Midterm 3 Flashcards
Aquatic Communities - 2 types
7 and 1
Marine: intertidal, sub-tidal kelp beds, continental shelf, open ocean, deep ocean, coral reefs and arctic/antartic
Freshwater lakes
Vertical Zonation
This is the phenomenon associated with the different strata.
Generally, narrow bands that species live within strata
Sub-tidal Kelp Bed Communities
Highest primary productivity of all communities on the planet
Provides physical protection to shoreline communities
Foraging and shelter for a large number of species
These are stratified habitats
Zonation of Pelagic Zone (5)
Epipelagic (0-200m) Mesopelagic (200-1000m) Bathypelagic (1000-4000m) Hadal (4000-6000m) Benthic - seafloor
Coral Reefs
Tropical waters have very little phytoplankton so coral reefs with zooxanthellae symbionts provide the basis of the trophic pyramid
Greatest species diversity on the planet
Highly efficient recycling of nutrients
Arctic (6)
mainly frozen ocean surrounded by land
4000m water depth, 3m ice cover
upper 15m reduced salinity from large rivers
A complex layering of Atlantic and Pacific waters
High abundance of plankton in summer, arctic cod, seals, beluga, narwhal, bowhead whale
The polar bear is a terrestrial predator
Antarctic (6)
Large frozen continent surrounded by the ocean 98% ice cover up to 2 km in thickness
Mountainous 4500m elevation
Low species diversity - bacteria, lichen penguins
Surrounding very cold oceans with high primary productivity and species diversity
Weddell seal, leopard seal, elephant seal, penguins, Orca, humpback
No terrestrial predator
Lake Classification (4)
Oligotrophic - clear water lakes (low productivity)
Dystrophic - stained (tea-coloured) lakes (low productivity), very acidic
Mesotrophic - intermediate productivity
Eutrophic - high productivity lakes
Lake Stratification Summer
Wind causes mixing within Epilimnion
Separating layer (thermocline)
With cold water below (hypolimnion)
Lake Stratification Fall and Spring
Constant mixing of the whole water column
Due to max density of water at night in fall causes it to fall and mix
In spring ice melt sinks and mixes
Lake Stratification WInter
Frozen top with an upper oxygen environment
And an oxygen sparse dead zone at the bottom
Due to decomposition occurring down there
Tundra
3-6 months of darkness with ice/snow Permafrost Cold hardy plants Surface soil thaws in summer 3 Strata -- Soil, ground, low shrubs Many aquatic/terrestrial insects Shorebirds, waterfowl (seasonal migrants) Hare, fox, wolves, caribou, grizzly bear, polar bear High productivity during spring/summer
Temperate Coniferous Forests (Taiga/boreal forest)
Conifers Few shrubs The ground layer of ferns and mosses Trees with monopodial growth 4 strata -- trees, shrubs, ground, soil Short summers and long cold winters (slow decomposition) Seasonal migrants Occasional hibernation/torpor for residents
Temperate Rainforest
Ancient trees
4 Strata with high 3D structural complexity
Multiple species of fungi, mosses, angiosperms
High insect diversity
Species-rich riparian zones
1000 yr for seral stage recovery, after clear cut
Greatest biomass/ha for all terrestrial ecosystems on the planet
Tropical forests
6 Strata
A - emergent trees over 60m (discontinuous)
B - up to 20m (discontinuous)
C - lowest trees (continuous canopy)
D - Shrub layer, tall ferns and herbs
E - Ground layer, herbaceous plants and seedlings
F - Root/soil layer (shallow and poorly developed)
High species diversity of most taxonomic groups
High biological turnover, high recycling of nutrients
A and F are connected by vines (many epiphytes)
Relative nitrogen levels in strata of different ecosystems
Arctic – Tundra has most (90%) in soil and Taiga has about 50% in soil
Temperate – Grassland has about 30% in soil and Deciduous forests have 40% in the soil
Tropical – Savannah and Equatorial forest have similar proportion with very little in soil (<10%)
Polar Cell
Between the arctic tundra and temperate forests
Cold dry air falls
Ferrell Cell
Between the temperate forests and the deserts
Subsidence zones, cold dry air sinks
Hadley Cell
Between equatorial forests and deserts
Hot moist air rises from the equator and forms cumulus clouds
High cool dry air moves north and south and cools more
Latitudinal Diversity Gradient
This shows that generally, species diversity increases as you move towards the equator
Diversity can also differ along with the same latitude
Ocean depth in terms of diversity
Unique in that increasing depth doesn’t seem to affect the species diversity
Very consistent across the different depths
Marine Productivity Trends
Highest productivity at the poles where the cold water is nutrient-rich
This is because water sinks at 4 degrees displacing colder water up mixing in nutrients
Desert across most of the open ocean
Decent productivity at the equator due to polar currents bringing in nutrients from the rotation of the earth
Terrestrial Productivity Trends
Most of the primary productivity on land occurs at the equator
During our summer the northern hemisphere has higher productivity and during our winter the southern hemisphere has higher productivity
Productivity is mostly controlled by a combination of temperature and rainfall
Sunlight variation from poles to the equator
They generally receive the same amount of sunlight (~ 1:1)
The difference is that the equator receives more solar energy from the direct impact of photons
Competition theory
At temperate latitude, the lower productivity causes broader niches and r-selection which don’t allow for as many species
At tropical latitudes, the higher productivity causes narrower niches and k-selected allowing for more species
Spatial heterogeneity theory
Increased spatial heterogeneity causes an increase in structural complexity and this allows for more niche segregation
This means more species
Environmental Age Theory
This predicts that the older the environment is following some kind of succession, the more species richness you expect to find
Increase species richness with environmental age
Major explanations for differences in species richness (4)
Primary productivity
Competition
Spatial heterogeneity
Environmental Age
Hypotheses on biodiversity, complexity and stability (3)
Diversity-stability hypothesis (Charles Elton)
The linear increase in stability as # of species increases (tropics)
Rivet Hypothesis (Paul and Anne Erhlich) The exponential increase in stability as species increase slows down as # of species gets large
Redundancy Hypothesis (Brian Walker)
Flatline of stability increases at large species numbers, a sharp decrease in stability if keystone species is lost
(Intertidal communities)
Island species numbers compared to mainland
There are disproportional fewer species numbers on islands for their area size
The slope of species numbers from the area is much lower on islands (this slope is independent of distance from the mainland)
What causes the cyclicity and high turnover of islands?
The lack of predators (predation) allows species to go above carrying capacity and then crash
This causes the cyclicity that allows for a high turnover rate
A small population of a species are prone to extinction
Essential features of Equilibrium Theory (3)
The number of species moves towards an equilibrium between extinction and colonization as a function of island area and distance
At equilibrium, actual species composition is in a continuous state of change as some species go extinct and new species colonize (high turnover as species equilibrium is reached)
Can predict numbers of species but not the species composition
What occurs after the defaunation of small islands
The small islands that were closest to the mainland has the best and fastest recovery
They also noticed that the species that persist on the islands after tend to be the species that originally occupied that island
Becuase those species had specific attributes for that niche space
Where does speciation occur on a 3D biogeographical process map?
The highest levels of speciation occur on isolated islands of a large area.
This helps to increase species richness on very isolated islands
Human Population Growth Trend
A rather gradual increase since 10 000 BC
With only about 1/2 million people in 1700
Exponential increase up to almost 8 billion people in 2021
Major Impacts on Earths Ecosystem from Human Population Growth (2)
Habitat loss and habitat change
Deforestation Classes (3)
Selective Cutting - removal of single trees by helicopter
Leaves small gaps in the canopy where seedlings can develop
Most similar to natural disturbance, cost-prohibitive in most areas
Variable retention - leave representative old-growth in each cut block (10-30% retention), low-profit margin due to high costs of road construction
Clear Cutting - remove all trees in patches up to 2000 ha (80-year rotation), most invasive, most widespread around the globe, greatest profit margin
Lateritic soils
Soils leached of silica after deforestation
Higher concentration of iron, manganese, aluminum, nickel
These heavy metals run into the ocean and kill corals
Fragmentation
This is a major threat to earth ecosystems that are caused by human population growth
Building roads increases the amount of edge present and this, in turn, increases the ecotone.
The result is a decrease in population
Habitat Change: Atmospheric contaminants (7)
Carbon dioxide Black carbon Methane Nitrogen trifluoride Chlorofluorocarbons Sulphur dioxide Radioactivity
Evidence carbon dioxide rise is due to burning fossil fuels?
Ice cores in the arctic allow us to see trapped air bubbles of CO2 from history
We can plot these to show the cyclic rise and fall of CO2 over time with a large spike in our time
Living plants absorb C12, C13 and C14 but dead plants absorb no more.
C14 is unstable and decomposes over time (all gone after ~1 MY)
Burning fossil fuels, therefore, releases carbon into the atmosphere with no C14
You can measure atmospheric levels of C14 and compare this to amounts of C12 and C13 in the atmosphere
Ecological impacts of global warming on terrestrial ecosystems (9)
Northern range expansion of southern species
Reduction or loss of Arctic species, seasonal migrants
Loss of tundra, permafrost, sea ice
Sea level rise and flooding of coastal zones
Increase major weather events
Loss of species with restricted distributions
Increased human mortality during elevated summer temperatures
Ecological shifts to early seral stage communities
Exacerbates the effects of habitat loss
Black Carbon
This results from the incomplete combustion of carbon
It is responsible for 50% of temperature increase in the arctic
Methane
A single molecule of methane is more impactful on climate change than CO2
Nitrogen trifluoride
Industrial gas used in semiconductor manufacture
Radiative efficiency and global warming potential are relative to a molecule of carbon dioxide = 17 200 times
Chlorofluorocarbons
inert non-reactive solvent Rises high into the atmosphere UV breaks off Cl and disrupts Ozone by making OCl OCl is broken and creates O2 This breaks down the ozone layer
Sulphur dioxide
Counteracts atmospheric warming but produces smog
This produces acid rain
Radioactivity
Does not directly lead to global warming as it produces very few greenhouse gases
The major issue is a nuclear failure, which comes with a high environmental, human and financial cost
Aquatic Effects (5)
Ocean warming Ocean acidification oil spills Industrial chemicals and Biocides Plastics
Ocean Warming
Results in melting sea ice
And major damage to coral reefs
Ocean acidification
This is caused by an increase in CO2 being dissolved in the ocean
Causes issues for calcifying organisms
Reduces iron availability to marine phytoplankton
Ocean acidification also poses a major risk to coral reefs
Industrial Chemicals and Biocides
These are often washed into major water sources either intentionally or without our knowing
They build up as they move through the trophic levels
The movement of animals can transfer these chemicals very far and even into pristine environments
The major threat to the integrity of earth ecosystems (2)
Habitat loss/modification
Overfishing/overhunting
What do we need to know, to understand the ecological impact of wildlife imports (2)
The population of the animals and the duration of the import
Intergovernmental Panel on Climate Change (IPCC)
Scientific authority of climate change
Major agency assessing global trends
1988
CITES
Convention on International Trade in Endangered Species
1975
Shelter Footprint (4)
How many people live in your household
What is the size of your home
Which housing type best describes your home
Do you have electricity in your home
Food Footprint (2)
How often do you eat animal-based products?
How much of the food you eat is processed, packaged, imported
Mobility Footprint (4)
How often do you drive
How often do you bus
How often do you carpool
The efficiency of your car
What is missing from the ecological footprint?
There are no mention of how many children you have
This is a major impact on your footprint
As population growth is one of the major drivers behind climate change
Kyoto Protocol (1997)
The objective was to reduce the rate of global warming by limiting the release of greenhouse gases
195 countries signed
ratified 2005, first implemented 2008-2012
Doha amendment in 2012
Paris Agreement (2015)
Aimed at limiting global warming to less than 2 degrees and pursue efforts to limit the rise to 1.5 degrees
194 countries signed (the US withdraws 2019)
IUCN definition of protected area
An area of land and/or sea especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and managed through legal or other effective means
IUCN category I
Strict nature reserve/wilderness area
Ia: Strict nature reserve: managed mainly for science (Ecological reserve)
Ib: Wilderness area: managed mainly for wilderness protection
IUCN Category II
National and Provincial Parks: managed mainly for ecosystem protection and recreation
Ecosystem and habitat protection
IUCN Category III
National Monument: managed mainly for conservation of specific natural features (World Heritage Sites)
IUCN Category IV
Habitat/species management areas: managed mainly for conservation through management intervention (Introduced species removal)
IUCN Category V
Protected landscape/seascape: managed mainly for landscape/seascape conservation and recreation (Orca Pass International Stewardship Area)
IUCN Category VI
Managed resource protected area: managed mainly for the sustainable use of natural ecosystems (Crown land)
Major IUCN Concerns (6)
Paper Parks Design Shortcomings: position and size Internal Threats External Threats Transboundary Effects Ineffective marine protection
Paper Parks
Park names exist on maps but with no implementation or enforcement
Design Shortcomings
Position of parks are chosen based on minimum political and industrial opposition and are ineffective to preserve biodiversity
The size of the parks are too small to preserve biodiversity due to the fragmentation effect
Internal threats
Infringement, poaching, fires, disease, groundwater reduction, invasive species, highways
External Threats
Outside the influence of management or control
headwater effects, dams, atmospheric, climate change, biocides, pathogens, invasive species
Trans international boundaries
These create migration corridors
And make barriers for dispersal and migration
Major Benefits of No-take zones (4)
Increased abundance of fish
The increased presence of larger fish with an exponential increase in reproductive output
Increased species diversity
Recovery of competitors, biodiversity and ecosystem processes
Classification of levels of threat of extinction (4)
Safe: 0.1 probability of extinction (P) in 100 years (Y)
Vulnerable: 0.2 P in 20 Y
Endangered: 0.5 P in 10 Y
Critically Endangered: >0.5 P in 10 Y
Approaches to conservation ecology (5)
Studies of fragmented areas Critical habitat approach Identifying biodiversity hotspots Park design Restoration ecology
Critical habitat approach (3)
Forest Age structure Nesting trees (snags) Nutrient pulses (salmon runs)
Park design (5)
Size and number (SLOSS debate)
Shape
Position
Corridors
Restoration Ecology (4)
Identifying major issues in restoration
Reconstruction of degraded habitats to pre-disturbance state (removal of exotic species)
Augmentation of ecosystem processes (identify and supplement limiting resources and critical species interactions that facilitate recovery)
Sustainable development (the long-term persistence of human society and environmental processes through intelligent and ecological management)
The tragedy of the Commons
Proposed by Garret Hardin
If the carrying capacity of a field is 100 cows (K=100 and N=100)
Each farmer gets 10 cows
If a farmer adds one more cow N=101 and K=99, this increases their income by 10%
If each farmer thinks the same way and adds one cow N=100 and K =~50 (overbrowsing)
Possible fixes for global warming (8)
Carbon tax
Carbon credits
Hydroelectric - high eco. impact, low cost, few emissions
Nuclear power - fission and fusion
Photovoltaics - high potential, low risk, no emissions
WInd - high potential, low risk
Geothermal - high potential globally
New technofixes: solar-hydrogen economy, high potential, low risk
Ecological options for the future (4)
Possible fixes for global warming
Reduction in human population numbers
A large expansion of terrestrial and marine protected areas (IUCN I and II)
Ecological role models, educators, leadership
Projected Earths population in 2100 (3)
At 2011 growth rate: 18.5 billion
With 2 child families: 8.7 billion
With 1 child families: 1.4 billion
