cows vs. elephants

[Guest guest]

Here is yet another sad story how meat eating is affecting wonderful wild

animals, through cattle grazing and global warming. The key quotes are: " The

study shows how the elephants lost out to cattle grazing on grasses. " and " " As

we have global climate change [which cows significantly contribute to], that's

going tochange the available resources. As you have populations increase -

andall African populations are increasing dramatically - then you'll havemore

competition for the resources " .

Peace, Dan

 

 

Elephant hair reveals competition

By Jason Palmer

Science and technology reporter, BBC News

The diet and behaviour of elephants evidenced by the chemical makeup oftheir

tail hairs shows how they compete with other species, researcherssay.

The six-year study,published in Proceedings of the National Academy of

Sciences, followeda single family of elephants in northern Kenya.

The study shows how the elephants lost out to cattle grazing on grasses.

It also shows the rate of conception rising as food and water resources become

more abundant each year.

The study is part of an ongoing research programme tracking theelephant family

using GPS receivers on each individual and determininga dietary history from

their tail hairs.

That history is laid out chronologically in an " isotoperecord " along the hair.

Isotopes are naturally occurring variations ofatoms that are chemically

identical but have a slightly different mass.

Different food or water sources that the elephants mightaccess contain

different ratios of isotopes of carbon, hydrogen ornitrogen.

The team's prior work in 2006 showed the power of themaxim " you are what you

eat " ; a clear record of the elephants' dietswas evident in the proteins that

made up their tail hairs.

'Out-competed'

 

“ You have to worry about the conflict of how humans want to use resources

and how wildlife wants to use resources â€

Thure Cerling

" Now, we have a long-term record so we can really see what one normalfamily is

doing over a long period of time, " said Thure Cerling, theUniversity of Utah

professor who leads the research.

In the new work, the team also analysed the content ofdeuterium - an isotope of

hydrogen - in the elephants' tails todetermine the source of the water they

drink.

" During the dry season, the river they're accessingcomes from quite far away,

so the water has had a lot of time toevaporate and change its isotope

composition, " Professor Cerling toldBBC News.

" Then during the rainy season, the rivers come up andthe whole isotope

composition changes and we're able to actually seethat. "

But the surprise finding came from one season in whichthe elephants apparently

did not eat grasses that should have beenreadily available.

" When the rainy season comes you get this big sproutingof grasses, but they

can't access it until it is 30 to 50 centimetreshigh, " Professor Cerling said.

" It's got to grow tall enough beforethey can actually yank it off with their

trunks.

" We have this one incident where they apparently missedan entire good season of

grass resource; the GPS data shows that theywere outside [samburu National

Reserve] in a community area where itappears that they had to compete with

cattle.

" They got out-competed in that situation. "

 

The team also noted that conceptions rose sharply just a few weeksafter the

rainy season brought abundant food and water.

" They bulk up during the rainy season, get into goodcondition, right as things

are starting to get good, " Professor Cerlingexplained.

What is more, the elephants' 22-month gestation periodmeans that the maximum

birthing period is shortly before things getgood again.

" That's right when they have adequate water and justabout the right time to

access this high-protein grass source, " headded.

Future conflicts

The approach gives an intimate look into the elephants' behaviour anddiet in a

way that traditionally could not be done. While that is oftremendous academic

interest to wildlife ecologists, Professor Cerlingsays the recent findings point

to an imminent problem of broaderinterest.

" It points out you have to worry about the conflict ofhow humans want to use

resources and how wildlife wants to useresources, " he says.

" As we have global climate change, that's going tochange the available

resources. As you have populations increase - andall African populations are

increasing dramatically - then you'll havemore competition for the resources.

" If you're concerned about preservation of wildlife then you have to worry

about that competition. "

 

 

 

Story from BBC NEWS:

http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/7992786.stm

 

Published: 2009/04/13 23:24:07 GMT

 

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