Study Investigates Impact Of Lions Living Alongside Giraffe Populations

[NamStay]

It is commonly accepted that lions are the only predators to pose a risk to giraffes on an individual basis but there has never been a study to investigate how the presence of lions impacts on the population as a whole.

Now, in the first study of its kind, published today in the journal PLOS One, Bristol PhD student Zoe Muller has found that if lions are kept in the same conservation area as giraffes, the number of calves is likely to be reduced, maybe as much as 82 percent.

Zoe, based at the University's School of Biological Sciences, said: "It is thought that lions preferentially target giraffe calves in the wild, and there is anecdotal evidence of this, including observations of lions eating young giraffe carcasses and of lion claw marks on adult females (thought to be a result of them defending their calves).

"However, no-one has ever investigated if this preference for hunting calves has an impact on the population as a whole."

This study investigates how the population demography of giraffes differs between two adjacent sites - one with no lions, and one with a high density of lions, and found that the presence of lions has a significant impact on the demography of giraffe populations.

In areas containing no lions, the giraffe population contained 34 percent of juveniles (individuals less than a year old) but in the presence of lions it only contained six percent juveniles.

Giraffe populations have declined by 40 percent in the last 30 years, and there are now thought to be fewer than 98,000 individuals remaining in the wild.

In recognition of their drastic decline in the wild, they have recently been listed as "Vulnerable" on the International Union for Conservation in Nature's Red List of Threatened Species.

However, conservation review is ongoing due to current debate over their taxonomic status, since some subspecies may be even more at risk of extinction than is currently recognised.

Zoe added: "This research has significant practical implications. Giraffes are a threatened species, suffering ongoing decline in the wild, and this research highlights how managing giraffes alongside lions inside a conservation area (a common practice in Africa) has detrimental effects for giraffe populations.

"The continual loss of juveniles within a population due to lion predation may lead to an unrecoverable situation where the population crashes, since population growth and sustainability rely on enough calves surviving until they are sexually mature.

"This research highlights the need for an urgent reassessment of how populations of giraffes are managed in the wild, given their Vulnerable Red List status and severe and ongoing decline."

The next steps for this research will be to replicate the findings in other areas of Africa. This is one case study from East Africa, and more research is needed to see if lions create the same effects in other giraffe populations.


Source: https://phys.org/news/2018-01-impact-lions-giraffe-populations.html

 

[NamStay]

Lions prey on young giraffes in conservation areas, researchers find

Giraffes are classed as vulnerable, with fewer than 98,000 in the wild – a drop of 40% in the past 30 years.

Researchers are calling for an urgent review into how populations of giraffes are managed in the wild when living alongside lions.

The giraffe population has declined by 40% in the past 30 years, with lions the primary predator to the world’s tallest mammals.

In a first, a study from the University of Bristol investigated the impact of the presence of lions on giraffe populations in the wild.

It found that the number of calves is likely to be reduced by up to 82% when lions are kept in the same conservation area as giraffes.

The work, published in the journal PLOS One, examined giraffe populations at two adjacent sites in Kenya – one with no lions and one with a high density of lions.

In areas with no lions, juvenile giraffes – less than a year old – made up 34% of the population, but made up only 6% in areas with lions.

Zoe Muller, a PhD student at the University of Bristol, warned of an “unrecoverable situation” if giraffe calves continued to decline.

“This research has significant practical implications,” she said.

“Giraffes are a threatened species, suffering ongoing decline in the wild, and this research highlights how managing giraffes alongside lions inside a conservation area – a common practice in Africa – has detrimental effects for giraffe populations.

“The continual loss of juveniles within a population due to lion predation may lead to an unrecoverable situation where the population crashes, since population growth and sustainability rely on enough calves surviving until they are sexually mature.”

She called for an “urgent reassessment” of how populations of giraffes are managed in the wild, given their “severe and ongoing decline”.

Giraffes are listed as vulnerable on the International Union for Conservation of Nature (IUCN) Red List.

There were approximately 151,702 giraffes in the wild in 1985, with the number dropping to 97,562 by 2015.

Threats to the population include illegal hunting, habitat loss, conflict between humans and wildlife and civil unrest.

“It is thought that lions preferentially target giraffe calves in the wild, and there is anecdotal evidence of this, including observations of lions eating young giraffe carcasses and of lion claw marks on adult females, thought to be a result of them defending their calves,” Ms Muller said.

“However, no-one has ever investigated if this preference for hunting calves has an impact on the population as a whole.”

The research will now be replicated in other areas of Africa, to see if lions create the same effects in other giraffe populations.


Source: https://www.belfasttelegraph.co.uk/...ervation-areas-researchers-find-36459158.html

 

[Hank2211]

An interesting study.

I note that the study looks at the “management” of giraffes and lions when the two are “kept in the same conservation area.”

This seems to be directed to areas of human management - such as is found in most of the parks and game fenced hunting areas of Africa. Those who think that we should leave nature alone should bear in mind that man has interfered in nature in much, if not all, of the world, and Africa is no exception. To step back in certain respects - such as letting lions “kept” in an area feed to their hearts content on one type of animal - may mean that the favoured meal comes under unsustainable pressure.

The bottom line is that once you intervene, it is very difficult to know where to stop. It is overly naive and perhaps even irresponsible to suggest that we “let nature takes its course” when we have already directed the course of nature.

I’m not a wildlife scientist, but I wonder if the solution may not be to stock the areas with much more game such as zebra and warthog which lions favour and which reproduce faster than giraffe? Alternatively, you could just allow some lion hunting, keeping the population down. This is a solution which has worked well in parts of North America where certain ungualtes were coming under intense pressure from wolves.

 

[CAustin]

Interesting study for sure.