Unit 4 - Managing ecosystems and biodiversity

Biomes

a form of ecosystems that are smaller than the biosphere

Hot deserts

(Middle of continents + western coasts; 14% of earth’s surface)

• High daytime & low nighttime temperature; generally light winds

• >250mm of rainfall annually; high evaporation rates

• Light colored soil that’s dry & sandy; top layer may be absent/very thin due to lack of vegetation

• Cacti have drought tolerant seeds with waxy cuticles to prevent water from escaping

• Human impact: mining, removal of rare species, & use of groundwater + drying out surface water

Tropical rainforest

(Equatorial zones of Asia +Central America & Asia)

• Temperatures range from 22-31°C; low diurnal temperature (difference b/t high and low temperature in the same day)

• 2000mm of rainfall per year w/ high humidity levels; daily convectional rainfall

• Red/yellow soil; high rainfall = nutrients + clays being leached out & replaced with aluminium oxide (high rate of decomposition)

• Tall + thin trees allow for light, thin bark eliminates the need to conserve water, & leaves have a waxy surface with drip tips to allow excess water to runoff + prevent algae

  • Helps support high biodiversity

• Human impact: deforestation, mining, urbanization, agriculture, & desertification

Grassland

(Middle of continents - away from coasts)

• Temperatures range from 20-35°C

• Up to 750mm of rainfall annually w/ wet summer; unpredictable rainfall

  • Distinct dry & wet seasons

• Red soil (high iron), highly weathered + porous allows for rapid drainage & thin layer on surface decays rapidly due to high temperatures

  • Soils aren’t very fertile; limited vegetation

• Vegetation: grasses & umbrella shaped trees

  • Trees are spread apart & root systems are either widespread (to absorb water) or deep (reach groundwater during dry season)

• Human impact: grazing, urbanization, & less biodiversity due to loss of habitat + hunting

Tundra

(North Asia + South America & South Coast of Greenland)

• Temperatures range from -34-12°C; strong polar winds

• Less than 250mm of rain annually & short summers

• Dark brown soil, permafrost (permanently frozen) sub layer, organic material at surface

• Vegetation: small plants that grow close together & are low to the ground

  • Waxy hair to coat them from cold & wind, shallow root systems due to permafrost

• Human impact: melting of permafrost (methane) & drilling for resources

Major abiotic factors of a biome

temperature & precipitation

Ecological succession

process of an ecosystem changing & developing

Primary succession

uncolonized areas → soil isn’t capable of sustaining life

• Pioneer species (lichens & mosses) will establish themselves on bare rock

  • Start formation of soils by breaking down the rock → grasses + shrubs can grow

• e.g) new lava flow, newly formed sand dunes, & newly quarried rock face

• takes longer than secondary

Secondary succession

colonized area that was disturbed or damaged (hasn’t eliminated all life/removed all nutrients)

• Soil is present; pioneer species = small plants

• e.g) where a mudslide occurred or trees have fallen

Intermediate community

change from the initial community, but the final stage hasn’t been reached

Climax community

final stage of succession; depends on climate

• Can take a few days to hundreds of years

Primary productivity

the rate in which energy is converted into organic material by autotrophs

GPP (gross primary productivity)

total amount of biological productivity within ecosystem/biome

• Energy production per unit area / units of time

NPP (net primary productivity)

amount of energy captured minus energy used for respiration

• GPP - Respiration

• Decreases as distance from the equator increases

Abiotic factors that affect productivity

CO2, water, and sunlight

Ecosystem productivity

a rate at which biomass is produced within an ecosystem

Pyramid of energy

shows feeding relationships of an ecosystem

• Greatest amount of energy at the bottom → ~10% transfer of energy b/t levels

  • Energy loss as heat due to respiration & excretion

Normal period of numbers

largest # of organism at the bottom

• Producers at bottom & tertiary consumers at the top

• Along with a pyramid of biomass can have an unusual/inverted shape

  • Number below can support upper trophic levels

Native species

originated & developed in a specific region/ecosystem and adapted to living there

• Indigenous: occurring naturally in a specific area; native to an ecosystem

Invasive species

outcompete other species in the area it has invaded → changes balance in the ecosystem it invades

• Can be native (outcompete other organisms in the ecosystem) or non-native

• Primarily spread through human activity & often spread rapidly

• Degrade native ecosystems → harmful to human health + local economies

Impacts of invasive species

grazing, competition, predation, & disease transmission

-environmental: soil erosion, excessive water consumption, decreased biodiversity + habitat degradation

-social: loss of agricultural land, reduced access to water, damage to infrastructure + reduced tourism opportunities

Benefits of conserving biodiversity

• Food security: protects plants, animals, & genetic resources that support soil fertility, disease regulation, & pollination of crops

• Economic growth + poverty reduction: many poor populations depend on natural areas for their livelihoods; forests provide timber, food, & water

• Combating climate change: forested areas can reduce CO2 levels & coastal ecosystems can lessen the impact of storm surges

• Medical resources: medicinal qualities in plants to treat illness

• High genetic diversity: greater stability → species are able to adapt to various conditions (e.g. disease & climate change)

• Cultural and recreational value: biodiversity reflects social values + local beliefs

  • e.g) a culture may use rivers for baptism

Methods of conserving biodiversity

• Protection of species + biodiversity

• Sustainable harvest: use of a resource that ensures its constant supply without harming future yields/causing irreversible damage to an ecosystem

  • Requires educational + legislative solutions

  • Optimal harvest (set % of resource is harvested) & systematic random sampling (set % of material harvested from a defined part of an ecosystem) are sustainable

CITIES (international trade in endangered species)

aims to ensure sustainable trade & protect endangered animals + species

• Limitation: hasn’t stopped illegal trade of protected species & voluntary participation

IWC (international whaling committee)

manage & conserve whale species globally

• Catch limits are still too high & lacks punishment for those who don’t comply

EU CFP (european union common fisheries policy)

• set rules for fishing fleets in EU waters

  • Limited applicability; West Africa is being overfished

ITTO (international tropical timber organization)

encourage sustainable forest management + tropical timber harvest & trade

• Large forest areas = hard to catch illegal harvesting

IUCN Red List

scientific info + tools to guide int’l actions in conservation

• There may be species on the list that aren’t

EDGE

aims to protect species on the verge of extinction & have unique evolutionary history

• EDGE Score: combined endangered conservation status + distinctiveness of species

Captive breeding

breeding endangered species in captivity with the goal of releasing them back into protected wild areas in the future

• Aims to develop a self-sustaining population of a species

• Can lead to inbreeding w/ weak genetic traits → lower survival rates

Nature reserves

legally protected area that is of importance for organisms or geology

• Conservation, protecting natural resources, & scientific research

National parks

protects landscapes, wildlife, & natural features of large areas that are of conservational, education, or scientific interest

• Protected by national laws

Rewilding

restoring an area of land to its natural uncultivated state

• Reintroduced species + communities can thrive → biodiversity increases & ecosystem health improves

Human impacts on tropical rainforests

• Deforestation: causes fragmentation + lost of tropical forests

  • Plants + animals in the fragmentation ecosystem remain vulnerable (those that do survive cause a rapid decline in biodiversity)

  • Loss of genetic material + biodiversity

• Exploration for + mining of minerals → forests being made into roads + infrastructure

  • Mining can lead to water, air, soil, noise, & light pollution

• Agriculture: depletes the soil of nutrients due to soil erosion

• Soils are thin + lack nutrients → due to leaching & heavy rainfall

  • Nutrients = stored in biomass

  • Completely deforested areas → soils collapse + high soil erosion

• Contributes to climate change → forests store a lot of carbon (e.g. in photosynthesis)

Sustainable management of tropical rainforests

• Preserve rainforests to: maintain biodiversity, protect the production of resources, manage climate change, & manage local water quality

• Debt reduction: many tropical rainforests are found in LICs that have high levels of debt

  • Instead of remove rainforests to generate income → some HICs agreed to write off debt

    • In return, HIC asks for the protection of an area of the rainforest

• Int’l agreements: manage species + forested areas through sustainable harvesting(e.g. CITES)

  • Need to include: educating those exploiting resources & providing consequences to negative action(s)

• Legislation + protected areas: establishment of anti-deforestation public policies + private measures can significantly protect forested areas, biodiversity, + forest’s ability to absorb CO2

  • Needs to be rolled out across countries w/ large areas of tropical rainforests

Human impact on Antarctica

• Climate change: warming oceans → loss of ice

  • Ocean acidification (from excess CO2) has caused a loss of biodiversity

• Fishing: overfishing leads to the loss of krill, which can lead to the collapse of food chains

• Tourism: increases potential of oil + sewage spillage (overall pollution)

  • Can disturb colonies of Antarctic animals

  • No individual gov’t has the power to set regulations

• Ozone depletion: CFCs → hole in the ozone layer in the stratosphere above Antarctica

  • Strong and frequent winds + storms

• Scientific research: helps understanding the continent + environment processes there

  • Can raise global awareness + used in formation of int’l laws

  • Research stations have a negative environmental impact

Managing the impacts of humans on Antarctica

• Legislation & int’l agreement (e.g. The Antarctic Treaty):

  • Features like: banning the mining of minerals, cooperation b/t countries in scientific investigation, & no nuclear testing/disposal of nuclear waste

  • Prohibits the import of non-native flora & fauna species w/o a permit

• Protected areas are continually set up

• Tourism control through agreements like the IAATO

  • Stricter agreements are being put into place (e.g. requiring a tour operator to have a permit)

  • Educate tourists, reduce noise & light pollution, waste management policies