×

UPSC Courses

DNA banner

DAILY NEWS ANALYSIS

GS-III :
  • 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


Formation Day

On 1st November, eight Indian states—Andhra Pradesh, Chhattisgarh, Haryana, Karnataka, Kerala, Madhya Pradesh, Punjab, and Tamil Nadu—along with five Union Territories—Andaman and Nicobar Islands, Chandigarh, Delhi, Lakshadweep, and Puducherry—celebrate their Formation Day. This date marks an important milestone in India

Turtle (Kachhua) Wildlife Sanctuary

The Turtle Wildlife Sanctuary, also known as the Kachhua Sanctuary, is located in the Varanasi district of Uttar Pradesh. It is recognised as India’s first freshwater turtle wildlife sanctuary, established to conserve endangered turtle species and support the ecological health of the Ganga River. Location and Extent The sanctuary co

Introduction of AI and Computational Thinking (CT) in

The Ministry of Education plans to introduce Artificial Intelligence (AI) and Computational Thinking (CT) from Class 3 onwards in the 2026–27 academic year. This initiative is part of the National Curriculum Framework for School Education (NCF-SE) 2023 and aligns with the National Education Policy (NEP) 2020. The aim is to prepare student

Sal Tree

Scientists from the Environment Department of Himachal Pradesh University (HPU) in Shimla have recently revealed that the Sal tree (Shorea robusta) is the most effective natural air purifier for combating rising pollution levels. Their findings highlight the tree’s superior capacity to trap dust, absorb gases, and cleanse the air compared

US Resumes Nuclear Weapon Testing

The President of the United States has ordered the resumption of nuclear weapon testing after a gap of 33 years, the last test being in 1992. This decision marks a significant shift in global nuclear policy and has far-reaching implications for geopolitics, the environment, and international security. Status of Global Nuclear Weapon Testing

DNA

03 Dec,2025

Toppers

Search By Date

Newsletter Subscription
SMS Alerts

Important Links

UPSC GS Mains Crash Course - RAW Prelims Answer Key 2024