Geography module 2

ecosystem

community of plants and animals that depend on each other and non-living elements to survive.

biotic elements

living elements, e.g. Plants, animals, microorganisms

Abiotic elements

non-living elements, e.g. Rocks, soils, climate

biomass

global ecosystems

Nutrients absorbed from atmosphere via photosynthesis

hydrogen, carbon, oxygen

nutrients absorbed from soil

Nitrogen, potassium, sulfur, magnesium

what does deforestation do?

strips nutrients from the soil, affects rate of photosynthesis and growth of the plant.

what type of woodland is epping forest?

deciduous forest

what is the weather like in epping forest?

mild and wet, like rainforest

layers in rainforest

ground, herb, subcanopy, canopy

Ground layer

leaf litter, moss

Herb layer

plants, e.g. Bluebells

subcanopy layer

small trees, bushes, birds

canopy layer

taller and older trees, e.g. Horse chestnut and oak

Nutrient cycle

* water and air penetrate soil
* Plant/animal matter breaks down into soil
* Decomposers break down organic matter
* Rocky subsoil breaks down providing nutrients to soil
* Soil stores nutrients which plants absorb
* Nutrients used to grow

where is epping forest?

north east of London, south east england between London and Stansted Airport

How has epping forest been managed?

SSSI - protect environment, used for timber resources and hunting.

Why are the bogs and ponds important?

they have their own unique species, including 20 species of drsgonfly

What is the forest the remains of?

a larger forest that colonised England at the end of the last Ice Age

Why is Epping forest a SSSI?

Complex food web, contains thousands of species such as many trees and 177 species of moss.

tree species found in Epping forest

beech, elm, oak, ash

producer species in Epping forest

lichen, moss (177 species), grasses, brambles

Consumer species in Epping forest

insects, small mammals, deer, 38 species of birds, owls, adders, foxes.

why are the trees deciduous?

to conserve their energy. Less sunlight and low average temp so little photosynthesis occurs.

Why do the trees have broad leaves?

maximise photosynthesis , green to absorb lots of chlorophyll for photosynthesis, broad to absorb lots of sunlight or water for photosynthesis

what happens to leaf litter?

Decompose and converted into humus in the soil and its nutrients are absorbed into the soil.

interdependence example

soil requires leaf litter as it provides nutrients for photosynthesis

How do people affect the forest

collect berries and flowers that in turn spreads seeds as they stick to clothes, deforestation

distribution of ecosystems

* desert and savanna around equator, where the most heat energy’s absorbed and hp winds, l rain
* Tundra and temperate forest furthest away from equator so receives less heat energy from sun
* Tropical rainforests close to equator- hot
* Mountains on plate margin - collision margin

Land closer to poles

sun has to pass through more of the atmosphere, more energy lost (air cooler), sun ray’s concentrated at equator but spread out at poles

biomass

mass of living organisms in a given area or ecosystem at a given time

food chain example

clover, snail, thrush, sparrowhawk

healthy food chain

biomass at each trophic level must reduce, energy lost as not all of prey eaten. Hunters use lots of energy catching prey.

What are deciduous trees often replaced with?

faster growing coniferous trees

what type of woodlands are under threat?

deciduous woodlands

Why are woodlands cleared?

create larger, more intensive farms

Make space for urban growth, e.g. building houses

Loss of biodiversity

* 70% of animal and plant species
* Lower biomass, less plants animals can eat
* Less plants so less nutrients in soil
* Primary consumers may die - less plants to eat

Water in atmosphere

* trees help control water levels in atmosphere by regulating water cycles
* In deforested areas, less water in air to be returned to soil- dryer soil, inability to grow crops
* Less nutrients and water in soil may cause animal deaths

Soil erosion and flooding

* trees help land retain top soil and water, which provides rich nutrients for forest soil.
* No forests: Soil erodes and washes away - causing farmers to move on and perpetuate the cycle.
* barren land left behind more susceptible to flooding

Desert

area receiving less than 250mm if rainfall, resulting in extreme aridity.

Location of deserts

* primarily along tropic of cancer and capricorn -30 degrees north and south of equator
* Continents such as N.America and Africa
* Atacama and Sahara desert
* Hot in the day, cold at night
* Little rainfall
* Sandy soil - cacti and shrubs

tundra

* high latitudes - above 60 degrees
* North Europe, Canada, Alaska
* Very cold winters, summers brief with little rain
* Few trees, vegetation includes shrubs, mosses, grasses
* Layer of permanent frozen ground, permafrost

Grassland

* two types: Savannah and temperate

Savannah grasslands

* between the tropics
* Distinct dry and wet seasons
* Low rainfall and most vegetation is grasses with scattered trees

Temperate grasslands

* higher latitudes
* No variation in temperature
* Less rainfall
* No trees, just grasses

Temperate deciduous forest

* mainly in mid latitudes, 4 distinct seasons
* Warm summers, mild winters
* Rainfall all year around
* Deciduous trees lose their leaves in winter due to colder weather

Polar

* around the poles
* Very cold, icy, dry- little grows
* Dark for several months a year e
* Growing season v short- two months

Tropical rainforest

* around the equator between tropics
* Hot and wet all yr around


* Area of lush forest, with dense canopies of vegetation - distinct layers

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Boreal forest (Taiga)

* between 50-60 degrees north
* Cold and dry winters; mild and moist summers
* Coniferous trees: Evergreen with needles

Tropical rainforest climate

* no definite seasons- same all year round
* Hot: Temp 20-28 degrees celsius (little variation
* High rainfall: 2000m per year. Rains daily

Why is it hot all year round?

sun’s energy more intense near the equator as it’s overhead all year round

Tropical rainforest soil

* not very fertile: Rain washes nutrients away
* Surface nutrients due to decayed leaf fall: Thin layer as decay is fast in the warm, moist conditions

tropical rainforest plants

* trees evergreen to take advantage of continual growing season
* Many trees tall and vegetation cover dense- little light reaches forest floor
* Lots of epiphytes, e.g. Orchids, ferns

What are epiphytes?

plants that grow on other living plants and take nutrients and moisture from the air.

Tropical rainforest animals

* rainforests have more animal species than other ecosystems
* Gorillas, jaguars, anacondas, tree frogs, sloths, howler monkeys
* Many species of insects and birds

Tropical rainforest people

* indigenous people that have adapted to life there
* Make a living by: Hunting, fishing, gathering nuts and berries and growing veg

biodiversity

variety of organisms living in a particular area

Tropical rainforests biodiversity

* high biodiversity- 50% of world’s species
* May contain half of all life on earth

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Why is the rainforest a stable environment?

* climate constant- always hot and wet
* Organisms don’t have to cope with changing conditions
* Always plenty to eat

Why do some species live in a small area?

* evolved to depend on a few other species
* Specific to certain habitat and food source

Causes of extinction

* deforestation
* Uncontrolled development

What does the climate help fungi to do?

* decompose dead plant material quickly
* Makes soil high in nutrients, plants grow easily

How do plants pass on nutrients?

* when eaten by animals
* Dense vegetation provides lots of food, animal pop. high
* Animals die, nutrients transferred back to soil, making it richer, encouraging vegetation
* Key part of nutrient cycle

What is a symbiotic relationship?

where plants and animals depend on each other for survival

Agouti

* rodent that is one of few animals that can crack open hard seed pod of brazil nut to eat the nut inside
* Bury them to sprout into seedlings
* Become extinct= less brazil nuts
* Some sell for living and some animals use them for food or shelter

Cecropia trees

* hollow stems and produce energy-rich foodstuff at base of leaves
* Ideal habitat for Azteca ants that use them for food and shelter - struggle to live without
* Ants fight off other species that want to live on trees
* Attack lianas that compete with trees for sunlight
* Without ants, trees vulnerable to predators

How are trees important?

* intercept and take up lots of water
* Release it back into atmosphere
* Moisture for more rainfall
* Less tree cover = higher risk of drought
* Stabilise soil with roots, provide nutrients when they drop their leaves
* Fewer trees = less protection from rain, nutrients wash away, plants struggle to grow

What are plants adapted to?

* high rainfall
* High temperatures
* Competition for light

how do trees compete for sunlight

by growing tall

Leaf adaptations

* thick, waxy leaves
* Pointed drip tips: Channel rainwater to point, encourage run off so weight of water doesn’t damage plant and no standing water for bacteria to grow in
* Waxy coating helps repel rain
* Drop leaves gradually throughout the year, grow all year round

Lianas

use tree trunks to reach sunlight

Tree bark adaptations

* thin and smooth
* Doesn’t need protection from cool temps.
* Helps water run off easily

Tree roots adaptations

* large and stable - buttress roots
* Support tall trees’ trunks

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Emergent layer

between 30-40m, only branches at crown, where there’s the most light

Main canopy

between 20-30m

Under canopy

between 10-20m, some plants have large leaves to absorb lots of sunlight

Shrub layer

between 0-10m

Strong limbs

* Animals who live high up in canopy
* Move around habitat quickly and easily
* E.g., howler monkeys

Short pointed wings

* some birds, e.g. Harpy eagle
* Easily manoeuvre between dense maze of trees

Suction cups and skin flaps

* sc helps animals climb, e.g. Tree frogs
* Sf help them glide between trees, e.g. Flying squirrels

camouflage

* look like objects in forest, e.g. Plants to hide from predators, e.g. Leaf tailed geckos

Adaption to low light levels-

* some animals on forest floor adapted to this
* Anteaters have sharp sense of smell, detect predators without seeing them

Nocturnal

* feed at night when it’s cooler to help them save energy
* e.g. Sloths

Ability to swim

* some animals can swim, e.g. Jaguars
* Help them cross river channels

The amazon rainforest

* largest rainforest in the world
* Area = 8 million km squared
* Brazil, Colombia, Peru, Venezuela, Ecuador

Deforestation in the Amazon

* 18million hectares lost 2001-12, 1.4 million hectares a year
* 30% lost by 2030 if rate not reduced

Reasons for deforestation

* commercial farming
* Subsistence farming
* Commercial logging
* Population growth
* Mineral extraction

Commercial farming

* forest cleared for cattle grazing or plantations

Cattle ranching

* main cause of deforestation
* 200m cattle and 450k km of pasture

Soy

* up to 250k km of land used
* Other crops, e.g. Corn, sugar cane, rice

Subsistence farming

* Land cleared by small- scale farmers to grow food for their families
* E.g. Indigenous people

Commercial logging

* full of valuable hardwood trees- mahogany
* Tempting to illegal and legal businesses

Mineral extraction

* gold, iron ore, copper
* Exported to help boost countries’ development
* explosives sometimes used to clear earth
* deep pits dug to reach mineral deposits

Population growth and migration

* puts pressure on forest
* Brazilian gov offers forest land to poor in overcrowded cities
* many farmers settled along the Trans Amazonian highway

Energy development

* hydroelectric dam building floods forest
* Construction of Balbina Dam, Manaus flooded 2400km of forest

Road building

* 4000km Trans Amazonian Highway connects brazil’s coast to peru, colombia and Ecuador via amazon
* New roads for logging opened up hard to access access: More destruction and threatening of forest

Impact on climate change

* trees remove CO2 from atmosphere - amazon stores 140bn tonnes of carbon’
* Deforestation releases it, causing global warming
* Up to 75% of Brazil’s CO2 from deforestation

Impact on soil erosion

* Br losing 100 tonnes of topsoil per hectare per year due to erosion, causing landslides and flooding in the future
* Less tree canopy intercepts rainfall and fewer roots to absorb it so more water reaches soil
* Washes nutrients away so reduces soil fertility
* Farmers must find new areas to farm, so more deforestation

Economic impacts

* economic development, esp farming has brought wealth to Amazon. In March 2018, Br exported almost $600m of beef. Br second largest exporter of soy beans
* Mining industry creates lots of jobs, e.g. Buenaventura mining company in Peru employs over 8000 people
* Logging contributes lots to economy, but can destroy key resources, e.g. timber and reduce attractiveness of area to tourists
* Local Br rubber tappers extract natural rubber from trees have lost their livelihoods as trees have been cut down

Global rate of deforestation

* 2007 to 2017, 22m hectares lost per year- increase
* Brazil and Indonesia accounted for almost half

Reducing deforestation in Brazil

* 2004-12: Rate decreased by 80%
* Paris Agreement: Pledged to reduce carbon emissions by 37% by 2025
* Increased global awareness has reduced demand for products from deforested areas, e.g. Supermarket Iceland stopped palm oil products from 2018

How deforestation has been reduced

* protecting over 44% of rainforest via funding from World Bank, WWF etc.
* Br Gov uses satellite imagery to prevent large scale logging