East African fish in need of recovery

FEBRUARY 7, 2020

by Wildlife Conservation Society

A study of East African coral reefs has uncovered an unfolding calamity for the region: plummeting fish populations due to overfishing, which in turn could produce widespread food insecurity.

In a newly published paper in the journal Marine Ecology Progress Series titled "Coral reef fish communities, diversity, and their fisheries and biodiversity status in East Africa," WCS Senior Conservation Zoologist Dr. Tim McClanahan reports that overfishing is widespread across the region.

The remedy, says the sole author of the study, is to recognize the need to rebuild fish stocks to ensure they are providing the maximum possible catch for the developing countries of Kenya, Tanzania, and Mozambique. The African continent has among the highest human population growth rates and associated food security issues.

"Whereas fish stocks within marine parks and areas in distant or turbulent locations were found to be at healthy levels, coastal areas open to fishing were another story," said McClanahan. "We have found that fish catches have been declining in Africa in recent years by a million tons a year, and this study shows that much of this decline in East Africa is due to declining fish stocks."

Based on a sample of 239 sites—data gathered over several years—the study and previous estimates show that 70 percent of the reefs have fish stocks below the levels that will produce the maximum fisheries yields. The few areas above this level were in marine parks, rural areas, and remote or dangerous seas.

The study further shows that low stocks not only affects food production but also the diversity of fish and reef ecology. Numbers of fish species decline rapidly when stocks decline below sustainable levels. This loss of species will have consequences for the long-term recovery and the potential to produce food.

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From vibrations alone, acacia ants can tell nibbles from the wind

Date:  February 15, 2019

Source:  Cell Press

Acacia trees are a prominent feature of the East African savannah. They're also a classic example of the long-standing and complex relationships between plants and insects, in this case acacia ants. The acacias provide food in the form of nectar and accommodation in hollow thorns for the ants. In return, the ants defend the acacias against nibbling elephants, giraffes, or other animals that would eat them.

Now, researchers reporting in the journal Current Biology on February 14 find that the ants are tipped off to the presence of herbivores by vibrations that run throughout the trees when an animal gets too close or begins to chew. As a result, the insects begin patrolling the acacia's branches more actively. Remarkably, the researchers show, the ants don't react when the trees' movements are caused only by the wind.

"The vibrations that occur when a mammal plucks a leaf are so powerful that they spread across the whole tree and are perceived by the ants," says Felix Hager of Ruhr University Bochum, Germany. "As a result, the ants are alerted within a fraction of a second and promptly orient toward the attacker."

Read on

Scientists uncover patterns of elephant poaching in East Africa

December 19, 2017, University of York

Scientists analysing data from aerial surveys carried out over one of East Africa's most important nature reserves have uncovered clusters of elephant carcasses close to some ranger posts.

The team, from the University of York and the Tanzania Wildlife Research Institute (TAWIRI), made the discovery while working together to address the problem of elephant poaching in the Ruaha-Rungwa ecosystem.

The study used data from three successive aerial surveys during the peak of the poaching crisis from 2013-2015 and revealed patterns of elephant carcasses across the region.

Wet season

Using aerial surveys and spatial analysis, the team revealed the poachers preferred to operate in the wet season – when swollen rivers meant travel by road was extremely difficult and tourism was minimal.

The study, which involved collaboration between the University of York and TAWIRI, also revealed the signs of poaching tended to be away from the main, well-equipped ranger posts, where the aerial surveys revealed fewer carcasses.

However, the data revealed elephant remains were found in greater numbers than expected close to three out of 13 outlying ranger posts. If carcasses had been as rare around outlying posts as near the park headquarters, overall there would have been seven per cent fewer carcasses.

Lead author, Dr Colin Beale from the University of York's Department of Biology, said a lot has changed since the surveys were done and the Tanzania government was working hard to address the problem, with evidence that poaching has since fallen substantially.

Read more at: 

'Golden jackals' of East Africa are actually 'golden wolves'

Date: July 30, 2015

Source: Cell Press

Summary: Despite their remarkably similar appearance, the 'golden jackals' of East Africa and Eurasia are actually two entirely different species. The discovery, based on DNA evidence, increases the overall biodiversity of the Canidae -- the group including dogs, wolves, foxes, and jackals -- from 35 living species to 36.

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17-Million-Year-Old Whale Skull Helps Place Humanity's First Steps

by Laura Geggel, Staff Writer | March 16, 2015 04:10pm ET

A 17-million-year-old beaked whale fossil is helping researchers solve a puzzle about the likely birthplace of humanity in East Africa, a new study finds.

The whale (Ziphiidae) lived when the East African plateau was substantially lower and covered by dense forests, the researchers said. Scientists have long tried to figure out when the uplift occurred, because when it did, the moisture from the Indian Ocean could no longer reach the trees and vegetation, and the area turned into a savannah, research suggests.

Extinct ancestors to modern humans may have lived in trees in East Africa, but after the area turned into grassland, these early humans gradually began walking on two feet, researchers suggest.


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East African honeybees safe from invasive pests ... for now

Date:

April 17, 2014

Source:

Penn State

Summary:

Several parasites and pathogens that devastate honeybees in Europe, Asia and the United States are spreading across East Africa, but do not appear to be impacting native honeybee populations at this time, according to an international team of researchers. The invasive pests include including Nosema microsporidia and Varroa mites.

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Conservation Efforts Might Encourage Some to Hunt Lions

Aug. 5, 2013 — Conventional wisdom holds that East Africa's Maasai pastoralists hunt lions for two distinct reasons: to retaliate against lions that kill livestock or to engage in a cultural rite of passage. But that view reflects mistranslations of Maasai terms and a simplification of their cultural traditions and their relationship with wildlife, a team of researchers led by a University of Colorado Boulder geographer has concluded.

Further, some conservation initiatives including those designed to save lions from being hunted have either failed to work or in some cases appear to have incited Maasai to hunt more lions as a form of political protest, the researchers report.

Such nuances are important, because it's harder to control the hunting of lions unless society knows precisely why lions are hunted, the researchers contend.

Many populations of Panthera leo -- African lions -- are falling, and the species is classified as "vulnerable" on the International Union for Conservation of Nature and Natural Resources' Red List.

Lion hunting is outlawed in Kenya and in Tanzania is limited to mostly tourists hunting with permits, unless the hunt is to eliminate a lion in defense of life or livestock. Still, lion hunting regularly occurs in both countries, usually without the hunters' following the law.

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Horned ghost crabs change camouflage from day to night

By Ella Davies, Reporter, BBC Nature

Horned ghost crabs change their appearance from day to night for camouflage, a study has revealed.

The species Ocypode ceratophthalmus builds burrows on beaches from Japan to East Africa to shelter from predators.

Researchers investigating young crabs' defences found they fine-tune their brightness to mimic their background.

The crabs reflected changes in their environment throughout the day, becoming lighter in the daytime and darker at night.

The findings are published in the Biological Journal of the Linnean Society.

Horned ghost crabs are named for their eyestalks which extend upwards resembling horns. The crabs are mostly active at night and juveniles are slightly translucent.

Dr Martin Stevens, working for the University of Cambridge, undertook the study with colleagues from the National University of Singapore.

Continued:  http://www.bbc.co.uk/nature/22025789

Largest Known Crocodile Could Swallow a Human

ScienceDaily (May 4, 2012) — A crocodile large enough to swallow humans once lived in East Africa, according to a University of Iowa researcher. "It’s the largest known true crocodile,” says Christopher Brochu, associate professor of geoscience. “It may have exceeded 27 feet in length. By comparison, the largest recorded Nile crocodile was less than 21 feet, and most are much smaller.”

Brochu’s paper on the discovery of a new crocodile species was just published in the May 3 issue of the Journal of Vertebrate Paleontology. The new species lived between 2 and 4 million years ago in Kenya. It resembled its living cousin, the Nile crocodile, but was more massive.

He recognized the new species from fossils that he examined three years ago at the National Museum of Kenya in Nairobi. Some were found at sites known for important human fossil discoveries. “It lived alongside our ancestors, and it probably ate them,” Brochu says. He explains that although the fossils contain no evidence of human/reptile encounters, crocodiles generally eat whatever they can swallow, and humans of that time period would have stood no more than four feet tall.

"We don’t actually have fossil human remains with croc bites, but the crocs were bigger than today’s crocodiles, and we were smaller, so there probably wasn’t much biting involved,” Brochu says.

He adds that there likely would have been ample opportunity for humans to encounter crocs. That’s because early man, along with other animals, would have had to seek water at rivers and lakes where crocodiles lie in wait.
Continued:  http://www.sciencedaily.com/releases/2012/05/120504171913.htm

Tanzania, Kenya, Uganda, Rwanda and Burundi agree trans-boundary eco-system management laws

BirdLife welcomes passing of law to secure trans-boundary ecosystems in East Africa

February 2012. The East African Legislative Assembly (EALA) has passed a crucial law that could transform how trans-boundary ecosystems and resources in East Africa are managed. EALA is the legislative arm of the East African Community, a regional block bringing together five countries, namely, Tanzania, Kenya, Uganda, Rwanda and Burundi.

Hon. Dr. George Nangale, the former Chairman of the Committee on Agriculture, Natural Resources and Tourism at EALA, and who moved the bill in 2008 was delighted to see it enacted. "I am glad to see this landmark bill go through, many thanks for the support from all stakeholders," he said.

The new law is considered critical since it establishes a mechanism for addressing developments of a trans-boundary nature that affect shared ecosystems. Among other things, it establishes a Commission that will supervise and monitor the implementation of policies on the management of such resources. It emphasises the need for Environmental Impact Assessment of projects with impacts of a trans-boundary nature, with the Commission playing a key role in the approval process.

"This is a welcome development. East African countries now have a good chance to collaborate and share information on development projects of a trans-boundary nature. It will no longer be business as usual" Said Mr. Deo Gamassa, the new CEO of the Wildlife Conservation Society of Tanzania (BirdLife in Tanzania).

Read on:  http://www.wildlifeextra.com/go/news/east-africa-transboundary.html

Wild dogs didn't go extinct in east Africa after all

In 1991, conservationists announced with dismay that endangered African wild dogs had gone extinct from the Serengeti-Mara region of east Africa. Now the latest genetic study reveals that this proclamation may have been premature – it turns out they almost certainly didn't go extinct at all.

A team of UK and US researchers genetically analysed a rare bounty of samples taken both from the dogs before their apparent extinction, and from new packs that naturally re-established in the area ten years later in 2001.

To their surprise, they found that almost all of the new dogs are genetically related to the original Serengeti-Mara population, meaning that some dogs must have persisted undetected in the region after 1991.

'The data suggest that there wasn't complete extinction in the region, which is encouraging,' says Dr Barbara Mable from the University of Glasgow, who led the study.

Mable and colleagues from the universities of Glasgow and California also discovered that the disappearance of the dogs in the early 90s had almost no effect on the genetic diversity of the population.

'The diversity maintained in the recolonising populations suggests that they could make a good recovery,' adds Mable. 'Their numbers have increased rapidly after 2001.'

Despite this welcome news, scientists are still puzzled about why the dogs disappeared in the first place, and then why they turned up again ten years later.

'Our findings still can't explain the puzzling cause of the disappearance of so many packs of dogs from the monitoring area. One possibility is that animals remained or moved to areas outside of the Serengeti national park that weren't monitored regularly,' says Mable.

'The terrain in this region is pretty inaccessible, and is marked by a density of trees, bushes and grasses, so it isn't easy to keep track of wild dogs, which tend to be on the move a lot.'

When the Serengeti-Mara packs first disappeared, there was much heated debate about the likely cause. Critics claimed that handling by veterinarians and conserationists may have accelerated their decline by somehow helping to spread rabies and distemper from domestic dogs to wild dogs. 'But this is highly implausible and there was no concrete scientific evidence to support these claims,' says Mable.

Indeed, the shock of the dogs' assumed extinction led the authorities to ban anyone - include veterinarians - from handling them. While this might have seemed like the best approach, the flipside of this stance meant that rabies and distemper vaccination programs designed to help safeguard this endangered species were held up.

So when it emerged that scientists had collected samples from the Serengeti-Mara wild dogs before 1991 and after their return in 2001, Mable and her colleagues were keen to investigate. They wanted to see if they could get to the bottom of the dogs' 1991 disappearance.

African wild dogs have huge home ranges, travelling as far as 250 kilometres to establish new packs. This led the researchers to come up with three possible suggestions for the ancestry of the new dogs.

Either the original population went extinct in 1991, and the re-established pack came from a completely different population; the original population didn't go extinct at all; or the new population is a mixture of dogs from the original packs and new migrants.

Mable and her colleagues discovered that most of the new dogs are related to the original pack, but they also found that dogs from completely different populations had made it into this new population.

'The dogs didn't return to the Serengeti itself, which may be because they're avoiding the growing lion population there,' says Mable.

'Our results highlight the importance of long-term field projects like this one to keep track of the genetic ancestry of endangered animals,' she adds.

African wild dogs have been classed as endangered by the IUCN Red List of Threatened Species for 22 years. Ongoing conflict with people, limits in the availability of their favourite prey - such as Impala, Greater Kudu, and Thomson's Gazelle - and habitat fragmentation, seems to responsible for their continued decline.

The study is published in Conservation Genetics.

Clare D. Marsden, Robert K. Wayne and Barbara K. Mable, Inferring the ancestry of African wild dogs that returned to the Serengeti-Mara,Conservation Genetics, published online 25 December 2011, DOI 10.1007/s10592-011-0304-z

http://planetearth.nerc.ac.uk/news/story.aspx?id=1140