Terrestrial Ecosystems Flashcards
Climate change is predicted to be a strong stressor on terrestrial and freshwater ecosystem
What are some examples of impacts on species?
- Shift in species ranges
- Many species will not be able to track their favoured climatic condition
- Reduced population vigour and variability
- Increasing numbers of invasive species
- Rapidly increasing extinction rates
What two big changes to climate are we expecting to see in the near future at high latitudes, due to climate change?
- Warmer at high latitudes
- More rainfall at high latitudes
- In particular for the winter
- (winter (top), summer (bottom))
How is rainfall expected to change in the tropics and sub-tropics due to climate change?
- Expected to increase in the tropics
- Expecred to decrease in the sub-tropics
What are Biomes and how are they controlled?
- Biomes are large scale dominant vegetation/functional types
- Biomes are controlled by climate i.e. temperature and precipitation
What is the risk to biomes due to climate change?
- Habitat loss or displacement of species
- Endangered survival of the associated species
Current the UK has a mean annual rainfall of ~150-200 cm and temperature of ~10 °C
Hence the natural biome is temperature deciduous forest
How could climate change affect this?
- Climate change is expected to reduce precipitation levels
- Mean temperature is also expected to decrease
- Push our biome into the Boreal forest
- Resulting in the vegetation community on land to change and hence other species within that area
What 3 factors can affect adaptive ability?
- Individual
- Genetic
- Mobility
For a specis to establish within a new area, they must…
- Colonise new areas
- where they maintain reproductively viable populations
Why may new habitats open up?
Because of abiotic and biotic environmental change
What is an extinction?
- Eliminates a species from all or part of its geographic range
- Extinction occurs when large numbers of individuals from a species are killed by biotic interactions or abiotic environmental change
- Limited extinctions within sub-regions of a species’ range are common
What is a dispersal and some reasons behind it?
- A dispersal can be defined as the movement of individuals away from others of the same species
- To find new habitat rich in resources
- Or evade competition influence of parent/siblings and other species
What is resilience/tolerance range?
- Species are limited in at least parts of their geographic range by abiotic factors: temp, moisture, nutrient availability, soil nutrients
- All species have specific limits of tolerance to physical factors that directly affect their survival or reproductive success
- The portion of the abiotic factor’s range of variation which a species can survive is the tolerance range
The level within the tolerance range at which a species or population can function most efficiently is termed the….
…optimum
A species can adapt on two different scales being…
1) Individuals change their physiology to fit into its environment - acclimatisation BUT is limited and not passed onto offspring
2) A group of individuals can produce offspring which are better suited to some set of environmental conditions - species adaptation as an inherited trait
What it the key difference between past and present climate change?
- The rate of climate change is a lot more rapid now
- But also even relatively small changes of ~2 °C can still have huge impacts
Climate has varied through time as a response to…
- Volcanic activity
- Releases of gas hydrates (methane)
- Solar forcing
Why is the current rate of climate change so concerning
Recent measured and predicted climate warming is occuring rapidly compared to previous changes giving eocystems limited time to adapt/migrate
What is an Ecotone?
- The transition area between two biological communities, where two communities interact
- It has some of the characteristics of each bordering biological community and often contains species not found in the overlapping communities
- They are good indicators of climatic change
What can be the issue with Ecotones?
The overlapping environments, mean that some species can colonise and outcompete the previous existing species
What can limited the expansion of tree-lines in alpine environments
- Moisture availability, particularly during seedling establishment
- Permafrost can limited tree-line expansion especially on northern slopes
- Available sites for germination
- High slope angles
Some key affects of climte change on habitats have been:
- Ealier ice-free
- Later freeze dates in lakes and streams
- Earlier breeding/flowing times
- Shifts to higher elevations/latitudes
What impacts can this have on species?
- Population densities-migration (biodiversity loss which could affect the whole ecosystem)
- Individual morphology development (growing season temperature - life cycle changes)
Around how much of the CO₂ emitted by human activities have been absorbed by terrestrial and freshwater ecosystems
1/4
(is this always going to be the case tho)
What is Net Primary Productivity?
Is the difference between the energy which is fixed by autotrophs and their own respiratory losses
What the 4 main factors for rising primary productivity of plants?
- Climate
- Leaf Area Index
- fraction of absorbed photosynthetically active radiation
- CO₂
Which areas of the globe have seen a rise in primary productivity?
Increases in North and South America
Increases in boreal zone
Increased in the Amazon (but this trend is predicted to not be sustained also similar in Congo basin)
Which areas of the globe have seen a decrease in primary productivity?
- Decreases in drier areas of North America
- Congo
- Peru
- Coloumbia
- Brazil
- Kazakhstan
What has happened to NPP since preindustrail times?
- Increase in NPP since preindustrialtimes with 5% (current sink strength is 2.6 PgC/yr)
- Possibly due to rising CO₂ levels but strong evidence is lacking
What has happened to ecosystem carbon stocks (biomass, litter and soil carbon) since preindustrial times?
- Ecosystem carbon stocks have increased globally
- Estimated increases in the global carbon stock is 0.16-0.2 PgC/yr
What is the predicted rates of extinction in the future?
Between 18-35% extinction
What affect can warmer oceans have on the biodiversity living within them?
- The associated environmental changes often include global warming and the development of widespread oxygen-poor conditions in oceans
- Hence less favourable conditions for survival
What types of biomes can vegetation distribution models predict and not predict?
- Tropical Evergreen forest
- Temperate deciduous forest
- Not predict western europe well
- Not predict Africa and Australia grassland/savanna/steppe (drought adapted vegetation)
Which types of biome are becoming more common with climate change?
- Boreal
- Conifer
- Temperate broadleaf
- Tropical grassland
Which types of biome are becoming less common with climate change?
- Tundra
- Alpine
- Boreal/Configer
- Temperate Conifer
- Tropical Woodland
- Temperature shrub land
Why is the Amazon becoming particularly more threatened due to climate change?
- Temperature increase and precipitation decreases mean
- Decreases in soil moisture
- Decrease in evaporation (+feedbacks)
- Decreased general primary productivity
Where are the big losses in biodiversity expected to happen?
Arctic and Mediterranean habitats threatened since much of the biodiversity is close to its climatic limits
To combat the rising temperatures, species might move…
Upwards of an altitude gradient (likely easier to do as less distance will need to be travelled)
Or Northwards
Why might migration rates differ for different species groups?
- Individals
- or seed dispersal
- Highest rates for split hoofed mammals and carnivores
- Differences linked to their tolerance range
- Resource availability
