UPSC Courses

DNA banner


  • 29 July, 2020

  • 5 Min Read

Source-sink dynamics

Source-sink dynamics

  • Source–sink dynamics is a theoretical model used by ecologists to describe how variation in habitat quality may affect the population growth or decline of organisms.
  • Since quality is likely to vary among patches of habitat, it is important to consider how a low quality patch might affect a population.
  • In this model, organisms occupy two patches of habitat.
  1. One patch, the source, is a high quality habitat that on average allows the population to increase.
  2. The second patch, the sink, is a very low-quality habitat that, on its own, would not be able to support a population.
  • However, if the excess of individuals produced in the source frequently moves to the sink, the sink population can persist indefinitely. Organisms are generally assumed to be able to distinguish between high and low-quality habitat and to prefer high-quality habitats.
  • However, the ecological trap theory describes the reasons why organisms may actually prefer sink patches over source patches.
  • Finally, the source-sink model implies that some habitat patches may be more important to the long-term survival of the population, and considering the presence of source-sink dynamics will help inform conservation decisions.
  • Recently tiger surveys in India has shown the tiger population in the source-sink in the ratio of 60:40. 33% of the tiger population in India lives outside its source i.e, tiger reserves.
  • It moves towards the sink due to a decline in the capacities of the tiger reserves to further hold the tiger population. 17/50 tiger reserves in India are going to achieve its maximum capacity to holf the tiger populations.

Ecological traps

  • Ecological traps are scenarios in which rapid environmental change leads organisms to prefer to settle in poor-quality habitats.
  • The concept stems from the idea that organisms that are actively selecting habitat must rely on environmental cues to help them identify high-quality habitat.
  • If either the habitat quality or the cue changes so that one does not reliably indicate the other, organisms may be lured into poor-quality habitat.
  • Ecological traps are thought to occur when the attractiveness of a habitat increases disproportionately in relation to its value for survival and reproduction.
  • The result is preference of falsely attractive habitat and a general avoidance of high-quality but less-attractive habitats.

For example, Indigo buntings typically nest in shrubby habitat or broken forest transitions between closed canopy forest and open field. Human activity can create 'sharper', more abrupt forest edges and buntings prefer to nest along these edges. However, these artificial sharp forest edges also concentrate the movement of predators which predate their nests. In this way, Buntings prefer to nest in highly altered habitats where their nest success is lowest

Source: TH/WIKI

World bank logistic performance index 2023

India is now ranked 38th out of 139 nations in the Logistic Performance Index (LPI) 2023 of the World Bank. From its previous rankings of 44th in 2018 and 54th in 2014, this is a notable improvement. Earlier, the Logistics Ease Across Different States (LEADS) Report 2022 was published by the Ministry of Commerce and Industry. About Logi

Smuggling of Gold

Airports discovered more than 63% of this illegal gold. The Department of Revenue Intelligence recently conducted the Golden Dawn Operation across India, seizing 101.7 kg of illegal gold valued at Rs 51 crore. Despite the fact that India receives a legal import of about 800-1,000 tonnes of gold each year, the illicit market is thought to be

India-Thailand Relations

Both parties expressed satisfaction with the ongoing bilateral defence cooperation at the 8th India-Thailand Defence Dialogue, which was held in Bangkok, Thailand. Cultural ties and mutual cooperation that have been shaped by thousands of years of lasting historical and cultural ties characterise India and Thailand relations. Highlight

Translocation of Elephants

The Kerala government's appeal of the order of the Kerala High Court is rejected by the Supreme Court. The Kerala government's appeal against the Kerala High Court's directive to move Arikomban (Wild Elephant), the "rice tusker" of Munnar, to the Parambikulam tiger reserve was recently dismissed by the Supreme Court.

Global Buddhist Summit

Global Buddhist Summit In order to improve diplomatic and cultural ties with other nations, the Ministry of Culture recently organised the First Global Buddhist Summit 2023 in collaboration with the International Buddhist Confederation (IBC). About the summit "Responses to Contemporary Challenges: Philosophy to Praxis" is


Search By Date

Post Feed

Newsletter Subscription
SMS Alerts