Climate change and migrants Flashcards
How are short and long distance migrants reacting
No overall change for SD LD migrants (about 12% of vertebrates) have been declining since 1970s
SD migrants both ranges predicted to shift north
LD north shift of breeding ranges, but non-breeding less consistent –> so have to migrate further in future
Some migrants having to travel 1000km more
Most SD having to travel further and all LD further
Why is it difficult to figure out what migrants will do
May have improved area on breeding ground but worse on non breeding so overall change may be nothing
also difficult because over multiple countries- difficult to streamline cons efforts
also very difficult to track
changes are not spatially uniform
How to model migratory process: flight ranges
Can calculate flight range with wing span, area, body mass, and how much fat it can carry etc. Then use equations alongside a set of assumptions (about fat loading, flight altitude to calculate the theoretical max distance and duration)
Pre-flight migratory potential and post-stopover flight potential
Cant always get data because hard to get data eg for small passerines, typically trackers have to be 1/10 of body size so it doesn’t impede on migration
Often more stop overs are predicted so ay arrive a couple of weeks later –> mismatch
What did the climatic atlas of Eu Breeding Birds demonstrate
N-Ne Shift among most species
These models (despite ignoring biological things) can be useful in flagging up spp that might be in trouble. Can highlight those likely to do well (blue tit, black cap, cirl bunting) so in less need of cons action and those which are in trouble (Audoin’s grill, Mediterranean shearwater, and cory shearwater)
Can also see species who will do well if they shift their range, but if they don’t (because no current overlap) will decline (scottish crossbill, spanish imperial eagle)
Why aren’t all shifts polewards?
Not only temperature that changes, ppt too
eg australia is predicted to have massive ppt changes in the east, but less so in the west - birds in australia are predicted to go all over the place
Habitat and dispersal often not included in predictions by including it, we can figure out if something can get there or not
How can we use Africa’s Important Bird Areas to idealise a network
IBAs are a series of areas that bird life international consider should be protected to protect species
about 1230 IBAs across Africa and associated islands
Selected based on:
1. spp of global consideration concern
2. assemblages of restricted range spp
3. assemblages of biome restricted spp
4. concs of congregator species eg waterbird species
Summarising across PA networks in Africa, about 90% of species retain some suitable climate within at least 1 PA in Africa. May just not be there atm. So don’t have to redesign the landscape. May have to captive breed and reintroduce if a species can get their themselves though or could survive there at a later date
