https://theconversation.com/ex...genetic-costs-136650



Exploitation changes leopard behaviour with long-term genetic costs

May 10, 2020 4.30am EDT

Authors
Vincent Naude
PhD student, University of Cape Town

Guy Balme
Honorary Research Associate, University of Cape Town

Jacqueline Bishop
Senior Lecturer in Conservation Biology, University of Cape Town

Disclosure statement
Vincent Naude receives funding from Panthera, the Peace Parks Foundation, the Institute for Communities and Wildlife in Africa, the University of Cape Town and private donors.

Guy Balme is currently employed by and receives funding from Panthera, a not-for-profit organisation dedicated to the conservation of wild cats globally.

Jacqueline Bishop receives funding from the University of Cape Town, the National Research Foundation, WWF-Table Mountain Fund, the Cape Leopard Trust, Panthera and private donors.

Partners
University of Cape Town

University of Cape Town provides funding as a partner of The Conversation AFRICA.


Throughout their range leopards are in rapid decline, having disappeared from North Africa, much of the Middle East and Asia. Declines have been so severe that the species is now considered vulnerable to extinction. No comprehensive estimates of the number of leopards remaining in the wild exist.

In southern Africa, 62% of leopard distribution falls outside of formally protected areas. This unprotected landscape is highly fragmented by both agriculture and urban development.

Threats to leopards include habitat fragmentation, killing for fear of livestock loss and poorly managed trophy hunting. Leopards are poached through deliberate or opportunistic poisoning and wire-snaring. Their body parts are also illegally traded for traditional medicine and cultural attire.

Conservationists are concerned that these threats contribute to the overall decline in leopard numbers. Conserving leopards successfully requires us to track population numbers and trends. However, leopards are notoriously elusive and occur at low densities, which makes monitoring difficult.

Threats to many wild cat populations across southern Africa are often age and sex-biased. How these threats influence leopard behaviour is poorly understood.

The research

Our study explored the long-term genetic costs of exploitation-driven changes in the behaviour of leopards. To do this we compared the social and genetic structure of two well-studied populations in South Africa; a protected population and one recovering from over-exploitation since 2005, where 50% of leopard deaths were human-related.

Using GPS collars, guide sightings and genetic samples, we gathered over 15 years of data to reconstruct home ranges and family pedigrees for 150 leopards across both reserves. This allowed us to examine the behaviour of related individuals over multiple generations, with and without exploitation.

Typically, female leopards establish territories close to their mothers, while males settle away from their natal range. At sexual maturity (~3 years), sons compete with surrounding males for access to territory and mates. Often overcome by these large established males, sons are forced to disperse out of the area, creating a “genetic out-breeding effect”. By “moving out” to establish a territory away from “home”, sons avoid breeding with closely related females.

Inbreeding at the level of sisters, mothers and aunts can have severe consequences in big cats. These range from physical defects like tail “kinks”, to severe reproductive costs and even sterility.

In both populations, we found that daughters established home ranges near their mothers. Here they benefit from the resource knowledge of their mother’s territory. In the fully protected population, sons dispersed out of their maternal home ranges, moving away from closely related females.

But in the historically over-exploited population, many young males did not disperse. Instead, their newly established home ranges overlapped with those of their sisters, mothers and aunts. Here, territory “gaps”, created by the killing of large males, allowed sons to escape competition and establish territories alongside their mothers.

The problem? Males in the exploited population stopped dispersing and, as a result, destabilised the out-breeding mechanism for this population. This increased the likelihood of young males fathering cubs with closely related females.

We found evidence of this with a father-daughter and two half-sibling mating events. Known breeding pairs in this population were also highly related, the equivalent of at least half-siblings. While the overall population was growing, it retained signatures of inbreeding despite over 10 years of recovery.

What does this mean for leopard conservation?

The risk of inbreeding in small, over-exploited populations is well known. However, few studies have the necessary long-term data to demonstrate this direct link. We show clear evidence of how exploitation can disrupt the dispersal behaviour of leopards, ultimately leading to inbreeding.

Our study is among the first to demonstrate these risks in a large solitary wild cat species. We emphasise that even “recovering” populations still carry the inbreeding “scars” of historical exploitation. While reduced genetic diversity exposes populations to the challenges of future disturbances, including disease outbreak, habitat loss and climate change.

Increasing evidence suggests most leopard populations across southern Africa are threatened by exploitation. Long-term genetic costs should stimulate discussion among scientists, reserve managers and policymakers who aim to effectively conserve this species.

The recovery of leopard numbers in historically exploited protected areas is crucial to safeguarding the 62% of unprotected leopard range from loss. Promoting movement between reserves to encourage gene flow requires suitable wildlife corridors for leopards, even through already transformed land.

Left unregulated, the unsustainable exploitation of leopards will have severe ecological and evolutionary costs. We have demonstrated that removing too many individuals, especially of a particular age or sex, can destabilise a population. By changing the social dynamics of individual behaviour and this increases the chance of inbreeding.

Population monitoring of leopards indicates that habitat loss and population declines are similar to lion and rhino. Yet their silent disappearance goes largely unnoticed due to their broad distribution and elusive nature. We have only just begun to understand and effectively conserve these magnificent cats.

This means now we have to put up with stupid studies on leopards, as well as rhinos and lions.

Someone should tell these brainless idiots to make up their minds.

South African has thousands of rhinos and lions, bred on farms.

And when people shoot one, all hell breaks loose!

These so called environmentalists and animal lovers are anything but!

Overall, the statement of worry about the decline of the leopard sounds a little bit like similar concern about the Cougar in the Americas.
Left to their own devices, the Cougar will expand their range to all environments suitable to their survival. When they move into towns, cities, and farms and ranches where their presence conflicts with humans, they are exterminated. Since they are largely nocturnal and reclusive, their presence is often not obvious and they are able to live on the fringes of human population centers. Hunters need to use hounds to have much chance of success.

The growth of the human population does present long term issues for the existence of all wildlife. I suppose that if we can put people on the moon and explore deep space, we will be able to address problems closer to home. One small step may have been the introduction of certain foreign species to game ranches in Texas where their presence pays for their upkeep. Some game such as Axis deer, Blackbuck, red deer, elk, warthogs, wild boar, and Aoudad has gone feral and free range outside the high fence properties where they were first placed.

At least they started out with a disclosure statement warning us they were going to be biased and full of shit.

What a bunch of crap.
A couple of loose stories about leopards.

A mate of mine has got a farm near Ellisras, his entrance is 24km from the tar on a dirt road. One morning after the rain he is first on the dirt road, opening his gate there is male leopard tracks passing his entrance in the direction of the tar. He lost the tracks when they went onto the tar.

A leopard is GPS collared close to him, 5 days later the cat is 160km away.

A leopard was injured or somehow ended up at a rehab centre close to Hoedspruit. The leopard is GPS collared and released and goes into the mountains. A month later this cat starts walking, walks through the streets of Hoedspruit at night and just continues through farmland, mountains, crosses roads & freeways and tribal areas to end up near Messina 200km as the crow flies. The leopard hangs around there for more than a year on mine property and the next thing starts walking back to Hoedspruit and goes in live in a valley in the mountains.

Years ago I was on an unsuccessful problem lion hunt with a good cat PH, I can clearly remember driving with him and he told me: "A cat's purpose on earth is to walk."
And walk they flippin well walk.
Young males don't disperse because of older males getting shot? I call bullshit - probably only the gay ones not trying their luck with the girls

To my mind logic is not applied well, if daughters establish near mothers there is a good chance to be bred by the dominant male ie. their father.

[quote]Throughout their range leopards are in rapid decline,

These idiots obviously have never been in the Luangwa Valley or many other areas of Africa where leopards are plentiful.

Mark

Agree with Mark and Balule.

If the much predicted by liberal nutcases apocalypse happens, the last three species to perish will be Cockroaches, which will be eaten by Rats, which will in turn be eaten by leopards.

Just because you can't find them doesn't mean they are endangered.