The research, a collaboration involving University of Queensland and Griffith University, published in Frontiers in Ecology & Evolution,and Ecological Solutions and Evidence, found that current lion counting methods for research/conservation purposes may be overestimating lion numbers and densities.

Lead author Alexander Braczkowski, formerly at University of Queensland, now a research associate at the Environmental Futures Research Institute

“African lions are one of the world’s most loved animal species and for that reason they garner both conservation attention and funding,” Mr Braczkowski said.

“Yet some experts believe their populations have experienced a 50% decline since 1994 when, coincidentally, Disney’s The Lion King was released.

“Current calculations indicate between 20,000 and 30,000 remain in the wild, scattered across 102 populations in Africa, however, our research suggests these numbers may be substantially lower.

“Most African lion abundance and density estimates are based upon track counts, audio lure surveys and expert solicitation – which are simply not informative enough to understand how lion populations are doing over time.”

According to Mr Braczkowski, as outlined in Frontiers in Ecology & Evolution, the methods being used to calculate lion abundance and density is lagging behind those adopted for other big cats, such as tigers, leopards and jaguars.

“Only by using long-term surveys using photographic methods to identify individual lions can you accurately track changes in population size, survival, density and sex-specific movements.

“Monitoring these parameters over time provides important insights into population health, that current methods like audio surveys or track counts, can’t. For example, our study demonstrated that large home ranges and skewed sex-ratios, can signal prey depletion and imminent population collapse.

“This technique, developed in the Maasai Mara by co-authors Dr Nic Elliot and Dr Arjun Gopalaswamy, compiles data on lion identities and their location, and subsequently uses power computers to determine the changes in lion density across the landscape.”

In their second research paper, Mr Braczkowski and colleagues assessed the ability of this technique to better understand the status of lions in Queen Elizabeth National Park, Uganda.

“This was the perfect place to use this approach since lions in Queen Elizabeth National Park spend a lot of their time up in trees, and it is relatively straightforward to get good pictures of them,” Mr Braczkowski.

“This lion population also carries great local tourism value, with each lion estimated to raise about USD$14,000 annually.

“Queen Elizabeth National Park is an unusual site where lions, owing to their unique tree-climbing behaviour are frequently seen by managers and tourists.”

“It is alarming to note that many continent-wide figures on African lion numbers are not backed by rigorous on-ground surveys,” said Dr Duan Biggs, a co-author on the studies from Griffith University.

“Accurate site-based estimates of lion population size are crucial to assess the effectiveness of conservation interventions.”

Mr Braczkowski and colleagues found lions in Queen Elizabeth National Park were now moving more and have larger home range sizes compared to the previous study conducted about a decade ago.

“Since larger home range sizes in big cats are often associated with lower animal densities due to less available prey, this is a concerning trend,” said Dr Arjun Gopalaswamy, a co-author and science advisor to the Wildlife Conservation Society’s Global Programs.

“There’s great value in using methods that keep track of lion populations directly and we urge conservation and research communities to cease using ad hoc, indirect methods and shift to more reliable and direct methods.”

“In light of the conservation threat due to the collapse in tourism in Africa it is now more urgent than ever to have accurate, reliable monitoring of lion numbers on the continent,” said Mr Braczkowski.

“It appears this is starting to happen, with the method being adopted by the Kenya Wildlife Service and partners to survey lions and other carnivores across Kenya.”

Source: Griffith University

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Tesla was part of an expedition into Gabon’s Abanda caves following up a tip about dwarf crocodiles living there. While crocodiles sometimes retreat to underground nests and dugouts during droughts, this is the first population of crocs known to live in caves.

African dwarf crocodiles are generally found above the ground throughout Gabon, but the cave-dwelling population is filling a unique niche in the ecosystem. The crocodiles can survive in the caves due to the plethora of cricket and bats that reside there, according to crocodile expert Matthew Shirley of the Rare Species Conservatory Foundation.

The as dwarf crocodiles (Osteolaemus tetraspis), also known commonly as the African dwarf crocodile, broad-snouted crocodile, or bony crocodile, is an African crocodile that is also the smallest extant crocodile species. Recent sampling has identified three genetically distinct populations.

Dwarf crocodiles attain a medium adult length of 1.5 m (4.9 ft), though the maximum recorded length for this species is 1.9 m (6.2 ft). Adult specimens typically weigh between 18 and 32 kg (40 and 71 lb), with the largest females weighing up to 40 kg (88 lb) and the largest males weighing 80 kg.

Testa and Shirley are part of the Abanda Expedition and recent research suggests that the animals may be evolving into a totally new species.

To test this, the researchers tested blood samples from the crocodiles found in the caves, and compared them with forest-dwelling crocs living outside in the area. It turned out the cave dwelling crocs have different genetic haplotype, which means that the reptile is adapting or mutating to life in the dark.

The current population size is not more than 100-200 individuals, according to Shirley.

Why are the crocodiles turning orange?

Testa and Shirley think it might be because of acidic bleaching:  “The crocodiles live in liquids — that’s guano (bat faeces) — and it’s quite a harsh environment. There’s a chemical attack on the skin and it bleaches the skin. But we don’t have means to prove that,” Testa told CNN.

The research team wants to find out and understand why these crocodiles started to live in these inhospitable caves. Is it to survive a past climate change? Is it to escape a predator? Did they get trapped here?

For more information about the expedition, please visit:

http://www.abanda-expedition.org

Photo credits: Olivier Testa, Abanda Expedition

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Humans routinely adjust communication to take into account information that they know is available to their audience, an ability assumed to be absent in other animals. This assumption may be premature. Recent studies show changes in primate alarm signaling to threats according to receivers’ risk. “A major confound in assessing animal mind reading capacity, however, has been eliminating the possibility of subjects reading the behavior rather than the minds of the others”, says Catherine Crockford of the Max Planck Institute for Evolutionary Anthropology. “Here, we overcome this confound by using a new experiment with a call played from a loud speaker to simulate the receiver. This means that there is no possibility for behavioural cues, other than the call itself.”

The researchers designed experiments to exclude concurrent reading of receivers’ behavior by simulating receivers using pre-recorded calls of other group members. Specifically, they tested whether wild chimpanzees emitted differing signals in response to a snake model when simulated receivers previously emitted either snake-related calls (indicating knowledge), or acoustically similar non-snake related calls (indicating ignorance). “As chimpanzees walked along a path they first heard the playback of a chimpanzee call and then as they continued to walk along the path, they saw a snake model”, says Crockford. “The playback was either a call associated with snakes, indicating the caller was aware of the snake, or a similar call not associated with snakes, indicating the caller was not aware of the snake.”

Crockford, Wittig and Zuberbühler found that chimpanzees changed their behavior at the snake depending on the call type that they had heard some seconds earlier. They found that chimpanzees not only monitored receivers’ awareness of a threat but also changed their communication depending on the receivers’ awareness of the threat.

The researchers conclude, chimpanzees are aware enough of another’s perspective to target information towards ignorant group members, suggesting the integration of signaling and socio-cognition systems was already emerging in early hominoid lineages, before the advent of more language-specific features, such as syntax. Crockford says: “Our results demonstrate that chimpanzees have achieved a crucial step within the evolution of language previously thought to be absent in all non-human communication – to fill another’s knowledge-gap.”

Source:
Max Planck Institute

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