Species distributions Flashcards
Direct change of distribution by CC
Climate changes cause the species to move/die out
Indirect change of distribution by CC
If CC causes the food a species relies upon to move/die out that species is effected –> takes a little bit longer
Example of SDM being right?
Great spotted woodpecker being in Ireland –> this was predicted so there must be some stock behind SDMs
Bird species turnover and SDMs in Africa
West africa largely unchanged for bird spp
But south and east aria has lots of predicted turnover, so advising land managers in this area for CC need to make sites as connected as possible
Can get different predictions because we dont know exactly what climate change will do in the future. There models also take no account of habitat, dispersal, demographic traits. These alter likelihood to track climate. People often consider several simulations when trying to predict what will/might happen.
Butterflies that differ in sd
comma
- high mobility
- generalist
- tracking climate
silver studded blue
- low mobility
- habitat specific
- restricted in area of apparent suitable climate
Birds into the uk by 2100
Traits may restrict ability to colonise
Estimated by 2100, UK will be suitable for 44 new birds spp and lose 10 spp.
Since 1990, 9 of projected 44 species have bred for the first time and 5 shown signs of breeding –> 25% predicted had shown signs in first decade of century
Can calculate colonisation period to see how long will take spp to get to UK (good predictor of which species will get here). Those that get here tend to be good and dispersing and have high fecundity.
How do you calculate colonisation period
distance of nearest population * generation time
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mean dispersal distance per generation
Incorporating uncertainty
Can be done by looking at causes of variation such as emission scenarios, spp distribution modelling, and method, variation in spp dist. Can test in predictors are robust with these uncertainties.
Allowing for uncertainties allows recommendations to be more robust. In a data set, some study found large variation in certainties
Movement of spp can also alter ecosystem services
If we predict a species will move we can plant eg conifer trees to facilitate movement in 30/40 years
Indicator
A species that are used to infer the state of the envirmnet
A group of species who weighted population trends (when taken together) reflects the average behaviour of the constituents spp group.
Some incr under cc some decr, some already reacting
Could see if spp already being affected eg farmland birds seen to be decreasing
- primarily arctic spp in the uk doing less well
- Mediterranean doing better
national indicators were developed (as some spp incr in one country and decline in others). These finer resolution spp show recent CC has impacted all bird species across Eu. Did USA too. Changes not only in rates but abundance and community compositions.
Why migrate
If insectivorous then in winter may not survive. If you switch your direct as blackbirds and blue tits do then you could
Adapted to change environment in and space and time
Avoid poor environment conditions enter that
Can evolve over time as adjacent habitats are utilised the species move apart there is often strong selective pressure
Many European and African migrants spread through Africa as the European winter develops Because changes in abundance Likely migrants and more risk from climate change than any other resident species
Populations me different breeding grounds so some parts of the population may be more at risk than others four example the common crane it is very difficult to select state on migrant species so we don’t know how much climate change will affect some of them
Types of migration
Stepping stone - migrate in steps
Circular
determining migration patterns
Radio telemetry very limited range to detect things cannot detect long-distance migrants unless you have a good idea of where they stop/end up
Colour marking
Satellite tracking precise data of individual movements tags are heavy and can’t be put on small birds
Genetic and isotope studies can give information on where subpopulation speding their time eg dunlin- those that winter in Southwest Europe are likely to have originated from Western Europe. those wintering further north and east are likely to breed in eastern Siberia. However this tells us a little information about migration routes. Or stopovers
Geolocators- track small migrants (about 10-15 g) according sunset/rise data and date can approximate locality however they do require individuals to be recaptured
Biology of migration
Many species moult all of their feathers prior to migration
Build up flight muscles- pre-migratory hypertrophy. Eat like crazy particular types of food high in certain nutrients so can put on lots of muscle mass
Changes in diet and eating behaviour
- prior to and during migration some spp switch to frugivory (fruit has higher calories) from insectivroy
- excellent nutrition- many carbs, some have unsaturated fatty acids and a few contain secondary compounds that vapour lipogenesis
- fruit has seeds that can be dispersed along migratory tracks
End result of hyperphagia is extensive fat deposits. Many european songbirds can double their weight during this period. This has been shown to be genetically determined, fat plays a major role as energy source for migration
A large part is tired subcutaneously in adipose tissues of skin. Occurs in morphologically adapted fat bodies. Most important in clavicle, coracoid, flanks, abdomin, pelvic and rump regions. Also liver and breast
Fat deposition is promoted by hyperphagia, feeding locality, food type, incr foraging, reduction of other activitys, warm stopovers and torpor (period of reduced physiological activity eg lower body temp and metabolic rate in hummingbirds). On return many arctic spp need sufficient resources to produce eggs too
Phenological changes could alter the availability of essential pre-departure fattening food sources
One big problem is if CC causes increase in migratory distance then birds need to carry more fat. We can estimate additional flight load in such scenarios. If flight load is too much for a bird to carry then it will need to make additional refuelling stops. Can work out how long they can fly for because fat is fuel. Part of burning fat processes releases water so they stay hydrated
Can look at fat stores of birds migrating to/from Africa. To get an idea of how quickly they burn off fat, and the typical ‘spare’ load they carry once they reach their destination
Migration and weather
They can take advantage of favourable winds, choose to migrate at favourable heights (especially for large birds), form V formations to maximise gliding times using terrestrial updrafts and by staying over land as much as possible. Some choose to travel at night too (save energy)
But weather patterns may change, where they refuel could change, could increase distance or thyemay have to find completely new routes
Conserving mobile spp
Pic on phone
Particularly impacted y changes going on in an area.
Climate determines where spp can and cannot go for physiological reasons
A decline in quality or loss of stopover sight can result in disproportionately large population losses. In each example (on pic) only two sites lost. population implications are highly dependent on spatial configuration of that loss. Understanding migratory connectivity can be crucial to managing mobile pop effectively,
Migrants
12% of the worlds vertebrates are long distance migrants. Glbal declines of migrant spp have been observed.
40% of afro-paleo-arctic migrants have declined since 1970s. We have an increasingly better understanding of the drivers of the decline, population losses attributed to CC, habitat loss, and magnitude of migratory movements. LD migrants decline far more substantially then SD migrants
Migrants are dependent on breeding grounds, staging grounds, and non breeding grounds
Causal factors of these changes could be climate, habitat changes, migratory status (SD/LD), body mass, or anthropogenic factors
To model LD migrants we have to consider breeding and non breeding ranges. Can we related changes in population trends to climate or other factors.
By looking at Climate Suitability Trends (CST) we can understand which area may be causing the decline.
By 2070, the european bee eater’s journey is predicted to increase by 1000km
Changing migratory journey
78 migratory species
LD and SD
SDM for breeding and nb range. Calculate migratory journey by randomly selected a point on b and nb range to calculate migratory distance. Repeat 1000 times to calculate geodesic distance. Tells us how variable the distance can be.
eg thrush nightingale- breeding range shifted north where nb range stays mostly similar
SD- both ranges shift north
LD- breeding range shifts north, nb range less consistent
50% of LD migrants having to make at least one additional stop over. Some LD migrations increase substantially in the amount of time they take. On average about 4 extra days, can be up to 10 extra days in some cases - delay could have substaintail effects on breeding productivity
Calculating journey length
info on the mass of bird
area of wing
wing span
alongisde assumptions about fat loading, flight altitude, to calculate theoretical max distance and duration a bird could fly.
Stopping to refuel adds on days, could have phenologicla mismatch
EU migratory spp egs
mean shifts of 500km between b and nb range. Exploring impacts of migratory journey and the physiology of migration under CC is something biologists have yet to address in detail
Black caps started staying in uk about 20 years ago. They are a population from germany that spend winter here. They get back to breeding grounds quicker with other UK –> assortative mating
Ring ouzel spp not just driven by UK climate but also by rainfall in north africa 2 years ago. They spend non-breeding season in morocco eating juniper berries. Takes 2 years for these berries to become edible –> difficult to predict how spp will respond
Where will novel climates occur
Can plot where climates will be most dissimilar. Look at mean summer and winter temps and ppt. In 2100, novel climates mostly around tropics and subtropics. Boreal/tundra/tropics/sub-tropics will disappear in some places.
About 1/5 of the land surface will be novel climates with 2 degree warming
understanding how organisms respond underpins predictions as to the types of ecosystems that might prevail.
Why are tropical systems of particular concern
high biodiversity
high carbon storage
v uncertain
Plant physiological responses to temp and drought
Leaves in canopy show a midday peak in photosynthesis. This coincides with a peak in terpenoid emissions- antioxidant. It mops up free radicals and reduces oxidative stress –> but only up to a point. After peak midday temps, terpenoid and photosynthesis collapse. Increase in Green Leaf Volatiles (GLV) are a sign of stress and senescence and turnover.
When warmest and driest concentrations of GLV in canopy highest. Higher than at other times of year. GLV are a signal of photo stress and reduced C uptake
In situ warming (Tropical responses to altered climate experiment TRACE). Modular, focusing o leaves, roots, and soil microbes. Single factor to separate effects of warming from other global change variables
- can have soil warming rods, understory heating with lamps, canopy warming resistance cables.
Tree mortality in drought
greater for larger trees
greater hydraulic change, high evapotranspiration in exposed crowns. If warmer climates drought stress –> lose larger trees –> reduce C sinks
In amazon, tree mortality rates increase while the C accumulation is in decline. Need to understand how novel climates will affect mortality/ forest and carbon dynamics in future
Novel communities pic
on p
