Climate Changeand

Biodiversity

Golden ToadBufo periglenes

Once abundant in the cloud-shrouded rainforests of Monteverde in

Costa Rica, no one has seen one since 1989.

Harlequin Frogs

About two-thirds of Central and South America's 110 harlequin frog species are believed to have vanished during the 1980s and 1990s. The primary culprit is the pathogenic chytrid fungus Batrachochytrium dendrobatidis, which has been favored by global warming.

Ivory Gull

                                                          

Birds and Climate Change

• More is known about them– not too many ‘fish-watchers’– ‘canaries in the coal mine’

• 9787 known living species– 21% (2,055 species) are extinction prone

(for a variety of reasons)• habitat destruction/fragmentation impacts ~85%• climate change is quickly emerging as a leading

factor

Impacts on Individual Birds

• are homoeothermic (warm-blooded)

• have a energy budgets

• must thermoregulate

• Q-10 effect

Case Study: American Robin, Turdus migratorius

• Why are they distributed as they are?

• What determines northern/southern limits?

• What determines migration routes?

Nesting

•where to build

•how many eggs

•how many clutches/yr

Ability to find food

What do they eat?

Being out of ecological synchrony

• tied to seasonal events: flowering, seeds, insect emergence, etc.

• phenology:– egg laying-UK-20 of 65 species studied were laying

8.8 days earlier– migration timing-Canada-1st spring sightings-63 yr

data set, 25 of 96 species had altered arrival dates significantly, most (but not all) arriving earlier

• some individuals are no longer migrating (e.g., Canada Goose)-nonmigratory populations?

• being out of step with food supplies may mean the early bird doesn’t get the worm

• species may be driven by different cues:– birds by photoperiod– insects by temperature

• examples– Spain: leaf out 6 days earlier, flower 6 days earlier than 1952;

fruiting 9 days earlier; but spring migrants arriving 15 days later.– France: Blue Tits almost double normal metabolic rate while

foraging. They must search harder for food because breeding cycle is behind the peak of insects-food is scarcer.

– Long-distance migrants from neotropics can’t predict the onset of favorable conditions on breeding grounds 1000s of miles to the north

Being out of ecological synchrony

Can’t they just move?

• many species-rich areas are already protected, e.g., national parks, nature preserves, etc.– if vegetation changes, habitats are lost

Case Study: Prairie Potholes

Case Study: Prairie Potholes

• provide breeding habitat for 50-80% of N.A. ducks, the most productive area in the world—a ‘duck factory’

• model based on – doubling of CO2 by 2060

– 2.5 ºC increase in temperature– no increase in precipitation

• results projection– number of ponds decreases by 67%– duck numbers reduced by 72%

What makes a species extinction prone?

• specialists (vs generalist)– habitat– food– nesting requirements– restricted range

• important to humans

• predators, diseases, etc.

Will ‘southern’ species replace those that are being squeezed north?

Ecological communities will be reshuffled

As species move they may have to deal with changes in – prey– predators– competitors– parasites– diseases– habitats that are less than ideal

Case Study: Hawaiian Honeycreepers

Honeycreepers

• once 29 species, now 19 due to habitat loss, disease, predators

• avian malaria, one agent, pushed their distribution to altitudes where the mosquito was rare

• 2ºC increase will reduce habitat by 50%, 96%, and 100% in their three established refuges

Reverberations through the food chain

..