Class 7 - tropical rainforest Flashcards
What biomes are present in the Amazon?
Forests, savannas, swamps, aquatic ecosystems
How big is the lowland amazon forest?
Covers 5.79 million km2 over 9 countries and is the largest continuous cover of tropical moist forest
How many tree species, plant species and trees are there in the amazon forest?
16,000 tree species, 50,000 plant species, 400 billion trees - 13% of all trees globally
What characterises the Western Amazon?
Most diverse forest, fertile soil, species rich, high stem turnover, lower above-ground biomass
What characterises central and eastern Amazon?
Poor soils, less dynamic, high biomass
Where is the largest tropical wetland on earth?
In the Amazon river basin
What characterises the Amazon river basin?
World’s largest store of freshwater, 15% of all fish species
What are contact areas between terrestrial and aquatic systems called and what characterises them?
Ecotones (contact areas) are important, they contribute to movement of animals, nutrients, promote habitat heterogeneity
What does the Amazon do with carbon?
A huge carbon store
What drives the spatial variation in carbon stock and biomass?
Driven more by soil condition than climate and more by spatial variation in tree mortality than productivity
What do the major river classes strongly determine?
Floodplain forest ecology and species
What has climate change done to the forest?
Some forests are already close to their thermal and hydrological limits of sustaining productive ecosystems – tree mortality rates are increasing
How much do freshwater ecosystems cover?
1 million km2
Mean annual rainfall?
Varies between 3000 and 1500 mm
How do the rainfall and soil gradients go?
Rainfall goes from most wet (northwest) to least wet (southeast), soil goes from most fertile (southwest) to least fertile (northeast)
What determines the composition of forest?
Soil fertility and annual rainfall
What is the total flora?
Between 15,000 and 50,000 species estimated
How many percent of vascular plants, birds, mammals and ambhibians in the tropics live in the Amazon?
18% of vascular plant species, 14% of birds, 9% of mammals, 8% of amphibians
What families contribute to most trees in the Amazon?
Fabaceae, Arecaceae (palms), Lecythidaceae are most abundant
Where is species richness highest and lowest?
Highest = Dryland forest, lowest = flooded forest, swamp forest, white sands
What is the white sand forest and what characterises it?
Found on pockets of highly leached deposits of podzolized white sand.
Ocupy 3-5% of the Amazon, species poor, high level of endemism
How much does savanna occupy in the Amazon and what annimals live there?
14%, white tailed dear, banded armadillo, maned wolf
What is unique about fish in the freshwater systems?
Sustain the greatest diversity of freshwater fish on earth
What characterises white-water systems?
Originate in the Andes or hilly rugged moderate elevations. Turbid, transparency between 20 and 60 cm, high sediment loads, near neutral pH
What characterises clear-water systems?
Start in cerrado region of central Brazil, draining the ancient Brazilian shield. Acidic to neutral pH
What charactises the black-water systems?
Origins in lowlands. Translucent, high in dissolved organic carbon, low in nutrients, transparency between 60-400 cm, low quantities of suspended matter, high amounts of acids
What is a wetland?
Ecosystems at the interface between aquatic and terrestrial environments, biota adapted to life in water or water-saturated soils
How much of the Amazon basin is covered by wetland?
30%
Define the two types of wetlands
Those with relatively stable water levels and those with changing water levels (10% of the basin)
How long does flooding last and how much does water levels fluctuate in seasonally flooded wetlands?
Flooding lasts up to 6 months, and water levels fluctuate up to 10 meters
What characterises seasonally flooded forest?
Contains 1,000 species of trees. Highly productive but less flora and fauna diverse than lowland forest
How much does flooded savanna cover?
200,000 km2 (fragile ecosystem)
What affects gross production the most?
Climate
The role of animals in the forest?
They increase nutrient cycling and the productivity of the forest
What controlls primate abundance?
Fruit production
What controls production of flowers and fruits?
Soil nutrient status
Why are aqautic ecosystems highly dynamic?
Flow of energy and nutrient recycling. Nutrients travel downstream and as the channel gets wider, algae can grow
What happens to algae in turbid white-water?
Algae growth is limited because of less light penetration
Why do wetlands contribute to carbon storage?
PEAT bitch
What is peat?
Type of soil with a top layer composed of at least 50% decomposed to semi-decomposed organic material
When is the maximum flow of flooding in the basin?
Varies between feb and jul
What is the role of the massive fish migrations in terms of nutrients?
Massive fish migrations transfer a small amount of nutrients from white-water to clear and black-water
Explain the co-evolution between trees and fish
Tree species produce fruit during the high-water season when fish invade the flooded forest – hundreds of fish have evolved to eat fruit, spread the seeds of trees over long distances. They also eat leaf-eating insects and carnivorous invertebrates – indirect feeding link between fish and trees. This brings monkeys and kingfishers to the forest, because the trees grow fruit and the fish are there
What does tropical forest affect more than any other biome?
Weather, freshwater, natural disasters, biodiversity, food, and health
How much land cover is covered by forest now compared to before?
From 12 to less than 5%
Why does it rain so much in tropical forests?
Tropical forests return up to 90% of the rainfall they receive to the atmosphere and winds in tropical forests produce twice the rain as winds elsewhere
How does deforestation affect the weather long distance?
Deforestation reduces the moisture and rainfall crossing oceans, making temperatures hotter and storms more intense
How does deforestation affect the dry season?
Declines in forest cover causes declines in freshwater supply and makes dry seasons last about a month longer
What kind of natural disasters do TF mitigate?
Tropical forests mitigate natural disasters like erosion, landslides, and floods, torrential rainfall, fires
What natural disasters can coastal forests mitigate?
Coastal forests reduce effects from storms, peak tides and small tsunamis
Why is high biodiversity a biological insurance?
Provides ecosystem stability and resilience, and ES
How do TF provide food security?
They provide food, pollitnation and pest control, people living near forests have better diets and nutrition
How much of global food supply depends on wild pollinators?
1/3, 70% of leading global crops benefit from pollination by wild insects and bees
What animals provide free pest control?
Bats and birds
How do mangroves provide food security?
They serve as hatcheries, breeding grounds, and nurseries for offshore fish. They also provide nutrients and food for fish living in them
What diseases are deforestation related to?
Malaria, ebola, yellow fever, avian influenza
How many of the drugs approved to treat cancer come from natural products?
Half
How does deforestation affect effect from storms?
Storms hit harder, mudslides occur, fields flood, rivers carry debris, silt damages offshore reefs and fishing ground. Soil erosion – rivers fill with silt which reduces water quality, diminishes hydropower, damages infrastructure
What types of forests have the lowest variety and quality of ES?
Degraded forest, secondary and plantation forest
What do tropical forests do with rain and fog?
Slow, capture and recycle fog and rain and pumps humidity back into the air
How much more are ES worth in TF than temperate in monestary value?
Around double
What do pest control and pollination depend on?
Biodiversity
What do fresh water supply and water purification depend on?
Healthy and intact forest
Define primary forest
Relatively unused by humans
Define secondary forest
Regrown after being badly disturbed
What type sof tropical forest exist?
Rainforest, moist forest, dry forest, montane forest, mangroves
Characterise a rainforest
Rainforests have high temperatures, annual precipitation at 1,500-3,000 mm with a short of absent dry season. Are evergreen with lush vegetation, tall closely set trees, continuous canopy with layers, tall trees, large number of species
Characterise a moist forest
Moist forest have a tropical climate, summer rains, dry season, between 1,000-2,000 mm rain, monsoon forests, cerrado, and wet miombo woodlands
What happens when it rains in closed canopy forest?
Many levels of leaves buffer the impact of rainfall, acting like umbrellas, distributing the water flow. Catch what comes down, sends moisture back up through roots and leaves, captures water underground, slows flows, cleans pollutants from water, recycles nutrients, influences weather
Example of how biodiverse the Amazon is
A single tree in the Peruvian Amazon could be home to more species than the British isles
How do seeds disperse?
They might have wings, they may be explosively popped from pods, or they hitchhike on or in animals
If we look at forest biomes, how much NPP and carbon do TF provide and store?
Tropical forests provide 33% of the world’s NPP from forests and store about 25% of carbon from forests
What is Evapotranspiration?
Capture energy from the sun and return it to the atmosphere, returns water to the atmosphere
How do TF shape weather patterns?
Creating rain, wind, and through teleconnections
How much of all moisture in the atmosphere passes through plants?
80-90%
What happens with the sun’s energy over TF?
About half of the sun’s energy is captured by vaporising water which cools the air
How do TFs photosynthesize?
Tropical forests photosynthesize daily, resting at night instead of in winter periods
What weather patterns does the Amazon for example affect?
Pacific monsoons, redirecting storm tracks which would cool Southern Europe and heat parts of Asia in winters
How do we avoid subregional savannization around the Amazon?
90% of it must be sustained
What happens in the Midwest if central African forest is deforested?
If Central African forests were cleared, rainfall in the US Midwest could decline by 35%
How do TF affect freshwater?
Tropical forests affect the quality, storage and delivery of freshwater. Improve water quality by preventing erosion and sediment flows to rivers and removing pollutants from water. Regain and release water during dry seasons
What is cloud forest vital for?
Downstream water supply. Fog represents up to 50% of water flow in coastal areas of Chile and Peru
What does TF do for rivers?
Decreases river temperatures from shade, and captures carbon
How do TF remove pollutants from water?
All pollutants are removed from water that trees restore to the atmosphere. Pollution is removed as water joins the groundwater through the infiltration process
What happens in deforested areas to water on the ground?
In deforested areas, soil becomes compact or erodes which affects how water can infiltrate the soil
What happened when Indonesian forest was converted to oil palm?
Converting Indonesian forests to oil palm plantation has increased water temperature, increased oxygen use in streams
Why can we not only concider the demand side of forest water use?
Forests do use more water and reduces flow for other uses, but we must consider both the ES from blue water (available to humans) and green water (available to plants)
Define riparian forest
Forests along waterways
What are riparian forests good for?
Anchor soils, reduce erosion, sedimentation, filter out pollutants before they reach streams. Leaf litter, fruits and seeds from trees are important to the diets of fish
What happens when water flow changes
Salinity changes
How much space do mangroves cover and how much carbon do they store?
Mangroves cover only 0,5% of global coast area but store a huge amount of carbon – along with wetlands as high as 90% of global carbon burial
Why are mangroves so great?
Because of the huge amount of organic matter they trap, they stop sediment from flowing offshore where it could damage marine ecosystems, it also helps build shoreline
What is significant about hills over 25 degrees slope?
In areas with slopes over 25 degrees, there is a strong link between deforestation, erosion, and landslides
Why do forests reduce landslides?
Roots anchor soils, moist soils are healthier with greater soil cohesion, forests quickly remove excess water through evapotranspiration
What happens during a flood?
Floods cause rivers to overflow, sediments can form up to 17% of floodwater volume, storms usually cause floods
How do TF prevent floods?
Evapotranspiration making water return to atmosphere, more water goes into the ground, good soil health reduce erosion
What can you call coastal forests in terms of extreme weather events?
A bioshield
How do mangroves reduce impact from wave events?
Because they break up and slow their energy, trap sediments and increases coastal elevation
What do wide mangroves help with when cyclones hit?
Wider mangroves significantly reduce deaths by cyclones and reduce height of small waves between 50 and 100%
What are fire intervals in TF?
Sometimes thousands of years
How do TF stop fires?
Fire is inhibited because in closed canopy forest, gaps are quickly filled, rainforest fires are often small, slow burning, and becomes extinguished at night when humidity increases
Do many trees die during fires in TF?
Fires cause high tree mortality because trees are not adapted to deal with fire
How endemic is Madagascar?
95% of plants
How can it be seen that biodiversity is in global crisis?
Tropical species declined by 56% between 1970 and 2010
Where are most of the threatened bird species located?
The Andes, Brazil and Asian islands
How do TF support inland fishing
Through healthy river systems
Is it only bees that pollinate?
No, in many crop systems pollination by wild insects was twice as effective than by bees
How does bushmeat help locals?
People around forests eat bushmeat, which provides protein, fat, iron, zinc, vitamin b-12
What protein do poor living among forests and rivers eat when times are hard?
Mostly fish
How much of fish catches depend on mangroves?
Up to 80% of global fish catches depend on mangroves in some way
Where are mangroves found, how many are left?
Mangroves are found in all tropical countries, but represents only 0.5% of the worlds forest, are being lost at 1% annually. Over 1/3 of all mangroves destroyed since 1980
What does tropical forests do to disease?
Tropical forests reduce disease prevalence, less malaria, less diarrhea
What does deforestation do to disease?
Deforestation leads people to come into contact with disease they otherwise would not have. Ebola, SARS, H1N1 are linked to wildlife and forest loss. Yellow fever is endemic to forests, but when trees are cut, it can drop to the forest floor
What do TF do to malaria?
Forests hold a high number of predators that eat mosquitoes, with less biodiversity mosquitoes have less predators, there are more things to bite with high biodiversity
What does climate change do to disease?
Warmer environments with climate change increase the area available for disease carrying animals
What are examples of natural medicine?
Frogs carry powerful neurotoxins, some plans and animals produce fungicides and antibiotics
In India, how many plants are used for traditional medicine?
Around half
How do fires harm health?
Fires release trace gasses containing carbon, haze, pollutants become transported thousands of kilometers
How much air pollution is caused by fires?
5-10%
What has happened to TF globally?
Tropical forests are fragmented and very few large intact forests remain – the Amazon, Congo basin and Indonesia are biggest
What affects tree growth rates?
Precipitation, solar radiation, temperature, soil moisture
Can photosynthesis acclimate to warming?
Photosynthesis in tropics can acclimate to moderate levels of warming, but beyond that there would be no net gain of carbon
What happens to trees when the climate warms in dry and wet forest?
In dry forests, warming would cause stomatal closure, and in wet forest it would cause changes in leaf biochemistry. Higher temps will increase respiration rates, and forests could become net carbon sources
What is the limit to warming where trees can still perform the same level of photosynthesis?
The limit might be 2 degrees warming, or they might already be operating at their limit
What nutrient is a limiting factor generally?
Phosphorus is a limiting factor I tropical forest soil
What types of trees in wet forests die most during drought?
During drought, more large size trees die
What has happened to the mortality rate of trees?
The mortality rate of neotropical trees has consistently increased since 1980s
How are mortality rates in dry forest compared to wet?
Mortality rates in dry forests much lower than in wet
What types of root systems handle drought better in dry forest?
During drought, deep rooted trees in dry forests more likely to die than shallow-rooted ones
Which type of forest is the Amazon shifting towards?
Drier forest
What happened during the droughts of 2007 and 2010 in the Amazon?
Droughts of 2007 and 2010 caused 12% and 5% of the southeastern Amazon to burn
What has happened in montane forests since the 90s?
Montane forests are highly sensitive to warming and changes in clouds and atmosphere and have had loss of biomass since 1990s. Even under a 2 degree increase, they are highly threatened
What does biodiversity do against climate change?
Tropical forests are more resilient to climate change when they have high biodiversity
What does climate change affect in tropical forests?
Climate change affects carbon stock, water availability, structure, and diversity in tropical forests
What has happened to biomass in the Amazon since the 90s?
Biomass in the amazon peaked in the 90s and has since decreased by 30%
When might carbon turnover reach 0 in the Amazon?
2030
What could happen to subtropical forests in the Americas?
They could become savannas
What does deforestation do?
Deforestation will strongly decrease regional precipitation and evapotranspiration and intensify dry seasons
How many people live in immediate vicinity of tropical forest?
800 million
How much of tropical forest is outside protected areas?
70%
What should we do with indigenous people?
Indigenous people have important knowledge and experiences, and recognising their land rights is a cost-effective action to address climate and biodiversity risks. Deforestation rates are 50% lower in indigenous areas of the Amazon, and their management is correlated with reduced carbon emissions
How does the tropical belt move with the seasons?
The tropical belt moves up in our summer and south in our winter
Example of a type of tree growing in the rainforest?
Strangler trees, which grow around a tree and eventually strange it
Main disturbances
Fire, hurricanes, floods, bamboo (huge areas of flowering, fruit, then death of bamboos)
Are rain forests similar across continents?
Yes, structurally, they all have diverse woody plants, strangler trees, epiphytes (ferns), many canopy layers, high species richness
How many plant species are found in New Guinea (area same as Sweden + Finland)
13,634 species
Most biodiverse places on the planet
Western Amazon, central America, Southeast Asia, Northern oceania
What color is the typical soil of the wet tropics?
Red
What is interesting about comparing rain forest with dry seasons to ones without?
The dry season does not directly correlate to total annual rainfall, stem thickness, total species - roots are affected more than shoots
Why deforestation in the Amazon?
Cattle pastures, soybean fields
What does climate change + deforestation + el nino equal
Extremes in both droughts and floods
