Biogeography - cetus.ucsd.educetus.ucsd.edu/sio133/PDF/Biogeography & climate change.pdf ·...
39
Transcript of Biogeography - cetus.ucsd.educetus.ucsd.edu/sio133/PDF/Biogeography & climate change.pdf ·...
Is the ocean homogenous?
Tagging of Pacific predators (TOPP)
Yellow: females Red: males • Northern elephant
seal distribution:
– Pupping on beaches
– Foraging in open ocean
Biogeography
• Determined by:
– Evolutionary biology: historical range
– Ecology: food availability, temperature
Plate tectonics & early records
From Berta et al. 2006
1 – early cetaceans 2 – early sirenians
Evolutionary biogeography: cetaceans Geologic events | Marine mammal events | Location
From Berta et al. 2006
Tethys
Southern hemisphere
N Pac. Arctic N Atl.
Evolutionary biogeography: pinnipeds Geologic events | Marine mammal events | Location
From Berta et al. 2006
Walrus | Sea lion | Phocid
N Pac. equator S Pac.
N Pac. Pan. seaway N Atl.
Ocean zones
Seasonal variability of ocean zones • Temperate region
– Wind important factor
Seasonal variability: coastal upwellings
• California Current system
Bailey et al. 2010
Blue whale tracks
Seasonal variability: coastal upwellings
• California Current system
Bailey et al. 2010 Block et al. 2011
Blue whale tracks
Seasonal variability: polar region
• Light important
– Productivity high in summer
• Seasonal presence common
Prey aggregation • Affected by oceanographic features: fronts,
eddies, ocean bottom
From Tynan et al. 1998
Blue whale catches Krill concentration
Species distribution
• Cosmopolitan species
– E.g. Killer whales (Orcinus orca)
From Hoelzel 2002
Blue whale stocks
From McDonald et al. 2006
Species distribution
• Anti-tropical distribution
– E.g.: Long-finned plot whales (Globicephala melas)
From Hoelzel 2002
Anti-tropical distribution
From Hoelzel 2002
Species distribution
• Pan-tropical species
– E.g. Spinner dolphins (Stenella longirostris)
From Hoelzel 2002
Species distribution
• Circumpolar species
– E.g. Beluga whales (Delphinapterus leucas)
From Hoelzel 2002
Species distribution • Endemic species
– E.g. River dolphins
From Hoelzel 2002
Coastal species • E.g. Porpoises
From Hoelzel 2002
Gender-variable distribution
• E.g. Sperm whales (Physeter macrocephalus)
Source: whaletrackers.com
Migratory species
• Prey driven: Most rorquals
• Ice driven: polar species – e.g. beluga, narwhal, bowhead
Block et al. 2011
Month of year
Temperature-defined distribution
• E.g. Short and long-finned pilot whales
Source: Duke University, OBIS-SEAMAP
Major reason for anthropogenically driven climate change
Results of climate change in the ocean I
• Increased acidity
Metabolic consequences
Calcification issues
Results of climate change in the ocean II
• Reduced productivity – positive feedback
(stratification)
Effects of sea ice reduction on marine mammals
From Moore 2006
Effects of sea ice reduction on Arctic marine mammals I
• Walrus, polar bear: longer foraging routes, crowding on shore (walrus)
• Ringed seal: decrease in subnivean lairs
• Longer presence by migrating species
Ringed seal lair
Effects of sea ice reduction on Arctic marine mammals II
• Change in timing of migration (presence & food availability mismatch)
– Grey whales: move south later
– Belugas: arrive coastally sooner
– Bowheads: linger along route
Antarctic marine
ecosystem
Effects of sea ice reduction on
Antarctic marine mammals
krill seals & whales • Sea-ice From Atkinson et al. 2004
Krill versus salps
From Atkinson et al.
2004
Other effects of climate change on marine mammals
• Distribution shifts – temperature driven
From MacLeod
et al. 2005
Other effects of climate change on
marine mammals
• Distribution shifts – prey driven
From Kerosky et al. 2012
Results of climate change IV
• Rising sea level
– Loss of breeding habitat
Hawaiian monk seal
Possible cumulative effects on
marine mammals
• Predator-prey interactions: – Polar bear & ringed seal
– Loligo squid and short-finned pilot whales & Risso’s dolphins
Other possible effects on marine mammals
• Toxins
– Increased occurrence of harmful algal blooms
(HAB)?
• Disease – 2012 die-off in Peru? Common dolphin &
Burmeister’s porpoise
Brevetoxin: Flewelling et al. 2005
