Settlements

Settlements can be described as being part of the urban hierarchy. Where they stand on the hierarchy depends on a number of factors, the main ones being population, the number of services a settlement has and its sphere of influence. The best way to show the urban hierarchy is by using a pyramid, as shown in the diagram later.

The most obvious way of deciding where a settlement ranks on the urban hierarchy is by using the population of that settlement. The larger the population, the higher the settlement is placed on the hierarchy.

In the UK, the largest city in terms of population is London, which most people would agree is the most important settlement in the country and so deserves to be placed on the top of the urban hierarchy for the UK.

After that the divisions between what is classified in each layer is a bit more vague. Different sources will have different numbers for how many people are needed for a place to be called a city rather than a town for instance.

However the most important thing to notice on the diagram is that as you go up the hierarchy, there becomes a lot less of that type of settlement. So, the diagram shows us that there are huge numbers of isolated farmhouses and hamlets. There are less villages and small towns and so on.

In the UK, many people would argue that only London should be placed in the highest rung of the triangle. However some other large cities, such as Birmingham, Manchester and Leeds are growing fast, and may be considered to have reached the top level as well.

Services are things such as retailers(shops), professionals (doctors, lawyers etc), entertainment, government functions and leisure. The theory goes that the larger a settlement is, and therefore the higher it is on the urban hierarchy, the more services and functions it will have.

In general in the UK, this is the case. London is the settlement at the top of the urban hierarchy, and it has the greatest numbers of services and functions of any settlement in the country. For instance, it has the major international airports, it is the seat of our national government, it has the widest range of shops, including very specialist ones, and it has the most renowned professional services. This is because its population is large enough to support all of the services.

A small village may on the other hand only have the population to support a pub, post office, village store and perhaps a small garage.

Villages and other rural settlements have found over the last 20 years that it has been increasingly hard for services to remain viable in these settlements. Small post offices and banks have frequently been closed down, as there aresimply not enough people using them to make them viable.

The number of services (functions) that a town provides normally relatesto the number of people living there.

There are however, two noted anomalies. These are examples of settlements that do not conform to the general pattern, and they are explained below:

Anomaly A: A Tourist town: Towns, such as Brighton, Blackpool and Eastbourne, that have grown due to the tourist industry, often have more services than their population suggests they should have. This is because many of their services are catering for the huge numbers of tourists who flood into the towns during the summer months. Hotels, guesthouses, restaurants, beach shops and ice cream stalls all are aimed to provide services for the tourists.

The extra tourist numbers swell the total population during the summer to a level that is more appropriate for the number of services provided.

Anomaly B: A Commuter Settlement: Many rural villages are becoming commuter centres, where people live, but work elsewhere. Many villages and towns around the London area fulfil this function.

Commuter settlements have a large resident population, but as very few of them actually work in the village, there is nobody to support any services. The commuters will do their shopping and banking in the city where they work. This means that these settlements will have fewer services than their population suggests they should have. Some commuter settlements are changing their services to cater for the different residents, with restaurants and cafes replacing the traditional village services.

The sphere of influence of a settlement describes the area that is served by a settlement, for a particular function. Its sphere of influence for different functions may cover vastly different areas. For instance a supermarket may attract people from a 20-mile radius, whilst a leisure activity, such as going to the theatre may attract them from far further away.

The larger a settlement is the greater its sphere of influence is likely to be, as it has a wider range of services and functions to attract people to go there. This is shown in the diagram below. A small village may only have a village store selling the daily newspaper and food such as bread and milk. People will only travel the shortest distance they need to buy these products. They are described as being convenience goods. In other words, something that you can buy easily and for the same price all over the place.

A larger town would have a wider sphere of influence because it would have shops and services that are more specialist, and so people would be willing to travel further to use them. An example might be a furniture shop. This sells comparison goods, in other words products that you might shop around for before going ahead and buying something.

There are two major ideas to consider when looking at the sphere of influence of a shop of service. These are called the range and threshold population of a good.

The range of a good or service describes the maximum distance that someone would be willing to travel to obtain that good or service. A newspaper shop has a small range because people will not travel far to use them. A cinema has a much wider range as people are prepared to travel much further to go to it.

The threshold population of a good or service is the minimum number of people needed to allow that shop or service to be successful. The more specialist a shop is the larger its threshold population is.

A newsagent will have a small threshold, where as a supermarket like Tesco's needs a much larger population before it can consider opening a store.

The function of a settlement describes all the main activities that occurin it.

These can be grouped into a number of headings, such as residential,recreational, retail, government, entertainment andindustrial.

Some settlements have one predominant function. This was particularly thecase when settlements were first established. Some towns performed important defensive functions, others were ports and others were important route centres for further exploration of a country (such as the gateway cities of Canada e.g. Calgary and Edmonton).

Most settlements now are multi-functional,which means that they perform a range of different functions, however some may be more important than others to a particular settlement. For instance a tourist town will perform all sorts of functions, but its main ones are concentrated towards the tourists.

Many settlements around the world have found that their functions have had to change over time. One such example is that of small farming villages finding that their residents are moving out to find jobs in the cities.

This leaves the village empty, apart from the older population. The village then may become a retirement centre, or commuters may move in and it could become a commuter village. Two good examples of the changing functions of a settlement can be seen in Benidorm (Spain) and the South Wales mining towns.

Example: Benidorm

In the 1950's Benidorm was a small, attractive fishing village bordered by fine sandy beaches. Few people visited it despite the attractive scenery andwarm summers. However over the next 20 years travellers discovered the lovely little village and began to flock there.

By 1970 Benidorm had been transformed from a small fishing village to a sprawling mass of hotels based around the needs of the tourists. The town had changed functions completely. By 1990 the resort had begun to stagnate, and the government was forced to step in with a scheme aimed at rejuvenating the resort and its facilities.

Example: South Wales Mining Towns

The villages of South Wales began their existence as small farming communities. During the Industrial Revolution, large deposits of coal were found in the valleys and the mining industry took off. Settlements grew due to this new industry. However by the 1930's the amount of coal being extracted was beginning to decline and by the 1990's all but one of the mines had been closed down.

The towns and villages that had relied on the coalmines began to decline. Some however have once again had their functions changed. Small villages have become centres for commuters to locate to, whilst the larger settlements such as Pontypridd and Swansea have benefited from being at the Western end of the M4 Corridor.

This growth corridor extends right the way to London, and so large companies such as Sony, Bosch and the Royal Mint have been encouraged to relocate to South Wales. The towns are becoming important industrial and business areas.

Often in geography models are used to try to explain something that we can see in the physical environment. During the 20^th century a number of models were developed to try to explain how urban areas grew. Although models show a very general idea of the shape of the city, all of the ones described here have aspects that can be seen in most cities in the developed and developing world.

Burgess's concentric ring model:

Burgess based his model on the city of Chicago

At its core is the CBD, or Central Business District. This is the area with the highest land price, which could only be afforded by businesses.

Around this is the zone of transition, which is where industry located. In many cities in the UK, such as Birmingham, this zone can be quite easily identified. However in most cases the industry has moved out, leaving the zone empty and in need of renewal.

Beyond the zone of transition are the rings of residential housing. As people became more wealthy they could afford to live further out of town, in bigger houses, with larger gardens.

The houses closest to the centre originally would have housed the workers for the inner city industries. Many British cities still have many of these terraced houses remaining.

As people moved away from the CBD, the houses closest to the centre would be taken by newly arrived immigrants to the city, either from elsewhere in the country or abroad.

Hoyt's sector model:

The sector model has a similar idea of a CBD to Burgess. This is still the area with the highest land price.

Hoyt then used transport routes to determine where his other sectors would be located. He still had a zone of transition around the CBD, but he also had industry fanning out from the centre along major transport routes. He assumed that "Like would attract like", which is why he decided that land-uses would concentrate to form sectors, rather being in rings, like Burgess thought.

The lowest class housing would be closest to the industry, and probably be located where the prevailing winds would blow the pollution towards them (and away from the higher class housing).

The high class housing also is in a sector of its own, running all the way from the CBD, where many of the residents would work, to the outer suburbs.

Harris & Ullman's multiple nuclei model:

This model was aimed at being more specific than the other two, however it also has become more complicated.

Harris and Ullman still have a central CBD, but they also have other smaller centres performing specific functions that Hoyt and Burgess decided would have been found in and around the CBD. Thus Harris & Ullman also havea business centre, and industrial parks.

Large cities do display some of these characteristics. London has different areas of its centre that have different functions: the City, Westminster, Oxford Street and the West End all have differing specific functions.

London has also grown to engulf other towns and villages, which have become smaller CBD's within the whole of Greater London. These CBD's act as growth poles, meaning that the city does not just grow from one central point, but from many spread around its area.

Waugh's model of a developing world city:

Based on cities of the developing world, using some of the ideas found in the MEDC models, but also incorporating the urban features only foundi n LEDC cities.

The CBD is still central to the urban area, and is the area of highest landprice. However around it is the most expensive residential areas. In someplaces, such as Sao Paulo, this means huge luxurious high-rise apartment blocks, whilst in others, such as Delhi, the former colonial areas are the most lucrative in which to own property.

Industrial development is along major transport routes, whilst there are also sectors of high-class housing.

The most striking difference between the LEDC model and the MEDC models is the remaining residential areas. They have been divided into three sections.The periferia are low class, poor quality houses. However they do have limited amenities and are permanent homes.

The favelas or shanty towns are illegal settlements, where the houses are built from what ever the people can find, and there are no basic amenities.In some cities, such as Sao Paulo, schemes have been introduced to help the residents of the favelas, and these people can be found in the sector of housing improvements schemes. (see section on Shanty Towns)

By drawing a transect of a city, you can quite easily identify the different zones, in much the same way as Burgess and the other theorists did. Transects help you to identify and classify zones, enabling you to compare the characteristics of each area. You can identify the CBD, the older terraced housing, and as you move further from the city centre the newer housing of the suburbs. The main zones to concentrate on are:

The CBD: The focal point of the city, with the highest land prices. The CBD is where shops will locate as they know it is the most accessible point for the people of the city. The high land prices mean that buildings tend to grow upwards, and this is why CBD's often have tall skyscrapers, particularly in American cities. The main functions of the CBD will include retail, entertainment, financial services and other professional services.

The Inner City:This is Burgess's zone of transition. The inner city in the 19th Century would have been the centre of industry for most cities. Low paid workers would have lived in the many rows of terraced houses that were built beside the factories. Nowadays, although the factories have gone, many of the terraced houses remain.The Inner city of many urban areas has undergone great changes. These are covered in detail in a later section. However once the industry moved out,the inner cities became areas in need of redevelopment. The first plan was to build tall blocks of flats to replace the terraces. This occurred in the 1960's and 1970's. During the 1990's Inner City redevelopment has taken the form of gentrification schemes aimed at rejuvenating the area, producing more of a community spirit, whilst trying to keep some of the old architecture.

The Suburbs: Many suburban houses were built in the period between the two World Wars, during the first half of the 20th century. Estates full of detached and semi-detached houses grew rapidly as public and private transport improvements allowed people to live further away from their place of work. During the 1960's and 1970's these areas also continued to grow.

The Rural-Urban Fringe: The rural-urban fringe is where most of the post war housing has been built. Usually in estates of mainly detached and semi-detached houses, the emphasis has often been on making the houses as spacious as possible. Again these housing developments were only possible thanks to the fact that most families now own at least one car.

The CBD's of cities throughout the world experience many problems, some of which are outlined below:

Congestion: Many British cities still have street plans that were laid down hundreds of years ago. The roads cannot cope with the ever-increasing numbers of cars and other vehicles. This can cause massive congestion problems, especially at "rush hour".

Solutions to the problems have included improving public transport (e.g. the trams of Manchester); introducing park and ride schemes (e.g. Oxford); pedestrianization (e.g. Exeter & Oxford); encouraging people to share cars into work and building ring roads (e.g. Watford).

In Athens (Greece) they have tried an extreme form of control by only allowing cars with odd numbers on their number plates into the city on one day, and then cars with even numbers the next day. Unfortunately this has led many people to own two cars, one with an odd number and one with an even one!

Lack of Space: CBD?s are limited in their outwards growth by the fact that the city encompasses them, and due to the fact that businesses want to locate as close to the centre as they possibly can. This has led to land prices rising to astronomical amounts. The only solution seen by most businesses is to build upwards, which is why CBD's can be characterised by the presence of skyscrapers.

Pollution: The major pollution seen in urban areas is air pollution, or smog. This pollution is mainly caused by the fumes given off by traffic and industry.

The most famous example of where this pollution haze can be seen is over Los Angeles, but most of the large cities of the world experience it too. Poor air quality can lead to an increase in the cases of asthma and bronchitis.

Air is not the only thing polluted in cities. Water can be badly polluted, and so has to be carefully treated before being drunk. It?s a horrible thought, but most of the water that you drink in London has already been drunk by 7 other people!

Solutions to pollution problems include: banning heavy vehicles from CBD's; developing cleaner fuels, and providing more litter bins in CBD's.

Some cities have encouraged the growth of out-of-town shopping centres to help traffic, land price and pollution problems, by taking some of the focus away from the CBD. However this can also have the negative effect of causing the CBD to decline.

As explained earlier the Inner City is also known as the zoneof transition.

Most inner cities of large urban areas once had industry located there, however this has almost totally moved out. The Victorian terraces built to house thefactory workers remain in many inner cities, however in some they have been replaced by huge tower blocks.

Although seemingly the solution to the problems produced by the terraces, the tower blocks also caused a wide range of social problems. Recently inner city planning has centred around rejuvenating the area in alternative ways, to try to encourage the growth of these declining areas.

The two examples below give an idea of some of the schemes that have been attempted in British inner city areas.

Example: Birmingham

Birmingham is a very good example of where, in the 1960?s, the local authority tried to rejuvenate the inner city areas by knocking down vast areas of Victorian terraces, replacing them with large tower blocks.

The terraces were seen to be old-fashioned, with poor living standards. Often they lacked things that we would take for granted, like central heating, and had inadequate kitchen and bathroom facilities. The local authority decided that the way to combat the problems would be to knock down all the old terraces and completely start again. Many other cities around Britain did the same thing.

The buildings were poorly built and soon began to need costly repairs. They had poor facilities and few green areas.

There was no sense of community for the people who lived there, leading to increased crime, vandalism and graffiti. All these things combined to make the area a dangerous one. Many areas of tower blocks were centres for drug traders and other criminal gangs.

The standard of living was poor, with illness and overcrowding a regular occurrence.

Most people would not choose to live in this type of housing, so it was inhabited by the poorly paid, unemployed or new arrived immigrants. This led to socialt ensions and in the early 1980's inner city areas in Liverpool, Bristol and London all experienced serious rioting.

Example: The London Docklands

After the riots of the early 1980?s a report by Lord Scarman proposed a new way of dealing with inner city troubles. It suggested that these areas should be subject to urban renewal (improving existing buildings) rather than redeveloping areas by knocking them down and starting again.

The London Docklands is the best known example of an inner city area that has been completely transformed in this way. The London Docklands Development Corporation (LDDC) was set up to renew the area.

Some of the things that have happened there in the past 20 years include: .

• The gentrification of old buildings. This basically means keeping the outside of old warehouses and gutting the insides. Often these are then refurbished to become very expensive riverside flats.
• The Docklands Light Railway and Jubilee Line extension have increased access to the docklands area, whilst the City Airport has allowed quick transfers to places throughout Europe.
• Low tax rates and rents have been used to attract large businesses to relocate to the area. Examples include the Daily Telegraph and many financial institutions. Canary Wharf Tower has been the centre point of this business influx.
• Housing has also been built, not just for the rich, young workers in the city, but also for the under-privileged groups who were living in the docklands area previously. Low cost housing has been built, and schemes set up to help people buy them.
• Community centres and services have been introduced to previously declining areas in an attempt to engender more community spirit. Leisure centres and shopping malls have all added to the community feel.
• Not all the residents are happy though, as many of the new jobs are too highly skilled for the original residents of the docklands, and they resent the new people coming into their area.

Shanty Towns are the illegal squatter settlements that characterise most of the large cities in the developing world.

They have occurred because of the huge numbers of people migrating from the rural areas to the cities, which just cannot cope with this massive influx of people. The main points to note about them are:

• The cities most likely to have shanty towns are centres for commercial and industrial activity as well as being transport centres. They are very attractive to in-migrants.
• Most of the new in-migrants have very few skills, education or money, so they will often find whatever work they can.
• Shanty towns develop on marginal land, often close to where the in-migrants hope to get work. The high cost of land near the CBD means that shanty towns are either built on the periphery of the city or in hazardous areas closer to the city centre.

In many world cities, plans are now in place to help formalise the slum housing,using schemes to improve amenities and living conditions. Examples of these self-help schemes can be seen in Sao Paulo (Brazil) and New Delhi(India).

There are a number of problems that are often associated with shanty towns:

• They are politically embarrassing to the Government, which is why many of them are now trying to help the people improve the shanty areas. The Governments feel that they may well discourage tourists from coming to the city.
• The houses are built of whatever the people can find, and are often major fire hazards.
• Their existence will reduce the prices of property in adjacent areas.
• They are home to many diseases and can easily be affected by environmental disasters such as landslides and flooding.

Shanty Towns are called different things depending upon where you area in the world:

In Rio de Janeiro and Sao Paulo (Brazil) they are called Favela's

In New Delhi (India) they are called Jhuggies.

In Calcutta (India) they are called Bustee's

In Lima (Peru) they are called Pueblos Jovenes

Example: New Delhi, India:

The Jhuggies of New Delhi occupy marginal land, usually beside transport routes or in hazardous areas.

They are built from recycled materials and the 400,000 shanty homes house over 2.4 million people. They have a very high population density and very poor facilities, such as toilets, which leads to increased occurrences of diseases such as cholera and dysentry.

By all building together (illegally) the residents hope that the area will become officially recognised and therefore will qualify for government funded public services, such as sewerage and electricity.

Many governments have bulldozed shanty towns to try to relocate the people, but this tactic hardly ever works. In Delhi they realised that the shanty towns should become the starting point for urban redevelopment and planning.

The government introduced schemes where the local community was closely involved in the planning and building of new houses. Often the government provided the materials, whilst the local people built the buildings. The government would then provide an improved infrastructure. This has occurred in many cities throughout the developing world.

The Delhi Authorities have also built completely new communities away from the old shanty towns, complete with good transport links to the CBD, where many people work, and the prospects of many jobs in the new area.

One such area is called Rohini. It was built in the 1980?s to house 850,000 people and provide 300,000 jobs. Similar schemes are planned for elsewhere in the city.

The Rural-Urban fringe is the name given to the land at the edge of an urban area, where there is often a huge mixture of land uses.

Often science parks, business parks and industrial estates locate in the rural-urban fringe as the land is cheaper, there is room for expansion and they are closer to transport links to allow export and import of goods.

Motorways and by-passes, such as the M25 and the Newbury by-pass have been built on the rural-urban fringe, much to the disgust of environmental groups who feel that the area should be kept as green as possible.

Recreational land-uses such as golf courses and leisure parks have been established in the rural-urban fringe.

Housing has also encroached into the rural-urban fringe, and small villages have grown as more people move out of the cities and commute to work.

Out-of-town shopping centres also find that the space available, good transport connections and cheap land encourage them to establish in the rural-urban fringe.

Farming still occurs in the rural-urban fringe, although the farmers often come under great pressure to sell their land for development. A farmer will make far more money from a sale if there is already planning permission for building to occur on the land.

Greenbelts were established to prevent the continued growth of many of the largest cities of England and Scotland.

They are rings of heavily protected open land circling an urban area. They aim to protect the surrounding countryside from development, and in some cases stop two large cities from merging. Planning permission is not usually granted for schemes on green belt land, although there is often great pressure to allow some proposals through.

The M25 is built through much of London's greenbelt. One of the main problems of the greenbelts is that they have led to people commuting further into work.

The map below shows where the green belts are located:

The Site of a settlement describes the physical nature of where it is located. Factors such as water supply, building materials, quality of soil, climate, shelter and defence were all considered when settlements were first established. For instance the site of Sydney, in Australia, initially took advantage of the excellent natural harbour and surrounding fertile farmland.

Paris was established at a point where an island allowed an easier passage across the river Seine as well as providing defence, fishing, transport, and drinking water.

There are a huge number of factors that have to be considered when trying to locate a new settlement. These can be grouped into four broad headings: climatic, economic, physical and traditional. The diagram below should give you an idea of how each one plays a part in the location of a settlement.

Aspect

Aspect and shelter are two of the most important factors that were used when deciding where to locate a settlement. Aspect relates to the direction in which the land faces. In the Northern Hemisphere the best slopes to locate on are those that face south, as they will receive the most sunshine, and therefore be best for agriculture. This can be seen clearly in many of the valleys of the Alps, where settlements have located on the south-facing slopes.

Shelter is also very important, particularly from the cold northerly winds and prevailing southwesterly winds in the UK. A good example of settlements being sheltered by their natural surroundings are the many spring-line settlements found along the base of the chalk escarpments of the North and South Downs. These settlements would also have benefited from the good water source and fertile farmland nearby.

Water supply:

A supply of water was probably the single most important factor in deciding where a settlement might be located. Not only do rivers provide a source of clean drinking water, they also provided a food source through fishing, and a transport route. Most of the world's largest cities are located on rivers, especially the point at which they reach the sea, as this was often the first point that explorers landed.

Dry point sites:

Water is vital to a settlement and is the most common factor behind their location. A dry point site is one that is slightly raised from the surrounding area, meaning that it is less likely to flood. Ely in Norfolk is a good example of this.

Wet point sites:

This refers to any site that has access to water, usually through being beside a river. Towns would either grow up along the river or clustered near the point at which the river enters the sea. Examples of wet point sites include the towns and villages of the Welsh valleys, which tend to extend along the flat valley floor, rather than up the steep valley sides. Spring line settlements in the North and South Downs are also good examples of wet point sites.

Defence:

In medieval times defence was one of the most important factors influencing the site of a settlement. The relief (shape) of the land often proved to be the best form of defence. Edinburgh castle sits on the top of a glacial crag, in an almost perfect position to defend itself, with very little chance for the attackers. In Italy, there are many walled hill-top villages, whilst the Maoris in New Zealand built their settlements (called Pa's) on the top of steep hills to prevent being attacked.

The other common natural feature used for defence is water, and in particular rivers. Both Shrewsbury and Durham are very good examples of where a meander of the river has formed an area of land bounded by water on three sides. This provided both cities with excellent defences, as they only had a thin neck of land to defend.

Resources:

The idea of resources covers a huge number of different things. For early settlers the most important resources were fuel, building materialsand food. Settlements grew in areas where wood was plentiful, stone easily accessible and good soil allowed agriculture to be developed.

Since those early days of settlement many different resources have become the focal points for the growth of urban areas. Some of these are listed below:

Mining: The coal mines of South Wales, Tin mines of Cornwall and large mining projects as seen at Carajas in Northern Brazil, have all encouraged the rapid growth of settlements aimed at housing the workers and providing them with all that they require.

Food: The farming area of East Anglia is one example of how small settlements will locate in areas conducive to good agriculture.

Oil: Settlements in Alaska and the Middle East have grown rapidly on the back of the oil industry.

Precious metals: Settlements in South Africa have grown after thediscovery of large deposits of precious metals such as gold. The most famoussettlement to grow due to finding gold is San Francisco, after the gold rushto California in 1849.

Route centres:

Route centres are often called Nodal Points. Anywhere where two routes meet has great potential for settlement. Often these are formed by the meeting of two valleys, but settlement nowadays will grow where two main roads meet. In the UK, York is a good example of a route centre. Birmingham also enjoys a very good location, where many routes join up, and this is one of the reasons for its growth to become one of the largest cities in the UK.

Bridging points:

Just as water is very important for drinking, fishing, irrigation and navigation, so the ability to cross the rivers is also very important.

Many towns and cities have built up at points where it was easiest to cross a large river. Exeter is one such example, crossing the river Exe.

However one of the best examples is Paris in France. The original town was based on the tiny Ile dela Cite, which is an island in the middle of the River Seine. This island meant they could build two small bridges across the river rather than one large one.

The new settlement also benefited from all the other advantages associated with being beside a river, as well as becoming a route centre due it being one of the only places to cross the river. Nowadays the island has been engulfed by the huge city that Paris has become, however it does still have many bridges going to it and is the point where the huge Notre Dame Cathedral is built.

The confluence of two rivers:

Just as two valleys, or roads, make a nodal point for settlement growth, so do two rivers joining. One such example is found in Khartoum in Sudan, where the Blue and the White Nile meet.

The situation of a settlement is the description of the settlement in relation to the other settlements and physical features around it. The situation of a settlement is the most important in determining whether it grows to become a large city or stays as a small town or village.

In the UK, Birmingham is an example of a city with an excellent situation. It is located central to the country, with excellent links by road to the North and South to London.

As cities begin to fulfil different functions their importance can increase or decrease. Their situation plays an important part in deciding which of these will occur.