Between extinction and survival of endangered populations


Populations of endangered species reach a critical point in their life where they either survive or evolve towards extinction. Therefore, efforts to predict and even prevent the extinction of biological species require a thorough understanding of the underlying mechanisms.

Between extinction and survival of endangered populations
The Siberian tiger is an Endangered (EN) tiger subspecies. Three tiger subspecies are already extinct 
[Credit: WikiCommons]
In a new study published in EPJ B, Hatem Barghathi and colleagues from Missouri University of Science and Technology, USA, have investigated how environmental disturbance at random times could cause strong fluctuations in the number of individuals in biological populations.

This, in turn, makes extinction easier, even for large populations. They found that environmental disorder can lead to a period of slow population increase interrupted by sudden population collapses. These findings also have implications for solving the opposite problem when attempting to predict, control and eradicate population of viruses in epidemics.

Between extinction and survival of endangered populations
Semi-logarithmic plot of the survival probability P, vs. time t for several population sizes 
[Credit: Hatem Barghathi et al./EPJ B]
To model biological populations, they performed simulations using an agent-based model. The behaviour of populations that become extinct can be analysed using techniques from statistical physics. These help us to study transitions between a state where the population is active and fluctuates in number, and an inactive state where the population goes extinct.

The authors find that in the presence of time-dependent environmental disturbances, the average time for a biological population to become extinct grows only slowly with population size. This allows even large populations to become extinct quickly. In contrast, in time-independent environmental disturbances, large populations have very long lifetimes.

Barghathi and colleagues also found that when a biological population is close to the transition towards extinction, the population undergoes periods of slow increase alternating with fluctuations leading to a sharp decrease in the number of individuals.

Source: Springer [July 12, 2017]

Comments

Post a Comment

Popular posts from this blog

Ötzi and Tuscany: long-distance connections in the Copper Age

Image
The copper from Ötzi’s axe comes from Southern Tuscany. In September 2016, Professor Gilberto Artioli from the University of Padua had already announced this when presenting his first research findings on the occasion of the Bolzano Mummy Congress which had been jointly organised by the Eurac Institute for Mummies and the Iceman and the South Tyrol Museum of Archaeology to commemorate the 25th anniversary of finding Ötzi’s remains. The copper axe of the Iceman [Credit: © South Tyrol Museum of Archaeology] Finding out about the origin of the copper was a complete surprise, as up till now archaeologists had assumed that the copper used in the Alpine region came from Alpine deposits or the Balkan region. What has not yet been ascertained is whether the Iceman acquired the copper from Tuscany as raw material or as a ready-made blade. Artioli’s publication furthermore establishes links to coeval metallurgical activity in Tuscany. Future research projects aim to retrace trading routes ...
Read more

New excavation season starts in ancient Sagalassos

Image
Excavation and restoration work has resumed in the ancient city of Sagalassos in southwestern Turkey. Monumental centre of Sagalassos: The urban quarter of Upper Agora  [Credit: Turkish Ministry of Culture and Tourism ] A team of 90 people from different countries will work in the excavation area this year and the works will continue for the next three months. A team of five experts from the city’s Mehmet Akif Ersoy University (MAKÜ) will give academic and technological support to the excavation. The head of the excavation team, Professor Jereon Poblome, said the most excavation would be done in the ancient agora area. “Our biggest excavation will take place in the eastern part of the upper agora, as the oldest building of Sagalassos was found there two years ago. As far as we have learned, there was a trade building in this area. This building was constructed in the second century B.C. and is the oldest official building of Sagalassos. Here is a rich place and our building is stan...
Read more

Ptolemaic buildings and bridge unearthed in Alexandria, Egypt

Image
The Hellenic Institute for the Research of Alexandrian Culture (H.R.I.A.C), directed by archaeologist Kalliopi Papakostas, has discovered ancient buildings and a bridge in the Shalallat Gardens area in Alexandria, Egypt. The Ptolemaic public building, where the carved tunnel has been discovered, was located in 2015  [Credit: ANA/MNA] According to the Athens Macedonia News Agency, excavations in the area have been ongoing for 21 years and archaeologists have now unearthed a long carved tunnel at a depth of 10 metres that sheds new light on the large public building from the Ptolemaic period that was found in 2015. The Ptolemaic public building, where the carved tunnel has been discovered,  was located in 2015 [Credit: ANA/MNA] Though its boundaries have yet to be revealed the building, which is thought to have had an arched ceiling, is of massive proportions. Excavation in the Shallalat Gardens in Alexandria, Egypt   [Credit: ANA/MNA] “This is a very significant discov...
Read more