Why lions, hyena’s, leopards and cheetah of Nairobi Park matter


Dear Friends,

Although Nairobi National park has the worlds highest density of lions, there has been no serious research on these top predators in recent times.  Now a scientific review has concluded that the decline of top predators can have  catastrophic effects on an ecosystem (see article below).

If they are right, then we should be very concerned for Nairobi Park and the entire Athi Kapiti ecosystem. Though the Nairobi Park lion population seems to be healthy now, at between 35 and 40 individuals (which may in fact be too many), we know very little about our leopard numbers, we have virtually lost all our cheetah, and wild dogs disappeared decades ago.  Hyena numbers are low and birds of prey are declining, Egyptian vultures visibly absent, and all other species of vultures are declining rapidly.

The article below must be taken seriously and we should initiate long term research on our top predators including vultures and birds of prey for the Nairobi Park and the entire Athi Kapiti Ecosystem. FoNNaP encourages students to initiate  research projects that are beneficial to Nairobi Park and we will offer any support available. FoNNaP members who are interested in accessing any articles based on research conducted in Nairobi Park  can access our scientific articles database which is available at our office at Nairobi Park entrance – just email fonnap1@gmail.com to find out more.

Leopard are amongst the most secretive and elusive of all the big cats. We are aware of only one ongoing research study in East Africa and it’s in Nairobi National Park! Thank you Simon Thomsett for this spectacular photo

Loss of Top Animal Predators Has Massive Ecological Effects ScienceDaily (July 14, 2011) — “Trophic Downgrading of Planet Earth,” a review paper that will be published on July 15, 2011, in the journal Science, concludes that the decline of large predators and herbivores in all regions of the world is causing substantial changes to Earth’s terrestrial, freshwater, and marine ecosystems. The paper claims that the loss of apex consumers from ecosystems “may be humankind’s most pervasive influence on nature.”

The review, conducted by an international team of 24 scientists, illuminates the patterns and far-reaching impacts of predation and herbivory on the structure and dynamics of global ecosystems. The researchers relied on both experimental and observational evidence, which provides a strong basis for their conclusions. “By looking at ecosystems primarily from the bottom up, scientists and resource managers have been focusing on only half of a very complex equation,” said Dr. Estes. “These findings demonstrate that top consumers in the food web are enormous influencers of the structure, function, and biodiversity of most natural ecosystems.” Apex consumers include animals such as big cats, wolves, bison, sharks, and great whales, and are typically large, long-lived, and not amenable to laboratory experiments. As a result, the effects of removing them from ecosystems are not easy to document. The team of scientists reviewed an accumulation of theoretical and empirical evidence on how the decline of top predators and herbivores has affected Earth’s ecosystems on land, in freshwater, and in the ocean. Their findings suggest that “trophic downgrading” — the ecological consequences of losing large apex consumers from nature — causes extensive cascading effects in ecosystems worldwide, especially when exacerbated by factors such as land use practices, climate changes, habitat loss, and pollution. “Our review of existing studies clearly shows that a top-down cascading effect in natural systems is both powerful and widespread,” said Dr. Estes. “There is an urgent need for interdisciplinary research to forecast how a continued loss of top level consumers will further harm the planet’s ecosystems.” This paper documents some of the negative effects that the widespread loss of these animals has already had on Earth’s biosphere, climate, biodiversity, and vegetation: * The reduction of lions and leopards from areas of sub-Saharan Africa caused the baboon population to swell. This unexpectedly increased transmission of intestinal parasites from baboons to humans as the primates were forced to forage closer to human settlements. * As large ungulates recovered from a devastating rinderpest epidemic in the Serengeti in Africa, herbivory increased, and the frequency of wildfire declined in that region. Wildfire frequency increased following the late Pleistocene/early Holocene decline of megaherbivores in Australia and the northeastern United States. * Industrial whaling in the 20th century resulted in the loss of large numbers of plankton-consuming great whales, which are now known to sequester carbon into the deep sea through deposition of feces. The result has been the transfer of approximately 105 million tons of carbon into the atmosphere that would have been absorbed by whales, contributing to climate change. “We must assume going forward that significant changes to the ecosystem are occurring when large predators and herbivores are removed from the top of the food web, and, thus, that efforts to manage and conserve nature must include these animals,” said Dr. Pikitch. “An old paradigm has shifted, and those who question this theory now have the burden to prove otherwise.” Science 15 July 2011: Vol. 333 no. 6040 pp. 301-306 DOI: 10.1126/science.1205106 * Review Abstract Until recently, large apex consumers were ubiquitous across the globe and had been for millions of years. The loss of these animals may be humankind’s most pervasive influence on nature. Although such losses are widely viewed as an ethical and aesthetic problem, recent research reveals extensive cascading effects of their disappearance in marine, terrestrial, and freshwater ecosystems worldwide. This empirical work supports long-standing theory about the role of top-down forcing in ecosystems but also highlights the unanticipated impacts of trophic cascades on processes as diverse as the dynamics of disease, wildfire, carbon sequestration, invasive species, and biogeochemical cycles. These findings emphasize the urgent need for interdisciplinary research to forecast the effects of trophic downgrading on process, function, and resilience in global ecosystems.

This research was funded primarily by the Institute for Ocean Conservation Science at Stony Brook University with support from The Pew Charitable Trusts. The paper is co-authored by the Institute’s executive director, Dr. Ellen K. Pikitch, and the lead author is Dr. James A. Estes, professor of ecology and evolution at the University of California at Santa Cruz. The research was funded primarily by the Institute for Ocean Conservation Science at Stony Brook University with support from The Pew Charitable Trusts. The paper is co-authored by the Institute’s executive director, Dr. Ellen K. Pikitch, and the lead author is Dr. James A. Estes, professor of ecology and evolution at the University of California at Santa Cruz.

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One response to “Why lions, hyena’s, leopards and cheetah of Nairobi Park matter

  1. The impact is world wide. Here is an article from the Washington Post of July 14: http://www.washingtonpost.com/national/health-science/decline-of-predators-such-as-wolves-throws-food-chains-out-of-whack-report-says/2011/07/14/gIQAaeY1EI_story.html

    Loss of wolves and other predators in the US has led to an explosion of deer in urban and suburban areas around metropolitan Washington DC-Maryland-Virginia where I live. This has increased the spread of tick-borne diseases like Lyme disease. Police now periodically have to cull the deer herds through organized, planned night-time hunting with lights. The meat goes to local food kitchens for the poor, so it is not at all wasted.

    As the article points out, overhunting of sharks has led to a growing population of a species of manta ray that eats oysters, and thus a decline in Chesapeake Bay oyster beds. Oysters filter and clean water.

    Best to all

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