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Biological Impacts
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You are El Nino Administrator. |
| Biological impacts around the world. |
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Item 4 24-MAR-1998 18:45 Susan E Yoder (syoder)
Hi, this is Sue Yoder, and I am back in my office. I made a brief survey of the kind of biological impacts that El Nino is having around the world.
Severe droughts in Australia followed by brushfires will make it a hard year for some of the wildlife, but if the wildlife in Australia is anything like that in Southern California, in probably is adapted to a fire cycle. California brush reseeds and sproats from the surviving root after fire, and many annuals germinate only after fire. Does anyone know if Australian plants do the same thing?
The Indonesian rainforests are burning away due to the escape of slash and burn fires. This spells serious trouble for the wildlife of the rainforests and the plants which are not adapted to a fire cycle.
More droughts in India and Sri Lanka and southern Africa probably spell trouble for their wildlife. In southern Africa, the large game tries to migrate to more habitable regions when the water holes dry up, but many do not migrate (territorial lions usually don't for example) or fail to find someplace better. Much wildgame will die in these parts of the world.
Across the Pacific the coral reefs are dieing due to warmer then average sea surface temperatures. This causes coral bleaching. The loss of this food source will cause more die-offs up the food chain.
In the Atlantic basin the milder hurricane season means that islands and coastal areas will very little damage from storms. This will favor coral reef communities in this part of the world too.
Some of the most serious losses in marine life will occur in the Eastern Pacific. We are seeing reproducive failures of marine mammals and birds due to loss of their normal food supply. Many breeding seabird colonies on the Farallon Islands off San Francisco, and the Channel Islands off Los Angeles are affected.
The southwestern US will probably see abundant plant growth in the drier desert regions which is good for wildlife there. It will also increase rodent and tick populations, so we can expect more incedence of Hanta virus and Lyme disease this spring.
The warm water on the Eastern Pacific has allowed species to migrate further north and south of the equator then they usually occur. Mackeral in particular are ranging farther north, and this impacts juvenile salmon on which they prey. The inbound runs of salmon are also apparently displaced northward. The FRaser River salmon stocks take a more northward passage via the Johnston Strait rather then the Juan de Fuca Strait.
I would like to here more news if you have it.
Sue,
Thanks for the summary of world-wide biological effects.
Since I am a birder, I am interested to know which species of seabirds are suffering the most in CA?
Also what is the Hanta virus that you mentioned?
Hanta virus is the etiologic agent of the severe pneumonia that occured in the "Four Corners" area of the U.S. several years ago. The area had had an unusually wet winter and the increased plant growth inthe area (especially a pinion nut) caused a massive increase in the rodent population. The rodents carry the virus and the main transmission to humans comes from exposure to rodent droppings.
Interestingly, an infectious disease internet network I belong to has reported a significant increase in Hanta virus in the last few weeks in parts of South America...I think it was Chile, but will have to check.
Was the wet winter in the Four Corners associated with an El Nino year?
Thanks Patricia for your info on the Hanta virus. Let us know about the recent outbreak of the virus in South America if you are able to find out more.
This is Sue Yoder again and yes Kristina, our wet winter in the four corners area is part of this year's El Nino, although we sometimes have wet winters in our deserts that are not associated with El Nino events.
Thank-you for the explanation on Hanta virus, Patricia. I did not know that the virus was in South America as well.
I will see if I can find out what seabirds are most affected on our offshore islands.
Hi, this is Sue again. I have been trying to find out more about the situation in Africa.
Kenya has been hard hit with heavy rains and flood conditions during November and January. This has caused some loss of human life, and severe damage to roads and bridges, making it hard to reach flood victims. Interestingly, an outbreak of Rift Valley Fever, which is historically connected to the Horn of Africa, has broken out and is affecting humans and livestock. (No reports on the wildlife, but it seems possible since this crosses species so well). Extremely wet conditions like these seem to favor this kind of outbreak.
In humans it has caused influenza like symptoms generally with no serious complications, but in livestock it causes abortions and jaundice and death in young animals such as cattle, goats, camels. Unfortunately a more serious form of RVF seems to have broken out that is more fatal, causing severe hemorraging. It is caused by a virus and is spread by mosquitos which of course multiply in wet conditions.
Just to show that not all news is bad, the greater and lesser flamingos are now doing well in Lake Nakuru, Kenya. The water levels are now back to normal from all the flood waters it has received, and the restored lake is the home for these 1.5 million flamingos.
For those of you interested in impacts, David Duffy and Peter Bryant are maintaining an excellent site that provides impact reports from around the world. These range from official news items to personal observations and from weather to fish.
It can be found at:
http://darwin.bio.uci.edu/~sustain/ENSO.html
I also just posted reports on the impacts of this El Niņo on coral reefs in the eastern Pacific, along with SST observations at:
http://www.ogp.noaa.gov/misc/coral/oisst/
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