

The five drivers are demographic, sociopolitical, economic, scientific and technological, cultural, and religious. They are created to have a significant influence to encourage or compel people that irresponsibly cause change within the ecosystem. The five drivers operate to promote and mitigate human impact on the environment.

Economic Drivers

The growth of economies has been fuelled by the use of resources

What is desertification?

The literal definition for desertification means making a desert as a habitable land transforms into a desert due to climate change and human behavior. refers to the expansion of desert conditions in places that were not deserts before. Yet this masks the variability and dynamic nature of many landscapes. A better definition might be: Land degradation in desert, hyper arid, arid, semi-arid, and sub-humid areas due to either natural causes (climate change), human activities (such as overgrazing) or some combination of both natural and human causes.

According to Middleton, conventional wisdomsuggests that WHAT is the most significant and direct cause of desertification? Of course, he also points to more deeply rooted causes such as . . . . . . Finally, what does he conclude about this conventional wisdom?

The most significant cause of desertification is the misuse of the land itself; this is inclusive of grazing, over-cultivation, and vegetation overexploitation. The primary source of why resources are often misused is social, economic, and political systems as they encourage and indirectly force the usage of inappropriate and irresponsible practices. (Middleton, 2018). While it is challenging to receive fast data of the correspondence of human actions and changes in drylands, the conventional wisdom to focus on dryland ecology seems to be a highly dynamic strategy. Middleton argues conventional wisdom would require a large scale to observe changes.

What is a negative resource?

The negative resource comes from the aspects of the human environment, such as people and institutions who also provide resources. Non-renewable resources are only available in limited amounts and they can only be found in specific areas. The regeneration of these sources is very slow, and, in many cases, there is just a limited amount of these resources thus causing them to be depleted much faster than renewable resources. A few examples of non- renewable resources are natural gas and coal which have taken million of years to form and be utilized, therefore there are only a specific amount of these resources to be utilized.

Sociopolitical Drivers

The organization of human society forms a diverse set of drivers influencing environmental change

Explain the philosophy of deep ecology.

The philosophy of deep ecology is based on nature as having an intrinsic value that calls for a profound shift in our attitudes and behavior. It often advocates a strong commitment to direct personal action to protect nature and bring about fundamental societal change.

'technocentric' and 'ecocentric' approaches

This plethora of different movements and philosophies can be divided into two camps:

Continuous Resource

To all intents and purposes will never run out.

Ecoterrorism

Typified by acts of violence, property damage, or sabotage against individuals and companies in the name of environmentalism. Such direct action is designed to highlight, prevent or interfere with activities deemed harmful to the environment

What area have high population desities?

Urban areas with levels of resource consumption, leading to large environmental impacts

DDTs (dichlorodiphenyltrichloroethane and related chemicals)

Used as an insecticide to increase agricultural production mainly from the 1950s to the early 1970s. Although its application in agriculture is now banned, use of DDT to combat malaria-carrying mosquitoes is still recommended by the World Health Organization, and DDT is used for this purpose in some tropical countries

PCBs (polychlorinated biphenyls)

Used for a variety of industrial applications from the 1950s to the early 1970s

Social ecology

Views most ecological problems as the result of deep-seated social problems brought on by the products of capitalism. Hence, environmental issues can only be resolved by dealing with problems within society

OK, deforestation has happened; so what? What are the consequences?

While deforestation allows communities to benefit from the forest's resources, the rate of forest removal becomes a threat to the forests' ecosystem. Typically overlooked, services provided from ecosystems support other systems for human life, regulating climates, water flow and nutrient cycles, and biodiversity and habitats for species. (Middleton, 2018). The loss from tropical forests creates an imbalance in the system of all services that no longer can provide resources and negatively affect the local environment, which is eventually affected globally. For one thing, there is no universally accepted and precise definition of a forest (usually defined as some % of land covered by the crowns of trees). For another, some areas are deforested, period, while others are merely degraded—and there are many opinions on how to distinguish between the two. Even the interpretation of satellite imagery can be different and impact estimates of deforestation.

Wild food gathering

Women in particular maintain local knowledge on a range of 'famine foods' which might replace conventional food grains.

Deforestation generally leads to an increase in runoff and stream discharge

a causal relationship demonstrated in studies of small watersheds (< 10 km2) throughout the tropics (Sahin and Hall, 1996)

Soil degradation

a common problem that is particularly severe in the tropics where rainfall is high, accelerating soil loss after initial vegetation clearance

The reason for the relatively modest krill catches is the establishment of

a limit on harvesting by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), an international body set up in 1981

Environmental issues stem from

a mismatch between extrinsic resources and natural resources

Example of a resource

a tiger may valued for its skin but viewed also as a dangerous animal

Traditional hard engineering structures, such as sea-walls and rock revetments, are designed to

absorb the energy of waves in order to reduce or prevent erosion and flooding

Pollution can occur because of catastrophic events such as

accidents and/or as a chronic problem, due to regular discharges from a sewage outlet for example

Any sustainable rangeland management approach must take

account of temporal and spatial variability (Joly et al. 2012)

The role of national government in deforestation

another factor in encouraging certain groups to use the forest resource, through tax incentives to loggers and ranchers, for example, or through large-scale resettlement schemes

Resources

anything in the natural environment that may be useful to humans

Corruption and centralized control

are frequent characteristics of developing countries, which often means that local communities lack power over their resources -There may be little incentive to invest in the future productivity of an area if future entitlement to that area is in question -There is an association between the environmental characteristics of a place and the well-being of its inhabitants: rural people living in chronic poverty tend to live in areas with low agricultural or natural resource potential

Transnational Corporations (TNCs)

are key drivers of the globalisation of economic activity -Investment by TNCs in developing countries has been portrayed as both an engine of growth and a major obstacle to development -Many TNCs are relocating their heavily polluting production activities to poorer countries -Global capitalism works to spread western cultural norms and practices (figure 2.5) -Structural inequalities also exist at the national scale -Figure 2.6 shows how these inequalities might be categorised according to their economic, political and social dimensions

Tiny particles of plastic debris (frequently called microplastics)

are so pervasive in marine ecosystems that we find them in seafood and table salt

Sociocultural imbalances

are superimposed on geographical patterns of environmental resources on all spatial scales -Imbalance theories, combined with human driving force theories, constitute explanations that help to explain the human dimension behind environmental issues (Table 2.3)

Remoteness

area far from the centres of economic and political activity in terms of physical distane and/or travel time

weakly integrated

areas not well-connected, both physically and in terms of communications and markets.

Drylands

areas that experience a deficiency in water availability on an annual basis, but precipitation in drylands is characterized by high variability in both time and space

low potential

areas with low agricultural or natural resource potential due to combinations of biophysical attributes including climatic, hydeological, topographical, soils, pests, and diseases. (often crudely equated with drylands and highlands)

Drivers occur

at all spatial scales across various time frames as well as in differing combinations

The generation of large quantities of atmospheric soil dust from drylands is also likely to have effects on

atmospheric processes, including cloud formation and rainfall (Choobari et al., 2014)

Dryland ecology

attuned to this variability in available moisture and is therefore highly dynamic

Putz et al. (2012) argue, well-managed tropical forests need to

be encouraged as a sort of middle way between deforestation and total forest protection

Contamination of the oceans by plastics and other synthetic, non-biodegradable materials from

both land- and sea-based sources is another pervasive marine pollution issue of growing concern

Population growth

both non-linear and exponential, and more people means a greater need for natural resources

Management of the coastal zone is necessary

both to limit damaging activities and to protect coastal resources, as well as to restrict development in areas prone to natural hazards such as hurricanes, tsunamis, subsidence and inundation

What drives the impact of the wealthy?

by their intense resource use whereas the poor may degrade the environment because they have no other option (Figure 2.1)

Human-induced increases in the atmospheric inputs of

carbon dioxide, and to a lesser extent sulphur dioxide and nitrogen oxide, have generated considerable concern about their roles in ocean acidification

Irregular

ex Bay of Fundy scallops, Norwegian herring, North Sea herring Moderate levels of variation indicating any possible cycles tend to be irregular

While these proposals seem sensible, the needs of national economic development cannot be denied - Brazil cannot just

cease development of its largest sovereign natural resource -These suggestions often come from developed countries that all but destroyed their own forests during their development, leading to interpretations of 'ecoimperialism' -In Britain, for example, almost the entire land area was covered by forest about 5000 years ago, reduced to just 5% by 1900

Rapid population growth rates

characterize many countries in the tropics also play a part

The national scene is often

characterized by a small elite group that has more power than people in more marginal groups, and is often manifested in a rural/urban divide

Plants and animals may also be affected by

clean-up operations or indirectly through damage to their habitats

Relationship between richer and poorer nations?

clear imbalances

The intensity, speed and relative permanence

clearance by human populations in the modern era put this form of disturbance into a different category

Pollution of the coastal zone comes from activities on the coast, in coastal waters and from inland; in the latter case, usually arriving at the

coastal zone via rivers

Death or loss of cultural identity is

common for indigenous peoples following deforestation - the indigenous Indian population of the Amazon Basin is thought to have fallen by 9 million since the arrival of Europeans

Reasons for increased grazing pressure include

competition for land as cultivated areas increase, pushing herders into more marginal pastures

Since land-based sources tend to be dominant, the worst effects of these pollutants are

concentrated in coastal waters adjacent to areas with large population densities

However, parts of the Great Barrier Reef face a pollution threat from land-based sources over the past 150 years, with adverse effects on

coral and seagrass ecosystems (Kroon et al., 2016)

Problem of technological drivers?

created by an increasing population can be countered by new innovations e.g. use of non-renewable fuels has led to promotion of energy conservation and renewable energy

At a large scale, changes in sea level relative to land, due to

crustal movements and changes in the overall volume of marine waters, can alter the nature of the coastal zone itself

The 'tragedy of the commons'

degradation of grazing lands, pollution of the air, and over-fishing of the seas

Numerous regional seas are showing signs of

degradation, in many cases with land-based sources of pollution being most prevalent

What are the five main sets of drivers recognized i The Millennium Ecosystem Assessment (MEA)?

demographic; sociopolitical; economic; scientific and technological; and cultural and religious

distinguish between the impacts of overexploitation and the natural variability of stocks

dependent upon species biology, migratory habits, food availability and natural hydrographic factors

Despite a lack of knowledge about cold-water reefs, we do know that many have already been

destroyed or severely damaged

River outlets also supply sediment to coasts, so that human modification of river regimes can have a

downstream impact

More recent thinking has replaced the idea that rangeland has a fixed carrying capacity, with the idea that

drylands are in a state of more or less constant flux, driven by disturbances such as drought, fire and insect attack

Natural, or 'primary', salt-affected soils are widespread in

drylands because the potential evaporation rate of water from the soil exceeds the input of water as rainfall, allowing salts to accumulate near the surface as the soil dries

Continual disturbances

due to shifting water channels, waterlogging and the unstable soils of flooded forests - reduce opportunities for competitive exclusion, meaning that climax is never reached

Ecocentrism

encourages fundamental changes to our ethical and moral approaches to nature

There may also be direct links between eutrophication and the risk infectious diseases because

enhanced nutrient loading can boost the abundance and survival rates of pathogens in aquatic ecosystems

A neo-Malthusian positive feedback resulting from an

expanding human population is frequently cited as the ultimate driver behind this form of desertification

Hard engineering structures are frequently viewed as

expensive, short-term solutions while, the soft engineering approach is often more long-term and sustainable

The history of commercial whaling has seen intensive catches of a species until it has been driven to the brink of

extinction

Farmers and groups directly involved

extracting physical resources rely on knowledge of those resources to make a living or survive

Extrinsic resources

include all aspects of the human species, all of which are renewable

Intensive grazing does not always result in a net loss of vegetation cover

grazing can result in a change in the types of vegetation e.g. by the encroachment of unpalatable or noxious shrubs into grazing areas

The depletion of nutrients means that

greater amounts of fertilizers have to be applied to maintain crop yields, while the declines in organic matter and soil stability have meant a greater susceptibility to erosion

Conversion of mangroves to agriculture, urban development and overexploitation for fuelwood or charcoal production are common drivers of loss, and sea-level rise could be the

greatest future threat to these habitats

It was early in the 20th century that whalers began to exploit the previously untouched waters of the Southern Ocean where several species go to feed on

krill

The north-western portions of the sea exhibit a regime shift from a diverse ecosystem that supported

highly productive fisheries to a eutrophic plankton culture, unsuitable for most higher organisms

The organization of society affects?

how people make decisions about their interaction with the natural environment and how such environmental governance is carried out

Droughts cannot be prevented, and the way governments respond to them tends to be reactive. This form of crisis management inevitably treats only the

impacts rather than the underlying reasons why some people and some sectors of the economy are vulnerable

Ownership and governance in the coastal zone are

important, but frequently complex: ownership is not always clear and can be liable to change, making effective governance more difficult

Localized effects of deforestation have been detected in the rainfall records in Central America

in Guatemala and adjacent areas, analysis of data from 266 meteorological stations by Ray et al. (2006) showed dry season rainfall to be far lower in deforested areas than in equivalent forested zones

Some aboriginal subsistence whaling is also permitted in

in a small number of places (Alaska, Chukotka, Greenland and Bequia), which accounts for a few hundred whales each year

Since the mid-1980s, the scale of whaling has been greatly reduced, but other threats such as ship strikes and entanglement in fishing gear, have

increased

Large phytoplankton blooms have become

increasingly common in the Black Sea as a result

In the Brazilian Amazon, more than a third of the forest is legally protected, in:

indigenous lands and other types of protected areas, and both inhabited and uninhabited reserves appear to be successful in reducing both deforestation and the occurrence of fire, the standard processes heralding conversion of forest to agriculture (Nepstad et al., 2006) -Yet, legally protected areas cannot be sufficiently extensive for the conservation of all ecological processes and species

Some environmental resources are owned by

individuals while others are under common ownership

Mangrove forests are made up of salt-adapted evergreen trees, and are found in

intertidal zones of tropical and subtropical latitudes, serving important roles as breeding and feeding grounds for many species of fish and crustaceans, and in protecting coasts from erosion

Many species are highly localized in their distribution and are characterized by

intimate links or narrow ecological specialization, resulting in a delicate interdependence between one species and another

Growth in the global human population

is one of the most clear-cut drivers of environmental change

One of the most widely discussed consequences of deforestation in the tropics

is the loss of plant and animal species

distinguishing between 'primary forest' and 'secondary forest'

is the result of human impact Even these data can vary, depending on the satellite sensors used, differing methods of interpretation, and other difficulties

One of the most striking social changes

is the rise of the city: virtually the entire human species lived rurally 300 years ago but today over 50% of people live in cities

Difference between the adverse effects of human action and the response of drylands

it can be difficult to distinguish in the field between the adverse effects of human action and the response of drylands to natural variations in the availability of moisture

For the Brazilian Amazon, Fearnside (2005) highlights the importance of slowing population growth and improving employment opportunities both in

labour-intensive agriculture and in urban areas outside the Amazon

The Great Barrier Reef off the east coast of Australia is one of the world's least threatened, thanks in

large part to its status as a marine park

'Fishing down marine food webs' has occurred in the last century

large, long-lived fishes at or near the top of marine food webs are initially targeted and then, as these species become depleted, a transition is made to catching smaller, short-lived fishes at lower trophic levels

Our understanding of warm-water coral reef ecosystems is much better - these reefs cover

less than 0.2 per cent of the ocean floor, yet support about a third of all marine species (Fisher et al., 2015)

A host of socio-economic, political and historical drivers work to produce characteristics associated with chronic rural poverty:

low potential; remoteness; less favoured; weakly integrated

Modelling studies indicate that projected ocean warming over the next few decades may make

mass coral bleaching frequent on reefs worldwide (Donner et al., 2017)

The operation of sedimentation and erosion that is superimposed upon such larger-scale processes also has

more localized impacts on the human use of coasts

Short-term impacts of trawling for demersal fish include

mortality of invertebrates, resuspension and redistribution of sediments, and physical destruction of habitats; long-term impacts may include changes in biodiversity and species composition, and reduction in habitat complexity

The high level of human impact in the Mediterranean results from

multiple drivers, including climatic stress (through increasing temperature and acidification), demersal fishing and ship traffic, in additional to pollution from land

Drawbacks of hard engineering include the destruction of

natural ecosystems and an enhanced danger of erosion along neighbouring parts of the coast

Soft engineering approaches are non-structural and tend to work with

nature in protecting a coastline by harnessing natural systems that can absorb marine energy

Changes in albedo over great areas due to a decline in vegetation cover, whether caused by drought or intensive grazing, could have a

negative effect on rainfall. Vegetation loss leads to a greater surface albedo, resulting in a cooler land surface, which, in turn, reduces convective activity and hence rainfall

Some scientists fear the frequency and extent of coastal eutrophication and associated algal blooms may increase with global warming because

nitrogen and sulphur stored in soil organic matter will be released into rivers if temperatures rise as predicted. Increased nitrogen losses are particularly likely

It is widely accepted that an exclusively scientific approach is

not providing all the answers to environmental challenges, and more diverse ways of understanding the environment are needed

Global economic inequalities are stark

one billion people live in luxury, while one billion live in destitution

Time lags

occur between identification of environmental concerns, formulation of policy, and the eventual implementation of policy and management

Ex of natural perturbations

occur on larger scales e.g. a tropical cyclone can cause tremendous damage over huge areas

Dramatic transformations in population and technology

occurred during the Agricultural Revolution of the late Neolithic and the Industrial Revolution of the 18th and 19th centuries

Oil affects marine life both because

of its physical nature (i.e. by physical contamination and smothering), and because of its chemical components (e.g. toxic effects).

Mass starvation is probably more a function of

of poor distribution of food, and people's inability to buy what is available, than desertification, although desertification, drought and many other natural hazards may act as a trigger

The devastation of seal and whale populations, and the depletion of some finfish, were clear examples of

of the tragedy of the commons

Why do drivers operate?

promote human impact on the environment and to mitigate such impacts

Timelags of decades to centuries identified between the onset of overfishing and consequent ecological changes because

other species of similar trophic levels took over the ecological roles of the overfished species until they too were overfished

Influence of the wealthy?

over environmental governance decisions, although the poor may also be active in forcing political changes

Accelerated erosion may result

over the longer term, soil is deprived of inputs of nutrients and organic matter from decomposing leaf litter

Local threats can be divided roughly into direct impacts caused by

overexploitation of reefs (overcollecting, damaging fishing techniques, and careless or poorly supervised recreational use), and indirect impacts resulting from other activities (siltation following land clearance, damage caused by coastal developments and pollution, and that caused by military activities)

the Southern Ocean has been the site of several phases of species depletion caused by

overexploitation, illustrating the process of 'fishing down the food web'

Common ownership does not always lead to

overexploitation, particularly when strong social and cultural rules control the use of resources -Some resources are underevaluated: air, for example, has no economic value so is prone to overuse

Using a range of proxy indicators and historical evidence, the first major human disturbance to all coastal zones studied (in a range of coastal environments) was found to be

overfishing of large marine fauna and shellfish

Ecological extinctions caused by

overfishing thought to have led to serious changes in coastal marine ecosystems over many centuries as overfished populations no longer interacted with other species

Soil erosion by wind and water is another result of the

overintensive use of soil, resulting from a weakened soil structure and reduced vegetation cover

the theory linking desertification and food production, though basically sound, is often

oversimplified and deserves further careful research -The link between desertification and famine is even more difficult to make

The effects of eutrophication in coastal waters include

oxygen depletion and increased phytoplankton blooms, increased incidence of fish kills, reductions in species diversity and reductions in harvestable fish and shellfish

Examples of extrinsic resources

people, people's skills, abilities, and institutions

In the Sahel many remain vulnerable to

perturbations, particularly drought, and longer-term ecological decline of desertification §However, long experience of coping with environmental dynamism has engendered numerous strategies for managing risk and variability (Table 5.7)

Example of renewable resource

plants, animals, clean water, soil

Less favoured

politically disadvantaged areas

The Mediterranean Action Plan (MAP) was designed in 1975 to address

pollution in particular, focusing on land use planning, urban management and pollution prevention

The effective loss of entire trophic levels has made coastal ecosystems more vulnerable to other human and natural disturbances such as

pollution, disease, storms and climate change

when previously productive soil becomes salinized as a result of

poor land management - this is called 'secondary' salinization

The impacts in some developing countries can be particularly severe, and chiefly on

poorer members of rural societies i.e. huge losses of livestock for herders

Technological developments enables?

population growth or occur as a result of it

Development of commercial fisheries, rapidly increasing

populations, the growth of coastal ports, and most recently the exponential growth of coastal tourism, have combined to put unprecedented pressures on reefs from both direct and indirect impacts

A mass replanting programme has also been undertaken in

post-war Viet Nam, successfully re-establishing many thousands of hectares destroyed by spraying with the herbicide Agent Orange (while there has been virtually no natural regrowth after the war)

Clearance for fuelwood has been the major factor behind the almost total disappearance of mangroves in Ghana and Côte d'Ivoire (Sayer et al., 1992) and continues to be the most

prominent driver of mangrove loss in Gambia and Senegal (Carney et al., 2014)

Installation of such structures has been successful in

protecting local stretches of coastline from physical change

Global aridity and drought areas have increased substantially since the late 1970s, when

rapid warming of the atmosphere contributed significantly to global drying

A simple management regime involves

removing all trees above a certain diameter during harvest, followed by removing all dead and deformed trees

Perpetual resources

resources from nature that are regenerated at the same rate or in most cases at a faster rate, the resource is being utilized. Resources such as solar energy will never run out due to the sun's long-lasting energy and will always be available for consumption. Another example would be wind energy since wind will always regenerate, be available, itself thus being a perpetual resource.

Aesthetic or intangible resources

resources that have no direct monetary value, yet they have value to the beauty and tranquility they might bring to an individual. Furthermore, it cannot be necessary directly utilized but it can bring in value due to its beauty and intrinsic value. Example of aesthetic resources would be visual resources such as the view of the natural environment (a sunset). Aesthetic resources importance might change over time because many times they are given worth depending on how essential people perceived them to be.

Overfishing of large predatory fish species such as cod, and their subsequent collapses in population, can result in the

restructuring of entire food webs, so-called trophic cascades that have been documented in several large marine ecosystems

However, the overall total mangrove area in Viet Nam had still declined substantially in the

second half of the 20th century

It can be difficult to distinguish primary forest from secondary forest that is the result of human impact

secondary forests more than 60-80 years old are treated as primary forests in the FAO assessments of tropical forests

Technocentrism

sees technology and economics as the answer to environmental problems

Most oil spills from

shipping worldwide result from routine operations such as loading, discharging and bunkering - activities that normally take place in ports or at oil terminals

Structural inequalities in the global system have evolved

since colonial times and are characterised today by control by wealthier countries over poorer ones (see Figure 2.3)

Globally, some 30% of the world's reefs are of value in the tourism sector and are particularly important in

small island economies

Introduction of mechanized agriculture with its large fields and deep ploughing, which further disturbs

soil structure and increases its susceptibility to erosive forces

There is widespread agreement in the scientific community that deforestation in the tropics is a severe threat to the

species and genetic diversity of the planet, although the potential magnitude of the loss is unclear

Ecology sets a range

species and vegetation where stresses change the outcome. Contradicting, the perceptions have been clouded by adherence to ideas of a fixed carrying capacity based on rangelands as equilibrium systems. (Middleton, 2018). So views on the sustainability of grazing in rangelands have often become polarized, matching the two principals opposing views of rangeland ecology.

Despite establishment of end-of-river pollution targets for adjacent river catchments, the Great Barrier Reef continues to face

stress from terrestrial pollution, fishing impacts and climate change

Island and coastal societies have long used coral reefs for

subsistence purposes, as sources of food and craft materials

Some types of disturbance of an intermediate magnitude and frequency

such as frequent flooding - appear to be a driver of high biodiversity in certain tropical forests -The Atlantic rain forest biome in southern Brazil includes a complex mosaic of forest types but flooded areas support greater species diversity than unflooded forest (Marques et al., 2009)

Groundwater that has become salinized may no longer be

suitable for other human uses (e.g. for drinking)

Less versatile and adaptable species, particularly insects, which tend to be very specialized feeders, are still less likely to

survive such disturbances

Differences in economic development along a North-South divide among Mediterranean countries, with associated limitations in

technical and financial capacity, have been identified as being the continuing central challenge

Thomas Malthus claimed (18th century)?

that population growth would outstrip food production, leading to famine, conflict and misery - this Malthusian perspective continues to influence views on environmental issues today

Despite variation in the global extent of tropical forests through glacial maxima,

the Amazon rainforest has been a permanent feature of South America for at least the last 55 million years

Coastlines on inland seas are also susceptible to changes in river discharge

the completion of a dam to facilitate agricultural, industrial and municipal withdrawals across the mouth of the Kora-Bogaz-Gol embayment is thought to have contributed to a decline in sea level in the Caspian of more than 3 m between 1929 and 1977 -However, a subsequent rise of nearly 3 m by 1995 suggests that climatic variations influencing fluvial discharge into the Caspian were more important

Drainage from salinized areas often increases

the concentration of salts in streams, rivers and wetlands, adversely affecting freshwater biota and in some cases resulting in a loss of biodiversity

The challenges of poverty cannot be divorced from those of desertification because

the degradation of natural resources contributes directly to low levels of well-being via the poverty-environment nexus

The location of the world's marine fisheries is governed principally by

the distribution of floating plants on which they depend for food, and the most important factor determining this phytoplankton production is the supply of nutrients, which is greatest in areas of upwelling

Grazing animals vs carrying capacity

the landscape to support grazing animals argues carrying capacity, and equilibrium involvement in a problematic nature as 'overgrazed.' The idea is exercised through Clements' (1916) model on the theory of vegetation succession and ecological stability. Nonetheless, ecosystems occasionally reach equilibrium because of disturbances like droughts, fires, and insect attacks. (Middleton, 2018).

The configuration of coastlines is constantly changing thanks to

the natural processes that operate at a wide range of temporal and spatial scales

concern over tropical deforestation stems from?

the perturbation to forests as local climate, water flow and nutrient cycle regulators

Sahelian populations includes

the poorest, the hungriest, the least healthy and the most marginalized people in the world

Carrying capacity

the population size of a particular species capable of being sustained surviving in a specific environment over a long period where the species can be dependent on limiting factors. Therefore, if the carrying capacity exceeds, then the habitat's degradation will occur, genuinely calculated in a stable environment. In comparison, equilibrium suggests elements such as rainfall, number of animals, and mobility. Presenting a landscape rapidly to adjust the process operating on the process and form reveals a cause and effect relationship, creating mobility.

Desertification reduces

the productivity of the land and, hence, less food is available for local populations. Malnutrition, starvation and ultimately famine may result

Directional felling reduces damage to the

the remaining canopy and facilitates log removal, while pulling out logs by cable reduces damage to the forest floor, allowing recovery before the next harvest

In northern Argentina, the tropical dry forests of the semi-arid Chaco have been exploited for more than 100 years, initially because

the wood made excellent railway sleepers, but more recent clearance has been for agricultural expansion, prompted by high grain prices and positive rainfall balances

Preventing systemic tropical forest abuse, a symptom of the underlying drivers of deforestation, means that

these causes must be addressed if more sustainable use of the forest is to be implemented

More than 70 per cent of the world's remaining tropical forest area

thought to be made up of degraded old-growth forests (affected by recurrent fires, road building, selective logging, fragmentation and overhunting) and secondary regrowth forests (FAO 2010)

Sustainable forestry to yield products such as

timber needs to mimic natural ecosystem processes, to conserve biodiversity as well as associated functions - carbon, climatic and soil-hydrological ecosystem services -§timber needs to mimic natural ecosystem processes, to conserve biodiversity as well as associated functions - carbon, climatic and soil-hydrological ecosystem services §Directional felling reduces damage to the remaining canopy and facilitates log removal, while pulling out logs by cable reduces damage to the forest floor, allowing recovery before the next harvest

What are fossil and archaeological evidence used for?

to infer past interactions between humans and their environment

Changes brought about by deforestation can also have global impacts via

to surface roughness and albedo brought about by deforestation can also have global impacts via hydroclimatological 'teleconnections' (Avissar and Werth, 2005) or via the carbon cycle

Krill are considered a keystone species, leading to fears that their overharvest might lead

to the collapse of the entire ecosystem

ex of actual removal of biomass by grazing animals and other effects of livestock

trampling and hence soil compaction, which hampers air and water circulation in the soil, hinders root penetration and limits seed germination

Drivers

underlying forces that compel people to directly or indirectly cause a change in the ecosystem

Clearance of forested land is

undertaken for a number of reasons, but most commonly to make way for the expansion of grazing or cultivation and/or to provide fuelwood

Different forms of pollution present challenges over different timescales because of the

variable times it takes for pollutants to be assimilated into the marine environment

Intensive grazing does not always result in a net loss of

vegetation cover - grazing can result in a change in the types of vegetation e.g. by the encroachment of unpalatable or noxious shrubs into grazing areas

Sustainable consumptive use of resources is

well established in the protected Bangladesh portion of the Sundarbans mangrove forest

Loss of vegetation can occur around

wells or boreholes - 'piospheres' - caused by grazing and trampling -But such areas are also typified by higher levels of soil nutrients than surrounding areas due to regular inputs from dung and urine, leading to their interpretation as 'sacrifice zones'

Non-renewable resources

which are available in specific places and only infinite quantities because although they are renewable, the rate at which they are regenerated is extremely slow on the timescale of the human perspective

Intensification of farming

which can result in shorter fallow periods, leading to nutrient depletion and eventually reduced crop yields

Changes in land use, such as cultivation, can increase sediment loads, for example

while conversely numerous rivers have had their sediment budgets depleted by the construction of dams

Major agricultural crops have a low salt tolerance compared to

wild salt-tolerant plants (halophytes), so salinization results in a regime shift from high productivity to low productivity and consequently to declines in crop yields

Sedimentation by the Büyük Menderes River into the Gulf of Miletus on Turkey's Aegean coast over the last 2400 years has today left the

§ancient port of Haracleia 30 km from the shore

At the regional scale,

§several modelling studies suggest that removal of 30-40 per cent of the forest could cross the threshold between two stable states, inducing a regime shift by pushing much of the Amazon basin into a drier climate (Oyama and Nobre, 2003)