Biomes, ecosystem goods and services, and farming systems

Welcome to Rural Environments: Biomes, Ecosystems, and Farming Systems

Welcome! Rural environments cover huge areas of our planet, from dense green forests and wide-open grasslands to organized crop fields and cattle ranches. In this chapter, we explore how nature organizes life across the globe through biomes, what vital goods and services these natural ecosystems provide us, and how humans utilize the land through different farming systems.

Note: Later chapters in this section cover "Rural characteristics and rural change", "Rural diversification, sustainability and management", and the "Rural fieldwork enquiry". For now, we are focusing squarely on biomes, ecosystem benefits, and agricultural systems!

Don't worry if all the terminology feels a bit overwhelming at first. We will break down every single idea into simple, manageable steps with clear examples and memory tricks.

Part 1: Global Biomes – Distribution and Characteristics

A biome is a very large-scale global ecosystem. Biomes are defined mainly by their climate (particularly temperature and rainfall) and have characteristic communities of plants (flora) and animals (fauna). The Pearson Edexcel specification requires you to know seven distinct biomes:

1. Tropical Forests

• Location and Distribution: Located along and near the Equator, roughly between \(5^\circ\) and \(10^\circ\) north and south of the Equator (for example, the Amazon basin in South America, Central Africa, and Southeast Asia).
• Climate: High temperatures all year round (averaging around \(26^\circ\text{C}\) to \(28^\circ\text{C}\)) with very high annual rainfall (often exceeding \(2000\text{ mm}\) per year), and no distinct dry season.
• Vegetation and Features: Dense, evergreen trees arranged in distinct vertical layers (emergent layer, canopy, under-canopy, shrub layer). Exceptionally high biodiversity (home to over half of the world's plant and animal species). Competition for sunlight is intense.

2. Temperate Forests

• Location and Distribution: Found in mid-latitude zones, roughly between \(40^\circ\) and \(60^\circ\) north and south of the Equator (such as Western Europe, parts of eastern North America, and East Asia).
• Climate: Four distinct seasons with warm summers and cool or mild winters. Moderate to high rainfall distributed evenly throughout the year (typically \(750\text{ mm}\) to \(1500\text{ mm}\)).
• Vegetation and Features: Dominated by broadleaf deciduous trees (such as oak, beech, and ash) that drop their leaves in autumn to conserve water and survive cold winter conditions. The forest floor has rich leaf litter that breaks down to create nutrient-rich soils.

3. Boreal Forests (Taiga)

• Location and Distribution: Found across high northern latitudes, generally between \(50^\circ\text{N}\) and \(70^\circ\text{N}\) in a continuous belt across northern Canada, Scandinavia, and Russia (Siberia).
• Climate: Very long, freezing, severe winters (temperatures frequently dropping below \(-20^\circ\text{C}\)) and short, mild summers. Relatively low annual precipitation, mostly falling as snow.
• Vegetation and Features: Dominated by evergreen coniferous trees (such as spruce, pine, and fir). These trees have needle-shaped leaves with a waxy coating to prevent water loss and flexible, sloping branches to shed heavy snowfall easily.

4. Tropical Grasslands (Savanna)

• Location and Distribution: Found between tropical rainforests and hot deserts, roughly between \(5^\circ\) and \(20^\circ\) north and south of the Equator (broadly across central and eastern Africa, parts of South America, and northern Australia).
• Climate: Warm to hot year-round (usually \(20^\circ\text{C}\) to \(30^\circ\text{C}\)), but marked by a very distinct wet season and dry season.
• Vegetation and Features: Wide plains of tall grasses with scattered drought-resistant trees (such as acacias and baobabs). Trees often have deep taproots to reach groundwater, thick bark to withstand fires during the dry season, and small or thorny leaves to limit transpiration.

5. Temperate Grasslands

• Location and Distribution: Located in continental interiors at mid-latitudes, roughly \(30^\circ\) to \(55^\circ\) north and south of the Equator (such as the Prairies of North America and the Steppes of Eurasia).
• Climate: Continental climate with extreme seasonal temperature ranges: hot summers and bitterly cold winters. Moderate to low rainfall (typically \(250\text{ mm}\) to \(500\text{ mm}\)), which is not enough to support natural forests.
• Vegetation and Features: Dominated by grasses (short-grass or tall-grass prairie) with virtually no natural trees except along riverbanks. Grasses have deep, fibrous root systems that anchor rich organic soils.

6. Deserts

• Location and Distribution: Found mainly around \(20^\circ\) to \(35^\circ\) north and south of the Equator, frequently on the western sides of continents or in continental interiors (e.g., the Sahara in North Africa, Arabian Desert, Australian Outback).
• Climate: Extremely arid, receiving less than \(250\text{ mm}\) of rainfall per year. Hot deserts experience high daytime temperatures (often over \(40^\circ\text{C}\)) and very cold nights due to the absence of cloud cover to trap heat.
• Vegetation and Features: Very sparse vegetation adapted to extreme drought (xerophytic plants, like cacti and succulents). Adaptations include water-storing fleshy stems, spines instead of leaves to stop water loss and deter animals, and widespread shallow roots or very deep taproots.

7. Tundra

• Location and Distribution: Found at high latitudes surrounding the Arctic circle (above \(60^\circ\text{N}\) to \(70^\circ\text{N}\)), bordering the Arctic Ocean in northern North America, Europe, and Asia.
• Climate: Extremely cold, dry, and windy conditions. Winters are long, dark, and bitterly cold; summers are very short and cool (barely rising above \(10^\circ\text{C}\)). Annual precipitation is very low (often under \(250\text{ mm}\)), earning it the nickname "cold desert".
• Vegetation and Features: Treeless landscape. Underneath the thin top layer of soil lies permafrost (permanently frozen subsoil). Vegetation consists of low-growing mosses, lichens, hardy grasses, and dwarf shrubs that grow close to the ground to shelter from freezing winds.

Memory Aid: The Latitudinal Ladder

To remember how biomes shift from the Equator towards the poles, picture moving up a ladder of latitude:
1. Equator (\(0^\circ\)): Hot and wet \(\rightarrow\) Tropical Forest
2. Just off Equator (\(5^\circ\text{–}20^\circ\)): Wet and dry seasons \(\rightarrow\) Tropical Grassland
3. Sub-tropics (\(20^\circ\text{–}35^\circ\)): High pressure, dry and hot \(\rightarrow\) Desert
4. Mid-latitudes (\(30^\circ\text{–}50^\circ\)): Continental, moderate rain \(\rightarrow\) Temperate Grassland
5. Mid-latitudes (\(40^\circ\text{–}60^\circ\)): Mild, wet seasons \(\rightarrow\) Temperate Forest
6. High latitudes (\(50^\circ\text{–}70^\circ\)): Cold, snowy \(\rightarrow\) Boreal Forest
7. Arctic edge (\(>60^\circ\text{–}70^\circ\)): Frozen permafrost \(\rightarrow\) Tundra

Key Takeaway for Biomes: Biome distribution is controlled primarily by global atmospheric circulation, temperature, and precipitation. Warm and wet conditions produce lush forests; dry conditions yield grasslands or deserts; freezing conditions lead to boreal forest and tundra.

Part 2: Goods and Services from Natural Ecosystems

Natural ecosystems are not just scenic landscapes; they provide essential support for human survival and economic activity. In Geography, we divide these natural benefits into two distinct categories: goods and services.

Ecosystem Goods (Physical Products)

Goods are tangible, physical items that humans extract directly from ecosystems to consume, build with, or sell. Think of them as things you can hold in your hand.

• Food: Berries, nuts, wild game, fruits, and fish harvested directly from natural ecosystems.
• Timber and Wood: Hardwood and softwood logs used for building materials, furniture, and paper manufacturing.
• Fuel: Firewood, charcoal, and biomass gathered by rural communities for cooking and heating.
• Medicines and Biochemicals: Plants containing natural compounds used to develop modern pharmaceuticals (for example, quinine for malaria treatment or chemicals found in tropical rainforest plants used in cancer therapies).

Ecosystem Services (Functions and Benefits)

Services are intangible processes and life-support functions that ecosystems carry out naturally. They keep our planet habitable, healthy, and stable.

• Climate Regulation and Carbon Storage: Forests and wetlands absorb vast amounts of carbon dioxide through photosynthesis, locking carbon away in plant biomass and soil, which helps regulate global temperatures.
• Water Cycle Regulation and Purification: Vegetation intercepts heavy rainfall, slowing surface runoff, preventing floods, and naturally filtering groundwater as it percolates through soil.
• Soil Protection and Nutrient Recycling: Plant root networks hold topsoil in place, preventing soil erosion. Decomposing organic matter recycles nutrients like nitrogen and phosphorus back into the soil for future plant growth.
• Oxygen Production: Plants and photosynthetic organisms generate the oxygen that humans and animals need to breathe.
• Recreation, Tourism, and Well-being: Natural ecosystems offer space for tourism, outdoor activities, cultural inspiration, and mental health benefits.

Common Student Mistake to Avoid!

Mistake: Mixing up "goods" and "services".
Simple Rule: If you can touch it, put it in a box, or sell it by the kilogram, it is an ecosystem good (e.g., a basket of fruit, a plank of timber). If it is a natural process or background function that maintains the environment, it is an ecosystem service (e.g., carbon storage, flood control, nutrient cycling).

Key Takeaway for Goods and Services: Ecosystems supply humans with physical resources (goods) and keep planetary systems running smoothly (services). Without these natural processes, modern human societies could not function.

Part 3: Farming Systems

Agriculture is the dominant human activity in rural environments. In geography, a farm is treated as an open system consisting of:

• Inputs: What goes into the farm. These can be physical (sunlight, rainfall, soil quality, relief/slope) or human/economic (labour, seeds, animal feed, machinery, fertilizers, capital investment).
• Processes: The activities taking place on the farm (ploughing, sowing, weeding, applying fertilizer, milking, harvesting, shearing).
• Outputs: What the farm produces. These can be useful outputs (crops, meat, milk, wool, money/profit) or waste outputs (slurry, runoff, emissions).

Classifying Farming Systems

Farming systems are categorized using three contrasting pairs. You must understand each pair and be able to describe how they differ:

1. Arable vs Pastoral Farming

• Arable Farming: The production of crops from cultivated land (e.g., wheat, barley, maize, vegetables, oilseeds). Arable farming typically thrives on flat or gently sloping land with fertile soils and warm, sunny conditions.
• Pastoral Farming: The rearing of livestock/animals (e.g., beef cattle, dairy cows, sheep, goats, pigs) to produce meat, milk, wool, or hides. Pastoral farming is often found in cooler, wetter, or upland areas where steep relief or poor soils make crop-growing difficult.
(Note: When a farm combines both crops and livestock, it is known as mixed farming.)

2. Commercial vs Subsistence Farming

• Commercial Farming: Farming conducted primarily for sale and monetary profit. The produce is sold to local markets, supermarkets, processing companies, or exported internationally. Commercial farms are closely tied to financial markets and modern supply chains.
• Subsistence Farming: Farming conducted primarily to feed the farmer and their immediate family. There is little or no surplus left over to sell. If a tiny surplus is produced in a good year, it might be traded at a local market for essentials, but profit is not the primary aim.

3. Intensive vs Extensive Farming

• Intensive Farming: Farming that uses high inputs of labour, capital, machinery, or agrochemicals (fertilizers and pesticides) relative to a small land area. The goal is to maximize yield per hectare (e.g., intensive vegetable farming, commercial poultry sheds, or high-yielding intensive rice paddies).
• Extensive Farming: Farming spread over a very large area of land with relatively low inputs of capital, labour, or chemicals per hectare. Yields per hectare are low, although total production may be substantial because the land area is so vast (e.g., extensive sheep farming in upland areas, or cattle ranching on open grasslands).

Combining the Classifications: Examples in Action

Farms are never just one thing—they combine these terms. Look at these examples to see how the three pairs work together:

• Commercial Intensive Arable: A large commercial grain or vegetable farm using high-tech tractors, computerised irrigation, and chemical fertilizers on high-grade soils to produce maximum crop output for profit.
• Commercial Extensive Pastoral: A vast cattle station in an arid or semi-arid grassland where few workers look after herds roaming over thousands of hectares with low inputs per hectare.
• Subsistence Intensive Arable: Small family plots growing wet rice in river valleys, requiring high amounts of human hand-labour and caring for every square metre of land, with all rice consumed by the household.
• Subsistence Extensive Pastoral: Nomadic herders moving goats or camels across dry savanna or desert fringes, using huge tracts of marginal land with minimal inputs to sustain their family.

Key Takeaway for Farming Systems: Every agricultural operation can be identified along three scales: what it produces (arable or pastoral), its purpose (commercial or subsistence), and how heavily it utilizes land and inputs (intensive or extensive).

Quick Revision Checklist

Before moving on to the next chapter, check whether you can confidently:

• State the global distribution and climate characteristics of all 7 biomes: tropical forests, temperate forests, boreal forests, tropical grasslands, temperate grasslands, deserts, and tundra.
• Explain how vegetation adapts to its environment in each biome (e.g., drip-tip leaves in rainforests vs spines and waxy coatings in deserts).
• Clearly distinguish between an ecosystem good (physical item like timber, food, medicine) and an ecosystem service (function like carbon storage, soil protection, flood control).
• Define and contrast the three pairs of farming systems: arable vs pastoral, commercial vs subsistence, and intensive vs extensive.
• Describe a farm as an open system with inputs, processes, and outputs.