Professor Kay Holekamp from Michigan State University has had a long term research program in the Masai Mara studying the spotted hyenas. We've been fortunate enough to know some of the great researchers that she has working for her. Their group has just published an enlightening paper. The abstract states:
We evaluated long-term patterns of human-caused mortality among free-living spotted hyenas (Crocuta crocuta) in a Kenyan game reserve and also assessed nonlethal anthropogenic effects on hyena behavior. We monitored naturally occurring vigilance in 2 clans of hyenas, 1 disturbed and the other undisturbed. The disturbed clan, living on the edge of the reserve, experienced much human disturbance from both tour vehicles and livestock grazing, whereas the undisturbed clan, living in the center of the reserve, also experienced tour vehicles but no livestock grazing. The proportion of all deaths with known causes that could be attributed to humans increased between 1988 and 2006 in the disturbed population; humans caused no mortality in the undisturbed population. Disturbed hyenas were more than twice as vigilant when resting, and they nursed their young closer to bushes, than undisturbed hyenas. Disturbed hyenas also were most vigilant on days when livestock were present in their territory, but we observed no effects of tourism on hyena vigilance. We next conducted playback experiments in which we used cowbells as treatment sounds and church bells as control sounds to determine whether hyenas from the 2 clans responded differently. After hearing cowbells, disturbed hyenas increased their vigilance more than did undisturbed hyenas. However, disturbed hyenas also increased their vigilance after hearing church bells, suggesting that disturbed hyenas may exhibit heightened responsiveness to a wide array of anthropogenic sound stimuli. Our findings suggest that human activities related to pastoralism are having measurable effects on hyena mortality, and that hyenas appear to be responding to this threat by modifying their behavior. DOI: 10.1644/08-MAMM-A-359R.1.
Just published in the Journal of Mammalogy. Get the full article here.
Friday, February 26, 2010
Wednesday, February 24, 2010
Fish Mortality - Lake Naivasha and the Mara River
An article just came out in the Daily Nation entitled, "Mystery of the lake's dying fish leaves experts in a whirl."
As you may remember, we have had similar events in the Mara River.
A few choice quotes from the article:
According to a research officer with Kenya Marine and Fisheries Research Institute, Mr George Morara, the initial investigations indicate very low levels of oxygen.
Most of the fish died at night or early in the morning, with very large sizes of fish, especially the spawning (females), being the most affected, according to the Aquatic Ecology expert.
The researcher said a lot of organic materials had been swept by raging storms into the lake, adding that the decomposition process demanded a lot of oxygen. The researcher said that fertilizer runoffs from farms can make aquatic plants grow faster.
“When the increased numbers of aquatic plants eventually die, they decompose and support high amounts of bacteria which use large amounts of oxygen,” he adds.
Mr Morara estimated the dead fish to be between 700 and 1,000. He said further laboratory tests were being undertaken to determine the real cause of the deaths.
As you may remember, we have had similar events in the Mara River.
A few choice quotes from the article:
According to a research officer with Kenya Marine and Fisheries Research Institute, Mr George Morara, the initial investigations indicate very low levels of oxygen.
Most of the fish died at night or early in the morning, with very large sizes of fish, especially the spawning (females), being the most affected, according to the Aquatic Ecology expert.
The researcher said a lot of organic materials had been swept by raging storms into the lake, adding that the decomposition process demanded a lot of oxygen. The researcher said that fertilizer runoffs from farms can make aquatic plants grow faster.
“When the increased numbers of aquatic plants eventually die, they decompose and support high amounts of bacteria which use large amounts of oxygen,” he adds.
Mr Morara estimated the dead fish to be between 700 and 1,000. He said further laboratory tests were being undertaken to determine the real cause of the deaths.
When Rivers Run Dry
With declining dry season flow levels in the Mara River, it is important to think about the potential impacts if the river were to ever stop flowing. The Great Ruaha River in Tanzania gives us a good opportunity look into that possible future, as it stopped flowing during the dry season in 1993. We just learned about a project in the Great Ruaha that studies the potential increases in disease transfer across humans, livestock and wildlife that are likely to occur when limited water sources shrink in size. Here's an excerpt of an article about the HALI project in the Great Ruaha River, Tanzania...
"To understand how the next disease like SARS or bird flu could arise, take a trip to the Great Ruaha River. It meanders for 300 miles through south-central Tanzania, flowing year-round from the vast Ihefu wetlands through the Ruaha National Park.
Or it used to. Starting in 1993, the river stopped running during the dry season. Some years, it's been silent for more than 100 days.
The river offers water to the safari-famous Ruaha landscape — a grassland twice the size of Vermont that's home to lions, giraffes, endangered wild dogs, and some 30,000 elephants. The river also has been a liquid life-force for groups of semi-nomadic farmers, including the Maasai, Barabaig, and Sukuma who live on the borders of the park — and have relied on the river for themselves and their prized herds of cattle.
With no water in the river for several months, people and animals have a hard time finding a drink. "This has created more overlap between livestock, wildlife, and people as they all go for the same dwindling water resources," says the University of Vermont's Jon Erickson.
Cattle, African buffalo, and farmers all drinking from the same pool and living in close proximity, creates a perfect opportunity for what scientists call zoonotic pathogens: diseases that can jump from animals to people, like rift valley fever and bovine tuberculosis.
Erickson, an associate professor in the Rubenstein School of Environment and Natural Resources, and his Rwandan graduate student, Michel Masozera, have been studying this problem in Tanzania since 2006.
They're leading one part of the HALI Project4— a Swahili word for "state of health" and an acronym that stands for Health for Animals and Livelihood Improvement. It's a collaborative U.S.-Tanzania research effort directed by Jonna Mazet at the University of California-Davis, funded largely by the U.S. Agency for International Development. HALI includes veterinarians, water biologists, and other researchers in California as well as at Tanzania's Sokoine University of Agriculture and the Wildlife Conservation Society. Erickson and Masozera are leading HALI's socioeconomic research through UVM's Gund Institute for Ecological Economics."
To read the whole article, go to http://www.uvm.edu/~uvmpr/?Page=News&storyID=15205
To learn more about the Hali Project, check them out at http://haliproject.wordpress.com/
"The illegal camps that threaten to destroy Kenya's Masai Mara"
The riverine forest on the banks of the Olkeju Ronkai, close to where it meets the waters of its sister river the Mara, has long been a sanctuary for critically endangered black rhinos. Two-thirds of Kenya's remaining population of these shy leviathans were until recently living among the fever trees in what was the largest intact forest of its kind in the Masai Mara wildlife reserve.
Today, the rhino sanctuary has been transformed into a building site, the tranquillity has been shattered and trucks deliver concrete into what is becoming one of the largest lodges in the Mara.
An alliance of conservationists, park wardens and eco-tourism experts are fighting stop the construction of the Olkeju Ronkai lodge which has already displaced the rhinos from their natural habitat. The development is being financed by a British family, the Sofats who trade in the UK as Somak Holidays, registered in Harrow, Middlesex.
An unpublished Kenyan government audit, seen by The Independent, reveals that the Greater Mara ecosystem is now weighed down by 108 camps and lodges, with more than 4,000 beds. Most of these units are flouting the law, failing to compensate local communities and not paying tax, the confidential report concludes. Nearly eight out of 10 of the camps surveyed have not carried out the required Environmental Impact Assessment while only 29 per cent of the camps are operating legally.
Read the full article here...
Get informed:
Flashback to a post we did on the Mara's sister, the Talek River, in July 2009. The Talek River joins the Mara within the Masai Mara National Reserve.
There are over 50 E. coli colonies growing in 1 milliliter sample of water from the river. The river smelled of raw sewage...The water levels are some of the lowest that we have seen. So where is all this fecal contamination coming from? It is difficult to say...but with the higher numbers of tourists staying in the lodges along the Talek River and the well known fact that many of the lodges do not treat their wastes...well...I'll let the facts speak for themselves.
Tuesday, February 23, 2010
In Flight
Here I am, jumping over a small stream in the Mau Forest - upper catchment of the Mara River. I made it...without getting wet!
photo taken by Mara Conservancy Will
Tuesday, February 16, 2010
Monday, February 15, 2010
Sunday, February 14, 2010
Saturday, February 13, 2010
Friday, February 12, 2010
Tuesday, February 9, 2010
Mara River Flows Newsletter - January 2010
"Under the Kenya National Water Resources Management Strategy (2006), water quality parameters are prescribed for different bodies of water based on their Resource Quality Objectives (RQO). RQOs are determined for a given body of water based on its ecological, commercial and livelihood importance. The lower Mara River, where these samples were taken, has been identified by the Lake Victoria South Catchment Management Authority of Kenya as being of high ecological importance, which should correspond to turbidity levels not exceeding 50 NTU. We have measured turbidity at this site 35 times in the last 18 months, and we have only documented turbidity levels below 50 once-- 43.2 NTU on Jan 11, 2009."
Saturday, February 6, 2010
Mara Conservancy Will...IN ACTION!
Mara Conservancy Will joined us for a few days as we sampled in the Upper Catchment of the Mara River.
At a man-made dam on the Kagawet River.
Crossing a bridge over the Anapngetungek River at the edge of the Mau Forest.
Standing on a small, rickety footbridge over the Chapkositonik River.
Jumping over the Anapngetungek River in the Mau Forest!
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