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
_______________________________________
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,
